Chevy Nova Forum banner

My engine is running WAY too cold

15K views 40 replies 14 participants last post by  JRouche 
#1 ·
Went for a putt today, it was 75* outside. I was driving at around 55mph for about 20 miles. The engine was as warm as it was gonna get and it was only at 153*. WAY too cold. And I have two sensors. One for my gauge and the other for the EFI computer, they both agree, its 153.

I want the engine (water temps) up around 185-190*.

I have a 185* stat in and it seems to work with the simple checking I have done. You know, idling the engine up to temp with the radiator cap off looking for the opening of the stat with an inrush of coolant. And I saw that. I can idle it up to 185*, the stat will open and close. I can see that with the coolant flow with the radiator cap off.

And idling through town I can get some nice heat. It will peg at 185* and stay there. I like that. Although 190* would be nice. It never gets above 185* no matter what. Unless I idle it on the driveway at a high idle (1500 rpm) on a really hot summer day and disable the fan. Then I can get some heat in the engine.

But if I go any faster than 30mph she cools WAY down, not "cool".

Id actually like to see 195-200* with my EFI mill. She runs SO much better with a lil heat.

I have the electric fan controller set to max temp. I dont even think the fan is turning on with any speed above 40mph. Its just too cold. And the outside temp isnt very cold. Its been 75* outside, that is not really cold, its perfect.

So my question? How can I get more heat!!

Any help would be great. Im running around with a cold engine that is sucking up fuel and basically in hibernation due to the temps. I need to heat things up a bit. JR
 
See less See more
#2 · (Edited)
Not trying to sound funny but I think your car is magic.:yes:

If I read your post right you say you have a 185* the fan isn't running & you can't heat more then 153* that can't be something isn't computing...


Anyways if you want more heat put a hotter t-stat in it.:yes:

I drove my car today on the fwy it was 175-180 on the street moving slower it would hit 200 then the fan would kick on coll it down to 180 till the fan shuts off this happens over and over in this cooler weather we are having... I have a 160* t-stat in mine.
 
#4 ·
Not trying to sound funny but I think your car is magic.:yes:

If I read your post right you say you have a 185* the fan isn't running & you can't heat more then 153* that can't be something isn't computing...


Anyways if you want more heat put a hotter t-stat in it.:yes:
Hmm, Ok Im trying to figure out what you are saying (I get the typing issue, I have that also).

But mainly I think you are saying the stat is the problem.

Yes, I would agree if it never actuated. But it does. It kicks in at the temp that it should. 185* Its opening up when the coolant temps finally get to 185*.

Only way I can get the engine up to 185* is if I run it at a high idle (1500rpm) on my driveway. No air flow through the radiator or engine.

Problem is the coolant temps never reach 185* if Im rolling more than an idle through town. If I get going to 40+ mph the coolant temps are still pretty low, 153 or so.

There is NO magic or anything but a frustrating problem for me. I want the engine to get to some decent temps. At this point Id settle for 180*.

And yes, Im thinking the stat is the problem. Not so much thats its a lower 185* stat. But that its opening all the way when it should not. Its not letting the coolant heat up in the block like it should and its popping open before it should.

Im just looking for some consensus before I remove the stat and replace it. I dont want to go through the work before putting it out here, just looking for ideas. JR
 
#5 ·
Great info. I have two separate sensors for the coolant temps. Both read 150*. It is too cold.

The fan is not even turning on from what I can tell.

I do have a massive radiator, but that shouldnt matter. The stat should keep the coolant in the engine long enough to warm the block up.

So yes. Its back to your first pick, bad stat.

Its prolly open when it shouldnt be and because the large radiator is there its cooling the fluid down too much.

So Im gonna replace the stat. It was a decent one.

Any recommendations for a manufacture for a new stat? JR
 
#6 ·
Maybe it is turbo engines are different but I have never known anyone that wanted their car to run hot.

In my experience power is made in a cooler engine.

Most experienced drag racers keep their block cool and oil at temp to make the most power.

I do not like to ever see my engines go much above 175 street or strip.

But, like I said maybe turbo engines are different.
 
#20 ·
Running "hot" is not great, pre-ignition becomes a problem. But hot for me would be anything above 210*.

