Oil leak on 4.3LX--Main seal?

[kneedragger]

OK, I have a 1994 Mercuiser 4.3LX. I am having an oil leak occur only under high RPMs, and it seems to be comming from the front of the motor.

If I keep it under about 4300--4500 RPMs there is not a leak, and so far this summer I have kept it full, and just not run it hard with great success.

I plan to try and discover the location of the source this weekend before winterizing, and just wanted to ask if this is a common occurance, or issue?

I assume in order to fix it, it is either a main bearing seal, or oil pan seal, and would reguire an engine pull to repair it.

Thoughts?

 

[Bt Doctur]

Re: Oil leak on 4.3LX--Main seal?

May be a rotted timing cover,if metal.Crank seal going bad.
What type of oil are you using and any additive.

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

May be a rotted timing cover,if metal.Crank seal going bad.
What type of oil are you using and any additive.

I am not using any additives in the oil, and I am running 20W-40, but have kept it topped off with 20W-50 castrol, because it is was avialable, and on hand.

Does the 4.3 have a history of rotted timing covers? If that is my problem, then that makes feel a little better. I would not need to pull the motor to replace it.

 

[z284u2try]

Re: Oil leak on 4.3LX--Main seal?

Sounds like crank case pressure if it leaks in the higher rpm. I would check to make sure you dont have a cracked ringland by removing the oil fill cap and check to see if its puffing like a freight train. I would also check the valve cover breather to make sure one is not clogged creating excessive crank case pressure.

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

Sounds like crank case pressure if it leaks in the higher rpm. I would check to make sure you dont have a cracked ringland by removing the oil fill cap and check to see if its puffing like a freight train. I would also check the valve cover breather to make sure one is not clogged creating excessive crank case pressure.

Great advice, thanks

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

Ok,
I did some further investigation, and think it is my main seal. Quick question, on my model (SN OF 314142), will it require the removal of the oil pan, thus requiring removal of motor?

Or, can i gain access, remove and replace the seal once the harmonic balancer is off?

Thanks!!

 

[fuzzybob]

Re: Oil leak on 4.3LX--Main seal?

You can download the oem service manual number 18 for free from the "Adults Only" sticky at the top of the forum. You can get all the info from it. Get the one for your out drive too. Welcome to iboats and good luck.

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

You can download the oem service manual number 18 for free from the "Adults Only" sticky at the top of the forum. You can get all the info from it. Get the one for your out drive too. Welcome to iboats and good luck.

Bob,

Thanks for the reply

Did that, and have read the manual section. Sort of "ben there done that".

However, it doesn't tell me whether or not this seal is part of, or connected to the oil pan's seal.

Anyone done one of these before?

 

[Bt Doctur]

Re: Oil leak on 4.3LX--Main seal?

there is no front main seal on the V motors, only seal is in the timing cover for the balancer. Yes, the timing covers do pin hole and leak.Pan should be lowered/removed to get proper clearance to do the timing cover

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

I thought I would follow up on my little mechanical adventure. I stopped at a Mercruiser dealer near my lake place (hour and half from home), and wanted a new timing cover gasket. He said he didn't carry those, and to just go to the autoparts store, everything croses over (later we discover he was wrong). I went to my local autoparts GM specialty store, and bought a front timing cover kit (Velpro).

After taking off the water pump, and the crank pulley off, I took it to a friend(near home) to pull the harmonic balancer off. We got that off, and came to find out there was one of those special shouldered bolts missing at about the 9 o'clock position. It was sunday, and most dealers were closed, so my good friend machined the shouldered part from aluminum, and put a standard bolt through the middle of it.

We removed the timing cover, and it was full of RTV Silicone. The main seal looked fine, but we replaced it anyway since we had it off. The Velpro kit had the wrong gasket in it, and did not fit(it looked Identical to the exploded parts diagram from Mercruiser website). I have the plastic cover, with more of an o-ring than a gasket. The velpro kit comes with a gastket that doesn't fit.

I did NOT want to pull the motor, and we were worried that the oil pan gasket would potentially dissentigrate further, if we lowered the front. I have the aluminum ribbed oil pan.

The timing cover even with the main crank seal removed had a hard time going on. We had to modify/remove portions of the lip that goes into the oil pan gasket, in order to not have to lower the oil pan.

