rklettke

I've got a 98 XJ with the 4.0 and aw4.

I upgraded to banks torque tubes and the 99+ intake (haven't started it yet because I need to figure out vacuum lines...) Anyways, there seems to be a lot of oil inside the old intake and on the intake ports on the head. At first I was thinking blow by but I don't have any oil inside the air filter anywhere I can see. Could the oil have seeped past my manifold gasket? (my valve cover leaks...)

Also I replaced the two elbows on top of the valve cover a few months ago. Pcv valves? One is just clean through I think. Or maybe they both were...

rklettke

Also, if anyone could give me the bolt size for the iac... I lost one of them and I can't get it off without removing the TB.

Alex V.

Severe blow-by can cause positive pressure in the valve cover and PCV system, but I'd first make sure your PCV valve and hoses are connected and working right. At idle there should be zero pressure or slight vacuum at the oil fill cap - if that isn't all right it could allow oil droplets/vapor into the intake. If oil from the leaky valve cover was getting inside the intake that'd mean you have a doozy of a vacuum leak and corresponding performance issues.

rklettke

I'll have to check that stuff. Do our xjs have an actual pcv?

cruiser54

It's very normal to see some caked on black crap in the intake runners.....

shooptube

Cruiser is right. This was what mine looked like when I pulled the intake.

rklettke

Yep that's just how mine looked.

salad

The CCV's job is to suck oil vapours out of the engine and into the intake. Totally normal. Older vehicles just barfed that stuff onto the road.

If you want nasty, look at a diesel with EGR and CCV from 1999-2006. The soot mixes with oil and creates a lot of hard gunk.

Clean it up and carry on!