Yanmar running hot

[Hud3]

Originally Posted by Chuck Baier

...We changed out the FW tank cap and the flange that it attaches to...

Chuck,

Just to clarify...

By "FW tank" you're talking about the engine, right? Not the plastic overflow tank.

[AnchorageGuy]

That is correct. Not talking about the plastic expansion tank.

[Hud3]

Dang! I thought you would have it solved with the filler cap assembly replacement. Hope you can find the culprit for a lot less than $5K! Good luck!

[AnchorageGuy]

Thanks Hud, Bad part is we could spend $5K and take off with the same problem. I suppose we will work it out somehow. We are here at the dock with the engine running in gear and the temp sits right at normal and with a guage on the tank it stays at about 6 PSI and when pressurized the tank will hold pressure.

[Boracay]

I'll second the suggestion about getting a heat sensing device (gun).

Use it at dock and then compare the readings with what you get underway.

An infra red camera would be even better.

[Chief Engineer]

Call the NAPA or Advance Auto Parts store for one of the infrared guns.

If there is a Sears nearby they sell them also.

[AnchorageGuy]

Have one of the infrared guns and the engine is showing 170 after running under load for 2 hours so overheat does not really seem to be the issue now.

[Chief Engineer]

They are great little diagnostic tools.

And I bet the first thing you did when you put the battery in was aim it at your hand....Right?

[AnchorageGuy]

No my head.

[Chief Engineer]

And you found that

a cooler head prevails.

I just had a thought......on your over flow bottle (I can't recall the yanmar container)
does it fill and draw from the bottom....or does it go into the top/lid and then thru a hose to the bottom?

[AnchorageGuy]

Chief, It fills and draws from a tube that goes into the top and extends down to just short of the bottom. First thing I did was to make sure that hose was not clogged or kinked.

[AnchorageGuy]

Here is another update. We have changed out the exhaust manifold/FW tank on the engine. This is one complete unit. Upon removal we found some corrosion in the exhaust manifold where the riser bolts on. The drain for the FW tank is right under this area so perhaps there is a pinhole here that is allowing exhaust gas into the FW tank and pressurizing it. It is possible that exhaust is getting in under pressure but the hole is too small to let fluid back into the exhaust. At least that is the theory from the mechanic and Mastery where the engine came from. Late tomorrow we head out and move north so we will know for sure if it is solved or not. Keeping our fingers crossed. We have also added a temp guage which we did not have before, in addition to the alarm and light. We sure hope this solves it.

[Hud3]

Good luck, Chuck! I have a 4JH3(B)E, so I'll be looking forward to hearing how the fix worked for you.