Water level going down in expansion tank

[pop pop]

HY GUYS I have another 170 problem!
Here is the problem the coolent level in the resavior tank seems to be droping slowly down to empty in about 1 week after filling it. I checked the compresion and all cylinders are about 145 psi with no water in the oil or oil in the water. could my pro blem be the heat exchanger. I also repaced the exaust riser elbo. The motor is a 1986 170 hp with alfa 1 drive. aLso I should tell you that there is no visable signs of leaks on or around the engine block.

 

[wire2]

Re: Water level going down in expansion tank

I expect the reservoir system has a rad cap? There's an adapter available for car rads to pressurize the system. NAPA or others will have them. Pump it up to 10-12 psi and see where the coolant comes out. The pressure *should* hold.

 

[pop pop]

Re: Water level going down in expansion tank

Done that and the presure drops right off but I cannot hear or see where it goes. PS Thanks for the quick reply

 

[stonyloam]

Re: Water level going down in expansion tank

Sounds like your head gasket is OK, but you could do a coolant system pressure check. Autozone will lend the tools for free. It not only checks the static pressure of the system, but also checks for excess pressure buildup while the engine is running, an indication of a leaking head gasket. The other two places to look are the riser gaskets on the exhaust and a leaking heat exchanger. You could try draining some of the seawater out of the exchanger (aft plug) to see if it has antifreeze in it, which could be from a leaking tube or gasket. Good luck.

 

[pop pop]

Re: Water level going down in expansion tank

Thanks I have already done a coolent pressure test and it will not build presure. Is there any other way to test the exchanger . Because of the leak I have strait water in it, so I wont be able to see anteefreze come out. Also can I hert my motor or over heat if the exchanger is leaking. I had the boat out last weekend and it ran fine

 

[Haut Medoc]

Re: Water level going down in expansion tank

Thanks I have already done a coolent pressure test and it will not build presure. Is there any other way to test the exchanger . Because of the leak I have strait water in it, so I wont be able to see anteefreze come out. Also can I hert my motor or over heat if the exchanger is leaking. I had the boat out last weekend and it ran fine

Depends where it is leaking.....
I would check the plugs & make sure that none appear steam cleaned.....
It should be fairly easy to isolate & pressure test the closed side of the exchanger, plug one end & rig a suitable connection with a Schrader valve & pump it up with a bicycle pump, just like you would when pressure checking a drive unit......
I would also make sure the oil is good, the 170 can leak at the water pump/cam seal.....
Hope this helps.....

 

[stonyloam]

Re: Water level going down in expansion tank

Thanks I have already done a coolent pressure test and it will not build presure. Is there any other way to test the exchanger . Because of the leak I have strait water in it, so I wont be able to see anteefreze come out. Also can I hert my motor or over heat if the exchanger is leaking. I had the boat out last weekend and it ran fine

You can buy dye to put into a cooling system to help find leaks. Like this http://www.autobarn.net/fluorleakdet.html Should be able to find it at the local auto parts store. Should also be able to get a black light for under 10 bucks. Look for it in the exchanger, or in the exhaust water coming out. If it is leaking out of the exchanger, it should be in both. Good luck.

 

[pop pop]

Re: Water level going down in expansion tank

I have checked the oil and the plugs and no sign of water so I am leaning towards the exchanger. THANKS FOR THE REPLIES