I can't seem to find a thread with exactly the symptoms I am having with my Volvo 940 Turbo engine, so I've posted a video here. There's a loud knocking sound, almost sounds like a diesel, until the engine warms up at which point the noise diminishes somewhat.

From what I can gather, it's either piston slap or a valve lifter problem. Here is a video of a cold engine start, with sound:

http://picasaweb.google.com/timallix...50460456794338

Thanks

 

I had a loud noise once and I had a devil of a time figuring it out. Then, I noticed coolant leaking from the water pump. Replaced water pump and noise disappeared.

 

Was yours a 940? Was the noise the same as mine, as per video? That would be great if it was just the water pump. I went to two mechanics today, one said the engine was F***ed and need replacing, the other spent a lot of time probing with his stethoscope, and then replaced the oil with 20w50. It didn't help, but at least this mechanic felt that it wasn't a bottom end problem.

 

Whatever it is, you had best start budgeting for a new engine or a rebuild. It's pretty far gone if it's piston slap.

Regards, Andrew.

 

Mine is a 1987 740 turbo, B230 FT, same engine as yours (with slight differences). I couldn't isolate the noise on my engine with a stethoscope either. Plus, I had a rather loud click, click, click when the engine ran.

Here's what I would do:

1) Engine off, look all around the water pump to see if there are dried vestiges of coolant, which look whitish.
2) Put car up on ramps, block wheels, pull off undercover if there is one. Run engine and look for any coolant leaks from the waterpump from underneath. Do not put hands or anything else near any moving parts! Also handy to have a mechanic's telescoping mirror to check around tight spots, especially where the pipe goes into back of the waterpump.

If there is evidence of any leak, I would first replace the waterpump rather than assuming you have a major, expensive problem. I've learned from many years that you isolate and cross off the easy causes and fixes first before jumping to conclusions that it is some other major problem.

Good luck!