Coolant in engine oil

[Ya Mahn]

On my last ride the engine temp light started flashing. I stopped opened the hood to find the coolant tank empty. No visible leaks on the ground. Engine oil is milky? Brought it home and assumed the head gasket was leaking. Removed the head to find no obvious signs of leakage? Where would the leak be from???

 

[quebecmoutainrider]

its more than likely the bottom gasket..do you change the studs.most cars when the coolant is being burnt..it is the bottom one...I am not sure of sleds. I think the coolant does not go through the head gasket..but it does go through the bottom gasket..

 

[mulot30th]

Which bottom gasket do you talk about?

Happened to me on a few different places (coolant leak in oil.

Only places this can happen is where coolant pressureis SUPERIOR to oil pressure...

So oil return from head is good potential place (which happened to me)
Also I got center rear stud long version on block and coolant found its way up the threads of the head nut on that stud... I corrected this by using a closed nut (same as the one that is bolted on outside of the head)

Then I had a reinforced head that had a leak through one of reinforcement points.... usedjbweld on that one.

Sleeved engine might do that also..


Good news... there are easy solutions to all these problems... but took us some time to figure them all out...

 

[Ya Mahn]

I have not seen a bottom pan or lower crank case gasket that has coolant passage. The water pump seal leaking? The engine oil cooler internal with a crack?

 

[mulot30th]

My experience... every problem of this kind have originated on HG, block's deck or head itself

 

[quebecmoutainrider]

the coolant would do exactly like mulot30th said.it would run along the stud threads and into the oil...the oil changed colour and got more in the case everytime you rode.and coolant would go low..my buddy spent many hours trying to figure this out..he ended up puting his own home made gasket..on the head,which stoped the coolant from leaking.he knew there was a problem with a leak,but he had to figure why it was in the oil..the gasket on the bottom was damged when the companie put the thing together..no like an idiot he didnt take pics to show yamaha..with the xtra hps it must have finally disinerated the gasket.we knew the coolant was getting into the crank,but where.so after takeing the thing apart,he noticed the green on the stud,so he figured it must be the crank gasket.which he was told was impossible..but it was.

 

[Ya Mahn]

I just finished removing the engine. I will split the crank case and look for any signs of leakage.

 

[mulot30th]

the coolant would do exactly like mulot30th said.it would run along the stud threads and into the oil...the oil changed colour and got more in the case everytime you rode.and coolant would go low..my buddy spent many hours trying to figure this out..he ended up puting his own home made gasket..on the head,which stoped the coolant from leaking.he knew there was a problem with a leak,but he had to figure why it was in the oil..the gasket on the bottom was damged when the companie put the thing together..no like an idiot he didnt take pics to show yamaha..with the xtra hps it must have finally disinerated the gasket.we knew the coolant was getting into the crank,but where.so after takeing the thing apart,he noticed the green on the stud,so he figured it must be the crank gasket.which he was told was impossible..but it was.

In my case, it was a longer than stock stud passing by the rear coolant passage... so it was opened to coolant and its pressure... that was the reason...

Never saw that happen on stock length studs.

 

[Ya Mahn]

I thought the threads in the block were blind holes. That sounds good. I will check them. In my case I lost a lot of coolant within 5 minutes.

 

[mulot30th]

I thought the threads in the block were blind holes. That sounds good. I will check them. In my case I lost a lot of coolant within 5 minutes.

Yes they are... with stock length studs.

 

[quebecmoutainrider]

it wasnt a stock sled..it was a turbo put on by him years ago..not sure if the studs were longer.but for sure they were not stock

 

[mulot30th]

Longer studs need block to be machined to bolt the in there.

If not, they are stock lenght...

 

[quebecmoutainrider]

I shall ask him and find out if he did change the studs..

 

[cmharcou]

I'm assuming you guys are talking about a turbo sled. Mine is 100% stock and I also have coolant in the oil and oil in the coolant vice versa in the reservoir. I'm going to take off the oil cooler tonight and inspect it. Looks like the oil cooler has both oil and coolant going into it. If it a seal is bad or its crack perhaps that is where its mixing. I tested the head and block and it was negative for any carbon monoxide.

 

[HURRICANE]

WATERPUMP SEAL.I'd bet my first born on it