Moss928

I have heard that occasional lifter noise is part of 928 ownership.

I am currently expeiencing it. It sounds like an old Singer sewing machine (not my own words). It began after sitting a few days (keep in mind that the car does sit more than it's driven.

I have driven it since (not for an extended period) and have reved it at 3K rpm for 10 to 15 second intervals with no positive/negative results (still tapping).

I understand that the most obviuous culprit for lifter (tappet as the manual says) noise is a sticky (and leaky) Oil pressure control valve.

The/a fix requires removing the valve cover and removing/cleaning the oil pressure control valve (somewhat of a delicate proceedure and out of my league). I have also heard that a good top oil like Lucas or Risolone will work (In my league).

I for one have been against adding "special" oil treatments. I stick with Mobile One. However, under the circumstances I might? Any thoughts?

I can always call my mechanic and have him do the cleaning proceeedure on the Oil pressure control valve. This requires me to book it three weeks in advance and money (how much I don't know).

None the less, I have had the car in and out of the shop almost all summer chasing down starting problems and replacing various parts (spending lots of money).

Is the shop avoidable?

Ed Ruiz

I solved the noisy lifter problem on my 86.5 928S by simply replacing the oil with Mobil 1 10W30. After about a month, the noise went away and never came back. On the next oil change, I went with Mobil 1 15W50.

On the 90GT I use a blend of Mobil 1 10W30 and 15W50 in the Fall (I just remembered, it's due soon), then replace it in the Spring with 15W50. So far the GT has not had any lifter noise problems. YMMV.

Randy V

Before your next oil change, add 1/2 to 1 quart of transmission fluid to the oil. Drive for up to 30 minutes at freeway speeds then dump and change the oil and filter.

The trans fluid contains detergents that break down the deposits that are preventing the spring ball within the oil pressure control valve from sealing, resulting in the collapsed hydraulic lifters that 'tick' until they are pumped up with oil.

It worked great on my '79!

Moss928

Thanks for the advice. I have read (and heard most recently) about adding Transmission fluid to the oil.

I have just recently changed my oil (Mobile One). What's the life on the ATF/New oil mixture? I have heard 500 miles. However, that may be a matter of opinion.

I certainly would not want to cause any harm by driving past the lifter solution. Yet, I would like to give the insides a proper cleaning.

Randy V

Due to the high detergent characteristics of ATF, it tends to degrade the lubricity of motor oil very quickly.

I don't know about maximum actual miles you can safely drive before your engine is damaged, so I'd stick with giving the car an aggressive 30 minute drive with the ATF immediately before doing an oil change.