Car is running a little hot

[Jimmyvonviggle]

I noticed my car is running a little hot the last time I took it out. Usually stays around 200 degrees, this time creeped up to 220. When I parked it and opened engine compartment, the engine seemed much hotter than usual, and I could hear coolant bubbling from overflow tank.

The next today I took it out again to specifically see if I could here if the fans were coming on. In the past it seemed like they would come on at around 210 and stay on until temp was brought down. Now I see that the fan comes on at a higher temp and when it does, does not stay on for very long.

Thank you for your help.

[Helirich]

The gauges have not proven to be very accurate. You might want to do the same test with a temp gun handy. Point it at the tube where the otterstat is located.

[Ron]

The gauges have not proven to be very accurate. You might want to do the same test with a temp gun handy. Point it at the tube where the otterstat is located.
+1...but, if there is a problem, it could be flow related. So it's better to point at the end of the heads/next to the sending unit...

[David T]

First things to check are the "O" switch, the cooling fan circuit breaker and check for leaks.

[Andrew]

What radiator are you running? 4194 always ran hot with the brass radiator. It would creep over 220 at highway speeds with the A/C on. I installed the Delorean Go radiator this spring. Now it stays around the 160 mark. :-)

[Jimmyvonviggle]

It’s running a new DMC Midwest radiator.

[cdrusn]

I always wonder why it's so important to let the mechanical and electrical systems determine what the temperature becomes. There are a lot of details that make the system run at a certain temperature. Thermostat opens and closes, fans come on or don't, radiator has no air pockets and is clean inside, a/c on or off, car is at speed or in traffic. Why don't you just avoid all of the worry about everything working as designed and just run a wire and bypass the otterstat and run the fans all the time? It won't damage anything and you won't have to worry about if your fans are on or off? Takes 30 seconds to run the wire and remove all doubt.

[David T]

The electrical system was not designed to handle that much of a continuous load. At least with the OEM fan motors. Today you can get much more efficient fans that consume a lot less energy. But it is still wasteful to run them all the time. Every car has a way to run the fans when hot and shut them off when not needed.

[Ron]

I always wonder why it's so important to let the mechanical and electrical systems determine what the temperature becomes. There are a lot of details that make the system run at a certain temperature. Thermostat opens and closes, fans come on or don't, radiator has no air pockets and is clean inside, a/c on or off, car is at speed or in traffic. Why don't you just avoid all of the worry about everything working as designed and just run a wire and bypass the otterstat and run the fans all the time? It won't damage anything and you won't have to worry about if your fans are on or off? Takes 30 seconds to run the wire and remove all doubt.It's so the oil will be between 230-260°F (colder, it don't clean/dissipate water; warmer it breaks down, heads warp etc.)

Me thinks the electrical system often handles the fans being on full time in hot climates, especially when the AC is on...

[Helirich]

It's so the oil will be between 230-260°F (colder, it don't clean/dissipate water; warmer it breaks down, heads warp etc.)

Me thinks the electrical system often handles the fans being on full time in hot climates, especially when the AC is on...

The fans don't really effect the oil temp. The thermostat does that. There really is no reason the water can't be cool all the time. If you run the fans all the time, you are loading the alternator all the time. I don't know if that wares it out quicker, but it certainly is drag on the motor, so it would lower mpg'. Also, if the fans have brushes, they will ware. Of course some say starting/stoping creates more ware.

In any case, as you mentioned, my fans are on all the time because of the AC.

On my truck (with after market fans) I have a switch that I can over ride the fan controller. I can turn them on at any time, like when I pull up to a traffic light. That way I get a jump on the cooling before the fan controller kicks in. I can also over ride it and turn it off when driving in deep water. Hmmm, don't know if I need that in the D.

[David T]

The fans cycle on and off by the "O" switch AND the A/C. Another reason you need the A/C to also cycle, so the fans can cycle AND you don't freeze up the evap coil. The whole thing is kind of Rube Goldberg, the way everything affects everything but nothing "talks" to each other the way new computerized cars do now. The A/C doesn't know what the "O" switch is doing and the "O" switch doesn't know if the A/C is on. As for oil temp, Ron is correct. If the thermostat is closed the fans aren't cooling the coolant because it isn't circulating in the radiator. That is why the "O" switch isn't supposed to turn the fans on until after the thermostat is open and turn the fans off before the thermostat closes. Here is a case of where you should get these parts from one of the Delorean vendors so you get parts that can work together properly. The settings for the thermostat and the "O" switch matter for everything to work right. And you do NOT want the fans cycling on the cooling fan circuit breaker. Very bad.

