Heat exchanger on my 3870 Hino 175-gctid359915

[PortHoleDiver]

Guys, probably a dumb question, but I am getting a small antifreeze leak from the bottom drain on the exchanger, on my port engine. All freeze plugs good, lid I think is good, will pressure test. but each time I go out I loose antifreeze, drips/runs on port side to rear of generator. Noticed dripping from the drain plug. Can this be removed and o-ring replaced if it has one? Probably time to change out the antifreeze, but can't find any of this in my manuals. Thanks for any advice.

[mmichellich]

Antifreeze must be changed at an interval no greater than 24 months, many do it at 12 month intervals.

[kwb]

No o-rings it is a tapered plug into the valve body.

Mine had been weeping before sending out manicoolers to have coated. I cleaned up the valve and no leaks upon reassembly - otherwise it was getting replaced with a pipe plug.

[Guest]

The aft bottom end of the manicooler is the worst spot for collecting the dredded brown sludge. Drain the coolant, carefully remove the side and especially the botttom inspection plates (don't break the bolts - use a smoke wrench if needed), and of course the drain valve, then clean, flush, and inspect all, chase all threads and bolts, and re-assemble with Hylomar sealant. The drain valve may need grinding or replacing if heavily scored or corroded. If you really want to go the extra mile, remove the manicooler, have cleaned, repaired, and finally ceramic coated. Good luck, Doug S.

[Tex]

mmichellich wrote:
Antifreeze must be changed at an interval no greater than 24 months, many do it at 12 month intervals.

True, but the question is, if you really do it.

My neighbor in docks, has not changed it for 10 years or more...

[mmichellich]

Tex wrote:
True, but the question is, if you really do it.

My neighbor in docks, has not changed it for 10 years or more...

If you do not do it, it will likely cost you a lot of cash with a manicooler casting with holes in it.

[Guest]

I change my antifreeze about every 5 yrs. Or so . Had my 1988 for over 20+ years never a problem . Earl took the coolers apart last, year they were like new. The coolent additives have improved over the years..

[PortHoleDiver]

But my problem was not if I should change it but how the drain was designed. I have not put 100 hours on the boat in three years due to wife's illness. I also would have to add roughly a gallon of antifreeze each time we would go out for a few hours. It would leak out and collect behind the radiator and caught in absorbtion pads and fresh added each time. Also there are two metal triangular pieces, one above the other in the fill area. Is the correct level between these two or do you fill up to the top one for the correct amount. Constantly loosing antifreeze has not required changing. Just wanting to know proper proceedure in using this drain, as it seems to be leaking here and the proper amount, ie the height, the level the antifreeze should be at. Can't find this in any manual.

[capt._ron]

The pointers under the cap, if you keep it above the lowest you should be ok. If you fill above the top pointer it will blow some out, at least mine will. When I change I fill so it just covers the bottom pointer that leaves enough for expansion when at operating temp.

[PortHoleDiver]

Thanks, got it. Also my mistake in typing. It, antifreeze, drains down to bottom of boat and goes toward the aft end of boat through weep holes in the stringers and ends up behind Generator; not radiator. Dang auto correct ha ha