Audi A6 clogged with sludge. Any suggestions?

[nikenick21]

I have a '99 Audi A6 2.8 that is evidently clogged with sludge. No oil is getting to the head. Long story short: Oil pressure warning light and buzzer came on. I shut it down and had it towed to my local European shop. They pulled the pan and found severe engine sludge. They removed the pump (still works fine) and cleaned it and the pick-up screen and as much gunk from the pan as possible. Refilled with oil and started; no circulation to the head as this was becoming quite audible. Inspected cam bearings: fine. Oil passages are clogged. They don't know what to do other than replace the motor.

Can this motor be saved? My local Audi dealer has a de-sludging
machine but didn't think it would help in this case. I bought
Auto-rx but obviously can't use it until I can get some oil flowing.

Anyone have any ideas?

 

[MGregoir]

Lots and lots and lots of kerosene and manual cleaning, maybe a trip to the hot tank for the heads.

 

[MrCritical]

Oil change history?

 

[wavinwayne]

For a case as severe as you describe, there is no easy (or cheap) fix. If you REALLY want to save the engine, you'll probably have to disassemble everything, have it cleaned manually, and then put it all back together and pray.

Other than that, you're options are not good, IMHO.

 

[Steve S]

Is there a drain back valve in an oil passage? Usually sludge is deposited in non pressurized areas .I am not familiar with the engine. Is there a service manual that shows the oil circuits?

 

[nikenick21]

I bought the car with 85k on it. Now it has 105k. I changed the oil with Mobile 1 synthetic every 5k. (I now know that this is not often enough.) Damage was already done by previous owner we think. I'm kind of willing to try about anything before having a used motor put in. Why not?

 

[MGregoir]

You would be better off buying a rebuilt motor and sending this back as a core for someone else to deal with.

 

[Gary Allan]

Hmmm... if I was faced with this ..hmmm..I'd probably try and configure a pump that I would tap into the oil pressure sender. Since you cant get a heat component, I don't know how good Auto-Rx would do ..so I'd say that some kero/diesel fuel thing might work. Just run it roundy round until you see flow from the top end. It may take many hours and several "sump" changes. Just leave the drain plug out and run the pump from the drain pan.

I don't know how long the pump would last in continuous duty, but the Sprector oil change kit would give you all the components to do this. I don't even know if the pump will produce the pressure that you require. It will provide you with all the essential hardware needed to do this.

I suppose you could rig it through the oil filter mounting threaded stud too

 

[Audi Junkie]

If your shop had the Bilstein machine, do that and then use the ARX as a follow-up. The Bilstein machine uses heated solvent. Just do a lot of changes of dino 10w-40, Pennzoil, and drive it until it dies.

 

[nikenick21]

No one in my area has the Bilstein machine. The Audi dealer and another shop have ones made by BG. I explained my situation and neither one thought it would help. Glad they didn't try to take my money though. Has anyone heard of filling the engine with diesel, letting it sit for a week, drain, repeat. Then add oil and filter as normal, start the car and hope? Anybody?

 

[alanu]

Honestly dont waste your time. If you dislodge all of the black grainy deposits you WILL THROW A ROD or clog the oil pickup screen and sieze the motor.

Trying to bandaid a plugged up engine will just cause you more grief. IMO all of these "try this" suggestions is a kind gesture but if the engine is plugged.....it is plugged. Any solvents will eventually screw up oil seals and in time YOU WILL plug up the pickup screen.

At least this moment in time you haven't thrown a rod so the crank and rod assembly is useable. I dont know how much money you have in your wallet but this problem will be an expensive one to fix. The ideal fix is to pull the motor and get it compeletely rebuilt. Those cars are such turds to work on. The "fix" will be costly both in the R&R and rebuild.

 

[addyguy]

With all due respect, alanu, there have been a ot of 'anecdotal' tales from people who have done major solvent flushes on sludged engines, and got them running again w/o any 'real' problems, as many would think.

I don't think the OP has anything to loose by filling the engine to the brim with kero/diesel, leaving it for a couple of days, and draining it out. Maybe do it a couple of times, and then do a 75% oil/ 25% kero flush w/ the engine running to see if the passages will clear.

The following is a really, really good thread on someone who had bad sludge on a Toyota Avalon and what he did to clean up the engine. Its really worth going through, as it seems to have worked wonders for his car:

https://bobistheoilguy.com/forums/threads/1996-toyota-avalon-1mz-fe-v6-engine-sludge-dilemna.73606/

Good luck!

