Thread: Are my pistons screwed?

The car I purchased was a one owner car. Was owned locally by the town dentists wife.....old couple. It had 100K miles on it and was traded in for a caddy STS. the car was BONE stock and maintained at the local dealership(they have a good reputation there) I doubt they caused the damage, as the car ran great for 4-5 months after we bought it. Oil was never ran low,coolant was topped off. It started running like crap well before it got cold out.

I will say this the coolant was breaking down,I'm assuming it was the original dexcool crap. There was alot of mud in the engine block passageways, upon tear down. I know that didn't help with heat dissapation but the car never ran hot. It was getting 30+mpg on the highway when she went on trips and high 20's the rest of the time. That too me was a good indication of how easy she was driving it and how good of shape the motor was in initially.

she said it just started running rough one day and the fuel mileage dropped off like a rock. I swapped cars with her and started going through it. Thats when i found smashed plugs,i wasn't immediately aware of the situation so I put in new ones and drived it for a few more weeks. It was ok but the mileage still sucked, I figured the motor was failing. Well long story short we got in a huge argument she took the car back and drove it as is. It died on the freeway and was towed to her place and eventually back to my garage.

So either it did get a tank of 87 and detonate itself to death and the resulting heat made the pistons chip out. Or it just failed from multitude of things,crappy coolant,possible 87 octane fill and high mileage. regardless I just want to get the motor back together and not have to worry about this happening again. because if others have had it happen when running 93 on a stock motor, who says it won't happen again?

Originally Posted by Bio248

if you drive your car normally this usually doesnt happen. i think its a case of bad luck, honestly. i beat my car like it owed me money and have torn it down on more than one occaision to find out all the pistons were there in good condition.

I normally drive my cars hard,but am rather anal with maintenance and PM's. I even beat the snot out of my geo and still get awesome MPG's. My ex had a lead foot at times but she toned it down awhile ago. She had terrible luck with her old G6,the TL was awesome then this GTPI guess I got a monday/friday built car.

Originally Posted by Liquifire

If it was bad due to poor assembly(your claim of a monday/friday car) I doubt it would have held on for over 100k

100K miles isn't **** in this day and age.

Originally Posted by Liquifire

yes...exactly...that is why if something will fail due to being assembled poorly it should fail way before that. If it is due to a freak metal compound bad then it could at any time depending on how far it is off from proper specs. It could be due to anything...you will never know bottom line. Sorry it happened to you, it could happen to anyone, but you are in the vast minority. The 3800 is known to be one of if not the longest lasting engines in general if taken care of properly. It just happens to be that you are in the minority, but no engine is perfect for everyone forever.

Poor assembly doesn't constitute immediate failure. Regardless I'll never know the root cause of the failure. I'd like to put this motor back together and not have to work it could happen again. Maybe the 3800 N/A motors, but it sure seems these GTP's have problems.

Originally Posted by up in boost

Wouldnt the ECU detect knock and then retard timming from keeping the engine from detonating when running 87 OCT???
Cause i know with my SRT-4 the ECu will lower boost and take some timming away when anyone runs 87 OCT. I only run 91+oct........

Yes they do,I wasn't sure if they did,but like said it has to be pinging to pull timing. And from the sounds of it, once you're pinging...you're too late.

Originally Posted by 01GTP

It will only pull timing after it all ready knocks. knock sensor it detects knock when it happens then pulls timing. So you engine has to be knocking for it to kick in.

YUP

Personally I'd keep that SRT4.

Originally Posted by Bio248

they take quite a bit of abuse, but any motor would go away under some of the conditions we put them under. the entire platform was never intended on being a race car.

like 95% of the cars on the road. I still wonder what the GTP would be like with a 5 or 6 speed MT.