Quote:
Originally posted by Jim Williams:
Hi, folks. Back again. After the rebuild of the 5 banger the engine seized at 400 miles off the repair/rebuild. Sounded like either a lifter or valve failed so you could hear it pounding into the cylinder until it seized. Apparently a rebuild will not fix this defect. I'm now in process under California's lemon law for a rebuy back of the vehicle. I do intend to replace it with another, but will "entice" the dealer to add the extended warranty without additional cost so I have some peace of mind. Any other of you rebuild customers having additional engine problems? This seems to be much more serious than originally thought so I thought I would warn you all about this potential problem. Anyone having the engine rebuilt is strongly suggested for the dealer to add on the extended warranty or you may be SOL down the road.
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I would bet, it is due to the rebuild, not the valve or head itself. The original problem with the intake valve will not cause the engine to seize; however, if not rebuilt correctly, problems will arise. When you say the valve hitting the piston, that sounds like a retainer off the valve stem, causing the valve to slip and hit the piston. If it sounded like many valves hitting many pistons, it could be the timing chain was incorrectly installed.
I hate to say this, but on any large repair like this, if the tech does not do everything just right, sh*t will happen.
That timing chain has to be perfectly aligned with the cam and crank gears, with the guides installed perfectly. Not a real hard thing to do, but the tech has to know what they are doing.
I will also say that the I-5 (and its sister the 4.2L I-6) are the hardest engines I have ever seen to replace a cylinder head. The axle has to be swung out of the way, or completely removed, to remove the oil pan, in order to get the front cover off, to remove the timing chain and guides. Literally, it is a pain in the arse to work on for a cylinder head repair. Average repair time is around 18 hours.
Good luck and hope you get one that gives you no problems.
From what I have seen and heard, there is no rhyme nor reason for this to be happening. No common thread can be found. No apparent line problems at the manufacturer, no weather related causes (all in high temp or low temp areas), and it is driving the engineering community crazy at this time.
Surprisingly, for the number of I-5s out there, the number is still low (200 or less nationwide that have been repaired, maybe another 50 being worked on but not claimed by the dealers, yet), but believe me, GM is looking for a root cause. (Sorry to say, but the greater number of failures helps to find the cause.)
We have an original captured test vehicle (been to Moab and back and driven all around MI and the south) in the back, with well over 35K miles and they are in the process of removing the head today to see what type of wear is on the valves. This engine runs perfectly, so it may not give us any clues.