Car: 1999 Pontiac TA/M6/125k on the clock w/ stock engine

so my car decided that all of a sudden it was gonna start hemorrhaging coolant (i run dexcool) from somewhere?! the only thing strange it did before i noticed this problem was that in stop and go traffic, it jumped up to 230 and then cooled back down to the normal 190-210 range. It only did that once? i know that this isn't normal. now this is my DD so i'm trying to be as careful as i can but, since then it drives normally with exception to the low coolant light on. i've checked the hoses around the water pump and radiator and there doesn't appear to be any leaks.

now, the car only "pukes" out coolant after you kill the engine. NO problem with it while running or driving, outside of the distinct scent of coolant.

my question: could this be coming from the weep hole on the water pump? if so, is it time for a new one? if not, what else should i look for and expect to pay?

 

Are the rad fans working? You can check it while its cold by turning the ac on.

 

Yeah they're coming on just fine

 

Thermostat problem? if thats sticking or not opening all the way can cause high temps/ overheating

 

i see what your saying, but would a bad t-stat cause coolant to leak out all over the front of my engine?

 

The gaskets between the block and pump fail often. More so w/ iron blocks, but still common.

 

Could be the water pump going out. I've seen weep holes do weird stuff before. See if you can get your hands on a pressure tester or get someone to operate the car in the condidtions that it leaks while you watch under the hood.
The t-stat could cause coolant to spew if it allows the engine to overheat.

 

so you're saying that the gasket around the water pump could be the culpriti didn't even think about those little guys. thanks! i'm trying to narrow this down as much as i can, what if it isn't the gaskets? what's the next likely suspect?

 

Also feel your rad hoses, rad, and cap. They should all be hot, especially the outlet hose after the t-stat. If your outlet hose is not that hot, it's more than likely the stat. On a sidenote IMO, dexcool sucks and causes a lot of problems with gaskets as I have seen many times. If it was mine, I'd find out what the problem is and flush the system completely and put multi-vehicle coolant in it, or even the green stuff. I see too many gm coolant systems get that dexcool sludge/sand crap throughout.

 

not much at the front of the motor to leak coolant. Pump, gaskets, maybe crossover. I mentioned the gaskets becaause they are easy to overlook. The weep hole in the pump is pretty easy to see. Look for stains down the front of the block under the water pump. If you dont see any stains, that might not be it.

 

thanks for all the quick replys! i'll check all of your suggestions and get back to y'all asap!

 

Yea pressure tester would be your best bet trying to pin point the leak, but if theres coolant on the front of the motor chances are it could be the pump..