 

[steve20]

I vote for the addguy's suggestion-just fill it with diesel/kero till it comes out the oil add hole-do not drive it like this let it sit etc

 

[Quest]

ummm...actually, I'm with Alanu on this subject matter: if the oil passages have enough clogs to restrict oil from getting to the vital heads and components, it's no use trying to do a kero/solvent/stoddard solvent flush for your risk of spun rod/bearing due to large pieces of dislodeged undissolvable pieces may clog the oil pump screen, or even get trapped in various critical passageways is extremely high.

Voting/votching is one thing, but from the owner's perspective: does he want to risk further damage to the engine (assuming that not much damaged done so far) only to take on you folk's prescribed solvent/kero flush? Or should he simply cut the chase and get a shop to tear the engine apart, dunk/clean it and then rebuilt it (stongly recommended)?

I would recommend the second option if I were him (for I have a social conscious to tell you my honest opinion based on experience).

Q.

p.s. I'll buy you a cup of nice joe when I'm in your neighbourhood someday, alanu.

 

[Audi Junkie]

I'd use the machine. If you do a non-running solvent flush, go ahead and crank the engine w/o spark to circulate it. Be ready to pull and clean the pan + pick-up again. Forget Auto-Rx until the engine is running and semi-clean.

 

[Gary Allan]

I still like my way better

Now (and I have to do this) "if you had used Auto-Rx, we probably wouldn't be having this discussion" (visions of some "pay me now- pay me later" Fram commercial

)

 

[addyguy]

I'm not going to deny there is a good possibility that with this much sludge, a solvent flush and running may damage the engine. But on the off chance that it does work (and as I said in my first post, we HAVE seen it work), the OP doesn't have anything to lose by trying it, and may save himself some money for a couple of years by doing this.

I mean, if he has the engine taken apart and rebuilt, he's spent the money and has a good running engine. If he trys to flush it, and it works, its cost him a lot less money. If it does the flush, and wrecks the engine, then he has to send the money to have it rebuilt anyway. At least if he trys the flush, he adds the possibility to the equation that the engine will run fine WITHOUT being rebuilt.

Just my thoughts, though!

 

[Volvohead]

For less than the cost of de-sludging and rebuilding that engine in the field (which is really the same thing here), he can likely get a factory rebuilt long block. Because most rebuilders don't overly care about the condition of the exchange cores, I would experiment with chemically de-sludging this one. The worst that happens is it blows and he swaps it out for a rebuilt one.

A non-running soak (or two) in kero, diesel or other heavy solvent is a good first step. After that, I'd drain, drop and clean the pan, re-clear the pickup screen and then run three or four Auto-Rx treatments with HDEOs to try and get the cleaning process started. Probably be dropping the pan a lot on this one, as you do want to keep the pickup open. But it might be salvageable.

This would be a starring case study for the ARX testimonials if it worked out.

 

[Donald]

The risk is the core charge. If it were me I would try something.

I'd also get a rebuilt before I had this rebuilt.

As other have said, sludge in a pressurized line is not normal.

I assume the oil pressure gauge was checked with a mechanical gauge?

If I wanted to to a solvent flush, I would also pull the valve cover and pour kero into that area so it drains down the oil return passages. DO it several times and just let it flow out.
Filling the pan with kero until it leaks out somewhere is also good.

I wonder if the return passages are so clogged that when the engine starts, the valve cover area becomes filled with oil, little returning, and shortly the oil pump sucks air.

Surprised that with Mobil 1 and 5K changes that this happened. It should have done cleaning, not let things get worse.

 

[OVERKILL]

Originally Posted By: Donald
The risk is the core charge. If it were me I would try something.

I'd also get a rebuilt before I had this rebuilt.

As other have said, sludge in a pressurized line is not normal.

I assume the oil pressure gauge was checked with a mechanical gauge?

If I wanted to to a solvent flush, I would also pull the valve cover and pour kero into that area so it drains down the oil return passages. DO it several times and just let it flow out.
Filling the pan with kero until it leaks out somewhere is also good.

I wonder if the return passages are so clogged that when the engine starts, the valve cover area becomes filled with oil, little returning, and shortly the oil pump sucks air.

Surprised that with Mobil 1 and 5K changes that this happened. It should have done cleaning, not let things get worse.



The M1 may have done some cleaning and dislodged something to cause this issue........