3.7 Merc Milky oil

[Contagious 1]

1988 Wellcarft 190 Classic 3.7 Mercrusier. Boat has been running well. About two weeks ago I changed the oil and filter, spark plugs, cap, wires, and rotor. Last week I began to see oil in the bilge and sought to find if there was a leak. Did observe milk shake like oil leaking from the rear lower starboard side of the engine and down into the bilge. I checked the oil dip stick and coolant and all looked good. No signs of issues there. Today, I pulled dip stick and found milky oil on the tip of the dip stick and that the oil level was high on the stick. Any suggestions as to the possible problem.

 

[Faztbullet]

If its water its manifold or oil cooler(if equipped) problem..if antifreeze most likely the oil seal on camshaft

 

[Contagious 1]

Thanks Faztbullet... That does not sound as bad as a rear main seal. It does have a closed cooling system... and the antifreeze in the reservoir does not have oil... Plan on working on this in the upcoming weekend.

 

[Scott Danforth]

the AF would not have oil, however the oil would have AF or water.

you need to check the oil, drain into a clear container let it settle out and check if its AF or raw water

If its raw water, it would be coming from a leaking exhaust elbow. most likely its AF.

common issues are water pump cam seals (google 470 + speedi sleeve)

most likely you had an over-heat as a result, so plan on a head gasket

 

[Contagious 1]

Got it Scott... Only seen water in the dip stick... nothing with AF. The substance looks like water and oil only, and not AF with oil. Yesterday I did picked up the head gasket as well as the cam seal... thanks foe the added insights..

 

[Scott Danforth]

make sure its a mercruiser gasket and not a sierra. the sierra ones may not work. you will most likely need a speedi sleeve for the cam snout

 

[Contagious 1]

Scott, I was reading another post on another thread about frosting. Before I saw the milky substance on the dip stick, I did see frosting substance leaking from the starboard side of the engine. And previous to that I did see that the oil on the stick was a bit high. Could it be just an issue of too much oil that on start up cause oil to splash all around inside causing the the white milky substance in the oil pan?

 

[Scott Danforth]

do you mean frothing?

very easy to check, read the second line of post #4 and follow that direction

 

[QBhoy]

Mmm. Feel for you. Sounds like you are the latest of many to be struck down by these horrible things. Likely one of many issues causing this. Once the chain reaction has started. There is seldom few come back from it.
hope you get it sorted...or stock a 3.0 in it, like most end up doing. All the best.

 

[Contagious 1]

Yes Scott I meant frothing... Thanks Scott and QBhoy.... Im not planning on changing the engine. This just started to happen and as far as I know the engine did not overheat. This started to happen after I changed the oil.... Will take this one step at a time... Thanks

 

[Contagious 1]

Finally drained the oil. First bunch that came out from the oil pan was clear water. It was quickly followed by milky oil substance. I did not smell any anti-freeze in the oil. After draining the milky substance, I did replaced the oil filter and motor oil. Prior to attempting to start I pulled the spark plugs. 3 of the 4 showed good firing; however, 1 plug was fouled, the last cylinder towards the stern. Ran a compression test on that cylinder and it showed 90psi. So, Im wondering if this is a possible sign of a bad head gasket? Or is it like Scott mentioned a leaking exhaust elbow?

 

[Scott Danforth]

now do a leak-down test and find out.

 

[Contagious 1]

thanks Scott... will seek to do such in the next few days and provide an update.... Comment/Question: I see that you have the Ferrari saying... Have you seen the Ford vs Ferrari movie?

 

[Contagious 1]

Im back posting the latest findings. So after a coupe of weeks I finally ran the leak down test and was unable to get anything definite. Given that the compression of one of the cylinders was low and that the oil was milky, I took of the valve covered and discovered two damaged pushrods. These were from the same cylinder that had low compression, which is the last cylinder towards the stern. One pushrod was slightly bent and the other bent badly, nearly breaking into three pieces. Took the head off and discovered rusty ports... see pics. I inspected the head and block and neither seem to be warped... Could this be something other than a bad head gasket??? Or could this be as a result of the engine overheating due to a bad impeller which then lead to a bad head gasket allowing water in the piston and thereby causing the two pushrods to get bent? I want to make sure Im not missing anything...

 

[Faztbullet]

Water does not compress and only way it would cause pushrod to bend is: valve did not open either to hydolock pressure or valve seized into position. You have more problem as possible bent rod/s,valve guide/head damage,smeared bearings through motor as polluted lubrication. IMO i would repower and junk this motor.

 

[Contagious 1]

Thanks Faztbullet... Thats not very encouraging... The motor was running well prior to the milky oil and it even ran after I drained the contaminated oil and replaced the oil filter. The pistons and cylinders all look good and the only bad cylinder both compression and burning wise was the last cylinder. Im not too thrilled about putting something else in it at the moment. I got the entire winter to fiddle around with it...

 

[Faztbullet]

If your going to try and fix it get a GOOD machine shop that knows Ford products. The pushrods are non adjustable and come in different lengths, so any head work may could change geometry specs

 

[Contagious 1]

Thanks... good point.... if the head is repairable just needing guides and valves, any other suggestions that should be considered?