96reddevil

Alright, I have a 1996 Trans Am M6 with almost 115,000 miles on it. It keeps running hot, especially since summer has hit here in Illinois. I just put a new 160 degree thermostat in back in March. On a cold day, it was about 40-50, it would go just a tick above the 160 mark, but on a hot day it'd run hot. Only had it hot the red once. Usually I don't drive it long enough to get super hot. It has pushed coolant out of the resivour once. On the high way it runs a steady 180, the second I'm in stop and go it runs hot. What's really got me baffled is that if Im rolling through town, I'll drop it into neutral and coast, the temp will go from the third tick mark, the one right before red, and drop down to 210, put ot back in gear, and under load it starts to climb right back up. Sitting at a stop light it will start to climb, and if I hold it around 2k rpm it will start to drop. My fans are ALWAYS on, even when I haven't turned the engine over, but just turn the key to turn all the electronics on(bought the car this way) I have a new water pump I'm about to install, and another new thermostat. This is just what I'm leaning towards on it. I'm just looking for some more insight on this, maybe someone has dealt with it before.

Thanks in advanced guys for the help.

food nd cars

I would start with the thermostat, make sure that you are bleeding the system properly. I would also make sure your coolant system isn't leaking.. especially through your head gasket.

gallardo259

sounds a lot like the problems i'm having. i've replaced my t-stat, waterpump, and flushed the system and it still overheats. one mechanic suggested the perhaps a hose was deteriorating/colapsing on the inside...not likely but possible. another possibility was a blown head gasket that when cylinder pressure increased it leaked into the coolant system thus 'pressurizing' it and also creating steam...idk about that though.

sorry not much help from me

96reddevil

Ok, how would I check the head gaskets?
I checked the anti freeze, and oil and they both look good.

96reddevil

Actually the hose the leads to the thermostat housing looks like its collapsed down, like not a lot of anything is running through it. This this could be something to do with it.

food nd cars

coolant pressure testing system can be rented from a local parts store. Make sure to use it correctly and "not" over pressurize the system.

Paul Bell

iTrader: (9)

I'm assuming you've properly bled the air out of the system and you don't have an under drive pulley?

Your symptoms show you have reduced coolant flow at lower speeds. I'd say this was a indication of a corroded/rusted water pump impeller that makes it smaller in size.

I'd replace the water pump first along with the thermostat, just for good measure.

If you still have the problem, perhaps the radiator is clogged. A new one would then be in order.

Paul Bell

iTrader: (9)

I'd say no. Your problem goes away at higher engine speeds. If the hose was crushed from suction, the overheating problems would get worse at higher speeds, not better.

96reddevil

Yes, I've bled the system. We're changing the water pump out tomorrow, thermostat, and flushing the system. I was really leaning towards the water pump. It just doesn't seem like its push coolant like it should. If it still does it, I'll get the pressure testing system, and go from there.

TheHeadFL

Don't forget to check your radiator cap. If its bad it will let your radiator exchange water for air when it thermocycles.... This will eventually push a lot of coolant out into the overflow.

Green97z

that sounds just like what happened to me... i checked everything head gaskets, New Thermostat, Coolant... turned out to be the radiator cap... i would check that

quik95lt1

iTrader: (7)

just out of curiousity hows the radiator condition itself??? any dirt and debris stuck in the fins?? alot of bent fins??.......sounds like this could be the case if the radiator just cant cool properly and at higher speed its forcing enough air through to cool it............i have run into issues like this before as well............i still run the stock rad and fans and at a car show on a 90 degree day my fans sucked a bunch of dead grass and stuff up into the front of the radiator and the car overheated very fast........cleaned it off and bam no problem.............id check that out

ahritchie

iTrader: (1)

THIS...had the same issue years ago in my 94....the waterpumps don't always just stop at once one day and die completely...sometimes it's a slow death choking coolant flow and not working at 100%...I guess the impeller slips or something. New pump, fixed. Might as well get an electric one.

Low N Slow

iTrader: (4)

What he said plus drop the fans and feel the radiator core surface after you run it. Mine was cool to the touch over about half the surface. Plugged internal passages in the core from the previous owner not changing coolant for too many years.

96reddevil

Well, here's what we did, and it fixed it.
We changed out the radiator hoses.
They were REALLY bad.
It actually explains it to.
When I would be getting on it, it would start heating up, because when the water pump would start sucking, it'd collapse the hose down to where there was little coolant flow.
We got the new hoses on, topped off on coolant, and took it to the track. Never seen above 200 with make back to back passes, and sitting in the staging lane. 180 in town, and a tick above 160 on highway/interstate.
Thanks for taking the time to help though.
I appreciate it!