oil residue

Probably a head gasket leak... Might be bad rings...... If it is a head gasket that is not so hard to fix, probably cost you about $800... rings,, oh well..

The car is already five years old. Make sure to check the oil often and keep oil in it and keep driving it...

It could also be the valve guide and seals. If this is happening on all, or most of the cylinders, that would be my first guess. Five years old is nothing to the rings, unless you are racing. Check the manufacturers website. It may be that they got a bad batch of seals.

If my slipping memory is still woiking: these animals had a tendency to weld the valve guides to the valve stems;guides going up/down with the valve.

Take off valvecover & crank engine, should be fairly obvious!

Do a wet and dry compression test, this will tell you if it's the rings or valve guides. I believe you'ld have other indications/symptoms if it was a head gasket, as suggested in one of the responses (i.e, water in oil, oil leak, etc.), could also be a cracked head but a compression test will give you a better clue. Could also do a leakdown test.

It would be nice if the info was fuller, mileage, usage, oil type etc etc.

I am always of the mind that cars that have had synthetic oil from new, (in spite of extended oil change intervals) show far less wear in the first 200,000 miles than cars who get standard mineral oil replaced every 3,500 miles or so.

My last 6 cars have only had Synthetic, some have achieved 400,000 kms., none have needed a new engine, one needed a new cylinder head as my wife filled it with petrol (it was a diesel) and went for a 150 mile autobahn run!!!! The cooling water was blown out and the motor overheated.....but the block/bottom end was still good and ran a further 100,000 kms!! We sold it still in a good running condition!!!

Was the oil residue only on the threads, if so it is only from an external oil leak (valve cover gasket) If the oil was also on the ceramic center of the plug, then the problem is more serious. Valve stem seals can be changed without removing the head. One other reason for oil inside the cylinder can be clogged oil return holes in the head. This is usually from oil breakdown. If the inside of the oil fill cap shows accumulation this may be your problem. This can be resolved with a valve cover removal and some scraping and cleaning inside the exposed area of the head. If compressed air is available it will help (quite messy though). Good luck.

The V6 Caravans were notorious for valve guide seal problems -- the guides actually loosened in the head, so oil would flow down the outside of the guide, even if the "seal" itself was intact. The 2.4 might have similar problems. Normal valve seal wear is another possibility, as is ring wear. If it's only on one cylinder, a head gasket leak could be the cause. A compression check (with and without oil) should tell you more.

If I were going to come up with a percentage likelihood, I'd say it is 75% likely to be in the head -- a comparatively easy fix. (In one best case scenario, you would pull the head yourself, after ascertaining the the rings are not the problem -- the reason for the wet/dry comp checks -- have it checked for flatness, replace the guide seals, and all the top end gaskets (as well as the water pump, timing belt, etc). You'd want to measure the valve guides and stems for wear, check the valve seats, etc. (If the head is off, you might as well give it a good going over.) A few hundred dollars and you'd be good to go. A pure guess would be that if you had this done it might be $1000 - $1500?

On the other hand, if it's the rings, then there are probably other areas of the engine well worn as well, and a full rebuild would be in order. My own preference is for a full rebuild versus finding a used engine -- because if you do it yourself, you then have an effectively brand new engine, rather than an unknown. (On the other hand, if you take it to an incompetent mechanic for the rebuild, you could have a never-ending source of problems.)

You didn't mention mileage. If you have 160,000 miles or more, you can assume you might be due for a rebuild.

Thormaster, One other possibility, check out the PCV (positive crankcase ventilation) valve usually stuck in a rubber grommet in one of the valve covers. There will be a hose leading to a vacuum source. If this is clogged it causes the engine to build back pressure in the valve covers forcing oil past valve seals. Relieving the pressure may relieve the problem.

Dragon