If I am going at a going 45+ mph no problem, temp is at a perfect 170, if I slow down for while, especially if I have been driving for a bit, or get stuck in traffic car shoots up to like 210-220 in about 3-4 minutes and then stays there... whats happening ? ad how do I fix it ? wether A/C is on or not it doesn't affect this from happening.
Thanks
Chris

 

mine does the same thing and im not sure if there is anything that can be done about it except putting in a lower temp fan switch because when your sitting still no air is being forced through the engine. it is normal for cars as old as ours to do that, newer ones are obviously going to cope with heat better.

 

THere must be something that can be done, at an expense of course, bigger/better radiator. independant transmission cooler, bigger fans ? better oil cooler ?
thanks
CHris

 

There is nothing wrong with 210-220 at lower speeds. Car engines are more efficient when hot, which is why chevy set up the primary fan not to come on until 220. These cars are bottom breathers, especially during this time of year, stop and go traffic, or low speeds, will usually result in hotter engine temperature. As long as it doesn't actually overheat (260 or better) there is nothing to worry about. NOW, if something has CHANGED, IE: you used to run cooler, there may actually be an issue. Otherwise, if both fans work, your coolant is good and there are no leaks, enjoy the car and don't worry about the temp.

 

THanks IROZINCO you eased my mind. what is the overall ideal running temp ?
thakns
CHris

 

Well, that sorta depends. For a STOCK car, the temp will vary between 195-220. This is assuming 195 thermostat, dual fan setup, v-8 (305 or 350) TPI. TBI and carb and v-6 (2.8L) cars are set up a little different, though the temps are still in about the same range under NORMAL driving conditions. These cars DO tend to have a sticky area around 45mph. Party it's the torque converter and partly it's the airflow (or lack therof!) Everyone seems to assume that cooler is better, and that's not always the case. A hot engine IS a more efficient engine, up to a point. Now, having said that, climate is also a factor. Obviously the car is gonna run hotter in the summer. People tend to wanna switch to a 160 Thermostat, and that has all kinds of repercussions with a TPI car. They also wire fans ON all the time. With a stock setup, these are sorta crutches. A cooling system in good condition, should work very well with a 195 thermo and the fans wired to the relays. Once you get into major modifications, all bets are off! So as long as your fan kicks on at 220, and your temp never gets much above that, drive the car and enjoy!

 

Additionally for example a stock 86 T/A single fan TPI doesn't even kick the fan on until 234°. This was lowered a bit when a PROM bug was discovered and an update was issued but the design is too run pretty hot.

Way too many folks dropping 160 stats thinking they are dramatically changing the characteristics of their cooling system.

They are not.

First stats have a margin of error, plus a range of operation from fully closed to fully open. GM installed 195 stats as a one size fits all application and unfortunately it does not.

A 195 stat in Nanook, North Dakota in dead winter vs. a 120° day in Arizona traffic with your A/C on will be two different beast.

The various stat temps should be used to fine tune the temperature operating range for the existing climate and conditions.

 

Yes, GM, set our cars up to run a little on the warm side for efficiancy reasons, but at the expense of engine life and some performance. Quickest and cheapest way to lower your temps is to wire in a fan switch so you can turn the fans on whenever you want. I'd also consider dropping in a lower temp stat..but not too low, maybe go to a 180 if you have a 195 in there now. All this would be less than $20. I installed a fan switch and wired both fans to come on at the same time. It drastically lowered my stop and go engine temps.

 

Got a question for you guys while this topic is still fresh.

What is the purpose of the oil-cooled engine option in the L98? Does the motor oil play a part in cooling the engine on top of the coolant + water? I've noticed and documented that the water temperature guage in my L98 tends to stay below 220 degrees a bit longer when a heavier weight oil (Mobil 1 15W-50) is put in vs. a thinner oil (Amsoil 10W-40). Plus, I've noticed cooling down time was significantly shorter with the 15W-50 than with the 10W-40.

...Or is this just me?

 

Thats exactly right, cooling the oil can lower engine temps. How much I'm really not sure. I've known alot of guys in my area to pull oil coolers from salvage yards and rigg them up to work on the 3rdgens. From what I've seen it does help.
With my fan switch and stat, my car rarely gets over 210 degrees.