Car is running a little hot

[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."

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 for one.

[Ron]

Ron and Helirich in this thread.



Attachment 66877

But, 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."

[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."

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.