Jeep Garage  - Jeep Forum banner

4.7 oil filler cap sludge problems

20K views 8 replies 5 participants last post by  emtclark 
#1 ·
Hi guys,
As always, I did a search on this first but didn't come up with anything useful. I have a bad problem with that yellowish, condensation-like sludge that is coming in from the PCV valve tube that empties into the oil filler tube. I've even installed the recommended plug that is supposed to eliminate the problem but it is STILL getting down into my crankcase! :(
Anyone else had this problem? I'm read to plug or disconnect the stinkin' thing but I'm sure it serves a vital purpose...
 
#3 ·
The sludge like stuff is not coming from your PCv, but it is condensation of moisture and oil mist into the cooler oil fill tube. Especially when you drive short distances in cold weather it happens. The PCV valve is there to take away bad gasses (from blowby) and moisture from the crankcase area and its not wise to plug it, because the bad gasses and moisture will mix with the oil and can cause sludge.
 
#6 ·
Thanks for the feedback. Unfortunately, the yellowish sludge-condensation is actually dripping out of the PCV tube so I doubting it's just "accumulating" within the filler tube. I do drive short distances to work each day (and enjoy "challenging" some of the other race-minded folks during my 10-mile trek to & from work). I am going to try the Sea Foam. Glad the TSB says, "Will not damage engine components"...:D
 
#8 ·
The sludge like stuff comes from an oil/moisture mixture mist which condensates on cooler areas, such as the filler neck. But it will also be drawn into the PCV line, since there is a vacuum in there. So also in that line, which is relatively cool when driving short distances, the condensation will occur. After shutting off the engine, some stuff can come dripping out of the PCV opening in the filler neck. Just take the car on a long drive and let it heat up sufficient and all moisture will disappear and the sludge like stuff as well.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top