What sludge

So my friend pulled his valve cover today to find this sludge. It's a BMW e30 with the m20 inline six. Car has 150k miles on it.

The sludge has a consistency of hot fudge.

Is this a case of "if it aint broke don't fix it" or do we attempt to remedy it?

What would GRM do?

I'd pull the motor, disassemble it, and clean each part one by one in the parts washer. Then I'd measure everything, hone/bore/skim/deck/cut, etc as necessary, and put it back together w/ good gaskets.

This is why I'm buried in overwhelming, insurmountable projects that are great when they're done, but I'm always depressed and tired.

Put the valve cover back on, run some detergent-bearing oil + Kerosene through it, and sell it ASAP.

motomoron wrote: snip Put the valve cover back on, run some detergent-bearing oil + Kerosene through it, and sell it ASAP.

Yeah, your friend can be "that guy."

Did it run ok before you pulled the valve cover? If so, do that^. Slap it back together and do a motor flush. I'd probably do a series of gentle motor-flushes in an attempt to get sludge out the oil drain w/o clogging the pickup. It would be a good idea to pull the pan and clean it out. Maybe a few times.

I don't know that I would sell it though. If its still running ok, it will likely continue to run ok once cleaned.

Car seems to run fine. We're doing a compression test on it as we speak.

201 psi high
187 psi low

most around 195

factory spec 142-156 psi

Not sure how accurate the tester is, but it seems to have read reasonable pressures in the past

The compression could be from the cylinders being carboned up,too. In which case go back to motormoron's suggestion of taking it all apart.

BTDT. Scrape as much of it out as possible, put the valve cover back on and call it a day. Change the oil in a couple of days.

Don't do anything to clean the sludge unless you don't mind pulling the oil pan in the off-chance that some sludge breaks off in gobs and plugs the pickup screen.

That said...

Oil change with pure ATF. Run it for a week or two, then do regular oil change. Top-up oil loss with ATF. After two quarts of top-up, change again. Pull the valve cover periodically to see if it's getting any better, and repeat as necessary. When satisfied, you can go back to a regular 3mo/3000mi interval (and not the 3 year/36,000mi interval that the car apparently had).

There's no problem with running ATF in an engine, it's basically a high detergent 5W20. I wouldn't use it exclusively on any kind of long-term basis, but I've long made a habit of doing the final top-up before oil changes with a quart of ATF, and my engines are always squeaky-clean inside. The 350k mile JT in my VW looks like new under the valve cover, as far as deposits go.

I've had good luck with AutoRx; others swear by Kreen. Both are slow sludge dissolvers (see BITOG for more details). Water through the intake does wonders for cleaning carbon out of the cylinders.

Top end sludge like that is often caused by a PCV system that's not working properly. Make sure all the hoses are intact (if they're original, they aren't).

I like atf, although I usually run half and half. The only thing to watch is if it starts to drop big hunks off goo into the pan, blocking the oil pump pickup. Scrape the top end, drop the pan and scrape it, atf it- if it doesn't blow up, you are good.

Ideal solution is to invent a time machine, go back to when the car was built, and bitchslap the original owner for not doing the required maintainance in a timely fashion.

Run some engine flush trough it, after afew minutes at idle. follow directions on the can Drain the old oil. Add fresh oil and filter.

2 qt. kerosene, 2 qt. light oil, run it, drop the pan.

Cure it or Kill it formula.

Dan

My Jeep 4.0 looked worse than that, but ran fine. There was some lifter tick and I had a leaky valve cover gasket, so I figured I'd replace the gasket and investigate. I didn't mess with anything, just put the old gasket back on and ran 1 quart of ATF in place of a quart of oil and topped up with ATF whenever it needed it. At the end of that oil change, I suspect I was close to 50% ATF. I pulled the valve cover again, and it looked considerably cleaner inside.

My biggest issue is that the ATF has dissolved the crap seals that were keeping things from leaking. I have to replace my rear main seal now because it's leaking pretty badly. Cleaning a motor internally WILL clean out a couple of gunk seals that you'll have to take care of, but I consider that a small price to pay for an engine that runs better than it did when I bought the Jeep.

