93 Grand AM 3.3 V6 Overheats intermittently

[imre]

Hi, I have a 93 Grand AM w a 3.3 L V6 w 96000 mi, it overheats intermittently. Flushed Radiator w engine running, new coolant fluid & 15 PSI cap. Thermostat opens OK (water presuure in hose after warm up). No leaks anywhere hot or cold. Two days ago it was 101 degrees, and I drove it about 35 mi (about 20 mi at 75-80mph, the rest at stop & go suburban driving. No sign of overheating, temp guage quite normal about 165- 180 (even went down 1 needle width after getting off freeway). Today it was only 97, made 3 short trips (< 10 mi), no problems on 2 legs, third trip, engine overheated, about 1 pint of coolant on ground from hissing radiator cap. Drove home (3-4 mi) cooled down OK except 2 blocks from home, temp guage needle jumped up to about 240!
Pontiac Shop Manual says to put in 3 tabs of GM#3634621 sealant after flush. I couldn't find any.

Does this sound like an "intermittent" head gasket? By the way, when I started it today, I got a light blue smoke from the exhaust for 1/8 mi. this is usually not the case. Time for a new car?

Thanks

Imre

[grfnkl]

Welcome to the forums. Check your oil, if you see and coolant or a milky substance then you are looking at a head gasket leak. At that point it would be up to you if you wanted to fix it or not, 96K on a 93 is pretty low miles for the year. as far as the whitish blue smoke, that normally means you have a oil leak in the engine. If it's a true white smoke then you would have a head gasket leak. Hoep this helps some.

Good luck.

[imre]

Thanks for your input. I just got back from a doctor's appointment, and I think I "caught it in the act"! It was starting to overheat (temp about 220) when I got home. I got a glove and sqeezed the upper radiator hose, no pressure, no flowing coolant! I'm off to get a new thermostat to replace my "intermittent" one. I've never heard of a thermostat doing this (it always opens at 180 degrees). It's a new one one me.

Thanls again, I'll post what happened after I replace the thermostat.

Imre

[jmc67]

I am having a similar problem with my car as well. I have a 96, grand am. In my case the temp gauge after driving for a few minutes will go as high as the solid line sometimes almost reaching critical point. This happens whether I am driving on a local road or on the highway. I did notice something, if I see that the gauge has reached the solid white line, and I put the car on neutral and I tap on the gas peddle it will take a few seconds and the needle drops back down to the half point. However, after a few minutes it will shoot back up. The car has a new thermostat, and the water pump was changed about 2 yrs ago because of a leak.

This morning before turning on the car, I checked for leaks (there were none) and checked to make sure there was enough coolant. I am completely puzzled and don't know what could be the problem. I am afraid I am gonna get stuck somewhere. Any clues what could be the problem? Could it be a pressure problem? Is it advisable to drive the car with the coolant cap off?

[imre]

Howdy JMZ67. As you can see above, I think I found my overheating problem. I forgot to mention that the oil (synthetic from Autozone) looks clean, just like when I poured it in 6 months ago. The cooling fluid (about a 60% coolant 40% water mix) is also like new (no oil or rust).

Getting to your problem though, I did'nt mention that occasionally my oil pressure guage jumps up to near full scale. I first noticed this while keepin an eye on the Temp guage just above it. I hit a slight bump and the oil pressure guage went back to normal. It's happened a few times since, and each time I "thump" the instrument cluster to get it back to normal. Obbviously there is a bad connection in the instrument clustyer. Could this also be your problem? If the cooling system does not over heat, just the guage, it might be so.

Imre

[imre]

JMC67 I forgot to mention, do not drive the car without the radiator pressure cap. It will boil over for sure. The pressure and the coolant raise the boiling temp of the water/coolant mix.

Imre

[jmc67]

Hi,
I didn't think leaving the cap off was a clever move. However, 2 weekends ago while checking for possible leak, I had the car running for almost 1 hr with the cap off (hood open and car parked) and nothing boiled over. What seamed surprising was the fact that the gauge remained steady at close to half point.

imre, you also mentioned that it could be a problem with the gauge itself. I can tell you that the gauge is infact working correctly. I had one instance the red indicator light on the car went on. And after parking and turning off the ignition, the fan stayed on. This was prove enough for me that the car was just 2 seconds from overheating. Would it be possible the cap may need replacing or the fact that the radiator is clogged?

[richtazz]

JMC67, your 96 has the 3100 (if it's a V-6) that is known for having intake gasket issues. You can look for seepage at either end of the intake along the seam where it meets the block and heads. Normally , you'll also get coolant in the oil (milky residue). The other place that motor leaks is at the "quick connect" fitting on the drivers side of the intake ust behind a nd below the thermostat housing. They crack and will start to seep coolant.

[jmc67]

Originally Posted by richtazz

JMC67, your 96 has the 3100 (if it's a V-6) that is known for having intake gasket issues. You can look for seepage at either end of the intake along the seam where it meets the block and heads. Normally , you'll also get coolant in the oil (milky residue). The other place that motor leaks is at the "quick connect" fitting on the drivers side of the intake ust behind a nd below the thermostat housing. They crack and will start to seep coolant.

This morning I checked the coolant level on the reserve tank and was at the level it is suppose to be in. I also checked the ground and the other areas you mentioned and no leaks. I still have to check the oil but am not sure if this should be done before using the car or after.

[chetwynd]

I had overheating issues with my 94 Grand Am a few years ago. Apparently there's some cooling lines that are too small, so rust and gunk clogs them up and caused my overheating problem. My car is worth about $1000 and I put $800 in trying to fix the problem to no avail. I finally told them to yank the stupid thermostat out and let it run too cold. For the last 4 years I've been driving it daily, it runs at about 120 degrees or so, the heater obviously doesn't work, and I've got about 150k miles on it. I think the computer thinks it's cold so it tells it to run rich, which is fouling my plugs and causing it to run rough and hiccup etc., but that's life. Any thoughts?