Engine Sludge

My friend's MOPAR - 97/98(?) Sebring Coupe has unbelievabley ended up with sludge in the crankcase. She took it to the dealer and they said the engine was shot and was her fault for using the wrong oil. ?????? How would they know that? Another mechanic (not Chrysler) said it was the fault of the engine and the 2.4 engine she has does this all the time, but it is not worth fixing. Anyone know what the truth is out there? Neither of these explanations sound right unless the "wrong oil" my friend used was Crisco, which, even though she's blonde, she's not dumb enough to do that !

If regular oil & filter changes as outlined in the owner’s manual are not adhered to, it’s quite possible for an engine to sludge up.

The 4 cylinder Chrysler engine is not a technical marvel, but many have gone well over 100,000 miles without any problems.

Please tell us what past maintenance this engine has received; it’s impossible to tell what the problem is or its cause from the info. given so far.

While Chrysler’s 2.7 liter engine is known for sludging problems, the 2.4 liter engine is not known for this issue. As a result, sludging would likely occur for one or more of the following reasons:

Not changing oil at the appropriate odometer mileage or elapsed time interval
Using the car for a lot of short-trip driving
Using the wrong specification oil (not likely)

If the car was used for a lot of short-trip driving, this means that the car should have been serviced according to the Severe Service maintenance schedule, rather than the normal schedule. As Doc noted, we need to have complete information about this car’s maintenance history and we also need to know under what conditions it was typically used.

Docknick, The Newer 2.4L Chrysler Engine Is A Technical Marvel, Right Down To The Dual Counter-Rotating Balance Shafts!


Depending on her driving habits and environmental conditions, sludging is the fault of the car owner for not changing the oil regularly enough.
In some extreme cases changing the oil every 3k miles OR (key word) 3 months is necessary.

I’ve seen more than one engine in cars with less than 25k miles on the clock trashed so badly due to oil sludging they were not even worth rebuilding.

Let’s look at that wrong oil thing.

Has your friend’s car had its oil changed when scheduled (miles or months which ever came first) in the owner’s manual (no cheating) and did the oil used meet the specifications listed for oil in the owner’s manual?

Yea, delayed oil changes and using the wrong oil can certainly cause engine sludge. They are not the only things, but until you rule them out, they should be considered the most likely problem.

It isn’t difficult to find out which oil was used and which one should have been used. Without knowing both, our answers won’t be as good. Hair color or smarts don’t have any bearing.

Wrong oil is pure bunk. As long as oil was changed at regular interval that is what matters.

It could be a mechanical issue that lead to sludging.

In the end it does not matter A single bit as this car is way past warranty and really nearing the average life of an automobile.

I would seek a used engine or simply junk it. The car is hardly worth any money with a running engine.

Does the engine run? Does it burn a lot of oil? Sometimes these can be cleaned up fairly cheaply by removing the valve cover and clearing out the oil drainback holes. If it was burning oil. this could stop it. After that, a general cleaning of the gunk from the top of the engine under the valve cover, a new valve cover gasket and a couple of oil changes using 10w30 or 15w40 could get this right back on track.


one instance of 25k miles no oil change


That Mazda situation is absolutely amazing!

As we frequently see in this forum, many people just seem to be unable to accept responsibility for their actions–in the case of that Mazda, the total lack of maintenance of a CX-7 for 25k miles. I know that I harp on this issue, but failure to accept responsibility for one’s own actions is at epidemic proportions in our society today, and I believe that it is one of our biggest problems.

Please note that I am not commenting on the OP’s friend and her Chrysler Sebring, as we are still awaiting information from him about that vehicle’s maintenance history and operating conditions.

Keith, That’s Interesting. What’s The Theory Behind The 10w30 Or 15w40 For A Couple Of Changes, Other Than To Increase Pressure?

One more thing. Are you the “legendary” race car driver that turned a hobby into a full-time racing business?

You sound very knowledgeable. Where does this come from if you don’t mind my asking?


Low temperature on an engine can cause sludge also. If you decide to try keiths fix check or replace the thermostat.