Just wondering what others may be seeing on temps? I have a 1981 stock with a 350/195hp GM crate motor installed. All ECM and other parts operating as was original.

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Tommy

190 deg running down the road would sound normal to me. The temp creeping up while stopped is also normal, since you don't have the same volume of air flowing thru the radiator. As long as the temps come down while moving, and they do not climb above 230 or so, I'd say yours is about normal. If it gets too hot, it will puke coolant. If it's not puking, then the temps are ok at that time. Another thing is, you can't really always believe what the gauge is reading...they aren't really all that accurate. If you have, or have access to an infrared temp gun, check the actual temp against the gauge, and see how close it really is.
 Make sure the radiator is clean, as in no bugs and stuff on it or the A/C condenser.

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

My 82 run about 190 - 200 water and 210 - 220 Oil. I do have an infrared red heat gun and my gages to match close.  So I’m sure on my car they are at least in the ball park. 

By the way we are looking at old cars and 40 years ago I did gage repair when we actually took them apart like you would watch changing pivots and shunts etc.   I guess all I’m saying is gages can change their reading over time so Adam is correct when he says they can be off overtime.  Some will not some will.  Never did that job long enough to get a feel for the why some did and some seemed not to. 

If you ever pull off the gage cluster you will notice shunts across the gage terminals and they will be different colors from your buddy with the same car.  Those are the calibration shunts.   My guess is the gage manufacturing specification was so wide that they had to be calibrated before installation to meet the accuracy requirement for the car.   Does not make a lot of difference unless you replace the gauge with another one.  

|UPDATED|5/26/2012 10:27:21 PM (AZT)|/UPDATED|

My oil and water temps also seem to reach the same temp range the longer I'm on the road.  Always around 190 for water 200 for oil.

|UPDATED|5/26/2012 10:28:51 PM (AZT)|/UPDATED|

My 74 runs just slightly above 200 on the highway.  I have noticed once or twice that if I stop at a rest area that when I restart the car, the temp has spiked.  It worried me the first time or two, but as soon as the engine is going and the fan running, that it cools right back down.

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I wanted a Corvette my whole life, but I never dreamed of all the wonderful people I would meet because of it!

I think my temps are around normal after too talking with a couple of other '81 owners on road driving conditions.........it's when I am stopped, engine shut off that temps climbs in engine compartment more and makes restarting a little harder.

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Tommy

Is engine crankaing at the normal speed when hard starting? If not it may be heat soak of the starter solenoid causing the hard start.....happens frequently with headers. It will start normally when engine has cooled.

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DanT

Yes Dan, engine spins over fine, believe just some extra radiant heat buildup in engine compartment once stopped and fan is not turning. With all still factory installed parts, air pump, ECM, AC etc it is a full engine bay with little air space to let escape so on those hotter days and harder runs reckon just need to pop the hood for a few to let the heat escape and not built up inside.

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Tommy

Try running a 165 degree t-stat....should lower water temp and help with excess heat.

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DanT

Have you tried a carb heat shield?

No have not, will look at that option, thanks.

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Tommy

|UPDATED|6/18/2012 2:21:57 PM (AZT)|/UPDATED|


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You may be experiencing fuel percolation in the carb due to the underhood heat.  A spacer may help but hood clearance is already tight on a C3.  Re-routing the fuel line might help as well or wrapping it with heat resistant material.  

I run a solid 180 . all the time .. This is because I run a 4 core rad with a 180 t-stat . 

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1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI 

I went with an aluminum radiator a couple of years ago and never see the temp. go any higher than 180. I always put the hood up when I first park it so as to protect the paint on the hood from engine heat. I agree that it must help with restarts, too. Kevin

Steve the issue is not water or engine oil temps too high but the buildup of heat under the hood once stopped. Since my '81 still has all parts as came off the assembly I have an engine compartment full and very little open space for heat to get out so the radiant heat buildup is what is kicking me......so for now after getting hot and stopping, when can pop the hood and let the heat escape.....until a better idea comes along.

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Tommy

I know guys that used to drive around all day with the hoods unlatched on Shark cars....and that was back when they were still kinda NEW! All due to the heat.
I always pop the hood release on mine if I am parked for more than a few minutes, and it stays unlatched all the time while in the garage.
You think yours get hot under there? Try working on a big block!!!


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Make sure that all of the foam seals around and above the radiator are intact and in place and if it still has a fan clutch, ensure that it is functional.

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1973 L-82 4 spd

Oh, now I get it!!  Its an in-bread cat!!!

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(click to see a larger image)

I am somewhat reluctant to go along with what appears to be the accepted idea that heat has built up causing a hard start after a shut down. I AM not saying this is not possible but a few things make me want to say something else is happening here.

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1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI 

I experienced hard starting after a hot shut down on several old cars back in the 70's.  When I say hard starting, I mean slow cranking like the battery is nearly dead, or timing is over-advanced.  I would have to wait awhile for things to cool down, then it would start up fine.  I think the starter motor got over heated.  That's why GM installed shields around the starter motor.

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1973 BB 4-Speed Coupe Project Car

I have heat issues as well. Not when normal driving then i run 180-190 but on race days when i push her im always around 220 obviously worse through out the day. My solution is going to be to ditch the old mechanical fan and install an electric pull type fan. On race days though I also open the hood after every run and use a pump type pestiside spreader full of water to mist my engine compartment, I also run with my headlights up to allow more airflow to the radiator. Our C3s will always have heat issues due to poor design for cooling. There is something like 3 foot of fiberglass nose and the like in front of the radiator not to mention the headlights hanging right in the way of airflow

Since the Shark is a bottom breather, the headlites really don't impede the airflow that much.  Overheating can be caused by a radiator that needs rodding out, missing foam seals, missing fan shroud, bad fan clutch, bad t-stat, collapsed hoses, not using a 50/50 coolant mix, and air trapped in the engine.

Hard hot starts can be caused by timing which can be worked around by putting a switch in the coil supply (non-HEI) and spinning the motor and then turn on the coil.


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1973 L-82 4 spd