Hi! Does anyone know the correct operating temperature of a 350 engine in my 78 Camaro?After startup the stock temp indicator climbs to almost 220F quickly, and then stays there for a while (see pictures). After driving for a bit longer the needle seems get right in the middle at 220 and if you're idling in traffic for longer on a warmer day I have seen it going very slightly over de 220F line recently. It did return to 220 after a while. Outside temperatures here are about 86F right now. I mostly drive it in city traffic, but even on the freeway when driving about 130 km/h it doesn't really seem to run cooler.

Engine is almost stock (I know it has been rebuilt back in 2011). I actually never paid attention to the temperature until this summer when I caught it almost overheating. Turned out to be a failing fan clutch, which has been replaced. I also had the radiator rebuild with a brand new cooling block very recently. I even flushed the cooling system multiple times. I checked the thermostat and it seems to have a 160F thermostat fitted.

Are these concerning temperatures on my car, or is it normal for these cars to run on these kind of temperatures? And if not, any ideas on what more I can do to sort this out?

Thanks!

 

Sounds right to me at idle for a stock car. Should go down some at highway speeds. I believe they had 195 deg thermostat from the factory.

 

Thanks! If this is normal I can stop worrying about it.
Originally it had a 195 indeed, but I'll stick with that 160 for now haha

 

A lower temp rated thermostat doesn't always mean a lower temp running engine. If conditions are right; hot outside, sitting in traffic, etc. that 160 stat may never close. The reason for a higher rated stat, is that will make the coolant stay inside the radiator longer, cooling it down better. Your stat starts to open at 160 degrees, is fully open at 175-180 degrees. Your coolant could be getting so hot, above the rated temps of the stat, that the thing could be staying open all the time when hot, with the coolant constantly flowing. That's not as efficient for cooling down the engine/coolant. I would try using a 180 stat, definitely not a 160.

 

That actually makes a lot of sense! I'm gonna try a 180 and see if how that goes. Thanks a lot!

 

When GM increased the temperature of the thermostat. I was told that was to improve fuel mileage. Normally to drop the "stuck in traffic temps" you need to make sure the fan is working properly, if it has a clutch fan you want to see when it engages and the the original shroud is install and that the coolant is using all the path ways in the radiator and nothing is plugged.

In circle track racing you can use a restricter in place of a thermostat or a low volume water pump which uses less HP also. Coolant traveling too fast to cool properly on a stock setup is not normally an issue unless you are going over 5000 RPMs for more then 5 minutes. Our circle track car ran for 6200-6700 RPMs for up 12 minutes. The restrictor we used looked like a sheet metal washer.

My 96 had a 165 thermostat and sitting in traffic it would reach 220 degrees but at highway speeds it fell back to 180 degrees weather it was summer or winter, ac or heat blowing. With those symptoms I am sure and better fan would have kept it cooler but 220 should not be a problem at idle.

 

Thanks a lot for the info! It has been really helpful because I have been struggling with the cooling system for a while now and did a lot of work on it.
The fan clutch was indeed faulty and has been replaced recently! The radiator block wasn't in a very good condition either so that also has been fully restored with a new cooling block, so that should be fine. The original fan shroud is in place too.
Actually I only use it in regular (European) city traffic and on freeways (I don't do any track driving), so I'm not really pushing the engine. I'm glad to hear 220 degrees doesn't sound concerning so far. I'm gonna have a closer look to see what it does on the freeways and change the thermostat to see if it makes some difference on those hot days as Camaro69 suggested. But seriously, if it reaches temps like this over here I really wonder how these stock cars ever kept cool in much hotter climates in the US like in Nevada or something haha