The C70 HPT with 288,000 miles has a weird growling sound that comes from the engine bay when I start it up cold in the morning. There is nothing in P. But when I put it in D - the growl is there for a few minutes (maybe 2-3 minutes). There's no sound when it is just in D, but when I rev the engine - the sound goes up with the RPM. and then it disappears altogether.

Any pointers? Help would be appreciated as always

 

Update: I took the timing belt cover off and the belt had rubbed against it. However the sound is still present. Its there only during acceleration/revving for the first few minutes and then goes. The sound is present in all gears and turning the steering has no effect on it. Help would be appreciated!!

 

I have the same problem from my '98 at about the same mileage, have you found the solution?

 

how long since you changed the serpentine (drive belt) and the timing belt? It could be one of the belt idlers/tensioners. Possible to also be the alternator or pw pump or AC clutch?

 

I sold the car 2 weeks ago with 315K miles on it. She was finally getting tired - Leaky fuel hose between fuel tank and filler port and worn out ball joints. AC system also sprung a leak somewhere. Still miss that car....

The growl was from the turbo. I changed to synthetic oil - 5w30 in winters and it reduced the growl. I used to let it warm up till 2 "ticks" on temp gauge and then drive - it never worsened. Also let it idle and cool down for 2 mins before shut down and you will be fine.

I got 25K miles with the growl and it never worsened. Just proper warm up and cool down for the turbo. Good luck.