prevent sludge in 2.7 engine 1

[frankiee]

I am getting an Intripid with a 2.7 liter engine.
I have not seen it yet but I will be going out today to take a look at it.
I read about the engines problem with oil sludge.
My question is: How can I stop the sludge from happening.
Additives? More oil changes? Hotter thermostat? Would a engine oil cooler help?
Thanks for any replies

 

[MikeHalloran]

1. Don't run it.
2. Use synthetic oil.
3. Use propane fuel.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

Like Mike said, plus change oil and filter regularly.

Regards

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[drwebb]

Long trip highway miles should be less severe for sludge than short-trip stop/go.

 

[FoMoCoMoFo]

inadequate crankcase ventilation can cause, or contribute to that problem.

 

[patprimmer]

FoMoCoMoFo

Are you suggesting a bigger PCV valve or something more sophisticated like a vacuum pump, or something more illegal like a big open to atmosphere vent.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[frankiee]

I did a bit of looking around on the net about it and (not that I believe everything I read on the net) I gather it happens to some and all of sudden. I looked the the engine and it looks good so far. I have not changed the oil yet because it is in the shop getting a safety certificate.
It has 162,000 KM on it and is in good condition.
Price was right (a gift)
I was looking for things I could watch for that are signs of it going to sludge up.
I am going to drive it
I live in a city so it will be stop and go.
I am not going to change it to propane.
I will change the oil regularly.
I will go to synthetic if that will solve the problem
I can monitor the PCV system closely.

It must be something that makes some of them last a long time and others to sludge up very early.

 

[FoMoCoMoFo]

Hi Pat, just an observation, I would never suggest anything illegal (at least not in a public forum) if this problem is common in that particular car I would suggest that it's a design problem, rather than a maintenance issue.

 

[FoMoCoMoFo]

or maybe i should say bad design requiring more frequent maintenance.

 

[patprimmer]

I kind of thought that.

I guess a bigger aperture PCV would not be to illegal, at least in spirit and effect even if illegal in detail.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[spdingtkts]

The most common problems with these engines are timing chain/tensioner/guide failures and engine failure caused by sludge blocking the oil pump pick up screen.

If I remember correctly, the timing chain tensioner is oil fed and the sludge problem contributes to that.

 

[dicer]

So where does the freash air for pcv come from in this particular engine?

 

[FoMoCoMoFo]

and what path does it take getting to the intake ? and in what volume ?

 

[Mechaniac]

The Chrysler 2.7 engine causes the oil to break down because of excessivly hot surfaces around exhaust passages that the oil travels on. The PCV has little to do with it in this case. I've worked on three in this regard, two had already sludged up and had rod bearing failures and one was opened up as a preemptive inspection for oil sludge. The oil sludge builds up to the point that it coats all non moving internal surfaces then pieces fall off and clog up the oil pump pick-up screen after a period of continuous running. The two I worked on that were already damaged had not recieved regular oil changes, both were several thousand miles past their last oil change limit when the failure occured. An inspection of maintainence records in the glove box showed this to be regular practice for the owners. The good one I removed the pan on for an inspection was a situation similar to yours where the guy had just got it. We ran a commonly availiable engine flush product in the crankcase and then removed the oil pan for a clean out and look over. That one was relativly normal inside and looked well cared for.

I would say that if you have doubts about the oil sludge on this car to do a similar flush and inspection on yours. The oil pan on that engine and chassis is readily accessable and could be removed and installed by most people with average mechanical apttitude and a normal socket set within four hours time. The front end will have to be high enough to work under safely. If you pay a mechanic the costs should be affordable and worth the piece of mind.

In any case your best defence is to run a pure synthetic oil with the highest viscosity possible. Look in your owners manual for the minimum wieght needed for your average temperature range and then find a synthetic that meets the minimum cold viscosity with the highest hot viscosity. A synthetic 5w-40 would probably be your best choice. Use that with regular changes at 3000 miles.

I wouldn't change any other parts such as PCV or thermostat from factory specifications. Do make sure they are all working properly.

Vernon

 

[RossABQ]

SeaFoam is very good for flushing this kind of stuff. It is sold in the US at places like AutoZone or PepBoys. It was developed for marine engines, if you add it to the oil and drive it for50 miles or so, it really makes a difference on the internal surfaces and varnish on lifters, etdc. If the sludge can flake off in big chunks, tho, I'd be inclined to just let it idle (no load) so you can monitor for screen plugging as it comes loose.

 

[dicer]

mechanic, so you are saying the oil is coking? Usually sludge is a mixture of oil and water, if the oil is coking it will stick to the area of the high temps. So where is the inlet air vent located?

 

[Mechaniac]

Dicer, if you look around you'll see the oil industry and most people are refering to the light tar like coating on internal engine parts as sludge. It's coking in a classic sence on the hottest parts but it also breaks down the oil and free floating coked oil gathers and builds up everywhere it can. I'm sure sludge could be applied to either. I used a putty knife on the windage tray and oil pan to just skim off wads of sludge. It's like a flakey sticky goo. Very messy. Toyota's 3.0 does the same thing if you let it.

The inlet air vent is connected to the air intake ducting between the filter housing and the throttles. On these engines those hoses are known to get soft and collapse at the PCV and fresh air so make sure they are still stiff enough or get new ones from the dealer, they aren't very expensive and it beats trying to make straight hose fit right.

Vernon

 

[frankiee]

The engine has no real signs of "sludge" when I look under the oil cap.
I just want to know how to prevent it.
I just got the car back to day and I have to change the rear disks and power stearing belt.
I will change the oil tommorrow. I am going to put is 100 % synthetic (5 w 40 I think)
I will change the oil as per severe service intervals.

 

[drwebb]

FWIW, in rating the parts coming out of the engine sequence tests that qualify motor oil performance, deposits are residues that won't drain off the parts like the oil does, and sludge deposits are those that can be wiped off with your finger and varnish deposits are those that can't.