Sludge like chocolate sauce is OK, even when it falls into the sump, it wont block the pickup. Sludge like the coating on fried chicken is another matter.

So I'd use one of the solvent methods above to flush (ATF, kerosene, snake oil, etc.), but I wouldn't drive it while flushing. Drive the car until it's good and hot, add the solvent, and then let it sit running at fast idle for an hour or two. Might have to block some of the radiator with newspaper to keep the temp up. Every 15 minutes, goose the throttle a couple of times. Pull the cover, and evaluate the sludge. Repeat for another hour or so as needed. When it's mostly cleaned up, drain the oil and solvent, change the filter, then fill with a good detergent oil, and drive.

Carter

first thing I said: "is that chocolate?!"
and I can second the water dissolves carbon like nothing else sentiment. just a mist will help you out immensely, I've seen it help out an ailing msp in person.

I'm with the flush and fill crowd.

I also didn't know that ATF was 5w20. Now I have some research to do.

personally. id fill it up with acetone till it was litterly at the top. let sit for 2 days drain it. pour oil through to wash it out. drop pan clean out pan. put pan back on. scheaffers oil with 1 qt atf for next oil change and recheck it. should be squeaky clean.

Taiden wrote: The sludge has a consistency of hot fudge.

I was just gonna say, it looks like this engine's had the Chocolate Wonderfall treatment

KATYB wrote: personally. id fill it up with acetone till it was litterly at the top. let sit for 2 days drain it. pour oil through to wash it out. drop pan clean out pan. put pan back on. scheaffers oil with 1 qt atf for next oil change and recheck it. should be squeaky clean.

Just had an idea....

1. Fill engine with solvent.
2. Bolt an ultrasonic probe to the block.
3. Profit?

DILYSI Dave wrote:

KATYB wrote: personally. id fill it up with acetone till it was litterly at the top. let sit for 2 days drain it. pour oil through to wash it out. drop pan clean out pan. put pan back on. scheaffers oil with 1 qt atf for next oil change and recheck it. should be squeaky clean.

Just had an idea.... 1. Fill engine with solvent. 2. Bolt an ultrasonic probe to the block. 3. Profit?

I like this idea.

That sludge is still soft i'd not worrie to much about it once it get down to the pan, Crusty stuff will grind a motor to death quick but this soft stuff should just disolve and filter out. I'd not drive more then 5 light loaded miles on ATF. Drain and refill with Castrol GTX and a quart of Risalone then change every 2000 miles for a few changes.

Acetone is great for loosening this crap but also not great for rubber seals...so unless you want to replace all the seals i'd skip it.

Is Seafoam any good at cleaning sludge out of a motor?

Also, when using water to dissolve carbon, how do you get the water in there? A bit in a vacuum hose? Alternatively, does Seafoam do as good a job as water at dissolving carbon?

(The seafoam questions are because I have reason to believe my Volvo 850 could have had some sludge and already ran seafoam through it, both through the intake and in the oil.)

dculberson wrote: Is Seafoam any good at cleaning sludge out of a motor? Also, when using water to dissolve carbon, how do you get the water in there? A bit in a vacuum hose? Alternatively, does Seafoam do as good a job as water at dissolving carbon? (The seafoam questions are because I have reason to believe my Volvo 850 could have had some sludge and already ran seafoam through it, both through the intake and in the oil.)

Water is done with a vacuum hose with a small orifice (I've used one of the tips from my MightyVac). I've heard Seafoam works, but never figured out why it would be preferable.

If you haven't already, go read the BITOG additives subforum; there's a ton of information over there, some of it actually documented.

I saw more than one goopy motor with that 'fudge' looking stuff cleaned thusly: stuff rags in any channel which will allow oil etc to drain back to the bottom of the motor, then pressure wash (yes, pressure wash!) the valve train stuff till the goop is gone. This works best if you have access to a real live steam jenny (steam cleaner). Remove the rags (duh), then change the oil (again duh) and add a quart of ATF. Run it for a couple hundred miles (the ATF detergents need some time to do their work) and change the oil when it's good and hot. Again use a quart of ATF, change again in a couple hundred miles and this time use regular oil etc.

Now, if the stuff is dry and crusty slam the valve cover back on and get rid of it quick.