Cooling issue

[Jeff K]

Ok, my car was 100% rock solid reliable after I restored it two years ago..

Now... Umm... not so much.

Current issue (and last I believe) is the cooling system. Very strange.

First... these parts have less then two years and 5000 miles on them

3 row radiator (all metal), Fans, Thermostat, Otterstat,Water pump, All hoses.

System was carefully bled twice. New 50/50 coolant. Pressure tested..no leaks

I checked the oil to see if head gasket is leaking. Oil seems fine (not like chocolate milk, amber and clean)

Last year, I drove my car in the San Fernando valley heat 105+ all day any day with the AC on. Never touched one quarter on the gauge.

Now it seems like it can idle forever at less then 1/4 on the temp gauge (with AC on) , but when I drive it.. the temp creeps up and up very slightly but consistently. It gets above half and climbing and I shut it down. Only seems to climb when I'm driving and not idling. Which is opposite of normal engine cooling issues.

I tensioned the belt, I thought maybe it was slipping at higher rpms.. still the same thing. Fans operating correctly.

Any suggestions?
Thanks
Jeff

[Jonathan]

...Now it seems like it can idle forever at less then 1/4 on the temp gauge (with AC on) , but when I drive it.. the temp creeps up and up very slightly but consistently. It gets above half and climbing and I shut it down. Only seems to climb when I'm driving and not idling. Which is opposite of normal engine cooling issues.

...Fans operating correctly.

Hey Jeff,

Can you elaborate on what your fans are doing? When you see the temperature rising, at what point or tick mark on the gauge do they turn on? Can you feel air flow if you look/reach under the front of the car? Are the fans running, seemingly normal, and then the temperature still rises to the point where you shut the engine off?

If the fans are okay, any reason to think the coolant isn't getting up to the radiator and back properly? Water pump? Blockage? Check valve? Prior to the car getting really warm, if you have the reservoir cap off the bottle (coolant still fairly cool at this point), can you see a little stream of coolant returning to the bottle?

Do you have an atuo bleeder on your car with the tee back into that return line? That small quarter turn hand valve is looking to be okay?

Your mention of last years drive to San Fernandino, is that the last time everything was working correctly? Did it work properly earlier this season? Anything on your new parts list changed between then and now when you're seeing the problems?

[DMC5180]

You may have a bad head gasket. Just because you don't see coolant in the oil, does not mean you don't have combustion gases in the cooling system. Does the coolant tank puke coolant when you shut it down (hot)?

Are you saying the fans are running but the temp still won't come down at idle or do you just shut the engine off at the 220 (Half) mark without waiting to see if the FANS bring the temp back down.

[Jeff K]

Thanks for the replies!

I do have the bleeder and I did check to see if it's working properly. It is. The coolant is flowing through the overflow bottle when warmed up.

The fans come on a hair before the quarter mark. They remain on and seem to be operating at the proper velocity. I cannot exactly verify this, but the rush of air seems the same to both. Also, I did check the voltage to the fans, it was correct(I think).. about 13.8.

The check valve that was mentioned.. where is that? Is it in the radiator? That I didn't know about it to check it.

The only other item is that my tension screw fell out of my pulley mounting bracket for my a/c. Thus my ac-belt was/is loose. I ordered another from DMC. (Could not find a 100mm fully threaded M8 locally). My AC belt is a tad loose. Don't know if this makes any difference.

It does not puke coolant when shutting down, the coolant looks very clean. It's so bizarre. The cooling system is not that complicated.

I did a spring project and restored the entire moving suspension. (Every ball joint, bearing, bushing etc). Can't see that making any difference in the cooling system.

[DMCMW Dave]

You may have a bad head gasket. Just because you don't see coolant in the oil, does not mean you don't have combustion gases in the cooling system. Does the coolant tank puke coolant when you shut it down (hot)?

Are you saying the fans are running but the temp still won't come down at idle or do you just shut the engine off at the 220 (Half) mark without waiting to see if the FANS bring the temp back down.

Assuming the fans are working . . . . . I was going to suggest the same possibility. At idle the combustion pressure is relatively low, so early in the failure you don't see a problem at idle or light load. Under load you start displacing the coolant with combustion product which forces coolant out of the engine and then it runs hot. As Dennis mentioned this should cause cooling to blow out of the overflow eventually.

