will259

Hey everyone new guy here first post so I apologise if this has been posted before. I have a 95 GT 5.0. No mods other than a cold air intake and flowmaster 40 series exhaust. I got the car about 3 months ago. everything was fine but the ac didn't work. I work at a garage so I had one of our techs charge it and it worked for 3 days. turns out the compressor was leaking. I had just the compressor replaced. and the AC has been working awesome. Now the car has started to over heat if the AC is on and only if it is on. So far I have replaced the radiator, cooling fan assembly,180 degree thermostat, flushed the system and had it tested for a head gasket leak. The head test was normal no exhaust in the coolant. I'm just stumped, The ccrm is working normally. the fan comes on at both speeds at temp. if it is cloudy or raining no problems. If the GA sun comes out the temp heads over to 230 in about 10 miles of driving hwy faster in stop and go. AC stays cold. when I shut the ac off it will slowly go back down to around 190 to 200. Any help would be appreciated

mindaugas

My 95 GT was overheating as well, I replaced the thermostat and the housing. The housing has a gasket and mine was gone so there was a small leak.

I also recently re-charged the AC and I've noticed the heat goes up a lot more with it on, but hasn't gone into the red. Not sure how much that helps but I've read the 5.0's run pretty hot regardless. If you don't have emissions you could try deleting the EGR, that's supposed to help a little with heat as well.

ucinn

Does this have the snake belt on it? Maybe belt slipping when AC is on(extra load) thus not as efficient water pump output. Just thinking out loud.

will259

I just did the alt which had a slightly bigger pulley and I had to get a half inch longer belt so it is new. I have a 180 degree thermostat in the car with a new gasket. I put an aftermarket gauge on it because I didn't trust the factory cluster.

will259

Oh and the smog pump was already bypassed.

88 orangepeel notch

I would first verify it is getting that hot with a good IR thermometer. Your right about the stock gauges and some aftermarket aren't much better.

Is the lower radiator hose in good shape ? Not that it's old and collapsing on itself when hot.

will259

Thanks for the responces. Ill check the hose I didn't look at it too close when I changed the radiator.. I did check it with the IR thermometer at the water neck on the intake and it did match the gauge at 210-215

rmodel65

when you start the car with the cap off can you see the coolant flowing?

will259

The hose looks fine. I do see coolant flowing but it looks slow. I don't know how fast it should look like it is moving though.

88 orangepeel notch

With the cap off, and engine up to temperature, apply alittle throttle. Say up to 1500-2000 rpm. The fluid level should drop down in the radiator and expose the cross tubes. There should be a fair amount of flow through them. It's kinda hard to explain, but it shouldn't just trickle thru those tubes, each tube should be flowing "easily" ?

If that seems fine, put the cap back on and then give the throttle a couple good revs while watching the lower radiator hose. Look for any signs if it collapsing from the water pump sucking coolant thru it. There should be a spring inside the hose the keep this from happening, but you never know...

Keep us posted