All,

I have an 95 850 Turbo SW with 126K miles. I just started hearing a pretty loud knocking at idle. It does not seem to change pitch or speed or loundess as I rev the engine. It seems to be coming from the top front of the car near the fuel injector rail. Any thoughts?

Thanks.

-Mike

 

Here some addtional inofrmation.

The performance of the car is fine.
I can not hear it when driving.
It soulds like a diesel engine from inside the car at idle.

Thanks.

-Mike

 

Motor mount? Just a guess.

 

Knocking or Tapping noise?

 

It is definitely coming from the top front of the motor. More of a knocking that a tapping. Similar to a diesel engine knock and about as loud. There is a little rumble to the sound. At first I thought it was a piece of metal hitting the engine fan. Could it be that the knock sensor is bad and I got a bad tank of gas? I am running 87 octane? Thanks for your help.

 

Bad news. It was 3 1/2 quarts low on oil! Knocking is a little quiter but still a knocking. I've had a small oil leak for a while but I must have chaged the oil just in time every time before it got too low. This time I drove about 1,000 miles longer before what should have been my next oil change. Live and learn. Would a heavier oil (heaiver than 10w-30) help?

-Mike

 

Maybe but not much.
Might want to look for another motor.

 

Knocking is completly gone. Car is running fine. The Oil Idot light never came on but it does illuminate when you first start the car so I know it's not broken. The tempature of the car never really increased either. I think I narrowly escaped a bad one. Now I just need to find out where the leak is. That will be a separate post!

 

Where is this leak at?
Has the PCV system ever been replaced? If it has not, a clogged or poor flowing PCV system will cause excessive crankcase pressure lead to leaks.
http://www.fcpgroton.com/volvo850oiltrapturbo.htm