Oil Leak Question

Discuss topics related to the CA18DE and CA18DET series engines.
User avatar
sjbsuperman1425
Posts: 2889
Joined: Tue Nov 06, 2007 2:24 pm
Car: 1989 Nissan 240sx
CA18DET
Location: Bay City, MI
Contact:

Post

Well everyone, I'm kind of puzzled at this oil leak I have come across

I have the engine on a stand and have been disassembling it to replace the water pump and front and rear main seals. In the process, I have found that there is both a decent oil leak at both the front and the rear of the engine, BOTH of which start just under the valve cover gasket area. So let me break it down:

The Front:
My concern is that I may have possibly installed the camshaft seals incorrectly. I used some moly grease (I think) the last time I replaced them and don't know if it just didn't seal correctly. The leaking starts just around the area but I'm not sure if that is where it was leaking from.

The Rear:
I''m 90 percent sure that the half moon seals were leaking and causing most of those problems.

A little site note, the valve cover screws were starting to back themselves out of of their holes. My guess is the valve cover just wasn't sealing and caused a pretty decent sized oil leak on the front, back and sides of the engine (mainly at the front and rear though). I am replacing the factory "screw" bolts and opted for allen head bolts and will torque those to spec. Hopefully these won't back themselves out.

Thoughts, comments, concerns? Thanks for taking the type to help me out.


User avatar
themadscientist
Posts: 29308
Joined: Tue Nov 12, 2002 3:30 pm
Car: R32 GTR, DR30 RS Turbo, BRZ, Lunchbox, NSR50 Sportster 883 Iron
Location: Staring down at you with disdain from the spooky mountaintop castle.

Post

Never had a CA18 that didn't leak around the valve covers. You are stunningly normal I would say.

User avatar
float_6969
Moderator
Posts: 19853
Joined: Mon Aug 26, 2002 1:55 pm
Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
2015 SV Leaf w/QC & Bose (daily)
Location: Topeka, Kansas
Contact:

Post

Yea, unfortunately, they tend to leak oil there...everywhere really, LOL. I think it's a lot to do with the PCV system. My last engine rebuild was the first time I was able to get the engine to stop leaking from all of the seals and it was the first engine that didn't blow the dipstick out. I had the 90°fitting behind the oil filter routed in full size hose up to nothing at first and it worked well at relieving pressure (I got NOTHING out of the valve cover ports), but it sprayed oil everywhere. So I tried stuffing some plastic scrubbers down the tube, but that didn't really help. Once they got saturated, it did the same thing. So I put an SR20 AOS on it and that stopped the oil from spraying everywhere, but then air started to come out of the valve covers. I just left it all open to the atmosphere eventually and it all seemed to work OK and none of the oil seals seemed to leak, but I only ended up with a couple hundred miles on that motor before I discovered the broken spark plug and damaged cylinder wall.

This go around I'm going to build a custom exhaust venturi and feed the crankcase vent straight to a suction created from the exhaust.

User avatar
sjbsuperman1425
Posts: 2889
Joined: Tue Nov 06, 2007 2:24 pm
Car: 1989 Nissan 240sx
CA18DET
Location: Bay City, MI
Contact:

Post

I think a lot of my problem was that the 5/8" hose at the 90* above the oil filter had collapsed on mine and basically pinched itself off not allowing the gases to go anywhere but out the seals and the valve covers. Also blew the dipstick out a couple times. I mean I'm to the point now where I can access all the seals on the engine, but I just don't know what is leaking lol

User avatar
float_6969
Moderator
Posts: 19853
Joined: Mon Aug 26, 2002 1:55 pm
Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
2015 SV Leaf w/QC & Bose (daily)
Location: Topeka, Kansas
Contact:

Post

Yea, if that hose was collapsed, that was likely the cause of most of your issues.

User avatar
sjbsuperman1425
Posts: 2889
Joined: Tue Nov 06, 2007 2:24 pm
Car: 1989 Nissan 240sx
CA18DET
Location: Bay City, MI
Contact:

Post

Say my front main was leaking because the crankcase was over pressured because of the collapsed hose, would it be safe to assume that it would leak after the collapsed hose was replaced and the cause, corrected?

User avatar
float_6969
Moderator
Posts: 19853
Joined: Mon Aug 26, 2002 1:55 pm
Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
2015 SV Leaf w/QC & Bose (daily)
Location: Topeka, Kansas
Contact:

Post

No, it won't necessarily leak, but they're cheap and easy to replace. LOL

User avatar
sjbsuperman1425
Posts: 2889
Joined: Tue Nov 06, 2007 2:24 pm
Car: 1989 Nissan 240sx
CA18DET
Location: Bay City, MI
Contact:

Post

yes they are. I bought the OEM Nissan CA gasket kit so I plan on using as much as I can lol. Still waiting on local Nissan dealer on parts though so I'm kind of dead in the water so to speak.. Thank Ryan and TMS!


Return to “CA18DE / CA18DET Forum”