4.3 crankshaft/housing oil leak - next steps?

[ShoalSurvivor]

greetings all. found oil in the bilge and isolated it to the crankshaft seal or housing. Does not appear to be an oil pan issue. I found no obvious corrosion around the housing (from what I can reach).

Lost about 3 oz of oil after a 3-day weekend - running ~ 8-12 hours at various speeds. The leak displayed in the photo is after cleaning and running to warm for about 4 minutes. I have done some research, but would appreciate experienced input here.

Is there more that I can diagnose before pulling the seat bench out for frontal access? Camshaft assembly is just above floor level, so I think I can access all of it once the bench is removed.

Is there a likely repair (ie. replace housing/seals) based on what can be seen here?
Does the repair likely require 1) removing engine, 2) removing drive, or 3) just gaining frontal access and removing belt/pulleys to access cover?

Am I in imminent danger of sudden, rapid loss of oil (ie..ruining the engine) or is this something that I can put off until after summer by managing oil with absorption pads and maintain oil level? We have many plans for wakeboarding and short nighttime cruises (concerts by boat) and I'll have time this fall for repairs.

thanks,
Michael

1999 Stingray 190LX
2004 Mercruiser 4.3L 225hp 4bbl
Quicksilver repower: SN: 90004747 Engine PartNo: 807736R11 date: 03252004 (original engine SN: L332123)
Alpha 1 Gen II - Transom: 0L517680 Drive: 0L192679 1.62 R (1.81R scratched on top) (original drive SN: L40356)

 

[Scott06]

greetings all. found oil in the bilge and isolated it to the crankshaft seal or housing. Does not appear to be an oil pan issue. I found no obvious corrosion around the housing (from what I can reach).
View attachment 408160View attachment 408161
Lost about 3 oz of oil after a 3-day weekend - running ~ 8-12 hours at various speeds. The leak displayed in the photo is after cleaning and running to warm for about 4 minutes. I have done some research, but would appreciate experienced input here.

Is there more that I can diagnose before pulling the seat bench out for frontal access? Camshaft assembly is just above floor level, so I think I can access all of it once the bench is removed.

Is there a likely repair (ie. replace housing/seals) based on what can be seen here?
Does the repair likely require 1) removing engine, 2) removing drive, or 3) just gaining frontal access and removing belt/pulleys to access cover?

Am I in imminent danger of sudden, rapid loss of oil (ie..ruining the engine) or is this something that I can put off until after summer by managing oil with absorption pads and maintain oil level? We have many plans for wakeboarding and short nighttime cruises (concerts by boat) and I'll have time this fall for repairs.

thanks,
Michael

1999 Stingray 190LX
2004 Mercruiser 4.3L 225hp 4bbl
Quicksilver repower: SN: 90004747 Engine PartNo: 807736R11 date: 03252004 (original engine SN: L332123)
Alpha 1 Gen II - Transom: 0L517680 Drive: 0L192679 1.62 R (1.81R scratched on top) (original drive SN: L40356)

Doubt you are in imminent danger of loosing oil pressure unless you dont top off. Biggest issue is the bilge water will get oil contaminated (more than normal).

You may want to search on here. one of the former mods Chris had a similar issue with a similar vintage 4.3 that I think ultimately was cause by the timing cover or oil pan as there was a ridge on one or the other that caused the leak despite several reseals.

most of the time to track this down you need to clean the engine with brake cleaner then watch the leak. A UV light can be helpful here. I had a antifreeze leak on a car and put UV dye in the AF, cleaned every thing off and then was able to easily find the leak with the UV light. I found the oil (valvoline) is also slightly UV reactive. Not sure if they make a dye that is ok to put in oil

the things to look for are the timing cover oil pan rail seals and front crank seal. Im not sure if they can be done in the boat, but if you can arrange the lifting mechanism I think you would be better off to jank it , do the repair and then run on the ground to make sure it is not leaking before re-install. This sounds like a lot of work but isnt that bad to run an engine on a pallet or even the ground

 

[ShoalSurvivor]

most of the time to track this down you need to clean the engine with brake cleaner then watch the leak.

Thanks Scott.
I have isolated the drip from under the crankshaft a seen in the photo. no oil above, none below. That drip is coming from the block side, right in the center of the shaft. Looks like seals to me, but I've read that seals are unlikely source.
I cannot get a better view in that space than what I was able to photograph, so I'm not sure how I could isolate any further without pulling it apart.

 

[kenny nunez]

After the engine is out look closely at the seal surface on the crankshaft. It may be grooved or there is a build up of rust which will cause pitting. Either way you can repair the surface with a Speedy Sleeve that will provide a smooth stainless surface. They come in many sizes and their web site is easy to understand.

 

[ShoalSurvivor]

After the engine is out…

in there any chance that I can repair this without removing the engine? I’d prefer not to, if possible.

 

[Scott06]

in there any chance that I can repair this without removing the engine? I’d prefer not to, if possible.

Not sure - I think this is the parts list for your engine -

https://www.marineengine.com/parts/mercruiser-sterndrive-parts/43l-gen-4bbl-reman/1g400000-up/intake-manifold-and-front-cover

it shows a plastic timing cover. these covers are single use and they dont sell the seal separately. of course these are just Gm parts not sure if the seal is available via automotive.

As long as you dont have to drop the pan to get the cover on off and there is room in front maybe.

 

[Bondo]

in there any chance that I can repair this without removing the engine? I’d prefer not to, if possible.

Nope,......

 

[ShoalSurvivor]

Nope,......

Can someone point me to the procedure for the balancer and housing removal?

thanks

 

[ShoalSurvivor]

As long as you dont have to drop the pan to get the cover on off and there is room in front maybe.

