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joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

I have a 1983 944 that runs fine but has a major varnish problem in the engine. The most annoying symptom is intermittant lifter tap. I have had the lifters out several times to clean them or replace them with others and the problem always comes back. Have changed the oil 6 times in the last 1500 miles, and flushed the crankcase with kerosene, and run additives like marvel and seafoam in the crank case between changes. Someone told me that I should put diesel in the crank case, and crank the motor a few revolutions to circulate it and then just let it sit for a few weeks before draining it out. I dont know much about diesel. I am hesitant to have a substance in the motor sitting in contact with seals and gaskets for weeks on end. Is diesel safe to leave on seals and gaskets?

sney · Joined: 24 Sep 2010 Posts: 18 Location: Calgary, Canada

I've always heard diesel in the crank case as a fake "helpful suggestion" you give someone you don't like in the hopes that they will cause expensive damage to their engine.
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Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Yikes, with the flaky oil cooler seals on the 2.5, I don't think I would risk it.
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joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

sigh. I guess that is why I asked.

924guy · Posted: Wed Oct 06, 2010 8:20 am Post subject:

use fuel stabilizer, it will clean the fuel system and dissolve the varnish better than anything else out there. about 1/2 ounce per gallon (half strength.) it will smoke a bit at first, that's the crap being ejected...

edit: dont put this stuff in the crankcase... i saw varnish and assume fuel system...
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bnoon · Posted: Thu Oct 07, 2010 5:06 am Post subject:

You've already tried kerosene which is basically equal to number 2 diesel anyway, just refined an extra step for less stink, so no advantage to trying it again. It's not a fake suggestion though as diesel/kerosene will disolve gunk in the crankcase and will also break up carbon on stuck piston rings if left to sit over a few days. You don't want to run it through the engine really, just circulate by cranking, then let it sit.

Does your issue only happen when cold or hot? Have you tried different oil viscosities in your oil changes? Does everything regarding lash in the valvetrain checkout?
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bnoon · Posted: Thu Oct 07, 2010 5:13 am Post subject:

Also, an actual "sticky lifter" can really qualify as about 3 things.

First: A plugged oil port, either in the lifter itself or in the oil passage feeding that lifter.

Second: As varnish in the lifter bore limiting travel.

Third: As broken or jambed pump up mechanism in the lifter itself.

Other things that can sound like sticky lifter: Debris around the valve seat, either carbon or metalic; other stuck items in the valvetrain such as rockers; bound valve springs; loose/worn valve spring locks...
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joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

The lifters are hydraulic obviously. The reason they tap is from bits of varnish breaking loose in the oil, and circulating up to the cam tower and plugging the oil ports in the lifters themselves causing them to loose prime. I have had the whole damn thing apart several times and replaced deflated lifters with other used ones that I have from my parts stock. and the car will run quiet for a short period then begin to get noisy again as the lifters begin to plug up with flakes of oil varnish. The Inside of this engine looks like it was spraypainted brown to give you an ides of the varnish problem. As I said, I have changed the oil many times and it always comes out with more little varnish specks in it. It is a frustirating problem as the engine itself is is extremely good shape wear wise, and otherwise runs outstandingly well. Dont want to waste 100 gallons of oil getting this crap out of the engine.

Rich H · Posted: Thu Oct 07, 2010 6:06 am Post subject:

Use an oil designed for a diesel engine.

Diesels are filthy smelly and dirty engines so the diesel oils are designed to have more detergents in than petrol oils, not good long term but a couple of hundred miles with it in won't hurt.
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bnoon · Posted: Thu Oct 07, 2010 6:31 am Post subject:

Ahhhhh I understand now. What you need is a FLUSH! Have you tried any of the engine flush products on the market to remove the sludge buildup? I've used this one http://www.amsoil.com/storefront/flsh.aspx and it not only removed the sludge, but even the brown dirty oil stain from the aluminum too! This was in my '86 Trans Am and it worked great!!!
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Lizard · Posted: Thu Oct 07, 2010 1:57 pm Post subject:

The 2.5l engine is a very clean internal engine.

The problem is not a build up of varnish and junk getting into the oil ports.

I know this because in order for that junk to get to the lifters it has to first go through the oil filter which would catch it.

The problem is stated in one of your posts.
You have done this job multiple times, yes?
Every time you have done it you have installed USED lifters, correct?

This last time, instead of spending a ton of money on oil, cleaners etc. spend it on a NEW set of lifters.
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joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

It worked. I filled the crank case with diesel and cranked the motor for 15 seconds, let it sit for 12 hours, cranked it again for 15 seconds, and let it sit another 8 hours and then drained it. The diesel came out brown. Running with 10w40 mobil 1 it is the quietest it has ever been. For a bit it had a very light tick, hard to even hear, but after 20 min of driving it faded away to nothing. I am shocked and pleased. Thanks Larry!!

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

After just 20 hrs the diesel came like this.

germ924 · Posted: Thu Oct 14, 2010 1:18 pm Post subject:

Joe do you think that maybe the old oil that was left in the system and filter could have turned the diesel this oil color?

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

no. The oil had been changed several times in the last few hundred miles. The last oil drained from the crankcase before the diesel was put in was very clean looking. Just had little brown specks in it.