[Jimmyvonviggle]

Thank you all for your comments. My temperature gauge has always been accurate and a laser thermometer has verified this. I think it is a terrible idea to bypass the otter stat and run the fan all the time.

The problem was the fans would kick on inconsistently and run for a very short amount of time. This is something I just noticed in the last 2 weeks. I also noticed more heat coming off my engine after stopping the car and raising the engine cover. I decided to replace the 40 amp circuit breaker. This now makes the fans operate as they did before.

The reason why my engine feels hotter is a bigger issue I will have to address. The engine is leaking a small amount of oil from the crankshaft pulley (I could be wrong but it appears from this area) and it is turning into a powder that covers the engine. I believe this is causing the engine to smell or give off more external heat in the engine bay.

[Ron]

The thermostat does that.The thermostat only sets the floor for coolant temp! Once open, it is then up to the design of the rest of the system.


There really is no reason the water can't be cool all the time.
Sure there is. The majority of wear happens when the engine is cold! It needs to warm up quickly (parts need to expand to size, oil needs to get to optimum temp range, O2 sensors need to heat up quicker on some. Not to mention trans oil and cabin heat...). That's the thermostat's only job.

It's not an either-or thing -- The coolant passages, fan(s), radiator (its flow, both air and coolant), thermostat all work in concert by design to keep everything within range.

[Helirich]

There really is no reason the water can't be cool all the time.



Sure there is. The majority of wear happens when the engine is cold! It needs to warm up quickly (parts need to expand to size, oil needs to get to optimum temp range, O2 sensors need to heat up quicker on some. Not to mention trans oil and cabin heat...). That's the thermostat's only job.
.

Let me rephrase that. There is no reason that the water in the radiator cant be cool all the time. In fact, it would help the thermostat do its job.

[Ron]

Let me rephrase that. There is no reason that the water in the radiator cant be cool all the time. In fact, it would help the thermostat do its job.
...It's not going to be cool all of the time if the thermostat ever opens.
There's no way cool water in the radiator (or anywhere else) could help the thermostat bring the engine up to temp.

Again, on a D, the system is closed, the thermostat activates (the rest of the system), not regulates. It just sits there open, once the engine is fully up to temp (except under extremely cold ambient conditions).
On some non-closed systems, they regulate, E.G., some marine applications.

[Helirich]

There's no way cool water in the radiator (or anywhere else) could help the thermostat bring the engine up to temp.

The thermostat's job is to keep the engine temps within limits. It doesn't need help warming the engine, but the vast majority of the time it's trying to keep the engine from overtemping. Cool water will help. The cooler, the better. (As long as it's not freezing)

[Helirich]

I always wonder why it's so important to let the mechanical and electrical systems determine what the temperature becomes. There are a lot of details that make the system run at a certain temperature. Thermostat opens and closes, fans come on or don't, radiator has no air pockets and is clean inside, a/c on or off, car is at speed or in traffic. Why don't you just avoid all of the worry about everything working as designed and just run a wire and bypass the otterstat and run the fans all the time? It won't damage anything and you won't have to worry about if your fans are on or off? Takes 30 seconds to run the wire and remove all doubt.

Got to thinking about this. You realize that for probably 60 years, that's how it worked. You start the car and the fan is running. Lol.

[Ron]

The thermostat's job is to keep the engine temps within limits.
No, it's job is to get the engine up to temp as soon as possible.


It doesn't need help warming the engine.
(You came up with that....because you have its main job wrong....)

Of course it don't. Besides not doing any warming itself in the first place, from start up, the engine is creating the heat, while the thermostat prevents the rest of the cooling system from cooling. It begins to open at ~180°F. At ~200°F it is fully open, setting the coolant's floor temp. As the engine and oil continue to get hotter, the thermostat just sits there, fully open.


but the vast majority of the time it's trying to keep the engine from overtemping.
No, the vast majority of the time it's wide open -- There is nothing else it can do once it's fully open *; the rest of the system is keeping the coolant (and engine) from exceeding the ceiling temp(s), where thermal clutch fans, Otterstats, or similar when equipped, is in control.

