Ok guys, I'm new here so I'll put you to the test. I bought my 97 LS a few days ago and just today it started smelling like antifreeze. I started watching the temp gauge after I started it up an hour after it had been running last. The temp gauge was at it's lowest point when I started the car at an idle, then very quickly went directly up to the mid section as soon as I pulled out into the road. It peaked about a 1/4 inch from the red mark and at the same time I took a sharp left turn I instantly started getting heat as the gauge went down to where it normally resides on normal temp. All the way home it would climb up, then on heavy acceleration it would put out heat, and drop in temp at the same time.

I bought a thermostat on the way home, so I'll do that when the motor cools down. I assume it's not a water pump since the acceleration causes it to cool back down. Do you think maybe it's an air bubble? I don't feel like doin' a flush but I will if I have to.

Thanks in advance guys!

 

Have you popped the hood and checked for any leaks?

 

where are you smelling the antifreeze smell inside the car or under the hood? if you smell antifreez in the car it mans that you need to replace the heater core. but so far your going the right direction with the thermostat when you do that check and titen the clams on all of the coolent hoses.

 

Have you checked to see if your fans are working?

 

if your smelling antifreeze somthings leaking...check it over

 

There are no leaks, the cardboard trick shows no drips. The faint smell of the antifreeze is outside the car, but after the car cooled down I noticed also that when I squeeze the upper radiator hose that the thermostat acts like it's stuck open (squeeze the hose and you can hear bubbling coming from the overflow reserviour). I ruled out the fans since half of the problem is that it doesn't throw heat inside the car.

It was getting dark when I parked the car. It looks like I have to remove the throttle body and intake to get to the thermostat housing, am I right?

 

It sounds like your fans may have stop working. I had a 97 MC ls with bad fan switches. I tried replacing the relays, fuses and even cussed at it a few times but they wouldn't come on. I ended up installing 2 toggle switches right into the relays, one for after the car warmed up and the other for when the AC was on. The 5 gen is famous for the fans going awol. I'm sure there's another way to do it but they way I did it worked for me. You can test this way: Start the car, let warm up and and turn on the AC. If the fans don't come on, your fan relays, fuses or (I've been told that it could be a problem with the PCM itself) other electrical problem causing the fans from coming on, are at fault.

 

I think I'm gonna swap out the thermostat, check my fluid levels and see if it's a simple fix. I can't imagine it's the fans since it seems to be a cabin-heat related issue. The temp gauge gets hotter, and there is no more heat coming through the vents... Then when the accelerator is pressed hard the temp gauge slowly goes down, and the heat comes back. Faulty waterpump??? Is the waterpump an easy swap in this motor? Where the car is this new to me it wouldn't hurt to throw a few new parts at it.

 

Replacing the water pump in the 5 gen is a breeze. Make sure you bleed the system afterward and clean the mating surfaces really good. BTW, have you noticed the WP leaking at all? Double check your fans just to be on the safe side since those cars are notorious for the fans going out.

 

do your thermostat install since you have it. bleed the car completely.

Drive. If it happens again and gets warm, pull over and try to bleed the car. If air keeps coming back and screwing you up it's likely going to be the headgasket.

happened in my 95 lumina 3.1L