Engine oil and Sludge

This is an interesting post. Some of the kissups who swear that you cannot have less than stellar performance from synthetics should comment.

Could be an engine that's prone to sludging (I'm no Jeep expert, but not really heard of that.) Could be crappy oil. Could be short driving. Could be all of the above.

I once helped a friend do the valve covers on a Tempo (this was 10+ years ago) and the insides of the valve covers and top of the head had what looked like chunks of bark in there it was so bad.

The wife's Beretta is 18 years old and the inside of the valve cover is probably still clean enough to eat off of. My 86 Jimmy's valve covers in 2005 were amazingly clean too. Same engine family.

I know this doesn't answer anything. Just my observations. I use Pennzoil oil. (And the ONE time I used Mobil 1, I experienced timing chain failure. Go figure)

Ray

Short trips and hardly ever reaching full operating temperature will cause that and other problems. Oil viscosity can also have some effect. In this kind of situation, I would:

1. Shorten the oil change interval to 2000 miles. 2. Operate the vehicle at highway speed for an hour or so, (all in one trip), at least once a week.

I'm afraid I don't know any effective way of cleaning out the buildup that's already there, short of a teardown.

Maybe the OP will tell us which synthetic he is using. Despite my snide remark about synthetics, I would not expect this to happen, no matter if he used synthetic or a good grade fossil oil, especially in light of his regular and short change intervals .

Something else must be going on here.

Something is wrong with your calculations. If she drives to work every day for 7-8 years that only works out to 6000 miles at the most.

I like the casual mention of "I installed new valve lifters this weekend" as if this is a normal maintenance procedure.

Take a good look at the PCV circuit. That is where the sludge may have first developed and restricted PCV flow would lead to more sludge.

Extremely short trips are classified as "severe duty" by car manufacturers and call for more frequent oil changes. More expensive brands of oil aren't really engineered to be better at addressing that type of driving.

-jim

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The short trips are the source of your sludge. The "detergent" additives in oil are only fully effective above about 140 deg/f. The crankcase ventilation system is usually the first to show signs and effects of sludging accompanied by reduce efficiency which accelerates the sludging process.

Having to replace the lifter is a sign of other problems. If the lifters have been affected by the sludge, you may have reduced oil pressure/flow to the crank bearings because of the sludge in the oil passages.

Castrol is usually pretty good about controlling sludge, but... not if the engine is not operating at normal temperatures. Ditto for the synthetic.

Absolutely! The additives in engine oils are only effective in engines at normal operating normal operating temps. The coolant will be at normal temps much sooner than the lube oil. Vehicle operating normall on trips less then 10 miles or so is considered severe service because there is not enough time for the oil to reach normal temps for the additives to work and the cold start condensation extracted from the oil thru the PVC system. This mixture of oil vapor and combustion condensate vapor is what causes the sludge formation. There is not much that can be done about sludge once it reaches a certain point. "Engine flushes" are usually a futile effort to avoid rebuilding the engine. If your engine still runs well and has good vital signs, I would put it on a diet of much more frequent oil change cycles combined with using it more frequently for drives for

25 miles or more. Note the synthetic oil will not be of much financial benefit under these conditions. Synthetic may provide easier starting if you live in a very cold climate. Make sure you use an oil of the proper grade. You should need nothing heavier than a 10w30 in that engine unless you have low oil pressure/high oil consumption and are looking for some borrowed time on it.

Lugnut

The 4.0 is known for sludge buildup on short trips.

It uses a CCV system instead of a PCV system. The CCV grommet at the rear top of the valve cover has a metered hole in it that needs cleaning. A paper clip is about the right size. The plastic tube from the grommet to the air filter or intake also plugs up with sludge. 'Usually' when this happens some oil spits into the air filter also.

The plastic tube can be soaked in throttle body or carb cleaner be and reamed out with a chunk of wire or maybe blown out with air. The tube and grommet can be purchased.

I had to clean our CCV system once a year because my wife also has a short drive. Too short to even have interior heat in the winter.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > My wife drives a 2001 Jeep Wrangler six cylinder. We bought it new and it

Your reply makes a lot of sense. Thank you, Dennis B.

Thanks, I'll check it out. Dennis

We drive the jeep other places too, store, gas station, Tennesse a couple of times, etc.

The lifters were noisy so I changed them and it wasn't easy. What's your point???

Typically lifters don't require replacement during the normal service life of an engine.

nate

THAT is a strong answer.. Thanks Mike.

By law (in the US) it is required to have a PCV system. I think on all engines this means at least 2 hoses to the closed crankase. One is connected to the intake manifold and one to the air cleaner. The one sucking fumes from the crankcase is the one that will get plugged or restricted. The other one is intended to only bring fresh air (from air cleaner) into the crankcase. If the one gets plugged then the other will blow back into the air cleaner. Even when not plugged, if the engine is under heavy load (vacuum is lowest and ring blowby the highest) it may blow back thru the air filter if the engine is worn.

-jim

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No, the law states that the crankcase cannot be vented directly to the atmosphere. How the manufacturers do it is up to them. PCV is one way, CCV is another.

The law is that the engine cannot vent to the atmosphere. There is no restriction on how this is accomplished.

I think the point is that 6 years for lifters is not normal. I think my

18 year old pickup has a stuck lifter. I've never changed lifters on any of my street cars. My friend's 20 year old Celebrity went to the junkyard with 200,000 miles and a knock from the mains, but original lifters.

Mike pointed out that your engine does appear to have a tendency to sludge up.

Ray

Closed Crankcase Ventilation and Positive Crankcase Ventilation are the same thing. The point was the hose to the air cleaner is not what plugs up unless the ventilation has already failed somewhere else for other reasons.

-jim

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Well when the 'CCV' system on the "USA" made Jeep engine blocks up, it also puts a lot of oil into the intake hose from the air filter, enough to fail emissions with high HC's, so it also needs a clean usually.

Jeep did away with the PCV system on their 6's when they did away with carburetors back in the 90's by the way. They use a CCV system.

Mike

They also tend toward noisy lifters, some sound like diesels. I have heard of quite a few folks changing lifters in the 4.0 just for the noise with everything else being fine.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos: