fourkidscrazy

Ok here it is I have a 1996 LT4 with 100 K on it, Just it that mark a month ago. The car is starting to run hot. It's been between 60 and 70 here in the morning. When driving it in the morning on the highway the temp is between 215 and 223. It also has a 160 deg stat in it. I installed the stat back in 1996. If I remember correctly last year in the late summer early fall the highway temp was between 180 and 200. I used a temp gun on the upper hose when I stopped the car and got around 174 on the upper hose and 140 on the lower hose. I even shot the radiator between he condenser and the radiator and the fins were around 110. The oil temp is also going up to around 215 highway driving. The water pump is three years old, I do not think that the temp sensor is bad because of the oil temp is also rising. I think that the stat is not opening up all the way, but before I start taking stuff apart dose anyone have any other suggestions. I also have checked the water level and it's fine.

WVZR-1

Well the t'stat is 17+ maybe 18 years old so I'd say it's maybe due. I can't imagine that if you did the water pump 3 years ago you didn't include a t'stat given it's age.

fourkidscrazy

It's the simple things that slip my mind

enventr

When replacing with a 160 stat make sure that you reprogram fans otherwise the stat does nothing but warm up the car slower

pcolt94

Sounds like a tired stat. That’s the fastest and easiest thing to do first. If that does not do it, then you can look at the radiator.

A 160 stat will cause longer warm up and a longer time to go into closed loop with increased fuel efficiency. I would use a 180 as it was designed for.

fourkidscrazy

Ok thanks for the info, I did not know about the fuel efficiency part. I just used the 160 stat to try and keep it running cooler. I did not have a programer to change the fan on temperature, so I just ran it like it was. The temperature got up to 228 today on the way home with outsde air at 76. After it cools down some, out goes the old stat and in with the new.

WAR EAGLE

don hall

You are going to learn that most t-stats are made by STANT, even the one that is packaged in the ACDelco box. According to STANT reps, all new t-stats are for both open and closed cooling systems.

If concerned, there is a t-stat that fails in the open position.

John A. Marker

You should also check the space between the radiator and the condenser. Remove the plastic cover between the two and check to be sure you don't have a build up of leaves and other road debris between the two.

When was the last time the coolant was changed?

pcolt94

I don’t want to sound like a broken record but just wanted to say you need to use a LT1 stat for that engine. Anything other than that might cause a problem.

Also at your 76* air temperature, 228 sounds a bit high if you're at cursing speed of 50 or better. If all is working correctly you should be down around 200 or lower usually.

fourkidscrazy

Thanks for all the help, I ended up going to Pep-boys and buying a stant 180 deg stat. It's all good now, drove around town and temp never went above 201 and oil temp was around 209 . Very happy now. As far as the space between the radiator and the condenser it's all clean. I flushed out the coolant last winter by pulling the knock sensors and draining the radiator. Again thanks for all the great advice, this site makes it easier to fix problems as they come up.