mercruiser-coolant draining in my oil!

[droptheline]

Hello, i got a inline 4 165 hp freshwater cooled mercruiser, my coolant was "disaappearing as i filled it and low and behold i found it in my oil pan, i have flush and flushed with two cases of oil, and it starts and runs fine for now, so where the heck is it getting in? i am good with car's but the pulmbing of a fresh water cooled engine seems to baffle me. Please help me if u can. Thank you very much.

 

[Fishermark]

Re: mercruiser-coolant draining in my oil!

I believe that model of engine (a nightmare to most people) had a common problem of the front cam seal leaking and doing exactly what you describe.

If you google "mercruiser 470 cam seal" you will find plenty of info. Others will probably chime in soon.

 

[droptheline]

Re: mercruiser-coolant draining in my oil!

well thats certainly a scarey possiability, I dont have a coolant leak in the front of the motor (hopefully good news) and i dont have to run the motor for coolant to get in the oil, 2 things that seemed to be needed when i googled it, is there a sure fire way to tell if the 2nd cam seal is my problem? any other possiabilities on what it might be? thank you for your info.

 

[Haut Medoc]

Re: mercruiser-coolant draining in my oil!

well thats certainly a scarey possiability, I dont have a coolant leak in the front of the motor (hopefully good news) and i dont have to run the motor for coolant to get in the oil, 2 things that seemed to be needed when i googled it, is there a sure fire way to tell if the 2nd cam seal is my problem? any other possiabilities on what it might be? thank you for your info.

Cracked block or manifold, but it is most likely the what Fishermark says....

 

[HT32BSX115]

Re: mercruiser-coolant draining in my oil!

I don't know how you KNOW that you don't have a coolant leak in the cam seal, But from what I read about the "470" series of engines that is one of the most common paths for coolant getting into the oil. Maybe both "lips" have to leak for this to happen....but whatever the cause you need to "get right on it!" as you probably are!

well thats certainly a scarey possiability, I dont have a coolant leak in the front of the motor (hopefully good news) and i dont have to run the motor for coolant to get in the oil, 2 things that seemed to be needed when i googled it, is there a sure fire way to tell if the 2nd cam seal is my problem? any other possiabilities on what it might be? thank you for your info.

 

[droptheline]

Re: mercruiser-coolant draining in my oil!

I am certain of nothing (other wise id be doin the damb thing u know) i just read what the fishermark said and it seemed to me what i was reading is that the engine has to be running for the coolant to leak past the 2nd cam gasket and that coolant should be leaking from the vent in the front of the motor (which is doesn't) so... can the coolant leak past the cam gasket without the motor running? i mean i had alot of water in the motor(like half a gallon or more) just from filling my cooling system, its as if i poured water directly into the block, it was not mixed with the oil ( cause i hadn't started it) so i guess ill have to poke around a little more thanks for your time.

 

[Haut Medoc]

Re: mercruiser-coolant draining in my oil!

Drain the cooling system & test with compressed air, before disassembly, you will hear the leak......
If it is that much water, it could be a cracked block.....
The above test will help you localize it....​

 

[droptheline]

Re: mercruiser-coolant draining in my oil!

Thanks im gonna try that asap. Can i ask anyone what the symptoms are when your exhaust manifold is rotted out? Let u know how the pressure test went. thanks again

 

[bruceb58]

Re: mercruiser-coolant draining in my oil!

I don't think its going to be exhaust manifolds. With the amount of water you are talking about, you would have a hydro-lock because the water has to go through the rings to reach the crankcase.

 

[Haut Medoc]

Re: mercruiser-coolant draining in my oil!

I don't think its going to be exhaust manifolds. With the amount of water you are talking about, you would have a hydro-lock because the water has to go through the rings to reach the crankcase.

I agree....
That much water is most likely not a manifold problem......

 

[jcho69]

Re: mercruiser-coolant draining in my oil!

hello droptheline,
did you able to fix the problem on your boat?
i have the same boat motor and the exact problem that you have.
i am still not able to find the solution. Please let me know if you know the problem. Thanks

 

[Uraijit]

Re: mercruiser-coolant draining in my oil!

hello droptheline,
did you able to fix the problem on your boat?
i have the same boat motor and the exact problem that you have.
i am still not able to find the solution. Please let me know if you know the problem. Thanks

Did you do a coolant system pressure test?

 

[droptheline]

Re: mercruiser-coolant draining in my oil!

hello droptheline,
did you able to fix the problem on your boat?
i have the same boat motor and the exact problem that you have.
i am still not able to find the solution. Please let me know if you know the problem. Thanks

I sure did fix it. Turn out the engine design was absolute junk and i put a 3.0 in. little less power but worlds better motor, i will never touch a 470 again as long as i live.

 

[HT32BSX115]

Re: mercruiser-coolant draining in my oil!

Another satisfied customer....

It could be worse.....you could have a twin with two (2) 470's in it!!!