Coolant in oil

[mklearl]

Hello. I had a Volvo penta 5.0gi which i teplaced last year with a new Crusader long block 5.7 last year switching over some of my Volvo parts such as manifolds and risers as they were only one season old.
After the initial break in season i winterized the boat and noticed throughout the winter there was a slight pudding of coolant (fresh water half system) right around the thermostat housing. I thought the worst as it was an extremely cold and brutal winter and my first time winterizing this particular engine.
fast forward to spring... I put the boat back into commission. Never saw any more coolant leak out of anywhere nor did I have to add any. The boat ran fine all summer. I religiously check the oil before starting every time and color and levels of oil all looked fine. Coolant level remained consistent. I put 65 hours on it this summer and added maybe a half quart of oil.
So I go to winterize it this year and the oil comes out a muddy brown color. Ill try to attach a picture. I've seen water in oil before in my gear oil and it was white like milky... it his is more brown like chocolate milk which leads me to believe it is coolant? Anyone?
So I have multiple questions here. If it is coolant that would suggest head gasket or cracked block or head. I'm trying to remain optimistic in this since I don't know how the head or block could crack if it hasn't been below freezing yet. I'm also wondering how to go about trouble shooting this. I know compression test and leakdown test. I'm fine with doing the leakdown but I don't want to run a compression test for several reasons... mostly because I have the boat winterized now and I don't want to run it up to temp. I've changed the Oil, fogged it with non ethanol fuel, drained the raw water and ran it to pump antifreeze into the raw water side. After doing this the oil was muddy again so I pumped all of it out and I'm going to put fresh oil back into it but I don't want to run it and contaminate the fresh oil again until I'm ready to dive into this to find the problem.... probably in the spring.
That being said, does anyone have any suggestions on what I can do in the mean time to troubleshoot without starting it? Any ideas on what may have caused coolant to get into the oil? Or am i wrong in assuming iy is coolant? If its raw water yake off the risers and look for water intrusion? Leakdown test? Possibly an intake manifold gasket? Should I squirt some mmo down the spark plug holes to get through the winter?
One last note... when running on the muffs I was trying to get it up yo temperature before changing the oil... it didn't seem to want to get above 160. Normally runs around 170-175. I waited a minute but didn't really think much of it and figured it was warm enough to get the oil out. I'm not sure if this has anything to do with it or not but I'm just trying to give as much information as possible to see if there are any ideas. One last thing.... periodically throughout the season it wouldn't start... as if the engine lost its fuel prime... I could get it started by dumping some fuel down the carb. Once it started it was fine and would be fine on a restart. Again not sure if this has anything to do with it... just throwing it all out there.
Any input is greatly appreciated!

 

[alldodge]

VP to Crusader change

Did you drain the intake manifold when winterizing? If not, the intake is probably cracked

 

[mklearl]

Coolant is the only thing that goes to the intake manifold... not raw water correct? I also ran it all summer without any signs of wayer in my oil. This all just happened during the fall best I can tell. Oil always looked normal on the stick when checking it.

 

[alldodge]

Coolant is the only thing that goes to the intake manifold... not raw water correct?

Correct, so you have closed cooling?

If so then pressure test your heat exchanger

 

[mklearl]

It's actually a half system... raw water to the exhaust manifolds. Will start with a pressure test on the heat exchanger. What pressure do you recommend?

 

[alldodge]

At least 15 and 20 would be good. The HE will have a cap with a pressure number on it

Could just drain and test the whole system which would be even better, and with coolent in the oil its probably a head gasket. If the HE was leaking it wouldn't get in the oil

 

[mklearl]

Right... I have no reason to believe that the he is leaking. I'm only guessing that it's coolant based on the color of the oil. If it was raw water I would think it would be more white color. However the coolant level hasn't changed from what I can tell. I removed the cap and it was right to the top. Still the same amount in the overflow as well. I know it doesn't take much to make the oil look bad but how do i know if it's coolant or raw water.

 

[QBhoy]

Although I’m not certain...I’d imagine raw water and internal closed cooling water would see no difference in colour in oil.
A strange one, but I’d be checking all interfaces like risers, head gaskets and also the engine driven water pump lip seal.

 

[Lou C]

If you are sure you have not lost any coolant, then it is more likely that you are getting water in the oil from the exhaust manifold to exhaust riser gasket, that is a known problem area on V/P engines and the gasket has been revised several times. Even though you already winterized it I'd suggest its worth your time to solve this problem now because if you don't get all the moisture out of the motor oil leaving it like that over the winter can damage bearings. And it takes more than one oil change to get the water out due to the fact that the oil just does not get that hot running on the water hose. Take off the oil cap and stick your finger in the hole, do you find a mayo like emulsion in there...water for sure....

 

[mklearl]

I put fresh oil in it yesterday but did not run it... I don't see the need to contaminate the oil more until I find the leak. The oil on the dipstick is still milky even without running the engine which the clean oil probably grabbed residual when being added.
crappy day today but I'll start with the risers. What exactly should I be looking for? Will the water be that obvious?
I can't say that I'm definitely not losing any coolant but if I am it is less than a cup in my opinion.
Thanks for all the suggestions.

 

[mklearl]

Is it possible this is from running on the muffs or letting water run through the hose too long without the engine running? I don't have the greatest water pressure out of a garden hose and think it would be less than that of my raw water pump. Just grabbing at straws here.

