Thread: 258 breather/pvc blow by problem

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My son has a 258 AMC Jeep that is blowing oil out the top from some where and he's wondering if removing all of the emission *&$@&$@ is advised or should he install an oil catch bottle?

Any other ideas would be welcome and I'm sorry I can't provide more info but I've been assigned to try and find out all I can without seeing it or working on it.

If anyone has any questions I can probably get the answers from a phone call to him.

Thanks for any help.

Em

Em, the 258CI engine was only used for four years (I think '87-'90), and the smaller 4.0L (242CI) engine actually boosted HP by quite a bit, especially when they brought in EFI. All of the I6 engines tend to be pretty much bullet proof, and stand up to a ton of abuse, but once they start blowing oil it's generally indicating a blow-by problem and time for rings. Have him do a quick compression check and I expect he's going to find a cylinder or two low. If he only finds one low one he might get by with just re-ringing the engine, but if they're all running low he ought to consider a full re-build or a replacement engine. "Crate" engines for Jeeps are very common, and likely as cheap or cheaper than trying to do a garage rebuild without having all of the necessary tools. The "emissions *&$@&$@?\" is not the problem here, and IMO he really needs to leave it functioning to pass his annual inspections with no guilt.

If the compression check is all good then he should look at the PCV & breather. The breathers on those 258's can be pretty restrictive, and if they get a little oily they pretty much plug, and oil looks for easier paths to flow.

thanks Roger, I'll certainly pass this good info along to him - - - - maybe he just needs to replace the pvc, breather caps and hoses first and then see what gives?

TA

Em

Originally Posted by MelloYello

thanks Roger, I'll certainly pass this good info along to him - - - - maybe he just needs to replace the pvc, breather caps and hoses first and then see what gives?
TA
Em

Em, a compression check costs nothing, and will tell him volumes about the health of the old 258. He can borrow a compression gauge from his local auto parts box store, like AutoZone, O'Reilly's, NAPA, PepBoys, etc, if he doesn't have one, or if he lost the one he "borrowed" from you....

Along with Mr. Spears suggestion, I'd say lift off the valve cover and make sure the oil returns are open. If it's a high mileage vehicle of unknown origin - perhaps he's the second or third owner? - then there's a chance the returns are blocked and it only takes the cost of a gasket to find out.

Good Point, Mike, we're gonna do an oil change when it warms up a bit and I think I'll get him to pick up a gasket and we'll do the oil return check first.

Roger, he hasn't lost but only misplaced the one he borrowed from me along with the dwell meter and etc and etc.

Em

Originally Posted by MelloYello

Good Point, Mike, we're gonna do an oil change when it warms up a bit and I think I'll get him to pick up a gasket and we'll do the oil return check first.

Roger, he hasn't lost but only misplaced the one he borrowed from me along with the dwell meter and etc and etc.

Em

Been down that road before and generally there is very little light at the of the tunnel

Originally Posted by NTFDAY

Been down that road before and generally there is very little light at the of the tunnel

I'd say that plugged oil returns is a false hope. The 258 is, at a minimum, 25 years old (assuming it's not been changed out before). Check the compression, and be ready for the news that it needs to be rebuilt.

FWIW, he's gonna sell it ASAP but wanted to try and trouble shoot this first - - - - - One more QUESTION if I may inject it here - - - - WHAT DEGREASER do Y'all recommend for cleaning up this kind of mess????

Em

Originally Posted by MelloYello

FWIW, he's gonna sell it ASAP but wanted to try and trouble shoot this first - - - - - One more QUESTION if I may inject it here - - - - WHAT DEGREASER do Y'all recommend for cleaning up this kind of mess????

Em

IMO, the easiest is to drive into a bay of your local spray it yourself car wash, put a plastic bag over the distributor and duct tape it, and let high pressure hot soapy water do the trick, but in some places you may want to do it later in the night, when they don't have an operator there. Lots of them have a "degreaser" setting (which tells you they have a grease trap on their drain), but spraying it down with Simple Green, Purple Power or something like that, and letting it soak for five or ten minutes works, too. You can do much the same thing with a pressure washer in your driveway, but it's cold water and you'll have all of the greasy mess to deal with.

Thanks Roger, I think we could swing that move in one of the less active car washes - - - - ANOTHER question, if I may? During my lifetime (ouch) I have owned and had friends that had cars with worn rings and they just used oil and smoked a lot. If this is the problem, then why is his Jeep spraying oil all over the engine bay instead of just smoking and using oil????

Excessive pressure in the crankcase, em The pcv is plugged and that pressure has to find somewhere to go.

Thanks Ken, looks like a good PVC enema is in the works real soon.

BTW, if I may hi-jack my own thread here - - - - they are coming out with a Buddy Holley Hologram Show that will be touring the Country soon so watch for it in your neighborhood.

Em

Thanks for the heads up, em
On a side note, when I got back from Okinawa in June 64 my dad bought me a really cherry 57 Ford Custom 2 dr post and since it was in California it was converted to a pcv system. The road draft tube was plugged and a mickey mouse pcv was put into a valve cover, and if memory serves me right, a hose from the air cleaner to the now closed cap on the oil filler tube. Sometime in Sept. the pressure built up so bad it shot the dipstick into the hood and spewed oil all over the right side of the windshield. Goodbye bottom end as it stated to smoke and make all kind of neat noises which caused me to get rid of it as soon as I could and I was shortly heading home to Ohio to pick up the 36 5 window anyway.

Originally Posted by rspears

IMO, the easiest is to drive into a bay of your local spray it yourself car wash, put a plastic bag over the distributor and duct tape it, and let high pressure hot soapy water do the trick, but in some places you may want to do it later in the night, when they don't have an operator there.

Reminds me of a older guy, who tried to strip paint off a International truck in the 70's, put a slurry of lye and water on it, drove it 10 miles to a out of town car wash and plugged the drains with all the paint that came off, somebody came by and asked what he was doing and he said " This things got to much pressure, its blowing off all my paint" He swears he drove it home in bare metal afterwards. (I tried it on a enamel paint job out of desperation but it did nothing but heat up my sheet metal)