1989 4.3 mystery oil leak :-(

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Oy.... guess I should have looked online before I went crazy! It sort of stopped raining enough for me to open the window on the camper top.... and I went through a little more than a can of brake clean. Spray, wipe, spray wipe - yeah it's nasty stuff, even the low VOC non-chlorinated stuff is still nasty.

While I was out buying brake clean, I did in fact also purchase valve cover gaskets. Like flipbro said - rule them out. Although I did not see any evidence of them leaking, the use of RTV silicone on both sides of the rubber gasket is sad. On the plus side - the valve train, springs and other internal look brandy-new. no sludge, etc...

Things that I have found in the last few days... Intake manifold not leaking (all dry). Oil appears from above head gasket, but not as high as valve covers. Oil is evident on both sides of motor from motor mounts back - more dominant on port side of motor (maybe due to more stuff hanging off motor?). If it was distributor... I can't see how it would get around the bosses on the rear of the block... so I'm still friggin baffled.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,464
Ayuh,..... Dust the Suspect areas with baby powder, 'n fire it up,....

The Look for oil streaks,...
The Cleanest lookin' oil stains you can find, are very, Very close to the Leak,.....
The movement of clean oil, keeps the leak area lookin' clean, but oily,.....
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Starting to sound like head to block leaks. I have a huge issue with intake manifold with both oil and water, but that is on the same type engine that you are dealing with, but in my SUV. So I will be changing mine shortly but with marine gaskets instead of the plastic types. They get brittle quickly from heat and cool cycles and crack and leak and I am not going back with plastic and rubber ones again... But yours sounds like head gaskets. One thing I have to say is, you never ever retighten pan, valve cover or any other type gaskets by feel. Each gasket installation takes a specific torque tightening to keep it from leaking. Too many times the tighter you tighten the bolts, the more they leak because you actually crush the gasket and it splits them and pushes them out of place... I learned that the hard way. Now when I change any gasket, I religiously follow the manufacturer's specific torque requirement and never have leaks again. I have rebuilt many transmissions over the years and after using a torque wrench and only tightening the pan bolts to the proper torque setting, I have not had even one little leak anymore. And another good thing to do is reverse tap the pan bolt holes back to flat before replacing them. Otherwise they are already funnel shaped from somebody tightening too much. So straighten them back to straight and flat before reinstalling them. Works every time.
 

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Ahhhh,,, when I said I got a turn or four on a bolt, believe me I was not wrenching down on them. I'm talking one finger on a box wrench, as I too have had experience with over tightened gaskets (and the countless oil pans and valve covers I have learned to straighten)

With a head to block leak... I would almost tend to believe that I would see a drop in compression? but I guess it actually does not have to be blowing through from the cylinders to cause an oil leak, now does it? But that would explain the oil on the back of the motor as well as the side of the motor - sadly, the oil is leaking on both sides.
 

Watermann

Starmada Splash of the Year 2014
Joined
Jan 12, 2013
Messages
13,747
I would be wondering about the guy who did the "refresh" I have to assume that the motor is a reman? I would be calling the guy, it sounds to me like something is very wrong with the gaskets if both sides are pouring out the motors life blood by the quart. Both sides are leaking so it could be the head to block gaskets that were used might be the wrongs ones.

Doesn't seem like your getting any where close to find a leak right now so here's another idea.

To find the leak you can rent a oil pump primer attachment for your drill at an auto parts store, remove your distributor and run the drill to build up oil pressure without having to run the motor (which makes it scary to have your face near)
 

flipbro

Master Chief Petty Officer
Joined
Feb 8, 2013
Messages
830
I dont think there are oil pasages through the head gasket. Oil gets pumped up through the push rods.. Head gasket is water and compression
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
I dont think there are oil pasages through the head gasket. Oil gets pumped up through the push rods.. Head gasket is water and compression
How do you think the oil drains back down to the crankcase then?
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,296
I would clean the block as thoroughly as you can with dawn dish soap. clean the bilge too. get it as sparkly clean as you can. Then run the boat on muffs with a bright flashlight, mirror and you will find the leak.

to get oil coverage like you are mention, you could have a fine mist of oil blow-by coming out of the valve covers and then condensing on everything.
 

flipbro

Master Chief Petty Officer
Joined
Feb 8, 2013
Messages
830
The drain holes in the head drain into lifter valley no were does it travel throughth head gasket..o and gravity
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,296
I have had oil leak between the head and block. it showed up as leaking around head studs. oil was seeping from the return holes running between the head and the MLS gasket to the outside bank of bolts and weeping thru.

