My 99 xk8 that I bought a few months ago had been sitting for 2 to 3 years. I repaired the A drum in the transmission and been driving since then. Just after I got it started I changed the oil and filter. Taking off the filler cap I noticed what you would call sludge on the cam and cam caps visible through the opening. It's been about 800 miles of driving since the oil change.
The sludge is still present but not as bad. Is there an additive I can use to help clean it up or should I just keep changing the oil at shorter intervals.

 

I would avoid additives in general, but a couple of the pros have suggested adding a qt. of atf right before oil change. Then drive a half hour or so and change.

I'm a little foggy as to how long to drive before changing, so maybe someone who has done this will join in.

 

I've done that on my 1999 Ram pickup (as Brutal suggested). I added about one-half quart of generic ATF I had sitting on a garage shelf for years and drove the truck another 200 miles or so before doing the oil change. The drained oil did indeed seem a little dirtier than it usually does at my 7,500-mile oil & filter changes on this truck, so maybe the detergent action of the added ATF had something to do with that....

 

The atf might be the way to go. I don't want to add anything harsh to the engine that will do more harm than good. The engine seems to be running good with 96,000 miles and i'm going to check here soon if the tensioners have been replaced.

 

That would be my suggestion too, a couple of hundred miles sounds reasonable.

 

This post has been edited because in this post I originally suggested using diesel spec engine oil to clean an engine's internals. However, it was quickly pointed out in the following post, this is not a good idea. Diesel oil has more zinc and phosphates which are not good for the cats. While it won't kill the cats, like using leaded gas, it is still not a good idea. Just another example of an old timer shooting from the hip because that's what we used to do in the good old days. :-)

 

DON'T USE DIESEL SPEC ENGINE OIL!!!! The additives put in diesel spec oil will harm your catalytic converters. That is why there are 2 types of oil. Do not use racing oil either. The heavy use of antiwear additives causes problems. There are articles all over the web about this. Just a heads up........Mike

 

You are correct. Don't use diesel oil in a car w/ cats. My bad for not doing the research before posting. See above two posts. Thanks Mike

 

The sludge itself is not doing harm and is simply an artifact of either abuse or possibly an engine fault, past or present. I'd monitor it's presence and if it slowly 'melts' away vs. increases in volume I'd call it good.

I would strongly recommend not adding anything to the oil in an effort to speed the process. The last thing you want is a 'blob' obstructing an oil passage.

 

Just look up Terraclean. There is also a UK TV program called Wheeler Dealers there is a Youtube video showing them using a Terraclean on an XK8.

Good luck.

Update.

Here you go sorry about the sound, there are better versions if you hunt for them.

 

The treatment they used on W/D is designed to burn off carbon deposits in the combustion chamber, valves, etc. The OP is looking for ways to get rid of sludge build up on the heads under the cam covers, in the oil pan, oil galleys, etc.

 

+1 not to mention that a modern engines in decent shape don't accumulate carbon deposits in sufficient quantity to affect performance.

Absolute waste of money.

 

The carbon deposits that are cleaned away are usually on top of the intake valves, and this has more to do with fuel quality than engine condition. Use top tier fuels to avoid this type of problem, or throw a can of Teckron in the tank every now and then. The intake valves usually have a build-up that looks like black pillows and effects starting, mainly due to the fuel charge being absorbed by the deposit. Deposits in the combustion chamber don't do much to hinder performance one way or the other.....Just 37 years of experience talking......Mike

 

My 40+ years of experience indicate that modern engines in good nick don't accumulate deposits on the back of intake valves. A non-invasive treatment like Terraclean won't do much to clean such deposits anyway.

I also see little difference in top tier vs. non-top tier fuels. Jag, unlike other OEMs, does not endorse top tier.

 

TOUCH'E.....If you want to run horse pee in your car go right ahead. Additives are put in fuels for a reason....Mike

 

I wouldn't recommend using ATF for engine cleaning. ATF was a good solution back when most were ester based which is a heavy natural cleaner, but now that most are based on similar oil bases as your average conventional and synthetic oils and modern oils have a lot stronger detergent packs than ATF these days. It won't necessarily hurt anything, but it's doubtful it will help. Diesel oil won't hurt your cats either as long as your engine isn't an oil burner.

 

I would like to thank all of the members for their responses, I have found it imformative. The problem I would think about using diesel oil is even if it isn't bad for the cats, but I even wouldn't take the chance, is that I is usally a heavier viscosity. The oil I use for my F350 is 15w-40 and I think that is is too heavy to use in our engines. I don't think I would have to worry about sludge blocking a passage way because anything that comes loose would find its way back to the pan and have to go through the filter before it would go through any passages. I am going to try the ATF and see if it helps, then I plan to change the oil at shorter intervals. I will update the progress. Thanks again for all the suggestions. By the way would that horse **** be male or female. There is a difference and one might be harder to get than the other.