Oil starvation after deceleration (engine break) on '93 300E 2.8 - PeachParts Mercedes-Benz Forum

dacia · #1 02-03-2003, 09:43 PM

Every time I decelerate to an almost stop (using engine break) and then step on the gas again I hear a noise reminescent of an old engine with valves out of adjustment. This happens mostly when I accelerate uphill after decelerating (using prolonged engine break) from downhill to a stop or almost stop. If I back off the accelerator for a moment and then accelerate again the sound disappears. The 104 engine has hydraulic lifters so it sounds to me that the lifters are starving of oil therefore the valves are noisy. Engine has 180k miles on it, burns about 1 quart of oil per 3000 miles (that is expensive syntetic quart) otherwise starting and running flawlessly. Any suggestion is appreciated.

Alex

PaulG · #2 02-04-2003, 04:06 AM

Dacia,

Had a similar problem on a previous car, turned out to be a failing brake servo.

It was sucking fluid from the brake resovior and burning it when I accelerated, hence the terrible noise.

To rule this out, check if the vacuum line from the brake servo to the inlet manifold is dry.......

#3 02-04-2003, 06:18 AM

i am sure your problem is related to "guidavalvole" but i'm sorry i'm not able to translate the name of this part in english!
it's a little part around the valve!

dacia · #4 02-04-2003, 11:12 PM

Thanks guys.

haasman · #5 02-05-2003, 01:51 AM

Are you sure it isn't pinging, as in predetonation. What grade fuel are you using?

#6 02-05-2003, 07:24 AM

It also sounds like pinging to me. Are you using Premium fuel and is your knock sensor okay? It is on the drivers side of the block. Check the wiring to it, and ensure that the ignition module wiring is all connected and looking good.

Maybe one of the pro techs can give you some other advice regarding troubleshooting and checking of the ignition module and knock sensor.

Good luck,

dacia · #7 02-05-2003, 11:09 PM

I am always using Sunoco Gold 94 octane. And it only happens after using engine break on a downhill. I just changed the oil and the spark plugs. So I think we can rule out pinging. If it was the knock sensor then the noise would be audible every time during acceleration from a standstill, not just after using engine break, I think. Thanks anyways. I will consult with my trusted mechanic.
Alex

haasman · #8 02-06-2003, 01:34 AM

I have always liked Sunoco ... so no octane problem .... please let us know what your mechanic finds.

Haasman