(*Extreme cold, bad thermal clutch fan, bad electric fan control, early style poor design, etc., will allow it to shut, because it is too cold!)



Got to thinking about this. You realize that for probably 60 years, that's how it worked. You start the car and the fan is running. Lol. Lol, starting in 1901 (DMG)??
Seems you have been thinking this way all along to me, while dismissing/ignoring the improvements made over the half century...

[Helirich]

Splitting hairs now? Main job, secondary job, who cares? Cool water helps the thermostat do its job. Is it wide open most of the time? Yes. In the south for sure. In the not to far north, I assure you the thermostat closes or partially closes lots of times. When I was young and lived in Pennsylvania, I had a car that I ran with no thermostat. It ran fine all year long, but it sucked in the winter. (No heat) I've heard that no thermostat will give you bad mpg's, but I never noticed that. I've concluded the number one job of the thermostat is heat. Lol.

In any case, you and I both know how the system works. I'm just pointing out that with the new brushless, low amp draw fans, there maybe advantage to just have them run all the time. I don't want to dismiss/ignore advances they've made in fan motors.


Edit, I just searched three differnt venders for cooling fan motors. None of them say if their motors are brushless. It seems like they would brag about it. Does anybody know if/who has them? I'm contemplating getting a new radiator and fans. I would really like brushless.

[Bitsyncmaster]

Edit, I just searched three differnt venders for cooling fan motors. None of them say if their motors are brushless. It seems like they would brag about it. Does anybody know if/who has them? I'm contemplating getting a new radiator and fans. I would really like brushless.

Have you looked at the specifications of brush-less fans? Just wondering what the advantage is. Maybe longer life since brushes may wear out.

[Helirich]

Have you looked at the specifications of brush-less fans? Just wondering what the advantage is. Maybe longer life since brushes may wear out.

Longer life is the number one thing I hear on my 4x4 forums. They are also more efficient than brushed, so more power to weight or size or amps. The 4x4 guys all swear the Spal fans are the best in the world. (Brushed or brushless, they make both kinds)

[FABombjoy]

~7qt of 20/50, a barely functional PCV design, and a 1/4 mile coolant loop. You want to add heat or your oil will get shitty in a hurry from moisture and fuel dilution. You absolutely get worse mileage when cold unless your engine is totally out of tune. On rare occasions I can see the affect of a cold day on coolant temps which show evidence of Tstat acting somewhat as a temp regulator but its rare, rather cool air temps, and only when cruising at a reasonable speed. It's still more than a floor than a regulator as generally above 50-60F and below about 30-45MPH means the actual job of temp regulation falls to the fans. I can bore anyone to tears with supporting datalogs if you'd like to visualize the numbers for yourself.

[Ron]

+1

[Helirich]

Have you looked at the specifications of brush-less fans? Just wondering what the advantage is. Maybe longer life since brushes may wear out.

They are claiming 40,000 hour life. They also say they are much more tolerant of vibration and dust than a standard motor. They are quieter also, but I don't think you can hear a motor because of the fan. They have diy kits on this site.

https://wizardcooling.com/accessories/fans/brushless-fan-packages/

Are our fans 10" or 12"?

I think I will be a ghiny pig on this. I'm probably going to order a new radiator from one of the venders and make my own shroud. Is there any consensus on the best radiator?

[Bitsyncmaster]

They are claiming 40,000 hour life. They also say they are much more tolerant of vibration and dust than a standard motor. They are quieter also, but I don't think you can hear a motor because of the fan. They have diy kits on this site.

https://wizardcooling.com/accessories/fans/brushless-fan-packages/

Are our fans 10" or 12"?

I think I will be a ghiny pig on this. I'm probably going to order a new radiator from one of the venders and make my own shroud. Is there any consensus on the best radiator?

That graph on the 10" looks strange. From what I see one fan draws 20 to 33 amps.

[Michael]

Ron and Helirich in this thread.