According to the Mercruiser Manual #25, there is a procedure and tool for replacing the seal without removing the cover "Oil Seal Replacement (Without Removing Front Cover)", however, the seal is not available without the cover.

To replace the cover, you have to remove the pan.

Has anyone replaced the seal without removing the cover? Where did you get the seal?

thanks!
Michael

 

[kenny nunez]

Try to remove the seal, there should be a part# on it. you can borrow a puller for the balancer from just about any auto store. Drill a small hole in the seal and with a self tapping screw on a slide hammer the seal should come out.

 

[ShoalSurvivor]

Try to remove the seal, there should be a part# on it. you can borrow a puller for the balancer from just about any auto store. Drill a small hole in the seal and with a self tapping screw on a slide hammer the seal should come out.

My motor is at my buddy's shop. he's got the tools to do this, I just don't know if others have replaced theirs with a non-mercruiser or non-marine seal. have you done this yourself for a marine engine?

also, the cover is plastic. Would I be able to seat a new seal on a plastic cover, or would it crack when trying? is that why all the shops sell the integrated cover/seal?

 

[Scott06]

My motor is at my buddy's shop. he's got the tools to do this, I just don't know if others have replaced theirs with a non-mercruiser or non-marine seal. have you done this yourself for a marine engine?

also, the cover is plastic. Would I be able to seat a new seal on a plastic cover, or would it crack when trying?

The timing cover and seal are just stock GM parts so there is no marine seal.
Would think you can match it up off of year via rock auto or napa or the Chevy dealer
do you own research but I would imagine a 2003 4.3 would be the same as you 04 engine… rock auto lists a front crank seal as in screen shot attched

whole timing cover is about $45 not sure I’d mess with a seal but if they sell the seal alone there must be some level of success driving it in the plastic cover

 

[ShoalSurvivor]

whole timing cover is about $45 not sure I’d mess with a seal but if they sell the seal alone there must be some level of success driving it in the plastic cover

thanks for all the info! the Mercury timing cover was $279. Amazing if these are interchangeable. for $45, I would replace the cover, which I believe means removing the oil pan cover as well.

Is there a way to match my REMAN serial number with that year engine, or does it just go by year?

 

[Scott Danforth]

mercruiser buys the GM part and multiplies their cost by 5x. the ECM, wiring and exhaust are the only things on that motor that Mercruiser supplied. everything else came from GM

here is Achris's write up of the same issue and how it was resolved

An oil free bilge...finally!

Well, it's been a long and torturous road, but (fingers crossed) I think I have finally fixed my front cover oil leak... To summarise. 2006 4.3MPI. Developed a front engine oil leak a few months after warranty expired. Pulled engine and found (plastic) timing cover broken where the sump...

forums.iboats.com

the plastic timing cover is junk from GM coming from their tier 1 supplier Pioneer.

 

[ShoalSurvivor]

mercruiser buys the GM part and multiplies their cost by 5x. the ECM, wiring and exhaust are the only things on that motor that Mercruiser supplied. everything else came from GM

This type of info seems like it's worthy of sticky notes. I mean, I don't want to put the poor marine parts vendors out of business, but I also don't think it's fair to have unnecessary 5x markups on parts.

Would be awesome for one of the site experts to detail comparative auto/marine engines, components to avoid using in marine environment, etc. Dare to dream.

I'm always amazed by the depth of knowledge and experience some of you have, and am eager to learn. Thanks!

 

[Scott Danforth]

like this.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

 

[ShoalSurvivor]

like this.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

OMG - YES, like that!! Thank you.

 

[Scott06]

This type of info seems like it's worthy of sticky notes. I mean, I don't want to put the poor marine parts vendors out of business, but I also don't think it's fair to have unnecessary 5x markups on parts.

Would be awesome for one of the site experts to detail comparative auto/marine engines, components to avoid using in marine environment, etc. Dare to dream.

I'm always amazed by the depth of knowledge and experience some of you have, and am eager to learn. Thanks!

the two biggest differences are electrical and fuel components, the rest is basically the same stuff GM uses in truck engines.

before Merc started making their own 4.5 and 6.2 engines they were buying base engines from GM. THis is an example of what a base engine is and contains-

5.7L (350ci) Vortec Base Marine Engine (1996 - Current)

5.7L (350ci) Vortec Base Marine Engine (1996-current Replacement)

michiganmotorz.com

both Merc and VP start with the base engine and add their unique parts to it. When I repowered my boat in 2015-16 I bought a new base engine from Mich Motorz, and was thus using the exact same engine the OEMs use.

there is no easy button just stuff you pick up by ignoring your kids and reading the iboats forum all the time ....

 

[ShoalSurvivor]

there is no easy button just stuff you pick up by ignoring your kids and reading the iboats forum all the time ....

According to inherited paperwork, have a "Reman Plus Series" reman engine. It was installed in spring 2004 with a new carb, ign, and fuel pump.
Quicksilver repower: SN: 90004747 Engine PartNo: 807736R11 date: 03252004
I generally use parts listed under: "MerCruiser 4.3L (Gen+) (4Barrel) Reman", but sometimes things don't jive with the parts diagram, like power steering hoses.
I'm not sure if this year model reman fits any of the models that you list in your history post. I'd appreciate any more background you can offer on my engine. thanks.

 

[Fun Times]

I'm not sure if this year model reman fits any of the models that you list in your history post. I'd appreciate any more background you can offer on my engine. thanks.

In searching back for a more detailed answer to the question above, I believe we may have covered this area for you, maybe have a quick glance back and see if it helps here any, https://forums.iboats.com/threads/spark-plug-part-number.762750/#post-5822771