Engine oil and Sludge

I've heard that "AutoRX" is good at removing gunk like this. Never tried it myself as it's too expensive to ship up here to Canada.

Short trips are going to leave moisture in the oil for sure. Sythetics might help, but you really need to take it out for a run once in a while.

Apparently synthetics did not help in this case.

the sludge was already there... synthetic oil didn't likely add to the mess and probably cleaned it some of it out.

He had changed to synthetics a year ago, and changed every three thousand miles. If the dino oil had been involved in the original sludge, which is not likely unless the crankcase ventilation system were the culprit in the first place, then the synthetic didnt do much of a job of dispersing the sludge and keeping it from recurring.

I dont think the oil is the problem.

Synthetic isn't a magic cleaner that removes the sludge that's already there. It can do some, but expecting it to clean out an engine is a bit much.

Just-a-wondering, for a short-trip engine would any benefit arise from closing up the cranckcase and plumbing it to manifold vacuum? Yes, there's a bunch of seal-related stuff you need to do, but just looking at it theoretically.

Dave

The CCV system 'is' plumbed into the intake manifold and has a constant 'metered' suction. In order for 'suction' to take place, there has to be an 'intake' matching the draw. Running a vacuum wouldn't draw the humid air out, it needs flow.

Now maybe if something could be rigged up to increase the flow across the head without messing up the fuel/air mix.....

Mike

Most filters do that, now. Cheap offshore stuff, even some of the "good" old brands. I use Pennzoil, and they still hold the oil up in the system. So far. Fram went to pieces about three years ago. I haven't tried the OEM filters, but I would expect they're still OK.

Dan

There are some synthetic oils that have a lot of detergents in them and also act as pretty good solvents. These oils _will_ clean out gunk. There are a lot more that don't. Whether the base is synthetic or not does not really have very much to do with how effective at removing varnish an oil is.

--scott

I can accept that not all synthetics have the glowing characteristics that are sometimes attributed to them, across the board.

I would not really expect many of them to be very good solvents. That isn't their role, nor is it always desirable. The polyesters are probably better at this than are the polyolefins.

I would still expect almost any sort of oil (with frequent changes) to have had a positive effect on the sludging that the OP has detected, but this would not seem to be the case....or, the sludge is forming so quickly that this effect is not noticeable.

Yes, and for a motor oil it often is not desirable, because it winds up causing issues with seals, and it also can get a lot of old varnish into solution and plug your filter up too.

For some applications it's a big deal... I am amazed at the ability of the Royal Purple Synfilm to clean old crusty gunk out of sleeve bearings on small motors, for instance.

Could be. Or it could be that the sludge is so extensive and so sticky that it's just hard to remove. Used to be on those old Valiants you'd pull the valve covers every year and scrape gunk out with a putty knife....

--scott

Can't disagree with the bottom line, but I still say that PCV systems will tolerate a whole lot more neglect than orifice type CCV.

That said, after reading this thread yesterday I pulled the metering orifice out of the valve cover of my "new to me" 1999 Jeep 4.0. The previous owner did a whole lot of short-trip driving (lives 4 miles from the office) interspersed with a good many road trips. Mine was clean as a whistle, despite the fact that he never used anything but the cheapest quick-loob places as long as he had the car (117,000 miles when I picked it up). So I'm still a little baffled as to why the OP's 4.0 sludged up so quickly, and I'm still inclined to suspect some additive that he used to quiet the lifters unless he posts back that he never used any such additive.

True. From the reading I've done over the last couple of years, it appears that there are a lot of synthetics on the market now that are decidedly inferior to the better "dino juice" oils. Furthermore, the good dino juices are now turning in longevity numbers (total base number, viscosity increase, and wear metal content) that rival the good synthetics.

Ruh??? I've had a whole lot of old Mopars (a Valiant included) and never had a sludge issue until Dad's 92 5.2, which developed the issue because it had that early-Magnum intake problem where the exhaust crossover passage leaks into the lifter valley.

Back in March of 06 I asked the groups what to do about noisy lifters on start up. I was advised to use synthetic oil and change oil filters. I was using Castrol oil and Fram filters. The Jeep had 58,000 miles on it. So I changed to Mobile1 Synthetic and Mobile 1 filters. This did work for about 3 or 4 months and they started clattering again. I tried several different filters but nothing helped. I never used any additives and I was afraid to run transmission fluid thru the engine. I don't know if the orifice was plugged before because my son cleaned the valve cover for me. I just know that it was clean when I checked it. The one thing that I'm going to start doing is driving it to work once or twice a week. I never realized how bad it is on these engines not to drive them good and hard once and a while.

Thanks all for taking the time to reply.

Dennis B.

You arent talking about those old slant six engines, are you? I have seen them that looked like the La Brea tar pits, BUT they may have had 300,000 miles on them.

I'd also keep a close eye on that coolant. You said it was losing coolant, and with all the other info I now have to wonder if there isn't some very, very slow path for coolant to get into the oil, increasing its moisture content and also slowly contaminating it with glycol, which gets really nasty when mixed with oil. It could be something as insidious as a casting flaw or porosity in either the head or block. That kind of thing is much more common on aluminum blocks and heads than on a solid iron engine like the 4.0, but its not impossible. Even with all the short-trip driving, it just doesn't sound like it should have gotten as bad as it did using modern oils- even "cheap" modern oils.

I would agree the missing coolant could have something to with it.

But even without that it is easy to see that in the winter time trips of only 1.5 miles can result in a complete failure of the crankcase ventilating system. Ice can build up in the tubing each time you make a trip and the engine never gets warm enough to thaw so after some number of such short trips their maybe no flow at all. Of course once the weather warms up the problem disappears but at that point you could have an accumulation of sludge.

-jim

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