SAAB sludge

I'm not sure this belongs in this forum, so if a moderator wants to move it, go ahead.

I trust the guys here for mechanical advice more than the people on the car forums.

I have an engine sludge problem. I removed the cam cover from my 1999 SAAB 9-5 (2.3l turbo, 4 cyl.), and found about 1/8' of sludge over the inside surface of the cam cover, and inside the engine surfaces (only on the stationary surfaces, not on the cams, sprockets, or chain). It is very dark brown/black, and seems to be a waxy substance that easily scrapes off. This car has 100,000 miles, and generally runs great. I bought it used about 8,000 miles ago, but with full service records. It had all factory required oil changes. I switched to synthetic oil when I got it. I do not know what the original owner used.

I presume this sludge exists throughout the engine (oil passages, pan, etc.) I will remove what I can get at through the cam cover manually, but would like to try some type of engine flush to remove it throughout the engine. (Removing the oil pan is a bear in this car -- it requires removal of frame and exhaust system components.)

So, what do the experienced mechanics here suggest for a flush? Products? Techniques? So far, I have heard advice to do/use:

1. Seafoam in the oil;
2. AutoRX flush (used in the oil);
3. Automatic transmission fluid (use in place of one quart of engine oil);
4. Kerosine (50/50 with the engine oil);
5. Do nothing.

Doing nothing does not impress me.

//

Get a name brand engine flush and follow the directions exactly.Get away from wax/ash based oils and get a full synthetic-Mobil one, etc.

you might want to search here for the best way to switch from dino to synthetic:

www.bobistheoilguy.com/

the dino oil waxes help to seal the inside oil seals.

if you switch to synthetic (mobil 1) in an old engine, it cleans the engine so well you might find some oil leaks on the driveway after a few months/years...but if you're running a turbo, the advantages of synthetic oil outweigh a few drips on the driveway...

I have used Rislone for this purpose and it works well. You add the quart to your existing oil and let your car idle for 20 minutes. Then you change the oil. This is good because you are only idling.

I also have used Valvoline All-Climate oil (white bottle) for many years and it cleans engines very well. I used it on my 1979 GS1000 and avoided the problems those who used Castrol GTX experienced, where the varnish from the oil would make the buckets and shims stick and bind.

Good luck

1 quart automatic trans fluid and about 3 tablespoons of laqure thinner, some may disagree running the thinner on a hot engine i'v yet to have a problem.

I would not use any engine flush or any thinners, when you run cleaners thru the engine that has sludge in, it washes the gunk to the pan, the oil pump screen will get stopped up and no oil means boom no motor

I run a engine service center for a major company.
(a little anonymity- no advertising here)
We handle hundreds of used engines weekly, from wrecking yards around the country.

Certain engines (like the Saab and the 2.7 Chrysler) are well known to us for the sludge problem.

The Saab problem is so bad that most experienced shops will not rebuild one for fear of subsequent warranty problems.

The problem is not just poor owner maintenance but also related to poor oil passage design.

I see no problem with flushing the engine.

I have had excellent results just filling (yes, to the top) a warm engine with kerosene, and letting it sit for 24 hours.
DO NOT START THE ENGINE- you will get a hydraulic lock.
Then drain the engine, pull the plugs and rotate the engine a few turns to clear the cylinders of fluid.
Run more kerosene through it until it drains clear in color.

Add oil, change the filter, and start it up.

Do a second oil change soon. Add something like SeaFoam. Do another oil change soon, following instructions. That should get you back to near normal.

Honest advice; just sell the car. There is no such thing as a good engine from that series of car.

Post edited by: FloridaBiker, at: 2007/07/07 08:53

apeman wrote:

I trust the guys here for mechanical advice more than the people on the car forums.

I have an engine sludge problem . . . would like to try some type of engine flush to remove it throughout the engine. (Removing the oil pan is a bear in this car -- it requires removal of frame and exhaust system components.)

So, what do the experienced mechanics here suggest for a flush?

5. Do nothing.

Doing nothing does not impress me.

//

BSKZ650 wrote:

I would not use any engine flush or any thinners, when you run cleaners thru the engine that has sludge in, it washes the gunk to the pan, the oil pump screen will get stopped up and no oil means boom no motor

I don't know if anything I say here is going to be much help.

The deposits you are seeing are probably due to oil vapor condensation; I don't think they are going to really be a problem, unless big pieces flake off and fall into the pan, which will happen if you start trying to blast them chemically.

The pieces will fall to the bottom of the pan, where they won't come out of the drain plug. BSKZ650 is correct, the pieces WILL get picked up by the screen and block oil flow.

So unless you are prepared to pull the pan after flushing the engine, get prepared to buy a motor after a flush.

You might want to check the PCV circuit on the car; that subsystem is supposed to draw oil fumes out of the crankcase so they don't build up deposits.

It might not look pretty, but it doesn't sound like, from your description, that the deposits are going anywhere.

I have heard of lubrication flush machines that are used as a service offered by oil change places. But the liability is on them, not you, if the motor fails after a service.

So that might be an option to look at.

A lot of products will clean out an engine, but I agree with others. At my shop we have had two vehicles (older ones) that had to have pan removed after cleaning. Be careful!! :dry:

KaZooCruiser wrote:

The pieces will fall to the bottom of the pan, where they won't come out of the drain plug.

I am curious why you think they will not be flushed out of the drain plug. These are not large crusty pieces -- the sludge is the consistency of semi-soft wax. It is not liquid, but with the right solvent, I hope it would become semi-liquid, so that it should drain out the drain plug (I would logically think).

I like FloridaBiker's idea of filling up the engine with Kerosine and letting it sit for a while, then draining and flushing until I get clear solvent. My only reservation is that I am not sure kerosine is the best solvent. I am going to try an experiment inside the cam cover (removed from the engine) to verify that kerosine does dissolve the sludge. If it does, I will use that method. If it does not, then I need to research what other solvent might work.

On another site someone suggested carb cleaner. My guess is that would destroy every rubber seal in the engine.

What other solvents should I test before choosing the right one to use?

No carb cleaner. Not good for rubber. Kerosene or diesel fuel will work fine. I use kerosene in my parts cleaner. Disolves engine sludge just fine. I once bought a can of Engine Flush, and when I opened the can, it looked and smelled exactly like kerosene (for about three times the price). But they recommended using it a little differently than Florida bikers method. The instructions said to just add the one quart and run the engine for twenty minutes at idle, then drain it. But I'd probably just do it the way Florida Biker recommends. Sounds more thorough. I'd probably also put a magnetic block heater on the bottom of the pan. The heat will make the sludge dissolve even better.

I like the heater idea.
Never done that, but will try it.

Last week my shop did 9 sludged engines, as I suggested.
All are working perfectly.