Best way to remove sludge from engine

Water seems to have gotten into the oil of my wife’s '98 VW Jetta.It apparently got in through the broken dipstick tube (thank’s Jiffylube).The result is a light colored pasty mess on the inside of the valve cover and most likely everywhere else.What is the best way to clean this sludge from the engine? I understand flushing it with a solvent based product can possibly cause problems.Could repeated oil changes, say at 500 miles thoroughly clean the mess out of there?

I’d put a half a can of SeaFoam Engine Treatment in the crankcase oil, drive it twenty miles or so, and change the oil and filter.


This water/oil emulsion officially known as “mayonnaise” can also be the result of repeated short trips that never get the engine hot enough to evaporate the water that naturally condenses in your engine when it is running cold. A coolant leak can also cause this. I would do one oil change to get the comtaminated oil out of there and then do a long freeway trip to get the engine hot enough to evaporate any remaining water.
I once worked with someone who always had mayonnaise in his oil. he always drove his truck to work even though he only lived a couple of blocks away. His engine probably never knew what it was like to run with the choke off. Why didn’t he just walk or ride a bike? I don’t know, I just don’t know!!! I think he had this idea that a car needed to be run daily.

Will the sludge clear up after the water is gone? I think I’ll try The SeaFoam,change the oil,then the long freeway ride.

You may need another oil change after that, but that’s cheap compared to taking the engine apart. Agree that strong emetics can loosen big chunks of crud that can plug your oil passages.

If your oil was not regularly changed over the lasy 10 years, be prepared for increased oil consumption once you get all the sludge out.

Actually the oil has been changed every 3000 to 5000 miles since it was new. I don’t think there’s much crud.

Good! Then you should be OK after doing what the other posters recommnded.

Since you apparently have the valve cover off all ready, I would remove the mayonnaise mechanically, that is brush, rags and solvent, from the inside of the valve cover and the top of the head. I would also check that the return passages are clear so that the oil drains back to the pan ok, then do an oil change.

I didn’t have the valve cover off I just ran my finger around the inside of it.That’s more ambitious than I was hoping to get.

I will only add that you should be using a high quality full synthetic oil. That will not fix it, but it can reduce future slugging.

Tester, I have seen SeaFoam mentioned on these forums many times. If a car with 80K miles on it is running fine with no problems will SeaFoam produce any benefit or should it be used only to correct a noticeable problem? In other words is there any preventative benefit to its use?

Personally, I would just change the oil, drive it 20 miles, and change the oil again to get out any of the remaining mess. If sludge was really your problem there are products you can buy and use to remove sludge form your engine. You drain a little oil, pour this stuff in, idle the engine for a few minutes, and do a complete oil change. I will caution you that these products are dangerous. You should not drive the car with them in the engine and you should follow the instructions to the letter. When used improperly, they can destroy your engine or eat through the engine seals.

If you are truely changing your oil every 3-5k miles then using something like SeaFoam or MotorFlush is fine. There shouldn’t be a in cleaning out the sludge. I’d just do a couple quick (2k) oil changes after.

My opinion is that if it is not broke don’t fix it. In a few cars that have a know sludge problem, it may be helpful to use it on occasion, but I would not do it on most cars. I believe this is one of those questions that can only result in opinions as there is just not enough hard data.

Don’t forget to get a replacement dipstick tube and dipstick. An ‘auto recycling’ place will most likely sell the tube and dipstick as a unit, anyway. Replace the rubber O-ring with either a new one or if the junk yard is careful, the original O-ring just might have made it through the process in decnt enough shape to re-use it. Replacement O-rings are available at any auto parts house and don’t cost a heck of a lot of moolah.

Joseph, high quality synthetic is a wonderful lubricant, but it has about the same or slightly more additives in it than regular “dino” oil. So if you do normal driving your engine should not sludge up if the oil is changed frequently (severe service), regardless of what oil is in the sump. Ingress of water, as OP experienced will turn any oil into a mayonaise.

Where synthetic oil really shines is very heavy and hot operation, where the oil will resist carboning up because of its superior Viscosity Index.

You may be interested in engine cleaner called Auto-RX to help with this. Check out their website.

The other thing you might do is trade cars with her for a while if yours is driven on longer trips. This would be useful if she does short trips.

I’d follow the advice offered by Tester . . . and others. I’d use the Seafoam and then change the oil after 20 miles or so. Then I’d change the oil/filter in another 100 miles (make certain that you get the engine warmed up for those miles) and again in another 100 miles. Three oil changes and a can of Seafoam might cost you $50. Post back . . .I know I’d like to know if you get rid of the mayo. Good luck! Rocketman

You may be seeing the results of some condensation under the oil cap. Just drive it on a trip long enough to get the oil hot enough to evaporate all the moisture.

If you are getting water in you oil, it probably isn’t from a loose dipstick, you may just be running it on short trips all the time. The oil isn’t getting hot enough to burn off the condensation.

Don’t use Auto-RX. Seafoam OK, Auto-RX not ok