Engine oil changes

[pete.wilson]

Hey

I have been told that you can add a quart of transmission fluid to your engine oil and drive it for about 100-200 miles max and change the engine oil, that it will clean out the block of any sludge build-up and open oil passages that are clogged or reduced flow, Is this true and is it recommended? I have a 99 Grand with about 130K on it and I sure don't want to harm my 4.7L but I haven't always been right on time with oil changes either. Thanks.

Pete Wilson
Kansas

 

[greybrick]

Sludge buildup depends on a lot of factors, type of oil, miles per change, type of driving etc. You might want to pull the oil pan and take a close look as that may indicate what sludge buildup you have throughout the rest of the engine.

Depending on what you find when pulling the pan you might want to consider AutoRX and follow that treatment to start cleaning the inside of the engine;

http://www.auto-rx.com/

Removing all of the internal sludge buildup may not even be possible depending on the present state of your engine as controling sludge buildup starts in the first few thousand miles in some engines.

.

 

[AndrewP]

There is no reason to do this. If it were a good plan, Jeep would tell you to do it. If you want to feel like you cleaned out a bit of gunk, get some "Heavy Duty" oil like Delo or Rotella. Run a couple of quick changes with that. Not only is the oil perfectly suitable for your motor, it has extra detergents that may aid in cleaning out the motor. I probably would not bother, and just keep up with regular changes.

 

[DaveInDenver]

When I bought my truck at about 100,000 miles, I ran a can of BG Products Engine Clean (I think that's the name) before my first oil change. After that, I just ran Syntec on regular change intervals.

When the timing chain broke (totally unrelated to oil maintenance, defective parts) last year at 187,000 miles, I got the chance to see inside the engine up close and personal during the build of the new one. The rods and crank were a nice dark caramel color, pistons still a dull light gray, rings in nice shape. There was no evidence of sludge, even very little build-up under seals. The wear inside was not bad at all, the cylinder walls still had good hone patterns and the bearings all still looked good. Had the timing chain not broken, which resulted in one of the piston faces getting an up close relationship with an exhaust valve, I'm sure the bottom end still had 50,000 miles in it.

So like AndrewP says, following the maintenance schedule recommendation of Jeep using good oil and filters is all you should need. I do think running synthetic oil helped my engine stay clean, it generally does have more detergents in it than regular oil.

 

[greybrick]

There's at least one Dodge Tech Service Bulletin about 'oil emulsion accumulation' for about that year of Jeep and Dodge; have a look at your model here, or look up NHTSA TSB #6092301;

http://www-odi.nhtsa.dot.gov/tsbs/

Maybe your dealership has a fix for sludge buildup if it's happening in your engine.

.

 

[DaveInDenver]

Well, there you go, see what the TSB says. A TSB would change things in my mind a little. One thing to consider if you do have significant sludge is that flushing it out is not necessarily the best thing. The last thing you want to do is break it all loose at once. That sludge has to go somewhere and that could easily be a vital engine passage that puts a hasty end to your engine's life.

In any case, follow the TSB and what the book says to do.

 

[madizell]

The way I read the bulletin, it is that the customer might complain about visible oil "emulsion" whatever in the oil fill port of the valve cover. This is quite normal with nearly all vehicles because oil vapor, present in all hot motors, condenses on cold metal forming the caramel colored coating we have all seen. This is different from sludge accumulation in the oil pan and oil passages. Sludge has in it condensed vapors as well, but also carries a high carbon content attributable to cylinder wall wash and coked oil arising from unusually high heat or abuse, infrequent oil changes, etc.

If that is all you are seeing in your Grand, I would ignore it. As for having missed a few oil change intervals, again I would not worry so much. Modern engine oil is getting better all the time, and while it is still best to change oil every 3,000 miles no matter what type oil you use, all of them will suffer extended oil change intervals. The oil may look really black, but it is supposed to because of the detergent content. The black in the oil is sludge not deposited in the block. Essentially, you throw away the sludge every time you change oil.

I would not use ATF as an engine lubricant. If you want to add something to the oil to boost detergent content, there are specific products for doing this. Stick with something actually made for the job. Why risk galling your rod and crank bearings to try something that has no engineering or test data basis? Years ago, when oil contained no detergent, folks used to put kerosene in the crankcase and run the motor to wash down the internals. But then, engines didn't last more than 40,000 miles either. Just because someone has done something like this and gotten away with it is no reason to do it. With 100,000 plus miles on your Grand, I would be very shy of washing down the bearings.

 

[pete.wilson]

Hey

Thanks for the advice. I read the TSB and I'm not conerned about it; I just cleaned mine this past weekend.

I did have in 1984 a mint condition 1977 Oldsmobile Cutlass Supreme with a 350v8 with less than 40K. I changed the oil every 3,000 miles using at the time Quaker State 10W-30. At 65,000 I had rocker knock; we changed all of the push tubes and cleaned it out and changed the oil. At 75,000 a rocker arm stud broke due to a collapsed lifter. My supervisor and I pulled the Intake manifold and found enough sludge build-up in the intake to make a heaping pile onto a metal trashcan lid. We installed all new lifters, pushtubes and rockers and then reassembled things. Never did quite run great after that and I got rid of it. I switched to Valvoline semi-synthetic and have run it ever since in all of my vehicles. I stilll try to change every 3K miles but sometimes it gets to 5K and then change. I thought if I could clean it out and help insure there isn't much sludge building up.

Pete Wilson