Re: Oil sludge elimination/prevention?

Beachrunner wrote:
Own a Chrysler Sebring with the V6 2.7L engine. I've read several
complaints about how prone to oil sludge buildup these engines are (and
the not so decent position of Chrysler corp. of not admitting the
problem or solving it). Mine is 58,000 miles and want to prevent and/or
eliminate possible oil sludge in the engine. I can see some of this
gunk like substance inside the oil filler cap. Car is running good, no
noises so far, just a coolant leak near a sensor assy at top left side
of engine that I'm going to have repaired/checked.

Any clues on how to eliminate and prevent oil sludge in these famous


1)For best protection, use a 5W-30 or 10W-30 full synthetic motor oil such as Mobil 1, Amsoil, Redline or Pennzoil Platinum Plus. These are expensive top of the line oils, but worth it compared to the alternative. You should be able to easily go 5000 miles between oil changes with these oils; perhaps further depending on your local climate and driving style. Use a good filter such as Purolator PureOne, WIX, NAPA Gold, Motorcraft, Amsoil EO, or Fram XG series *only*. Filters are not all the same quality - stay from the cheap ones.

2) Other good oil choices would be Quaker State Q advanced synthetic (good for about 4000 miles in my 2.7); Valvoline Synpower or Valvoline MaxLife Synthetic.

3) For non-synthetic oils, Castrol GTX and Havoline come to mind as well-proven oils. These should be changed at around 3000 miles in this engine. These oils will go alot farther in other engines, but the 2.7 is hard on oil. Theses same oils would easily go 7500 miles in a Honda Civic. But not in a 2.7.

4) Maintain the cooling system ! This is important to minimize the risk of water pump failure or failure of the water pump seal(s). Since the water pump is inside the engine, a coolant leak will leak into the oil and will create mud-like sludge in no time flat. The water pump and it's impeller were built around the coolant. Use either Mopar Long Life coolant (orange stuff - but it is NOT the same as Dexcool which is also orange), or Zerex G-05 (sames stuff as the Mopar). Do NOT use any other coolant. If the cooling system has been ignored, have it thoroughly flushed and re-filled with 50/50 coolant/distilled water.

5) Methods of getting rid of sludge are controversial. Solvent flushes will definitely clean some of the sludge and varnish. But they are harsh, and may accelerate wear in the main and rod bearings. And it may also cause large sized pieces of sludge to dislodge and potentially block off a narrow oil passage - thus creating a worse problem.

Many of the additives sold in auto parts stores are useless.

I am currently working with a gentle long-term internal engine cleaner called Auto-Rx. Inside my oil cap and the little bit that I can see down there looks pretty clean. But my PCV hoses and heat exchanger regularly produce little bits of coke and tar, which tells me that just a few inches from my oil filler cap, things may not be quite so rosy. I've just started it and I don't know how well it work on my engine. I still have a couple of months to go before I'm finished. I am monitoring it with oil analysis, dissection of the oil filters and compression readings. I may pull the valve covers off for inspection.

You can read about Auto-RX here :

Here is a very interesting photo documentation of an Auto-Rx cleaning of a sludged engine :


Relevant Pages

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