3.0 penta water in oil new head gasket no cracked block

First post but have have been doing tons of research and maintenance on this boat before I decided to post here.

The back story is I bought a 1999 glastron with volvo penta 3.0 on cl with 190 hour. The owner stated it head a blown head gasket, it was overheating and that there was water in the oil. I Got it and removed thehead and had it magnufluxed, decked and had the valves reseated. Put all new seals including thermostat, head gasket, exhaust gasket and a few other small seals and gaskets. Rebuilt the carb and put all new seals in it as well. The block had perfect compression with no signs of cracks and did a pressure test on it and it was fine. Also went ahead and replaced the gimbal bearing, Jack shaft seal, exhaust bellow, gimbal bellow and changed lower unit oil.

That being said I changed the oil with new oil filter about 5 times to try and flush all the old oil out until I got good oil coming out after change. I would run it with muffs about 15-20 minutes on land everytime. The last oil change oil came out perfect. So put a new wix filter on it and filled it with higher quality oil. Ran it with muffs for about 20 minutes and the oil was perfect on the dipstick. I was satisfied. Forward and reverse on muffs was very smooth so I was satisfied for my next test.

Took it to the lake to go camping and before launching i ran it on muffs again for about 20 minutes and checked the oil again and perfect on the stick. Also installed a secondary water temp Guage next to the motor in the back just to make sure I was not over heating. Block after 20 minutes on muffs got up to 150 and stayed. Water temp on the cluster showed 175 but itsit's sending unit is on the thermostat. So no signs of overheating.

Launched the boat and ran it for about 10 minutes on the lake checking everything I could. Boat ran spectacular. Idled perfect, no signs of over heating, great top end and acceleration. Got it back on the trailer checked the oil and hazy oil. Didn't think much of it so I took it back to the campsite thinking it would be ok for when the family came out to tube all day the next day. Woke up the next day to prepare the boat once again and when I checked the oil it was milky just like when I first changed it before the head gasket install.

I am stumped. No signs of water intrusion on land even when ran hard on muffs and the block getting to fully warm temperature. The oil was questionable after launch but was way worse in the morning even after the boat was not ran or touched over night. The boat is completely fine and you wouldn't even know there was a problem unless you checked the oil.

So my question is where is my water coming from? Why is it find on land but in the lake it's not? And why did the oil get worse after sitting not being touched overnight? Please please please help.

Re: 3.0 penta water in oil new head gasket no cracked block

sorry to say this but it sounds indeed like a cracked block. tiny cracks may start only to leak when you get full flow from the raw waterpump what is not reached on muffs so all was "fine" running it on muffs.

i think the most common place on the 3.0 is behind the manifold. you may remove it and look in this area. other possibilities would be a cracked head or the head gasket.

cheers

Re: 3.0 penta water in oil new head gasket no cracked block

I appreciate the respons.

I'm a mechanic but on cars and don't understand boats hence all the questions.

Can't you explain how water coming from the inlet on the lower unit on muffs is different then when in the water. Not saying you are wrong or don't believe you just so I can learn for future reference. I took off the manifold and inspected both the block and the manifold and all was good. The headgasket is brand new and machine shop did indeed verify a blown headgasket before decking, magnufluxing and reseating the valves. So the head being the problem is almost for certain out of the question. That is why I'm so stumped. Not saying that it couldn't be the block because there really is no sure fire way to check especially in a boat. I just want to rule out any other possibilities like plugs I don't know about or gaskets or seals or anything other then the typical head or block suggestions. The boat has absolutely no symptoms of malfunction other then water In the oil. I would figure a cracked block would over heat when exhaust gases get in and regardless of muffs or fresh water water cooling the block passing over cracks would get in regardless if the block was fully warm. Again I ask sspecific questions to be sure before I junk the motor.

So if there are any other suggestions besides block and head please add your opinion.

Re: 3.0 penta water in oil new head gasket no cracked block

Ccuddey said:

I appreciate the respons.

I'm a mechanic but on cars and don't understand boats hence all the questions.

Can't you explain how water coming from the inlet on the lower unit on muffs is different then when in the water. Not saying you are wrong or don't believe you just so I can learn for future reference. I took off the manifold and inspected both the block and the manifold and all was good. The headgasket is brand new and machine shop did indeed verify a blown headgasket before decking, magnufluxing and reseating the valves. So the head being the problem is almost for certain out of the question. That is why I'm so stumped. Not saying that it couldn't be the block because there really is no sure fire way to check especially in a boat. I just want to rule out any other possibilities like plugs I don't know about or gaskets or seals or anything other then the typical head or block suggestions. The boat has absolutely no symptoms of malfunction other then water In the oil. I would figure a cracked block would over heat when exhaust gases get in and regardless of muffs or fresh water water cooling the block passing over cracks would get in regardless if the block was fully warm. Again I ask sspecific questions to be sure before I junk the motor.

