Oil spray at highway speeds

Oil spray at highway speeds


Columbus, OH
1982 CJ5. Has a 232 engine (78 model), 3.8 liter straight six. 3 speed P.O.S. transmission. 31" tires, no lift. Fairly stock in that regard.
Hey folks,

I just purchased my first older model Jeep (82 CJ5). It has the 258 6 in her, T-150 3 speed (I'm pretty sure it's the T-150 at least). I noticed a small leak by the gasket valve cover when I bought it and we fixed it. However, now as soon as I hit the highway an oil tornado ravages the passenger side of the engine (to the point it's on the hood and leaking through the firewall onto the floor). It doesn't leak at all when idling or driving around town, we cleaned it and tested this three times. Only when you get up to 50+ does it start spewing. It wasn't spraying at all when I bought it. So another words we fixed the small leak and made a monster leak. Any suggestions on what to do from here? There's no oil on the driver side at all, just the passenger side.

A pluged PCV
It could be blow by at higher RPM is Building pressure and causing the 'new' valve cover gasket to leak of the passenger side. Double check the valve cover gasket. Sometimes they will slip halfway out of place when putting it back on.

Shake the PCV valve. It should rattle. Or try putting a straight fitting to the air cleaner. If the air cleaner fills with oil, you probally has cracked rings causing all that blow by.
Sounds like maybe you left something unconnected?

Where's the oil coming from?

I could see oil blowing out the dipstick/valve cover hole if you left the pcv valve out.
We were thinking it was the PCV valve since the leak is definitely from the top down. We can't pinpoint where it is exactly because it only happens at highway speeds and when we open the hood oil is literally everywhere. The valve itself still rattles when you spin it, but I've heard that doesn't necessarily mean it's still working? Might be wrong though. We're going to pick up a PCV and replace the hose as well and see of that fixes it.

Does this sound like a possible RMS leak? I've never had one and have no idea what to expect if that's what it was. Thanks for all the help though!!
what does RMS stand for :confused:
Rear main seal
I'm with 73CJ. Sounds like blow by. Pop the oil fill cap off, bring it off idle to the RPM it leaks at. There shouldn't be a ton of "air flow/oil coming out. If there is you need to check the compression.
It's not a rear main seal. When they leak you will not have oil under the hood it all will be underneath.
@73CJ and mtnwhlr - That's our next step, we picked up the PCV and the hose today and are going to strap them on tomorrow and take it out on the highway and see if it's still blowing oil all over the place. If so we'll check for compression issues.

On a side note, for the compression test you need to do one test without using a few drops of oil and a second test with a small amount added into the cylinder (if it's not within 10%) correct?

I'll post an update tomorrow evening once we determine if it was the PCV valve or hose (keeping my fingers crossed).
I don't know about the oil. Just pull your coil wire so it's not trying to start and I always hold the throttle wide open. With a good motor they should all be within 10 to 15psi of each other.
If the engine seems to run ok, I don't see blowby causing what you describe as such a large volume of oil. On my turbo'd or SC's cars, I had a couple mishaps and they would blow a bit of oil out the dipstick. But I was literally blowing boost into the crankcase. A quick way to check for blowby is to take the oil filler cap off while the engine is running. You should see what looks like exhaust or steam coming out if you have blowby. Sometimes you can kindof hear it when you cover and uncover the hole. When I have dealt with this, I still didn't have a ton of oil spraying out. I even forgot to install a pcv and drove my car for months and never had oil spraying everywhere.

It seems like something must be flinging the oil. Is the oil concentrated in a spray pattern around the belt(s)? Or if the oil cap were off entirely, I could see the rockers throwing oil around. Those are the only two instances Ive had where oil was flung all over. Oil cap off and a leak by the belt.