66877

[Helirich]

That graph on the 10" looks strange. From what I see one fan draws 20 to 33 amps.

That site is all over the place on amps/watts. Like it's not clear if the 15" fans ar 300w or 500w and some duel fan setups say per fan and others say total.

Of course the venders don't even say what the amps are on our fans. I'm to measure the amps on my D. I have a 12" or 13" Spal fan on my project truck and I know it draws 22 amps. It is not brushless. I would say it blows more than both of our fans. But it probably has a better fan design.

[Bitsyncmaster]

That site is all over the place on amps/watts. Like it's not clear if the 15" fans ar 300w or 500w and some duel fan setups say per fan and others say total.

Of course the venders don't even say what the amps are on our fans. I'm to measure the amps on my D. I have a 12" or 13" Spal fan on my project truck and I know it draws 22 amps. It is not brushless. I would say it blows more than both of our fans. But it probably has a better fan design.

I've measured some OEM DeLorean fans to draw 15 amps each. Most vendor fans run from 7 to 9 amps each. Looks like your going to need to run 8 AWG wire for your dual fan power.

[Helirich]

I've measured some OEM DeLorean fans to draw 15 amps each. Most vendor fans run from 7 to 9 amps each. Looks like your going to need to run 8 AWG wire for your dual fan power.

I see they talk about 1000-4000rpm. I guess you can set or vari it. I suppose that will effect the amp draw.

[David T]

It's not just the running (continuous) ampere draw, the start-up current is over 60 amps! It is such a load on the system, you can feel it in the accelerator pedal as you drive when both fans come on! Fanzilla was a BIG improvement, it staggered and soft-started the fans. The new Spall and Spall type fans are way more efficient and draw a LOT less current than the OE fans. Brushless is the way to go, they will run a lot longer before they wear out and a lot less noise on the electrical system and less radio interference. Not only do the Spalls use less current, they move MORE air. The way to go is to use a relay for each fan and stagger them so they don't start together (easy to do with solid state relays, you set one with a delay). The whole cooling fan circuit is so under-engineered, especially by today's standards. The other thing that might be an improvement would be to move the "O" switch to the radiator. I don't know why DMC thought it was a good idea to stick it in a pipe by the motor. On most cars the fan switch is in the radiator outlet tank so if the coolant needs to be cooled by the radiator, that is the place to know what the temperature of the coolant is, not the temp of the coolant coming out of the motor going to the radiator. So many things that could be done better as far as the cooling system and electrical system is concerned. As for the thermostat, it does actually modulate but if it is very hot or very cold it will be open or closed. The thermostat is what is supposed to maintain a stable temperature for the motor and make the motor warm up faster. The radiator is supposed to be designed to overcool the motor AND the automatic transmission and the fans also have to cool the A/C condenser. If the radiator didn't have surplus capacity the fans would never shut off and the motor would just get hotter and hotter. Exactly what happens if either or both fans don't work, the cooling fan circuit breaker pops and resets, or the radiator is clogged up on the air or water side or the radiator is full of air. Complex subject. Bottom line, the cooling and electrical systems could use a LOT of improvement.

[Ron]

Splitting hairs now? Main job, secondary job, who cares? Cool water helps the thermostat do its job. Is it wide open most of the time? Yes. In the south for sure. In the not to far north, I assure you the thermostat closes or partially closes lots of times.
lol
The only reason I said "main" job is because I agreed with part of what you were saying- that the thermostat does [rarely] close after the engine is up to temp. (But that is it keeping the rest of the system from dropping the temp too low, and causing damages -- Its job. ;-) I thought the part with the "*" would make that apparent...



