Kohler 5E - What is this part

[firecadet613]

Having a hard time finding this part on the schematics, it's not the heat exchanger (heat exchanger bolts to it).

Twice now, I've found a bit of coolant on the bottom lip of that freeze plug and today it was about an inch low in the overflow tank.

Just starting to troubleshoot this. The backstory is I bought the boat last year, 13 year old boat with 31 hours on the Kohler 5E. Ran a bit rough during the sea-trial but the mechanics had it running smooth after letting it run for a while. It runs fine for me. Last year I took apart the sound shield to check the coolant and overflow tank (ended up tossing the damn sound shield) and found the overflow tank dry and just water under the pressure cap (previous owner always stored indoors heated). VERY glad I decided to check it out before the winter (I store indoors cold). Genset runs fine, aside from the coolant I've found twice there and a bit low today.

Any suggestions on where to start would be appreciated. What temp should I be seeing with my infrared temp gun, when its all warmed up?

 

[We’reThere]

Following this... Have noticed the same issue on my low time 2015 5EKD. Not a substantial loss of fluid, but sounds to be the exact issue you’re having.

 

[Wanderer 290]

Replace the the cap on the heat exchanger. A.k.a. Radiator cap.

 

[firecadet613]

Replace the the cap on the heat exchanger. A.k.a. Radiator cap.

I've got one on order....swore I replaced it in the fall, but can't find it in my notes. Cheap fix - hoping that's it, but not sure that explains the coolant on the side there.

 

[We’reThere]

Ran the genset a couple of hours over the last weekend. No apparent leaks for me from the cap itself. I’m worried there are very small cracks around the area in question on the heat exchanger. There is no significant loss of coolant, but enough to see as shown in the picture below.

I’ll likely let it ride for now and get a mechanic’s opinion this offseason.

 

[firecadet613]

I put a new cap on mine over the weekend and ran it 4 hours. All appears to be good so far, with no pooling of coolant on the freeze plug.

 

[We’reThere]

Great news, thanks for the reply! Did it look like coolant was coming from your old cap or was it similar to my pic?

I’ll plan to order a new cap either way to try it out.

 

[firecadet613]

Great news, thanks for the reply! Did it look like coolant was coming from your old cap or was it similar to my pic?

I’ll plan to order a new cap either way to try it out.

Not 100%, but I'm hoping so. It's either that or the freeze plug is leaking is my thoughts. Hopefully we can get out again this weekend and add some hours to the generator. My boat's an '07, picked it up last year with 630hrs on the motors - 31 on the generator! They like to run and not sit....

 

[We’reThere]

We just bought our ‘15 about a month ago... generator had 10 hours on it before sea trial. We’ve nearly tripled that now.

 

[pyro]

I also get a very small drop or two exactly at that plug. Assumed it was the cap. I bought a new cap, but couldn't get the old one off last time I tried. It's hit or miss whether I see fluid there. I would even see it during the winter in storage so I think it has something to do with expansion of the fluid due to temperature.
Another trick is to wrap a paper towel around the cap to see if it's leaking from there.

 

[firecadet613]

New cap is on, no fluid loss...but still getting coolant pooling there...if I wipe it off, next trip out we'll run it for a few hours and it's back...