1991 240 Engine Knock

tylka · Post by **tylka** » 09 Sep 2007, 22:51

I recently just bought a 91 240 with 176k miles on the odometer. I bought the car to repair and just drive, but I am needing help diognosing the problem. There is a knocking noise coming from the motor that isn't constant, but only stops for a second or two. The oil looks clean in the motor and the timing belt was changed around 136k miles and is still intact. There is oil coming from behind the timing belt cover, but not sure where. I took the valve cover off and can't see anything obvious but suspect I'll have to keep digging? How should I go about finding the problem? It looks like the car has been kept up for service, but the fellow I bought it from didn't know what was wrong with it. Thanks for the help.

outofworkjoe · Post by **outofworkjoe** » 10 Sep 2007, 16:58

Piston slap is common, at start up what type engine oil are you useing?I like Max life 10 w40.

tylka · Post by **tylka** » 10 Sep 2007, 22:16

Drove the car down the road for a friend to listen and the knock got a bit worse. We both came to the conclusion it is a rod, so right now I think I located another motor to put in the car.

volvoaddict007 · Post by **volvoaddict007** » 11 Sep 2007, 21:06

hi tylka,

A spun rod bearing should be pretty obvious. The 240 pistons don't have skirts so they slap around in there and can start sounding like tractors even after warmup but they can keep goin. Even though the sound is there after warm up is it more pronounced when cold ?

If you take a piece of garden hose/ fuel line and put put it up to the oil pan ( and your ear of course) it should get pretty loud near the bad bearing but unless that sounds like a ballpeen hammer even from outside the car, my gut feeling is you just have a slap happy 240.

I would ask the previous owner how long the noise has been there. If it's been a long time then it's not a rod bearing. If it came on suddenly and recently then you may be correct.

A spun rod bearing should be leaving metal particles in the oil as well.

176k is nothing for those bearings...

va007

tylka · Post by **tylka** » 18 Sep 2007, 22:51

I ended up getting another 240 that has been wrecked but has a good motor. After I get the car going again with the donor motor, I'll tear apart the old one and see what the deal is. Thanks for the input.