As the head gasket gets worse, so will the problem. The break is between the cylinder and the cooling jacket so coolant never gets in the oil or vice versa. You will also eventually notice steam from the exhaust when you first start the car that will go away relatively quickly as it burns off.

[DMCMW Dave]

This is, BTW, why we tend not to be a huge fan of the self bleeder, at least not the kind where there is no shutoff valve. With the bleeder open, the combustion product will bleed out to the bottle, and make the problem less visible until it's really bad. Normally, without the bleeder, you get a lot more warning that something is wrong. As coolant is displaced from the engine the water temp gauge will go up a lot faster, scaring you into turning it off, before the engine is hot enough to be damaged.

This is why Toby's bleeder has the valve - so you can use it to bleed the system after service but keep it closed during normal operation.

[Jonathan]

Disregard the check valve comment Jeff. There isn't one and I mentioned it only as a thought if anything extra was added when you rebuilt the cooling system.

Dave... care to elaborate more on what "steam from the exhaust" looks like? I have seen moisture "spit" from my exhaust at times if I leave it idling in the driveway for extended periods. Not so much seen while in the air as it is a few drops on the ground behind the car where it would have landed after leaving the exhaust tips. Same thing/different thing? I know when you see cars in cold weather just leaving for the day they often will have exhaust you can see, i.e. condensed water mist type thing.

I have not once closed that valve on the auto bleeder since the day it got installed. Likely just never knew I needed to. That might be the risk in some of the things we get for our cars, or repair, or upgrade, is they don't always come with dos and don'ts. Not that all of them need to, but there has been a handful of things on the car I didn't realize were in need of adjustment and sometimes just stumble upon it later on. Would the best thing for the bleeder valve on my car be to close it? (and monitor temperatures afterwards).

[David T]

There are some uncommon things that can cause the symptoms you described. Check the base timing and the mechanical and vacuum advance. Check the valve adjustment. Test the coolant for combustion gases. How is your gas mileage? Are your brakes dragging? Do all of the tires have the correct pressure? Is there anything blocking the grill, like a license plate? Is there debris in the condenser coil or radiator? Is there a spring in the suction hose? Is there a small hole or at least a check valve in the thermostat? Did you bleed the air out of the radiator too?
David Teitelbaum

[DMCMW Dave]

I have not once closed that valve on the auto bleeder since the day it got installed. Likely just never knew I needed to. That might be the risk in some of the things we get for our cars, or repair, or upgrade, is they don't always come with dos and don'ts. Not that all of them need to, but there has been a handful of things on the car I didn't realize were in need of adjustment and sometimes just stumble upon it later on. Would the best thing for the bleeder valve on my car be to close it? (and monitor temperatures afterwards).

The idea is that you do your coolant maintenance, refill the system, leave the valve open for a while to make sure all the residual air is out of the system. Then close it. Then, if a problem crops up and air gets in for whatever reason, the system will function as designed and give you a high temp warning before the system runs dry. So the valve is actually closed most of the time. With the bleeder open when you get a high temp reading it really is dry and may be too late.

I typically tell people the "open all the time" bleeder setup is just fine if you are in the habit of checking your coolant level about as often as you put gas in the car. Not terribly convenient, as you can't really check the level at the gas station (hot!) and time gets away from you otherwise. But if you are a maintenance freak and keep an eye on things, it's OK. You are looking for a relatively sudden need to add coolant fairly often, where on a good system you should almost never need to top it off.

[Jonathan]

...But if you are a maintenance freak and keep an eye on things, it's OK. You are looking for a relatively sudden need to add coolant fairly often, where on a good system you should almost never need to top it off.

Thanks for clarifying, Dave.

Based on what you've described, I'd be better off leaving the valve closed. I looked back through my logbook and I hadn't checked the level since April 2012. I checked it last night and it is still right about halfway full in the bottle and the same bright green colour as usual. Nothing obvious saying there is a problem. Good to know about the sudden need to add coolant indicator.