So if there are any other suggestions besides block and head please add your opinion.

Click to expand...

Ayuh,... Welcome Aboard,... The difference 'tween on the muffs, 'n in the pond, is Load,...

Ya can put a Load on the motor, 'n make it Work on the muffs, without Load, a motor ain't really bein' Tested,...

You can Pressure test boat blocks, Quite easily,...
Block off, 'n isolate the Block's coolin' passages, drain it, 'n pressurize with 'bout 10/ 15 psi of air,...
Then Listen,... You'll Hear the leak...
By listenin' from the various "Holes" in the motor, you can figure out, 'bout Where the crack is,...

I'm guessin' that after ya pull the motor, flip it over, pull the pan, 'n Look, you'll see a Crack runnin' along side the coolin' jacket, opposite the drain plug, Inside the block,...

Btw,... a Cracked block creates absolutely No runability issues, other than water in the oil....

Re: 3.0 penta water in oil new head gasket no cracked block

Ok thanks for the info. Good to know about "under stress" conditions as opposed to running sosolely muffs.

Hopefully someone will chime in with something other then block. Might be my problem but just want to see if anyone has any knowledge of water in oil besides just block or head. If no one chimes in with anything different I will just have to bite the bullet and pull it. Say goodbye to a fresh boating season and convince the wife that the boat was still a good idea.

Re: 3.0 penta water in oil new head gasket no cracked block

Ccuddey said:

Ok thanks for the info. Good to know about "under stress" conditions as opposed to running sosolely muffs.

Hopefully someone will chime in with something other then block. Might be my problem but just want to see if anyone has any knowledge of water in oil besides just block or head. If no one chimes in with anything different I will just have to bite the bullet and pull it. Say goodbye to a fresh boating season and convince the wife that the boat was still a good idea.

Click to expand...

Ayuh,.... Drain it, 'n do a pressure test, before ya throw in the towel,...

A sharader valve, 'n a plug or 2 is all it takes,... yer a Mechanic, it's a piece a cake,...

Re: 3.0 penta water in oil new head gasket no cracked block

when you get a sudden and significant water intrusion into the oil ( is oil level high ? ) there are not much possibilities what it could be beside a cracked block or head - when you have no issues with engine runability it points more into the block direction.

all me known theoretical possibilities for water in oil are

-block
-head
-headgasket
-leaking manifold

some of them would initially give you water in cylinders and bad running characteristics.

like bond says- pressure check it, you will check so the head and the block.

you of course might be lucky and it was just just a last part of old water after the gasket change , but this makes only sense when you did not have a significant rise in oil level after the boat ride.

Re: 3.0 penta water in oil new head gasket no cracked block

Thanks everyone for their response. I think I have decided that the block could be the only cause. So i have located an engine in my area but was needing some more info if you guys could help.

My boat is a 1999 glastron sx175 I volvo 3.0 4 cyl. with a volvo penta sx-m lower unit. The engine I found was out of a donor boat. A 2001 suntracker the motor is a mercruiser 3.0 4cyl. also the guy states that it is a 140 hp i thought they only came 135 hp? I have been told that these engines are the same the only difference is carb and accessorie components like alternator, starter things like that. I'm almost positive that they are both Gm 181.

So my question is will it bolt up and will my sx drive work? Or will I only be able to use the block and have to switch everything good from mine to the donor? It will only cost about 200 for the entire motor all the components come with it. It is need of a rebuild because of loss of compression but no cracked block and a rebuild kit only cost around 200 as well. So for around 500 including some machining work I could have a fresh engine ready to go. Just need to know if this will work or if I have to find a true volvo motor.

Re: 3.0 penta water in oil new head gasket no cracked block

the block is a GM 181 and the same in volvo or mercruiser. you will have to swap the accecoires and , but i,m not sure , the flywheel.

one question will be what about the raw water pump because e.g the merc alpha has the impeller in the drive where volvo has it in the engine compartment and belt driven. so check if you can easily attach it to the merc block .

before you do that i would recommend to verify the cracked block on your engine. regarding engine power , well , volvo claims 135 hp for the GL, on some models volvo claims 150 hp on the GS , mercruiser says 140 hp- whatever is the thruth, its basicly all the same engine.