oil sludge build up

[vzfox]

On my 1989 GMC C1500...while changing the oil lately, I noticed a large amount of "sludgy-gummy" build up beneath the valve cover(s). So far it isnt affecting the way it runs or drives, but from the way it looked I am afraid it might soon.

I was thinking of running an engine flush thru it to try to clean the build up, but wanted to check here with you guys first to see what kind of flush you would recommend.

I also realize that the best/professional way to do it would be taking the valve covers off and cleaning the valves manually, but I live in an apartment where it is difficult to do major work on a vehicle. I also dont have alot of monies to pay someone to do it.

thanx again for your assist.

[2000CAYukon]

What color is the sludge? Does it look milky?

How does the coolant look? You could have a leak in the engine oil cooler or worse a bad head gasket.

A leak down test might be a good idea.

//2000CAYukon

[Mr. Smith]

Originally Posted by vzfox

On my 1989 GMC C1500...while changing the oil lately, I noticed a large amount of "sludgy-gummy" build up beneath the valve cover(s). So far it isnt affecting the way it runs or drives, but from the way it looked I am afraid it might soon.

I was thinking of running an engine flush thru it to try to clean the build up, but wanted to check here with you guys first to see what kind of flush you would recommend.

I also realize that the best/professional way to do it would be taking the valve covers off and cleaning the valves manually, but I live in an apartment where it is difficult to do major work on a vehicle. I also dont have alot of monies to pay someone to do it.

thanx again for your assist.

Before you change the oil ldrain a quart of oil and add a quart of ATF and run it. Barring that you could add a quart of diesel fuel and run it at low speeds for a while. YMMV

[alan &marge pepper]

oil sludge is caused by an engine that is driven short distances. it is caused by condensation which means that the engine needs to be driven at lease 8 to 10 miles for it to get rid of it each time it is driven there is a lot of cars and trucks that have this problem but is ignored.
but just to check for a coolent leak is after it sits for a day lossen the drain plug and see if there is any water, coolent thier. water or coolent will always go to the bottum of any oil base product. hope this help you. alan

[vzfox]

There is no coolant leak.....the "sludgy" build up is dark (black) in color and looks like you could take a screwdriver and scoop some out.

So, from what I am gathering from you guys is you wouldnt recommend an "engine flush", but rather ATF or DIESEL fuel?

thanx for your assist.......i do appriciate it.

[maxwedge]

I'd be very careful with this engine flush at the point this condition is at, you may block the oil pick up with the resultant debris loosened. This engine needs more than an chemical clean up based on your description. I'd pull the pan first and see what's what. Based on age an possible lack of maintenance over 18 years, this is more than meets the eye here.

[vzfox]

I do know that the bottom portion of the engine was rebuilt approx. 50k miles ago (by the way, the odometer reads 253k miles).....I did not own it at that time and not real sure what was rebuilt/replaced. But if you think "flushing" it with anything will possibly do more harm than good, I will leave it alone and just keep changing the oil regularly.

thanx for the assist again.......