Heat exchanger drain cock leaking

[Jim L]

Last weekend I noticed what I feel was diesel fuel below my engine in the catch pan. Last night I went down to examine the issue to find what appeared to be diesel fuel, but could be coolant, leaking from the heat exchanger drain cock. It felt very oily smelled like diesel but not sure, had a purple color to it. It was getting dark so did not tackle with tools other than trying to tighten with my hand that was a no go. This is a 2GM20F with 1,700 hrs on her.

Jim

 

[jviss]

heat exchanger drain cock

I'm not familiar with that engine. What's the "heat exchanger drain cock?" Do you mean the block, the coolant drain?

 

[sailme88]

When coolant and lube mix it is usually always a head gasket. The transference goes both ways depending on temp and pressure. White exhaust ( not gray) is also an indicator. There are chemical swatch tests that will prove glycol in the oil sump and oil in the glycol. Start with one of the afore mentioned contamination tests.

 

[Claude L.-Auger]

The drop I see is definitely from the manifold drain petcock. There is normally a plastic tube that runs from it down to the pan below the engine. Is color same as what is in heat exchanger ? I would use some pliers and delicately try to turn it open (counterclockwise), let some coolant out and then shut it off to see if it eliminates the leak. If not, you can replace it with a new one or even jury-rig a bolt with same thread in its place until you find one. Don't forget to refill the heat exchanger !

 

[kloudie1]

Drain cock is exactly that.. a drain cock on the heat exchanger/exhaust manifold housing on the GM series Yanmars.. There are others on the block..
If ya open the "radiator cap" and look at the coolant, It may be the reddish or purpley color from a slight leak from the little drain cock.. it may be only a drool from the cock that is evaporating and leaving a high concentration of coolant residue..?
EDIT: M. Auger beat me to it on this one.. we are saying the same thing (almost)

 

[kloudie1]

If it continues to leak and ya need one, the part # for a new cock is 119620-49290 and they are around $30 each.

 

[Jim L]

Wow Guys that was fast, thanks all. Great advice I will give it an attempt this weekend with both the chemical test and opening up the petcock with pliers during the daylight. Guess I can pick up the test swatch at West Marine. Pretty sick I even picked up some new terms. It is actually a pretty steady drip maybe 1 every 3 seconds.

 

[Jim L]

slick

 

[Jim L]

I now have a thoroughly cleaned out cooling system. But, get this, the leak turned out to be a leak from my secondary filter. The feed fuel line entering the filter was not secure. It apparently vibrated loose from the replacement a year or so ago. Fuel was running along the supply line to a point where it was in contact with the petcock. The fuel was then departing the fuel line over to the petcock because they were in contact with one another. Once I tightened up the fuel supply into the secondary filter and made a gap between the fuel line and the petcock it dripping stopped.