As I stated, clean everything, then fire it up. you will find the leak.
 

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Holy Crap... it's been a month and I haven't touched the boat! ;-( Life.. well work got in the way. Took this week coming up off to hopefully get this mess sorted out - so that I can start working on the things I KNOW need attention (like rebuilding the cockpit, since it was stripped out to be more of a fishing boat).
I did however get a dye kit for the boat.... and, well.... ummm.... a bilge boom - just in case :) Let's see how this weekend progresses! My bodd has my keys and my phone.. so only things standing in my way this week are honey-dos.
 

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Okay... weekend was a bust for the boat :-( spent the weekend fixing things on my aunt's house and my mother's house.... Sometimes it sucks to be handy :) Got the compression test done today. All between 150 and 170 on a cold motor, all plugs out and closed throttle. Since they are all pretty close (20PSI of each other on a cold motor) I don't think I have a dead cylinder causing my problem. Tomorrow - if all goes well I will dump the dye in the motor and run it for a while and start searching. Maybe I got lucky with just the valve cover gaskets... but I want to be sure before I put it in the water again.
 

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
WEEEEELLLLLLLLLL..... Got the dye in the motor. Ran it for about ten minutes, went through different RPMs, etc.... noticed the bilge turning yellow - YOWSA! shut the engine down and started looking. First thought was "Oh Crap!" Starboard side is covered in oil and dripping down from flywheel. First thought is rear main is GONE! looked on port side and low and behold a greenish glow did appear on behind the oil filter.. ran it up to the distributor. Yes, there is a steady stream coming down from the distributor - so I am thinking the oil makes it way down... hits the flywheel and gets sprayed all over the starboard side of the engine?? Guess I will be pulling the distributor and replacing an O-ring this afternoon. :)
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,464
Ayuh,.... Changin' the distributor gasket is an Easy fix,....

I believe you'll find it's a flat paper gasket, not an o-ring,...

Ya Do know how to pull, 'n properly drop in the distributor, Right,..??
 

dozerII

Admiral
Joined
Oct 25, 2009
Messages
6,527
Any chance your 4.3 has the oil pressure switch next to the distributor? If it does check it real close cuz it would be a more likely spot for your oil leak than the distributor as it is under full pressure.
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Any chance your 4.3 has the oil pressure switch next to the distributor? If it does check it real close cuz it would be a more likely spot for your oil leak than the distributor as it is under full pressure.


Rear intake gasket.....:facepalm:....Hopefully its the switch
 

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Pull and install a distributor... yeah - TDC, a few scribe marks(or white marker) and I might get lucky and nail it on the first drop back in! :) Sorry... O-ring thing is a Mopar thing. Paper gasket seems a bit flimsy.
When I traced the dye up.. I did look very closely at the oil pressure switch (due to the oil on the motor) and inspected the rear of the intake really closely. There are what appears to be two places under the distributor where the oil is coming out. now dye around the pressure switch and no dye at rear of intake. I will TRY to get a picture before I tear into it this morning. Not sure how it will work.

I really really hope this cures the oil leak issue. Next will be to get the oil and dye cleaned up off the motor and out of the bilge and try this again to make sure no more other little gremlins in there.
 
Last edited:

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Well crap.... as I looked deeper into it, being the motor was cool - yeah.. its the rear of the intake gasket that is leaking right UNDER the distributor. Of course I cant be sooooo lucky for it to just be the distributor. But not too hard to do either. Just a bit more than a half of an hour job ;-)
 

moparron

Seaman
Joined
Jan 22, 2015
Messages
52
Intake has a new gasket....funny, but Mr. Silicone everything left a gap in the goop on the rear of the intake. Previous owner HAD to have had issues too and either it wasnt that bad yet, or he is full of bull! Started just to make sure my distributor marks were all correct. Bumped the key and she started right up. Only ran her for a 30 seconds or so... but she sounds a lot better?? must be all in my head!

Tomorrow.... if the rain holds off. I will check to make sure there are no leaks. MAYBE Sunday get some water time in! :)
 
Last edited:
Top