When I was young and lived in Pennsylvania, I had a car that I ran with no thermostat. It ran fine all year long, but it sucked in the winter. (No heat) I've heard that no thermostat will give you bad mpg's, but I never noticed that. I've concluded the number one job of the thermostat is heat. Lol.
I would have also concluded that there is in fact a good "reason that the water in the radiator cant be cool all the time." :deviltail:


In any case, you and I both know how the system works. I'm just pointing out that with the new brushless, low amp draw fans, there maybe advantage to just have them run all the time. I don't want to dismiss/ignore advances they've made in fan motors.
Yeah, I think we are closer together than the conversation might make one think...
I've always liked electric fans and brushless ones the most. But I don't see having them on while the thermostat thinks the engine is too cold. ...since the best you could do is build a reserve at the ambient temp, which wouldn't last more than seconds, I don't see a good return on the investment, fuel, wear and tear, etc. ...If it's cold out, you don't need them -- If it's hot out, they fans are already going. (All of which a thermal clutch fan does not ignore. ;-)



Edit, I just searched three differnt venders for cooling fan motors. None of them say if their motors are brushless. It seems like they would brag about it. Does anybody know if/who has them? I'm contemplating getting a new radiator and fans. I would really like brushless.Summit (https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=brushless%20fan%20) for one.

[Ron]

Ron and Helirich in this thread.



66877But, but, ...but the tolerance is only .001cm!

And he doesn't split hairs down the middle!

[Ron]

It's not just the running (continuous) ampere draw, the start-up current is over 60 amps! It is such a load on the system, you can feel it in the accelerator pedal as you drive when both fans come on! Fanzilla was a BIG improvement, it staggered and soft-started the fans. The new Spall and Spall type fans are way more efficient and draw a LOT less current than the OE fans. Brushless is the way to go, they will run a lot longer before they wear out and a lot less noise on the electrical system and less radio interference. Not only do the Spalls use less current, they move MORE air. The way to go is to use a relay for each fan and stagger them so they don't start together (easy to do with solid state relays, you set one with a delay). The whole cooling fan circuit is so under-engineered, especially by today's standards. The other thing that might be an improvement would be to move the "O" switch to the radiator. I don't know why DMC thought it was a good idea to stick it in a pipe by the motor. On most cars the fan switch is in the radiator outlet tank so if the coolant needs to be cooled by the radiator, that is the place to know what the temperature of the coolant is, not the temp of the coolant coming out of the motor going to the radiator. So many things that could be done better as far as the cooling system and electrical system is concerned. As for the thermostat, it does actually modulate but if it is very hot or very cold it will be open or closed. The thermostat is what is supposed to maintain a stable temperature for the motor and make the motor warm up faster. The radiator is supposed to be designed to overcool the motor AND the automatic transmission and the fans also have to cool the A/C condenser. If the radiator didn't have surplus capacity the fans would never shut off and the motor would just get hotter and hotter. Exactly what happens if either or both fans don't work, the cooling fan circuit breaker pops and resets, or the radiator is clogged up on the air or water side or the radiator is full of air. Complex subject. Bottom line, the cooling and electrical systems could use a LOT of improvement.I think the best place for the Otterstat would be in the head -- That's where the heat source and parts most prone to heat damage are.


FWIW- I'm going to beat the dead horse one more time:
As you said, "...the "O" switch isn't supposed to turn the fans on until after the thermostat is open and turn the fans off before the thermostat closes."
So the Otterstat & fans are what regulates the coolant temp anytime the coolant is above ~200°F (not very hot)....

[Bitsyncmaster]

I see they talk about 1000-4000rpm. I guess you can set or vari it. I suppose that will effect the amp draw.

They also say you can't control them with a switch or relay. Now what does that mean? With the paperwork so poor and the price so high I would not want to experiment with that manufacturer. Now if you want me run some testing, you know I would love to do that if you ship me one.

[Ron]

That site is all over the place on amps/watts. Like it's not clear if the 15" fans ar 300w or 500w and some duel fan setups say per fan and others say total.

LMAO - From that sites FAQ:
"If I use a lower temperature thermostat will that help my system run cooler?

No, running a lower temperature thermostat will not bring down engine temperatures, it only controls OPENING TEMPERATURES.

The only "benefit" is that you have now increased the amount of time it will take for your vehicle to reach operating temperature. A thermostat is supposed to modulate, just like the thermostat in your house turns the furnace on and off. When the coolant reaches the thermostat setting it opens and lets coolant go through the radiator. The radiator, if capable, will drop the temperature down to a point the thermostat modulates."

[Helirich]

They also say you can't control them with a switch or relay. Now what does that mean? With the paperwork so poor and the price so high I would not want to experiment with that manufacturer. Now if you want me run some testing, you know I would love to do that if you ship me one.