Im not looking to run it hot, just warm, which to me with my fuel injection, aluminum heads, 10.5:1 compression is around 185-190. Id like 190-195 but that might be a lil hot for the valves and pistons. It is a 1st gen engine. For an LSX I might think about 190-195. They flow OH so much better. Alot of cooling effect with the intake charge. But on my old design intake Ill be happy with 185-190.

At 153* its way too cold and the fuel is not able to take advantage of the higher compression. So the combustion chamber gets "water logged" Yeah, its not water, its fuel. But fuel logged just doesn't sound right.

But my engine is "fuel logged". Meaning the fuel is lighting off, but because the chamber is so cold its just lighting off enough to rotate the engine.

There are so many byproducts in pump gas that unless there is a major amount of heat in the chamber they just dont burn. So they foul everything up, cool the combustion chamber even more and make for a crappy running engine.

You need heat in the chamber. Not to be confused with air intake temps. The colder the better.

Internal combustion engines like heat. As long as its removed very quickly. They dont like "heat soak" where the entire mass is really hot and there is no place for the heat to escape.

Ever thrown a fan belt and the engine temps went to 210. Engine prolly felt pretty light (throttle response) up to the point where it either died or you saw the temp gauge.

Yup, a 200* engine will burn all the fuel (and pistons and valves) and be running the best it ever has. But, it wont live long like that.

Yup, heat is the internal combustion engines favorite enemy. It loves the heat, as long as you remove it very quickly, mainly from the heads.

If you can keep the engine very hot, and keep the heads just under that you WILL make power and have efficiency.

But its a crazy tap dance mixed with a country line dance. The tap dance wants to take over and heat things up very fast and kill the parts. The line dance wants to slow things down and keep it all controlled. The key is to get them all to dance together. Then you have a productive engine. And productive means HP and fuel efficiency. JR
 
#7 ·
Motors are more efficient once they come up to temperature. Of course they do like cold incomig air, but the motor itself needs to be up to temp to burn off any condensation. I find this especially true if you are running aluminum heads. For instance, I drove to the track one time and let my car cool down and then did one run. Put some heat in the motor and did another run and the car ran faster. If you already have your setting for your fan set to max, then look at putting a 190 thermostat and see what happens. You can always do what the big rigs do if the weather is too cold and place a piece of cardboard over part of the radiator. Experiment with it until you get it where you like it. Like you said though it's not that cold where you are so I would definitely look at the thermostat first as its the cheapest and quickest to fix other than the cardboard fix. Good luck
 
#22 ·
Yup, it just started. Mainly cause the car hasent been driven until this point. Its a new engine build and I have 300 miles now. Its been like that for the entire 300 miles. New engine build. Heck, new car for me. 15 years of building it, first miles of driving it. Im loving it!!!! But yeah, its been this way from day one, which was 300 miles ago.

And I think you are correct. I think the stat is due for a swap out. JR
 
#13 ·
I'm with everyone else here, it sounds like water is going past the thermostat at freeway speed, is it possible that you have enough coolant pressure to force the thermostat open at freeway RPM? I also wonder are you running a heater and could that be contributing to the issue? My car runs right at the thermostat # 195 deg. unless I do what you do and hold the rpm up sitting in the driveway with the fan disconected.
 
#15 ·
I had one of the guys at work install the thermostat backwards and it was running hot so I don't think that will do it. Shouldn't matter whether are not it has a heater connected. Heater being a small radiator in itself, I still don't think it would cool that much more.
 
#29 ·
If your radiator is too efficient, then you could do away with the thermostat and try different restrictor plates instead.
I dont think you would want to run an engine without a T-stat. It will overheat and wont keep the engine in its optimal operating temp.

The T-stat is not there to keep the engine cool. Its a thermostat. Its meant to keep the engine at a certain operating temp. Its an old idea, the thermostat. Its really an old piece of technology. But the thing is, when its working it really does work. JR
 
#23 ·
That's ok.

I know plenty of guys that like to run hot 185-190 but not me. IMO 210 is to late and your just doing damage to your engine.

I see better power from a cooler engine.
Definitely on the strip it is better to keep as cool as possible.
Hot oil good, hot block bad.
And on the street I like it to run about 175-180 tops.
I drove an iron head vortec 355 over 300 miles and got about 20 mpg, and never saw temps over 180 with over 450 hp. Then raced all weekend and drove home the same way.

