88 XJ 4.0L Engine Question

[2000F150SAS]

Have an 88 XJ with a 4.0 and 145k miles. Have a Rusty’s cone air cleaner and its leaking engine oil out it. It’s not pouring out but needs to wipe down after a week of driving. Also, just started leaking around the valve cover gasket (was replaced 6 months ago), leaking around the fill cap (it’s new) and leaking around the rear seal. The motor is acting like is building too much pressure and pushing the oil out. I checked all the vacuum lines on top of the valve cover and they are clear with good vacuum. Any ideas?????

Thanks

 

[jeepbme]

Rear seal is normal for 4.0's
How about PCV?

 

[2000F150SAS]

PCV Valve

Checked it once maybe i'll just replace it.

Thanks

 

[8379qtj10]

Well had one that the PCV system gum'd up from the inside, motor ran great but blew oil out the air box after PCV after PCV

 

[rob92xj]

Replace the CCV harness and PCV line it is building too much pressure, had a 87 Comanche in the other day that the customer made up his own and after replacing it with the factory parts the truck ran much better.

 

[rob92xj]

Rear seal is normal for 4.0's
How about PCV?

That is a diagram of the 91 and later CCV (PCV) system basically the same but the Renix(87-90) system is different.

 

[Chris_M]

It's also possible that your rings are worn, and you're getting lots of blow-by

 

[millercustomfab]

Sounds like rings and valves. Have someone do a leak down test on it to find out. That engine is one of the best ever made, but the first 10K miles are the most important in an engines life and there is no telling what that was like for that engine. At worst you need a rebuild, which may not be that bad depending on the condition of your components