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Overheating and shaking issue with 99 Grand Prix GT

Pontiacidaho

New member
So yesterday I drove out to Nampa and my GP was fine until I got to Nampa. Once I got there, the temp gauge started going up a decent amount past 210. Well, the last two weeks or so, the low coolant light randomly comes on and then goes off. I've been full on coolant. Idk why it keeps popping on. The low oil level light came on the other night and I was a bit low on oil so I put some in. Well, it started trying to overheat a bit again this morning when I drove it. I was thinking it was the thermostat so I went and bought a new thermostat and put it in. After I put it in, whenever I start the car now, the engine shakes and chugs and no coolant goes the main radiator hose (normally when the car is running, the hose can't be squished because it's thick from all the fluid running thru but you can squish it now when the car is running). Somehow, the coolant isnt getting to the radiator now. And the overflow tank is pretty flow. All of the coolant t in the overflow tank isn't getting sucked into the radiator either. So I have no idea what's going on. This is really the only major issue I've had with the car. Also, when I started the car after replacing the thermostat and putting everything back together, it smelled really bad of rotten eggs. Any suggestions on what could be the problem?
 


Rotten egg smell and chugging could be a cat converter being plugged up. A temp gun on the cat could show that, or at night it could start glowing red. Double check that no coolant is dumping into the oil and that you didn't bump a major vacuum line off the throttle body.


If you didn't bleed the coolant system of air after the thermostat replacement, you need to do that still. There is going to a giant pocket of air that won't allow coolant to flow properly.
 
Where is the bleeder for the thermostat? Is that the little screw looking thing on the top of the metal piece that holds down there thermostat? Do I need to turn it a certain way? Ive been wondering if my cat or something has been plugged up. Haven't had as much power lately as I normally do.
 
Yes, that is where the bleeder is. Top off the coolant in the radiator and start the car, let it warm up and open the little bleeder screw a few turns to let air out, close it and do over again many times. It should start spitting air with some coolant out, once it's pretty much all coolant then it should be good. Cool it off and top off the radiator again.
 
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