I have a 99 Dodge Ram with a 318. Several months ago the engine developed a strange Noise that I was told was Pre Detonation. The Check Engine light came on and it was discovered the piston in the Number 4 cyclinder had a hole burned in it. The truck only has roughly 55k miles on it so I decided to replace the motor. I bought a reman motor from a reputable company in Nashville Tn. After pulling the old motor the mechanic found oil in the intake and failed intake gasket. the new motor was installed, I also replaced the catalytic convertor. after driving the the truck for roughly 500 miles the same problem came back, Guess what,,,same problem,,,another burned piston. Engine was removed , this time the intake gasket had not failed and there was no oil present. Engine was shipped back to the company and after 2 weeks they said it was caused by Pre detonation,Second engine was shipped and installed. This time we had the intake check by a machine shop to ensure the bottom was not warped, it wasnt. All the injectors were checked before being re installed , after the motor was installed and running check engine light came on saying Faulty o2 sensor. it was changed. We took the truck to a Dodge Delearship and they did several updates to the computer and reset some settings per SB that were for the motor. I just picked up today and am somewhat scared to drive it in fear of ruining another motor. My question is do any of the issues I ahve described sound like a problem that would cause a burned piston?, The Repair shop that has done the work is very reputable and stood behind the motor, so I am not out any money other than the original cost of replacing the motor. Any Input would be Appreciated

 

You were either experiencing knocking (detonation) or pre-ignition ... different process ... identical results. Read up on them here: http://en.wikipedia.org/wiki/Engine_knocking or here: http://www.streetrodstuff.com/Articl...ne/Detonation/

You can eliminate a possible source of pre-ignition by making sure your wires are routed as per this TSB: http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

The original damage could have been caused by detonation arising from the plenum (intake) gasket failure as it causes the fuel/air mixture to be adulterated by engine oil.

Either one can cause severe damage like what you have experienced. You should be able to hear it when it happens.

 

failure of the plenum belly pan gasket is a very common problem with these engines. this might be what you're calling the intake gasket. it creates a lean condition, which is much hotter than normal, and can cause severe damage to the engine like you experienced. this condition is often associated with a pinging sound. this is why you should not continue driving the vehicle when its pinging. the best long term fix for this problem is the replacement of the steel belly pan with an aluminum pan, something dodge should have done years ago.

anyway, the computer updates the dealer has performed are known as the death flash, as it removes some of the timing advance, which will reduce pinging tendencies, as well as turn your truck into a pig. the flash is irreversible unless you buy an unflashed used pcm or a performance program.

the original failure is not surpising, although the extent of the damage is unusual. the second failure is surprising. i'd say you've got a good shop the way they've stood behind the engine without trying to screw you over. They're also doing all the right things. The injector tests, intake check, software updates, cat replacement are all valid. All of those things can create lean condition or excess heat.

I think you should go out and drive it. if you get any check engine lights, pinging, or anything abnormal, then just take it back to your shop asap.

 

OK,,,I drove the truck about 15 miles this morning out on the Highway. When I forst cranked it , I could hear water running thru the heater core from the inside of the truck. When on the road I can feel what appears to me to be a shudder in the motor,,almost like something is out of balance,,,it feels underpowered to me and sluggish,,,which shouldnt be the case with a new motor. When I got it home ,I removed the radiator cap and started it ,,,,I saw no bubbles and did notice the top radiator was rather limp,,in other words I could squeeze it easily,,,at no time did the temp gauge get anywhere close to showing the motor as being hot. If anyone has any ideas I sure would like to hear them,,,,I am tored of fooling with this thing,,,

 

air in the heater core after a coolant drain is a little bit normal. if overflow tank is full it should work itself out in a few days. nothing to worry about provide engine temp stays normal.

shudder doesn't sound good. i get some shudder when in overdrive and going to slow (40-50), but it usually clears at 50-55. it also goes away with OD off, which is how i usually drive.

you might want to get your mechanic to take a ride with you. maybe with a scan tool hooked up. you might have some skip or misfire going on.