Afraid with my Heat Exchanger

[Mario Tranquilein]

hi my 671 non T 1974 have they original HE, I dismount them and put new O rings gaskets,clean the core etc. One of the motors run at 170 at 1,400 rpm without termostat and every day I checked the water always need half of gallon of water I use only fresh water here in the Caribbean. The other motor could not be need water in two months easily. i tried to find and sign of a leak but no luck on that one, a friend toll could be water bowling but at 170?. The motor never smoke of any kind and runs perfectly,clean motor oil,excellent oil prs,fire at one turn but yesterday when I taked the radiator cap out (is also new) I noticed a little of grey stuff. I'am afraid that could be oil getting in the water but is very little the amount. It could be a head gasket blow, HE pass out, raiser rust in the interior or what else? I have another trip to saint Croix and needs this out of my mine. Please any advice in this? Thanks a lot. Mario

[Boatsb]

Sounds like a leak. can you put a pressure tester on it?

[Mario Tranquilein]

Hi: where can I put the preassure gauge? and what do you think it could be the grey stuff? Thanks

Sounds like a leak. can you put a pressure tester on it?

[REBrueckner]

A half gallon refill frequently means either you have the engine too full of coolant and it simply dribbles out the drain via the pressure cap OR you have a leak. Can you tell if any is going in the bilge???

You can buy a cooling pressure tester at most automotive parts stores...it fits on the heat exchanger in place of the pressure cap. Just pump to maybe ten or 12 psi and see if it holds that pressure...compare with the other engine if you need a reference....

What "gray stuff">>>????? where??

[yachtsmanbill]

Mario... if you are running water, put an ounce or two of red food coloring in the water to find external leaks. A little crud on the bottom of the HE cap is to be expected on a 40 year ols 8-53N. ws

[Canuck Dennis]

a new rad cap should have no "crud"

[Mario Tranquilein]

Hi: I found a grey stuff like tooth paste (but grey) in the radiator cap a very little but what could it be? I use chelak in the gaskets 3 months ago but chelak is brown. I was afraid that could be oil mixed with water but I think that will be coffee color not grey. I will try to find the gauge in the mean time. Thanks

A half gallon refill frequently means either you have the engine too full of coolant and it simply dribbles out the drain via the pressure cap OR you have a leak. Can you tell if any is going in the bilge???

You can buy a cooling pressure tester at most automotive parts stores...it fits on the heat exchanger in place of the pressure cap. Just pump to maybe ten or 12 psi and see if it holds that pressure...compare with the other engine if you need a reference....

What "gray stuff">>>????? where??

[yachtsmanbill]

Oil floats on water. Si?? Any crud (petroleum based) will find its way to the top of the HE. Gray or putty color is normal. A spoonful isnt bad. Now if it came oozing out when you opened the cap, thats another story. Actually, thats a good sign that its not running too hot. Temps are good at 170? Then you really should have a 180 T stat in there. That may disolve the crud with hotter water. ws

[Mario Tranquilein]

Hi: I removed my termostat because I was thinking that the motor are running hot, then the other motor start marking erratic temps too so I decided to changed both gauges and problem solve. But i don't take the time back to put the old termostat and confirm if it is good or not. Thanks to everyone for the help I fill more comfortable knowing that grey putty is normal. I hope one day find for when they came. Thanks