engine sounds like a diesel when cold

exit69 · September 25, 2003

Just bought this 95 Jimmy and in the mornings when it's cold the truck's engine has a rattling/knocking sound much like the sound of a diesel truck and this noise lasts a good 15-20 mins. When I leave work in the afternoon even at startup there is no such noise.

So when the temperature outside is warm no noise???

The noise may even sound like it's coming from a leak in the exhaust pipe...but only when it's cold outside.

Not sure if it's related but I also heard an arcring noise from one of the spark plug wires under the hood.

mjsmith1223 · September 25, 2003

Hmmmm...

My '93 S-10 Blazer had a little lifter noise when it was cold in the mornings. Once the oil started to warm a little it went away. My brother-in-law has a Jimmy, '96 or 97, with balance shaft issues. Makes the motor more noisy all the time. You could try listening with a hose to see if you can pinpoint where the noise is coming from: top end, bottom end, etc.

Check the wires when its dark. You might be able to see the arc. Might be a good idea to just put a new set of wires on it anyway if it hasn't been done in awhile.

Hope this helps.

Mike

Grand Haven, MI

exit69 · September 26, 2003

Well this morning I listened to the truck from the outside and the noise does actually sound like an exhaust leak, probably from the manifold area...but does that make sense? that the noise goes away only as the temperature outside warms up???

FEAC · October 12, 2003

Well this morning I listened to the truck from the outside and the noise does actually sound like an exhaust leak, probably from the manifold area...but does that make sense? that the noise goes away only as the temperature outside warms up???

It could be a exhaust leak, and/or your truck is just cold as heck. When my 350 first starts up it sounds kind of like a diesel.