I read that, but my friend has confirmed that if you ground the sensor wire, they can be controlled by a relay. They will just go to full speed after ramp up. I believe that one of these 10" fans moves more air than both of our stock fans. So if I run two, (for redundancy) I would want the rpm' slower. That way it would run quieter and less amps. My goal would be more air flow and less power draw. Of course it would be nice if one quit, the other could be turned up to make up for it.

[MrChocky]

...It's not going to be cool all of the time if the thermostat ever opens.
There's no way cool water in the radiator (or anywhere else) could help the thermostat bring the engine up to temp.

Again, on a D, the system is closed, the thermostat activates (the rest of the system), not regulates. It just sits there open, once the engine is fully up to temp (except under extremely cold ambient conditions).
On some non-closed systems, they regulate, E.G., some marine applications.

Ron, thanks for your careful and specific explanations. I wasn't particularly aware of how all this worked (although in fairness, I hadn't really dug into it). This is much more useful than the vague hand waving that has now seems to be the norm here in lieu of actual advice.

But a more practical question to bring this thread back on track. How can I test the fan operation on my project? i.e, get them to run at all, since I haven't seen them do so. The compressor and blower motor are presently disconnected. I think if I disconnect the otterstat (now correctly rotated, although looking pretty toasty) and set the fan level to 4, they'll be forced to run. Obviously I can go and try this myself, but an exact explanation would help too.

[Ron]

YW!

(This thread will never be back on track...but the OP solved his problem ;-)

There are two circuits for the fans:
1. For normal coolant temp regulation (LOL), just disconnect the two wires (Green, and Black with Orange stripe) going to the otterstat and connect them together (Key ON).
2. For the AC override, disconnect the Pink wire at the compressor clutch and apply 12V to the harness side.
(Or turn the Key ON, Mode Switch to any AC position, and jump the two wires going to the AC cycle switch, located in the right front wheel well.)

[Ron]

...I was wondering why you were saying to set the fan to level 4..So I looked at the Owners Manual and saw something I never noticed anyone mentioning before:

"Fan Speed Control (2)
This knob is used to vary speed of air flow fan. Operative only when Heater/Air conditioner selector (3) is at off." :swear1:

[MrChocky]

...I was wondering why you were saying to set the fan to level 4..So I looked at the Owners Manual and saw something I never noticed anyone mentioning before:

"Fan Speed Control (2)
This knob is used to vary speed of air flow fan. Operative only when Heater/Air conditioner selector (3) is at off." :swear1:

Oh, Ron. Now you know why I like precision.

Anyway, shorted the otterstat, and fans run. Although it does sound a bit like something is bouncing around in one, although it's not really something you'd hear when driving. Problem for another time.

[Helirich]

...I was wondering why you were saying to set the fan to level 4..So I looked at the Owners Manual and saw something I never noticed anyone mentioning before:

"Fan Speed Control (2)
This knob is used to vary speed of air flow fan. Operative only when Heater/Air conditioner selector (3) is at off." :swear1:

Hey Ron, I'm very clear on the cooling system operation, but I'm not clear on this at all. What exactly are they saying here? Is the "air flow fan" the interior fan?

[Ron]

Hey Ron, I'm very clear on the cooling system operation, but I'm not clear on this at all. What exactly are they saying here? Is the "air flow fan" the interior fan?Yep, "(2)", below:

66890

FWIW- There is a searchable PDF Owners Manual in the Resources section HERE (http://dmctalk.org/showthread.php?2755-DeLorean-Owner-s-Handbook-Manual&p=37475&viewfull=1#post37475).

[Helirich]

Now I understand what you are saying. They screwed up. Did you find out why he sets it to 4?

[Ron]

Oh, Ron. Now you know why I like precision.

Anyway, shorted the otterstat, and fans run. Although it does sound a bit like something is bouncing around in one, although it's not really something you'd hear when driving. Problem for another time.:thumbup:

[Ron]

Now I understand what you are saying. They screwed up. Did you find out why he sets it to 4?Not really. Since he said he hadn't really dug into it, I guessed that he may have been thniking "Max" or ??. About that time the wife decided it was time for me to get back to painting, so....