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84 CJ7 Leak

Okay, so y'all helped me with my last dilemma (the mystery of the Jeep that would run for fifteen minutes then die for the rest of the day....I just replaced everything between the Fuel Tank and the newly rebuilt carb, and something did the trick!), so maybe you can help me with a question: This is my second twenty year old (almost) Jeep, so I understand the concept of old Jeeps leaking oil. No big deal. What I don't understand is why it sometimes leaks oil and sometimes doesn't. For about a year, the Jeep leaked nary a drop. Now (after the fuel problem), it leaks. I took it to my mechanic, and he said it was the rear main seal - he also said it's not worth fixing for the small amount that is leaking (he predicted $1000 to replace the seal right - any thoughts on that?). I remember on my 78 CJ5 when I bought it, the first thing I did was replace all of the fluids with synthetics. Big mistake. The thing leaked like a sieve. Perhaps on this one, I should use a slightly thicker oil or an additive for older engines.....any thoughts on that? I live in FLA, however, so I don't want anything too heavy. BTW: It's an 84 CJ7 with a partially rebuilt 258, Clifford Stage One and header. One other question: On a Holley Carb (Model 4160, I think - it's a 390 CFM with side hung float, see:

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how doI lean it out? Since I had it rebuilt, the exhaust gases is really richsmelling - burns your eyes if you get too close.....Which screw do Iadjust??? Thanks - I appreciate the advice!!!!Ron

Reply to
Ronald Keller
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Ronald Keller ( snipped-for-privacy@tampabay.rr.com) wrote on Monday 22 September 2003

07:52 pm:

Ron,

Could also be the oil pan seal. Mine's similar, except it stops leaking when I get half a quart below "full".

Reply to
Michael White

When an engine and driveline gets up to temp and stays there for a good long time, the gaskets and seals begin to do their own thing. Leak or stop leaking. My rear ring and pinion seal stopped leaking after a really good off-road season. I checked the level and it's still full. My Jeep used to leak somewhere between the engine and bell housing. After feeding it for a month, it quit after I started using it as an everyday driver. I guess the seals and gaskets revitilized themselves. Keep a close eye on them. Also, keep a good eye on the all the bolts to the trany, etc. I noticied mine had loosened some, causing seepage.

Reply to
Paul Brogren

said it's not worth fixing for the small amount that is leaking (he predicted $1000 to

Yes, your mechanic is a thief! It's about a two hour job to replace, plus the cost of the seal, pan gasket, oil & filter. If that comes to $1k, hey, bring it on over & I'll do it for you for $950!

It can alos be the vavcle cover gasket, the pan gasket or a host of other little places where it can spew. Best thing to do is de-grease the engine throroughly wit a good cleaner and high pressure wash. Then run it a good ways at temp & look for any signs of seepage. Start at the highest spot on the engine & work your way down & around. If there's no upper engine or external seal seepage then it's likely the main.

Reply to
Gerald G. McGeorge

After messing around the top of the engine or the valve cover it leaks?

99% it is the valve cover. Those suckers leak if you look at them sideways, let alone if you do work around them.

If you heat up the engine and while it is running run a clean rag across the rear of the head below the valve cover and find oil, you have found the leak.

The cover will drip oil down the back center and do a sweet imitation of a rear seal leak.

Even if it is a rear seal, it can be done in your driveway in an afternoon. You just have to drop the oil pan and pull off the rear bearing cap to replace the seal.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

R>

Reply to
Mike Romain

BEFORE YOU SPEND A SINGLE DIME ON THAT REAR MAIN SEAL, spend a couple of rolls of dimes on a valve cover gasket.

The oil gets pumped to the top of the motor and drips to the bottom again. The front of the motor is raised above the rear of the motor, and the gasket likes to break near the firewall, right next to the low point. Do you suppose if the oil flowed to the low point and pooled a little before draining back to the bottom, and there was a hole in the gasket, the oil would not be able to tell the difference in a hole that drains to the bottom, and one that drains to the outside?

If you really need a rear main, I'll do the job for $500, and a 12-pack.

Reply to
Jeff Strickland

Good advice. I went under the Jeep and tightened everything up - I didn' want to "overtighten", however, I just gave everything a good half turn (which required some elbow grease). There is still a leak, however.... I'll just keep my eye on it and on the oil level - Thanks again - Ron

Reply to
Ronald Keller

Where do you live? - I'll bring it over....

Actually, I think (I know) my mechanic was being tongue-in-cheek when he said it, but it seemed to be more involved that what it was worth - at least in his opinion.

Hey - if I was going to get it done - anything else I should have done at the same time, in that location?

Thanks for the advice - Ron

Reply to
Ronald Keller

Is it really as easy as that? No hassling with the engine or the drive shaft or anything else? That sounds so easy, I might be tempted to do it myself....

Reply to
Ronald Keller

Good advice, Jeff. I'll do that this weekend and see if it makes a difference -

Ron

Reply to
Ronald Keller

I can do one in 3 hours easily, hand tools with a cold beer on the ground beside me...

Figure a half day with 2 guys and some beer... ;-)

Cleaning the oil pan gasket is the worst part. I use a razor blade knife to get the worst, then I get a brass wheel for a drill and give it shit. A brass wheel isn't as likely to scratch or gouge it.

Then clean it and the block side really good before installing the new gasket. Acetone, coleman fuel, lighter fluid, brake cleaner, anything to cut the grease off totally. I like cork gaskets and a skim of RTV on the metal sides. Seems to work best for me.

The valve cover, which is likely your problem is an easy one to seal tight too if you do it right.

It has to be super clean, even a fingerprint will cause a leak, with a thin skim of RTV silicone on the cover and the head with a cork gasket between. You then tighten the cover 'finger tight' with a small 1/4 drive wrench and don't breathe on it after for 24 hours so the RTV cures.

It then won't leak.

My plastic one only has the two top valve cover bolts holding it on, no side bolts and no leaks... :-)

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

R>

Reply to
Mike Romain

I like to use a nut driver on things like this...

Earle

Reply to
Earle Horton

I can put too much on a nut driver, I snap hose clamps 'way' too easy... I like the little socket wrench. I hold the head steady with my first 2 fingers and thumb and use my baby finger for the torque.

Mike

Earle Hort>

Reply to
Mike Romain

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