We cleaned every nook and cranny of the plastic cover, and the block, and surrounding areas with alcohol, and used some liberal amounts of Honda Bond gasket material (my friend swears it is much better quality than anything he has ever used).

I am waiting a little while before adding fresh oil to the motor. I know this is not proper proceedure, but I hate threads without closure. I hope with the new bolt, and the newly applied sealer, I can get 4-5 more years, without any leaks.

In a couple of months I will water test it. Hopefully, it will hold!! Let the finger waving begin.

 

[achris]

Re: Oil leak on 4.3LX--Main seal?

.... I have the plastic cover, with more of an o-ring than a gasket. The velpro kit comes with a gastket that doesn't fit.

And on the front of that plastic cover are cast the following words...

"NON REUSABLE PART. REPLACE IF REMOVED"

And if you removed and replaced it with the sump pan in place it is almost certainly going to leak....

Also the serial number you quoted is for your transom assembly, not your engine....

This is not finger waving. It's just that I am dealing with leaking covers on my own engine... and it's a lot newer than yours.. http://forums.iboats.com/showthread.php?p=2491116#post2491116

Chris........

Edit....

I just got your engine serial number from a different thread (on temp gauge) and according to the diagram, you should have a metal timing cover....
Curiouser and curiouser

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

Edit....

I just got your engine serial number from a different thread (on temp gauge) and according to the diagram, you should have a metal timing cover....
Curiouser and curiouser [/QUOTE]

Chris,

I read your thread, and I am glad to know I am not alone in this. Although it sounds like you are depending on the dealer, and mechanics, and I am actually doing it myself.

You bring up an interesting point, regarding numbers. Maybe someone here can determine if my motor was ever replace/repaired/bastardized with a newer block. My motor is older(94 votec) than yours, and my motor is carbureted, eventhough it has the Fuel Inj pick up on my timing cover. It is not being used, and no electrical connections go to it.

Here are the numbers I have, the spark aresstor (black plastic) cover OF266584, engine block number 14099090M.

As far as comments about regarding reusing the cover, well all I can say, is you have the power of "I told you so". I know I am taking some some shortcuts. Especially by not lowering/removing the oil pan to make the lip of the cover "dig" into the pan seal.

I thought Don's post from the Volvo book regarding the fact that you should measure the distance from the oil pan to the transmission with a feeler guage. I do not believer Merc addresses this in their manual. Plus I did not realize that this gasket needed these types of tolerances.

 

[achris]

Re: Oil leak on 4.3LX--Main seal?

...I read your thread, and I am glad to know I am not alone in this. Although it sounds like you are depending on the dealer, and mechanics, and I am actually doing it myself....

I'm doing all the work myself as well... I only deal with the dealer to get the parts. Had Merc honoured a warranty, the dealer would have been doing it...

 

[kneedragger]

Re: Oil leak on 4.3LX--Main seal?

I'm doing all the work myself as well... I only deal with the dealer to get the parts. Had Merc honoured a warranty, the dealer would have been doing it...

Thanks for the clarification. Also the post that mentioned removing some aluminum material with a flat file, I thought was a good suggestion. Especially since Merc is not helping with the warranty. It does seem like your issue revolves around lack of tollerances between your aluminum pan, and your block. Also, I am reluctant to pull my motor. It sounds like you have done it a couple of times, and are getting good at it. I may ask for advice one day. Also, I do not have an alignment tool, and that alone is big deterrent.

I REALLY hope my problems stem from faulty/inferior gasket material, and a missing bolt(the long shouldered one, in the 9 o'clock position). I will keep you posted, and in return, I want to hear your outcome. As I mentioned earlier, I think unfinished posts do this site unjustice.

IMHO.

 

[achris]

Re: Oil leak on 4.3LX--Main seal?

T.... Also, I do not have an alignment tool, and that alone is big deterrent....

Don't let it be... I just remove the top nut from the side mounts and make sure I don't move the lower nut. Goes back in with the engine in exactly the same position. (I've checked many times.)

Takes me 2 hours to remove the engine and about 2 1/2 to put it back in.... But that's only when I'm taking it slow.. If I try and go fast it takes longer... go figure.

Chris........