larryk@tektronix.UUCP (Larry Kohn) (09/22/84)
I would appreciate some advise about the cause/s of what seems to be rather major failure of my car's engine. The car is a 1978 Pontiac Le Mans (4-door). The engine is the standard V-6. The car has a/c, power steering and brakes with about 53,000 miles (mostly short trips). The car has received regular maintenance (tune-ups 2x/year, oil/lube every 3-4K or 3-4 months, etc.) For some six months I've experienced intermittent stalling (real random); hesitation (now and then) upon accelerating from a stop, or when making a right turn (never a left). Computer analysis didn't find anything. Tune-up didn't stop it. About two weeks ago, the stalling became more frequent and I wasn't able to restart the car until after it cooled down completly. "Ah ha!" says I, "now they'll have something to fix." Little did I know. Well the repair shop tracked down the problem to be a worn timing gear (made out of plastic, of all things). As the mechanic is buttoning things up after replacing the timing gear and chain, he hears a strange noise when he revs up the engine a bit while under the hood. So he pops off the valve cover and finds the rear oil return to be clogged with sludge. Today I'm told the cause of the noise is the failure of #3 crankshaft bearing (bottom half) which has allowed the piston rod to slap around. The oil pump screen was found to be clogged with sludge. The recommended solution is to replace the crankshaft, bearings, #3 piston and rod, and all piston rings. I have no real reason to suspect anything hokey going on with the repair shop, but needless to say, the bill is going to be steep, and I kind of won- der. My questions are: Is all this plausible? I've put more than 100,000 miles on two previous cars under similar driving and maintenance without any major engine problems (maybe my number came up). Any idea as to cause/s? Are such failures preventable? If so, how? Anything else I should know? Please reply by mail. If there's any info of general interest, I'll post a follow-up. Thanks in advance.