Ive seen situations where oil is coughing out the carb; but there were significant mechanical problems and it ran like :dung:.
The engine runs great, no sputters at idle or problems picking up or maintaining any speed. We don't think it's leaking out of the PCV valve, but instead the valve is clogged which is forcing it out of every weak orifice in the engine (possibly dip-stick tube and passenger side of the valve gasket cover). We'll check for blow-by tonight after we check the PCV valve.

Secondly there's no oil near the fan or near the belts at all, so nothing is flinging it. We checked that as soon as we opened the hood and saw the disaster. It's more focused towards the back of the engine by the firewall and back end of the engine. We're 'hoping' that if the PCV is clogged, oil is leaking out of the valve cover gasket and with every bump that makes the Jeep get lift-off the oil flings itself around. Whether or not that is possible OR true we'll determine after we get it back in the garage.

Regardless we'll check for blow-by as that seems to be a common recommendation! Thanks!
Is the engine overfilled with oil?
@rlitavecz: We actually did have about a quart over the full-mark on the dipstick when we checked on Sunday but we drained about two quarts out and added it more carefully. It was sitting about two-hairs shy of full after we drained/re-added. We assumed (wrongly) that it was just trying to push that quart out. The highway test resulted in oil everywhere though and it dropped to about 1/2 between the add and full markers.
Quick update: we changed out the PCV valve and hose, put some oil in it so it was a couple hairs above the 'full' mark on the dipstick, and got her up to 55mph. There didn't appear to be any leaking or spraying, also did some hills and etc. to get some pressure built up in the engine. Dipstick reading remained the same after we parked it back in the garage. We took it down to the car-wash and hosed out the engine/hood so there was no oil residue remaining from the previous sprays and have it parked in the garage to dry for the night. Going to try getting it up to 65-70 tomorrow and maintain that speed for about 15 minutes and see if there's any spray at all. Will let y'all know how it goes tomorrow evening. Thanks again for all the help!
Just to add to this s!#*-show. We took it up to one of our good friends (a mechanic who has a few Jeeps of his own) and he could see it leaking from the valve gasket cover. We're apparently inept at spotting things. Turns out that our rubber valve gasket cover is a p.o.s. He recommended just using a gasket sealer and taking the rubber thing out entirely. So we listened, sealed it up, and started to bolt the valve cover back down. Needless to say we lost the back screw in the process, tried to put in a new one, and snapped the s.o.b. and now have half of a screw in and no way to get it out. She'll be headed up to the shop in a couple days to have them drill the screw out since we don't have the tools to do it. Probably just have them seal it up with the gasket sealer too cause we're about fed up with the damn thing.

So :chug: to another few days of waiting to get this thing resolved.
I know those bolts are small but you can get it out.

Pull the valve cover off and see if there is any piece of the stud sticking out. If there is you can do two things:

Try using a GOOD set of pliers to grab it and turn it out. I say good because channel lock makes a set just for this. It has some sharp teeth at a good angle that bite. Generally, a common set of pliers will not bite well enough.

Try grinding a groove into it for a flat head screwdriver.

If it is flush with the head, try using a small chisel and tap out at the edge in the correct direction to back it out.

If you can't do any of those, go buy a good extractor set with left hand drill bits. Cheap sets just have the easy outs and they tell you to drill a hole with a regular bit. This just tightens the bolt. Most times the left hand drill bit will bite into the bolt and back it out for you.

Thats what I did in that order when customers came in with your problem.

You can do the same stuff a tech will do, you just need the tools.
We got the bolt out and sealed it up. Drove it 2 1/2 hours home to Columbus and the damn thing had oil all over it again. Checked the dipstick and it dropped about half a thumbnail (was sitting about half a thumbnail over full when we left, leveled off at full now). Ran fine the whole trip, no sputters or rough driving (except what you'd expect driving 120 miles in a jacked up Jeep).

Taking it up to the shop today to see if they can spot the leak in it, cause we're about fed up with searching. It did switch to leaking back on the driver's side rather than the passenger side. Seems to be by the driver's side valve cover (and back by the firewall) and around the carburetor now.

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