1989 4.3 mystery oil leak :-(

[DaboatnutinWA]

Thanks for posting up with what you found. I have the same engine in my Sea Ray so I was watching closely in case mine develops a oil leak. Glad you got it figured out. Hope the sea trials go well for you.

 

[moparron]

No Title

YIPPIE, wahoo... and all that other stuff.. .no more oil leaking!!!!

During my test though... sad sad moments too. Motor was running smooth, temp right around 175, oil pressure at about 45psi, all seemed good, then it had a hiccup of sorts... a rattle. so I throttled it down from 3200 to idle and it stalled?? Okay maybe.. my down throttle was a knee jerk response to the rattle - I'll give it that. Went to restart it and it it was hard to start.... like suddenly I had 13:1 compression or something. It did kick off after a 3 or 4 revolutions... but that rattle was still there??? temp was still 175-ish, but it had crap for oil pressure... around 8psi? So I shut it down.. checked oil - level still good. opened the oil fill cap and had smoke of some kind of smoke (didn't smell, so heavy steam maybe?) coming out of the valve cover. I guess it's time to pull the plugs and do another compression check :-(
Honestly though - I put the cover over it and just walked away.... I don't know how much more of this I can really take!!! I fix one thing, then another thing goes wrong... each step seems to be getting worse and worse.

I go back to work on Monday and also filled with trying to spend some time with my grandmother before the inevitable... just not in the bloody mood to start over on the boat AGAIN! But on a good note.... the oil leak is fixed.

 

[Tail_Gunner]

Chin up moparron every boat has her secret's and you will find them all over time. Go spend time with your grandmother the boat can wait another day.

 

[moparron]

Been almost two weeks.... life is continuing to get in the way of the boat But I had 15 minutes today... pulled the cover off enough to get up there. Turned the key and the motor turned over fine and fired right up within 1 revolution. Granted no water was hooked up, I wanted to see if it was still turning over hard (like it had 15:1 compression). This is one half of a test.. other half will be with water hooked up when I get a few minutes again.
My father seems to think that just maybe a stray piece of old intake gasket got in the water port and may be sticking the thermostat or something and I am getting false reading on the engine temperature, and I had overheated the motor. So I started to devise a series of tests - based more on shortest time to complete versus any other order.
1) see if the motor turns over "normal" when cool - PASSED
2) Same as #1 but with water supplied (in case one cylinder is trying to compress water)
3) if #2 passes.. compression check again
4) if $3 passes... pull thermostat housing and see if dear ol' Dad is correct

 

[Idlespeedonly]

#6 intake port looks like is has rust in it?
Also the back wall of the lifter valley has quite a lot of rust on it to.
Have you checked the manifolds for cracks?

 

[moparron]

WHAT?? Check for crack?? aside from water not spraying out of them.. ummm no. Some of the rust MIGHT be due to the large gaps on the back of the intake... were all my oil was exiting the motor. AT LEAST I HOPE

 

[moparron]

Well Howdy! Been awhile. Been a crazy almost two months... let 5 people go at work and I have only replaced one of them so far (help is so hard to find). Been nursing a back injury for about 6 weeks now... AND buried my grandmother last week. With all of that .. figured that I needed to spend time with that hunk of fiberglass adorning the yard. Pulled the thermostat housing... nothing stuck in it (so much for the easy fix! So did another compression test and compared to the compression test I did on 4/4 - did it the same way. All plugs out, cold motor, carb and choke closed (or resting position) - results are slightly odd - april results listed first and as you look at the "front" of the engine:
170/110 160/155
130/170 155/150
155/145 145/140

Notice the changes in #4 and #6?

As a refresher... I replaced the intake gasket in April, due to a nasty oil leak on the rear of the manifold. When I test ran the motor.. after about 6 minutes it stalled out and I was experiencing high heat on the starboard (#2,4&6) bank of the motor. Could I possibly have an intake gasket that dropped??? I'm sort of thinking #4 and #6 are sharing air they shouldn't be??

 

[moparron]

I reckon y'all are as stumped as me?