 

[alldodge]

Is it possible this is from running on the muffs or letting water run through the hose too long without the engine running? I don't have the greatest water pressure out of a garden hose and think it would be less than that of my raw water pump. Just grabbing at straws here.

No, don't see that, the water should have no way into the motor if its operating correctly.

Since your doing this on a hose and not in the water, it probably is your exhaust system as Lou said. Remove the impeller from the pump and run the motor for a short time (maybe a minute). This will lube everything and there should be no new water in the oil. With water in the oil, it needs to come out before putting it to bed. Water sinks to the bottom so the water is being pushed thru the bearings before the oil

 

[mklearl]

I have a sneaky suspicion that during the new installation the mechanic reused the gaskets when he swapped the manifold and risers over... don't see any gaskets on the parts list. Thanks again for the suggestions. I'll keep you posted.

 

[mklearl]

So I pulled the risers and didn't see any obvious signs of internal leakage. Figured I go a little bit deeper and check the manifolds... if both those checked out I could at least rule out the raw water side. Pulled the manifold and set the port manifold on the transom and saw a little residual wayer in one of the ports. I think this would be it. Time for new riser and manifold gaskets and as many oil changes as it takes.
Thanks again for all the suggestions.

 

[Scott Danforth]

drain the block, pressure test the block. you may have a cracked head

only way to know is to pressure test. and to test, the block must be drained first

 

[mklearl]

Man... you're always bringing me down. Lol.
Not doubting it and I definitely want to know for sure. But why would I have pure water in a port of the exhaust manifold if I had a cracked block? I feel that the water is coming from the riser and into the manifold, not into the manifold from the engine. Does this make sense? My wheels are turning now and another thought, since I couldn't see any obvious problem with the riser gasket was that there was a crack in the exhaust manifold itself... how do i test for that?
if I pressure test the block how do i go about doing that? Drain the block and then just pump air into that same drain hole?

 

[Lou C]

OK
you can test your exhaust manifolds for cracks or rusted through areas by propping them up level. Then put a funnel in the hose that feeds the manifold and fill it (Carefully, flammable!!!) with Acetone, which has less surface tension than water. Then let it sit a few hrs. If you see any moisture in the ports that match up with the cyl exhaust ports, then the manifold is junk and you need new.

They are only one year old? If so and you find no leaks, I would next take em to a machine shop and have the mating surfaces machined 100% flat. If those were aftermarket manifolds, some when new, are not machined flat enough to seal. If you are really careful, you might be able to do this yourself with a large belt sander. They should be flat to less than .003", preferably even less. When I checked the Barr aftermarket ones I used they were really good on the machining, like less than .001" when checked with a straight edge and feeler gauge.

Then re-assemble using the OE gaskets if you have em already and follow VP's instructions. Don't forget to carefully re-torque after the engine has run up to temp. After that, disable the ignition and remove all the plugs, and then crank the engine with starter and look carefully for water dribbling out of the plug holes. You should see none. If so you done good and keep running it up to temp and changing the oil to get the remaining water out.

I would only suspect a cracked cyl head if you had a bad overheat, which you are not saying at all. Cracked heads are usually due to bad overheats or poor winterizing.

One last thing, when you repowered this boat....did you reuse the old intake? If so, and the mating surfaces were not checked and properly prepared (ie removing all old gasket materiel, and checking them for flatness, less than .003" I believe is GM's spec) you could have an antifreeze leak right at the joint were the water passage for the thermostat housing meets the front of the cyl heads but then you should have seen your coolant level dropping, which you have not said is a problem.
You got water in the exhaust, deal with that first, then move one....

 

[mklearl]

The manifold and risers have been used for 3 seasons (May be 200 hours). I re powered last year but reused the manifolds and risers as they were only used for 1 season at that point. They are barr aftermarkets.
I found that acetone trick in the stickies... forgot about that. Thanks.
intake manifold was new with the engine.

 

[mklearl]

Also, how much to machine both riser surfaces and manifolds. I paid around $1k for the Barre manifold and riser sets with bolts and everything. Is it cost effective to just get new manifolds and risers? Volvo gives an instruction booklet... yes, a booklet on installing riser gaskets. It doesn't say anything about getting them machined but does give the parameters for the surface but indicates this is something that could be done by the average Joe like me.

 

[Lou C]

Did you use them in salt or fresh water? I've used manifolds in salt water as long as 6 seasons without problems, so I think you might be able to still use yours. You want that sealing surface to be really flat, not eroded etc. If its eroded by rust pock marks then I'd take em to a machine shop and have them 'decked' professionally. Barr is good quality and I have not had leaks with their standard gaskets, installed with Permatex aviation sealer and re-torqued after the initial run in. I guess if Volvo says you can do it, it depends on if you have a way to clamp it in a vise and carefully use a belt sander. Just measure the flatness with a good straightedge and feeler gauges to make sure. You only take off enough to clean it up, nothing more.

I'm not sure what a machine shop would charge, that depends on where you are located...but its a lot less than a new set of manifolds/elbows. If you do need them, they may sell them here, or you can look at local vendors for Barr Marine.

If you want you can get an oil analysis on that old motor oil and see what they say. If its water then you're on the right track, if its antifreeze there could be other problems. One way to know....