Valve Stem Seals - 15w50

[elafilos]

Hello guys.

As some of you know, last year I got a replacement engine for my beloved KJ - which I bought new back in 2003. The engine came from a fairly shady dealer and had been sitting for quite a while in his shop (2-3 years). The engine was swapped, all issues where solved and the KJ is up and running since July 2024.

But (there always need to be a but), my valve stem seals are probably shot.

All the symptoms point this way:

1. Nice blue clouds after idling for long enough (5-10 mins)
2. Blue Smoke after coasting a lot (long descents for 5-10 km) then stepping on the gas
3. Discrete blue smoke after cold start (nothing major but smells)

No oil burning while running hard or revving.

Anyways, long story short my car is consuming around 1lt/1000km which is excessive and running into the risk of destroying my cats. A rebuild is planned for September and I was thinking of running it with a thicker oil aka 15w50 during summer as a temporary measure to ease valve sipping past my stem seals. Greek summer is hot - aka temps not dropping lower than 25-30c even at night.

Currently running LM 4100 5w40.

Any ideas / thoughts?

 

[KJowner]

Oh no! You have had some bad luck with that engine. You might have some luck with thicker oil.
When you do the rebuild check the valve gides for wear, if they are loose then stem seals won't help.
Another thought...
I have never worked on a V6 Jeep but I have changed stem seals without removing the heads on other cars, as long as the guides are OK, have a look on YouTube, there are some good videos.