Thread: rough engine then wont start

Hey guys, Just had a problem With my grand prix and had to get it towed! so i just got home from getting it towed to gm and thought is share.

To start off I have a 99 grand prix gt coupe.

My car was running fine this morning. so this afternoon I was leaving my friends house and when i started my it was running rough! i dont know why, no check engine light so no missfires. My friend told me it made a loud clicking noise when i started it but i didnt hear it from inside the car. So i went to turn the car around to see that maybe if i gave it a shot it would go away and it did, but then it was hesitating to up shift.

so my plan was to bring it home not use it on sunday and bring it to work on monday and check it out then. (im an apprentice mechanic by the way)

So i got onto the highway and it wouldnt switch to 4th gear. still no check engine light or anything. When i got off the highway 2 mins later my check engine started flashing and the engine was running rough again and also was hesitating to switch gears. I pulled over as soon as i could poped the hood with the car still running and the engine was going crazy so i turned it off.

I checked all the spark plug wires at both ends, they were not loose or anything, checked my oil level it was fine! i didnt notice a had almost no coolant left in the reservoir! Also noticed that arounf the thermostat the red liguid gasket stuff was all melted around where the thermostat is.

I went to start the engine and it only cranked no start! while i was cranking it thick white smoke came out of the exaust! That would be burning coolant right?

I tried to start it a couple more time but would crank for a second and stop. the last time it tried it i hear like a crashing noise and then i think it seized.

Thanks for reading guys. leave some comments please!

LIM gaskets. It probably hydrolocked and maybe even popped a piston.
Goodwrench is going to rape you.
How many miles on the car?

Originally Posted by Rico

LIM gaskets. It probably hydrolocked and maybe even popped a piston.
Goodwrench is going to rape you.
How many miles on the car?

whats the LIM gasket? lower intake manifold? and for miles well im from montreal canada so its in kilometers and it 133 000 km's so roughly 80k miles. all was well untill this! all happened in 1 day!

but my guess is il be needing a new engine witch really sucks how much do those go for any idea? and any idea how long it is to swap one?

LIM lower intake manifold (aluminum)
UIM upper intake manifold (plastic for the L36)

You should have towed it directly to the shop. The troubleshooting is simple.

Troubleshooting:
Drain engine oil; any coolant in oil? I'll bet there is!
Drain coolant.
Remove spark plugs.
Crank engine; any coolant spurting out? Any 'metallic' noises?
Check all cylinders for compression; 110 psi?

Determination:
1) Coolant in oil, bad compression and 'metallic' noises while cranking.
Motor needs to be rebuilt or replaced.

2) Coolant in oil but all cylinders have good compression.
Replace LIM gaskets, UIM with EGR/gasket upgrade. If this were my vehicle I'd change the head gaskets as well. Coolant in a cylinder puts a tremendous amount of stress on the piston, rod, crank, valves and head gaskets. With the heads removed you should inspect the piston, bore, head, valves, lifters and push-rods.

The "How To" section has great tutorials concerning LIM and UIM repairs.