[AllanC]

I am attempting to help a relative with a 1999 Chrysler Cirrus with 2.5 liter V6 and 4 speed automatic transaxle. Odometer reading is 236,000 miles. Car has started experiencing severe misfire to the extent that the check engine lamp flashes repeatedly when running. Engine while running is exhibiting blue smoke which seems indicative of excessive oil burning in the combustion chambers.

I am going to perform a compression check on each cylinder to see if there are variations in pressure and which might indicate ring and/or valves problems. Also I am going to check and replace spark plugs and ignition wires to see if the severe misfire can be eliminated.

Is the 2.5 liter Mitsubishi designed V6 susceptible to the oil seals popping off the valve stems? This was a problem on the Mitsubishi 3.0 liter V6 Chrysler used from 1987 through year 2000? Are there any other problem areas I should inspect that are peculiar to this Mistsubishi family of V6 engines?

 

[dana44]

Plugs and wires and cap, check compression during that job, yes, that is the proper thing to check first. From there, if the miss goes away after the tune-up, then yes, problem fixed, if it doesn't, or if the compression is low in one or two cylinders, squirt a couple drops of oil into each cylinder and see if that stops the miss by raising the compression (sealing the rings better), or if it continues, next thing to check is then the fuel injectors themselves. With this many miles, and if the miss continued with the oil in the cylinders, rings can be ruled out the greatest, but time to pull the heads and see if there is a burned valve. At this time, the injectors themselves need to be checked and cleaned, what with the fuel/air ratio maintained through the electronics, good chance the problem of a burned valve (if it is that), was the restult of a bad, sticky, dirty, injector.

 

[mrneuro]

We had two 3.0L's in the family, and the valve seal/guide issues didn't happen overnight. They started with slight smoking and oil consumption at idle around 50-60k and got worse fairly gradually. If the blue smoke and CEL started happening quickly, you're probably looking at something more serious.

If Check Engine is flashing, check for codes. Make sure the PCV valve is working properly.

 

[John Wood]

The computer error codes may give you a hint, especially if it is showing 1 or 2 cylinders and it is repeatable after clearing the codes. I agree that wires, plugs, distributor cap, and rotor are all good possibilities unless you can confirm that they have been recently replaced. Inspection of the plugs may tell you a lot.

I hope this setup is a bit easier to work on than the 3.0, but probably not. I just did the valve cover gaskets, cam plugs, spark plugs, and even replaced the alternator brushes in my minivan this past weekend. Once you remove all that you need to for access to the rear (right) bank, you might as well do as much as you can because the labor is substantial. Good luck and nice to hear about the high mileage on these 2.5's.

 

[AllanC]

All very good suggestions. Unfortunately this engine in the Cloud cars is akin to working on a 90s GM front wheel drive. Thanks.

 

[digitalrailroader]

I'm not sure if the Spark Plug Tube Seal Problem in the Neon Engines extends to the 2.5L V6s, but that's another suggestion.

 

[ImperialCrown]

With the upper intake plenum off, you will have good access to both the distributor and rear bank plugs and wires.
Some of these engines did smoke from worn valve seals. Seals can be done with the heads on the car and the special tool (MD998772A).
Give yourself plenty of time for this service. A new timing belt, pulleys and w/pump can also be done if the car is going to be kept. The rings and bottom ends of these motors were very durable.


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