'97 STS with 169K mi, always serviced at local Caddy dealership and at times myself.

Last week, my car was overheating, with code PCM 1645 being set over and over. Took it to dealership on Monday. After few hours, was told that head gasket are bad and sensor senses coolant in the engine !!!!!

$3500 to replace them.....sheesh.....

Then later, coming back, just 2mi from home, there was a bang in the engine, and fumes/smoke came through all vents, i shut down the A/C and engine. The fumes smelt of coolant and it took many minutes for it to go away. The low coolant warning came on.

After that, I was heart broken for 2 days about my baby that I have so well maintained, or not it seems. Not sure if dealer did something right at the end.

So, now I've been looking for a new car and also for an STS engine. I need a 2nd car anyway. I found an engine with 120K mi on it total P&L - $2200. Not bad but not sure about the mileage on this engine either. Can anybody help with the following:

Can anybody tell me what happened there with the bang and the fumes?
How come the fumes came through the A/C vent?
Where can I find an STS engine online?I have searched the forum many times, but didn't find anything......Thank you for everybody's help in advance.

I believe there's a company called custom innovations that sells timeserted northstars. If you are replacing the engine I would strongly suggest you buy one that has been timeserted to ensure you don't have the same problem. If you put a used one in, especially with 120K you risk having the same problem and having to pull the engine again. AE engines i think sells remanufactured northstars, not sure about the timeserts though. Try looking at ebay but again, don't put an engine in there that hasn't been timeserted, its just asking for issues down the road.

Not sure about that bang, could have been a number of things, more than likely though it was a piston hitting a valve. I don't know why smoke would come out the vents.

Better read the "Radiator" thread below before you buy an engine from Custom Innovations.

Wow, thats an enlightening thread, nevermind my recommendation for custom innovations, try the company ae-engines.

Keep in mind that any used engine has the potential to have the same problem down the line unless you pull the heads and Timesert it before installing it. If you do, it should outlast the car.