Leaky rocker covers

[KWAWD]

Noticed the other day that there are a couple of leaks in both rocker covers.
Not seeping, just a show of black "powder" stain in those areas.

I was surprised as the KH has no visible leaks after 200,000 k's and the AWD has only done 40.

Is there much work in replacing these? I notice the rear is obstructed by the plenum chamber.
Is this something i should get done urgently, or does it matter if it waits a while?

[Madmagna]

Clean it, check the bolts are tight (not over tight) and watch it for a while

You really can not compare 1 car to another in this sense, the mileage really does not play a part either as a low mileage car often has had lots of short runs, many more heat up and cool down cycles thus gaskets can go hard

[MadMax]

Noticed the other day that there are a couple of leaks in both rocker covers.
Not seeping, just a show of black "powder" stain in those areas.

I was surprised as the KH has no visible leaks after 200,000 k's and the AWD has only done 40.

Is there much work in replacing these? I notice the rear is obstructed by the plenum chamber.
Is this something i should get done urgently, or does it matter if it waits a while?

The black is carbonised oil, pretty hot there as the oil is close to the exhaust. If it gets bad, you will smell hot oil and see blue smoke rising from the rocker covers at the exhausts after a run.
Pull one of the front plug covers off, chances are the spark plug seals are leaking too.
Yes, you can't compare cars. Bought a TL with 136,000 km, leaking gaskets with blue smoke rising off the exhaust manifolds and oil showing in the plug tubes. No such problem with the TJ I bought 2 years ago with 111,000 km on it.
On the TL the rocker cover bolts were very loose. Tightening the ones I could reach to 3.5Nm with a quarter inch torque wrench solved most of the leaks, but of course I can't reach most of the rear bolts, and as there was oil down the front plug tubes, it all needs to be done.

[magnaforce]

Just had mine done on the tj, 116000km at moment, my rocker cover gaskets started doing same thing at about 104000km, i kept putting if off every service because only got worse very gradually but then it caught me off guard & started to leak slightly down side of engine & onto the headers! so at 115000km service I had them done. I should of done it earlier, would of saved me alot of engine cleaning !

[KWAWD]

Thanks guys, i'll check the plug sockets once the cars back from the repairer, and try tightening up the bolts.
I guess theres a tightening sequence, but i'll just be doing a quarter turn thing unless they're really loose.

If i do need to have these replaced, is there much work involved? I assume remove the plenum, plugs, covers?
What about injection rails and wiring? Is there a gasket for the plenum? Does oil need to be drained?
Apologies fir all the questions...

[MadMax]

Don't need to drain oil.
Steel gasket on plenum, reuse.
Tightening bolts: Use a 10 mm spanner, can just get to the back ones without removing anything, might fix the problem if the tube seals aren't leaking. Only need to tighten the outer 3 bolts on each cover seeing this is the lowest point where they leak. Some of mine needed over 1 full turn to get them up to 3.5 Nm - probably gasket collapses over time.

[KWAWD]

Hmm, was just reading some posts about "thin" oils and seals which got me wondering. I used a 5W full synthetic in the last two flushes. Prior to last week i hadnt noticed these rocker cover leaks. Can there be a connection?

[dreggzy]

5w is pretty thin. Try going to a 10-50 or even a 15-60. Driving short distances often relate to this issue as the hot/cold cycles harden the gasket. I don't think oil viscosity would have much to do with it.

[MadMax]

Prior to last week i hadnt noticed these rocker cover leaks.

Were you looking for it though? These little things sneak up on you, not smart to assume it started 60 seconds before you looked.
Oil viscosity has little effect, as long as your PCV system is in good condition and pulling a bit of a vacuum in the crank case. If the crankcase is running positive air pressure because the valve or hoses are blocked, leaks will appear at the weakest spots - cam covers, oil filler cap, cam/crank seals.

[KWAWD]

5w is pretty thin. Try going to a 10-50 or even a 15-60. Driving short distances often relate to this issue as the hot/cold cycles harden the gasket. I don't think oil viscosity would have much to do with it.

Its probably had a history prior to me of short trips. Now its getting a workout Hmm, if u dont think viscosity makes the difference then why did u say switch to 10W? Actually i wanted 10 on the last service but they didnt stock it. I may switch over again soon.

Were you looking for it though? These little things sneak up on you, not smart to assume it started 60 seconds before you looked.

Well i've been watching it occassionally. I do recall it was "as new" looking back in Jan, but i couldnt say when it started to show.