[Ron]

I typically tell people the "open all the time" bleeder setup is just fine if you are in the habit of checking your coolant level about as often as you put gas in the car. I don't like the fact that the hottest coolant is sent to the bottle and right back into the engine with this setup.

===
$.02

Not to mention that if air gets to the aftermarket bleeder, it will go to the radiator w/o it, and, the Reservoir Connection Hose #7 (http://store.delorean.com/c-331-1-3-1-radiatorpiping.aspx) will serve as a "bleeder" (the air will be pushed AND drawn into #10 and sent to the bottle, as designed). The aftermarket bleeder only helps get the air out that is going to come out anyway if people would be patient and let the thermostat open a few times before final top off (The first time it opens the coolant cools it off and it may shut before all of the air is out.) Afterwards, I agree, it just hides problems. Snake oil, venomous at that.

[David T]

I don't like the fact that the hottest coolant is sent to the bottle and right back into the engine with this setup.

===
$.02

Not to mention that if air gets to the aftermarket bleeder, it will go to the radiator w/o it, and, the Reservoir Connection Hose #7 (http://store.delorean.com/c-331-1-3-1-radiatorpiping.aspx) will serve as a "bleeder" (the air will be pushed AND drawn into #10 and sent to the bottle, as designed). The aftermarket bleeder only helps get the air out that is going to come out anyway if people would be patient and let the thermostat open a few times before final top off (The first time it opens the coolant cools it off and it may shut before all of the air is out.) Afterwards, I agree, it just hides problems. Snake oil, venomous at that.


You should be checking the coolant level, tire pressures and oil level at least once a month or before a long drive. Other owner checks include checking all exterior lighting, glass, and tire condition. All owners should get into the habit of checking their cars regularly, and not just their Deloreans. On aircraft you are supposed to do a "Prefilight" before every flight! You get to know what is normal and what is "not right" because you regularly are looking around at things and will notice something unusual.
David Teitelbaum

David Teitelbaum

[cybercusp]

You should be checking the coolant level, tire pressures and oil level at least once a month or before a long drive. Other owner checks include checking all exterior lighting, glass, and tire condition. All owners should get into the habit of checking their cars regularly, and not just their Deloreans. On aircraft you are supposed to do a "Prefilight" before every flight! You get to know what is normal and what is "not right" because you regularly are looking around at things and will notice something unusual.
David Teitelbaum

David Teitelbaum

Agreed. I like to scan the car's gauges every few minutes or so just to make sure the indicators are in their nominal positions. I had one overheating condition that was caught quickly just because of the routine gauge scan.

[jawn101]

Agreed. I like to scan the car's gauges every few minutes or so just to make sure the indicators are in their nominal positions. I had one overheating condition that was caught quickly just because of the routine gauge scan.

Speaking of which, am I the only one who finds that my hands block a lot of very important readouts? A while back I was driving with a marginally connected alternator because my hand at 2:00 was blocking the battery light. Caught it out of the corner of my eye on a turn once and have been much more attentive ever since.

[cybercusp]

Speaking of which, am I the only one who finds that my hands block a lot of very important readouts? A while back I was driving with a marginally connected alternator because my hand at 2:00 was blocking the battery light. Caught it out of the corner of my eye on a turn once and have been much more attentive ever since.

I've had that problem too.

[Jonathan]

Speaking of which, am I the only one who finds that my hands block a lot of very important readouts? A while back I was driving with a marginally connected alternator because my hand at 2:00 was blocking the battery light. Caught it out of the corner of my eye on a turn once and have been much more attentive ever since.

For how I sit in the seat and with how high my head is towards the roof of the car (door headliner recessed area), I can't see any of the top row of warning lights... turn signals, headlights, highbeams, etc. It's the lip of the binnacle that is in the way in my case rather than my hands. I constantly look around at everything watching for warnings, etc.

And speaking of the pre flight routine and listening or watching for noises or strange things while driving, I've gotten myself such a wild imagination for every last noise or bump or rattle that I've started to keep the stereo loud enough to drown out the majority of noises. Waaaaay too often I drive around and get spooked by some noise even though it almost always is nothing to be concerned of. Kind of a trade off of trying to enjoy the car without being overwhelmed every two seconds by the "what the heck was that?" noise.