Like you said, heat is an engines worst enemy.
I prefer to make em last by keeping them away from their enemy.
 
#31 ·
Your problem has to be with the thermostat. It should close if the temp goes below the rated value and only open when the coolant is warm enough. You could have an air pocket developing that's giving a false reading if the sender is not immersed in coolant. If you car is low in the front, air can get trapped. Try bleeding the air out. Jack the front end up so the rad cap is higher than the heater core. Run the engine and see if it burps out the air.
 
#35 ·
Good point. But... Thats not an issue. Im thinking a lower cap pressure wont come into play because the temps are way below the pop off pressure for the cap.

But besides that, I look at a radiator cap as a pressure relief valve. It will only open up when the pressure (because of high heat) is very high. And it opens up and pukes the coolant to the ground, or all over the engine or a puke tank.

I have a puke tank. And no, the cap has not opened yet. Dont think it will with 153*

But thanks for the input. Always happy for ANY input. JR
 
#36 ·
Cold Engine

Following up on an old thread, I'm curious if you ever resolved your problem w/your engine not heating up. My 66 Sedan has the same problem now for about 5 years and 11,000 miles. I have a ZZ4 w/ Fast Burn Aluminum heads.
I run a reverse rotation (not to be confused w/reverse flow) aluminum water pump w/all stock sized pulleys, presently a 195d stat and a PRC aluminum radiator.

In hot weather it runs around 195-200 all the time. Electric fan cycles on/off as it should. But, in cold weather it won't get more than 150-160. And I can verify that by the warm..... not hot air coming from the heater, lol. I have tried several different thermostats with no change. Electric fan never comes on as I can verify by an indicator light in the car.

I recently drove it on a 800 mile round trip. It would be around mid-day each day before the temp would get up to 195. As one post suggested blocking part of the radiator, I am considering doing just that.

I'm 61yrs old and have built many cars, but this is the first time I've had this problem. I've had plenty of heating problems.

Sorry for the long post, but I would like to solve this mystery.

Thanks,
Lynn
NC
 
#41 ·
Following up on an old thread, I'm curious if you ever resolved your problem w/your engine not heating up. My 66 Sedan has the same problem now for about 5 years and 11,000 miles. I have a ZZ4 w/ Fast Burn Aluminum heads.
I run a reverse rotation (not to be confused w/reverse flow) aluminum water pump w/all stock sized pulleys, presently a 195d stat and a PRC aluminum radiator.

In hot weather it runs around 195-200 all the time. Electric fan cycles on/off as it should. But, in cold weather it won't get more than 150-160. And I can verify that by the warm..... not hot air coming from the heater, lol. I have tried several different thermostats with no change. Electric fan never comes on as I can verify by an indicator light in the car.

I recently drove it on a 800 mile round trip. It would be around mid-day each day before the temp would get up to 195. As one post suggested blocking part of the radiator, I am considering doing just that.

I'm 61yrs old and have built many cars, but this is the first time I've had this problem. I've had plenty of heating problems.

Sorry for the long post, but I would like to solve this mystery.

Thanks,
Lynn
NC
Hey Lynn. Thanks for checking in to see if I fixed it. I totally forgot I made this post and kinda dropped the ball when it came time to work on it and say what I came up with.

I started a new post because I forgot I made this one, wish I could combine the two. Ill work on replacing the stat and post the results on this http://www.stevesnovasite.com/forums/newreply.php?do=newreply&p=1750536 thread.

I sure hope the fix is not to block the radiator, cause really, I bought the large radiator with hopes that I wouldnt have any cooling issues. If I have cooling issues in the opposite direction (too cold) that would suck. I need the coolant to get to 185-190 and stay there for proper performance, mainly fuel efficiency.. JR
 
#38 ·
Cold Engine



Thanks for the post....but I have changed the stat several times, most recently about a month ago just before my trip. This time with a 195d Stant "Super-Stat". No change. Having retired from the Auto Parts business (36 yrs) I have sold hundreds of thermostats and replaced many myself and fully understand how they operate or should operate.

I guess it's possible, but it's hard for me to believe each one I've put in this car has been bad.

Any suggestions on a "brand" or "type" I should try? I don't mind changing it again. I'm open minded and will try any suggestions.

Thanks again.....Lynn
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top