My boat is being a boat . . .

[tpenfield]

OK - the starboard engine is going all-in on the cooling system woes. Not only is the water pressure an issue, but coolant reservoir is overflowing. I also noticed the coolant temperature would go a bit high and then recover back to normal.

I'm thinking that either the H.E. cap (radiator cap) has come loose, or is not holding its rated pressure.

Looks like my work for next week is lined up

 

[tpenfield]

Having a slight panic attack . . .

In thinking more about my overflowing coolant reservoir, one of the causes of such is a blown head gasket. Other common causes are the thermostat failure, and the 'radiator' cap (H.E. pressure cap) failure.

I had not thought about it until now, since the engines are fairly new and have only 300 hours on them. I'll be checking things out this week. Hoping that it is something simple (usually never is)

 

[Lou C]

Ted I would think that with the low hours the thermostat and/or pressure cap are much more likely causes.
You could do the clear hose test (replacing the hoses feeding the manifolds/elbows) to see if there are air bubbles in the coolant; or alternatively you can get one of those combustion gas testers which will tell you the same thing. Might be more convenient than removing hoses with the cat converter exhaust then having to bleed out the air. Suggestion; get one of those Lisle radiator funnels for bleeding coolant & testing. I have used one for a long time & it makes refilling & bleeding out air SO much easier. No mess no spilled AF & you can see that all the air is out.
You could also do an oil analysis & if you see AF showing in the oil that is a sign of head gaskets starting to leak. I had this with my boat; the HGs were starting to leak even before the overheat in 2013. The sign was high wear metals & sodium (from salt water cooling) in the oil. The overheat was caused by a hose popping off not the head gaskets themselves. It ran fine 2 more seasons then they failed in 2016 & I had water in 2 cyls.
After I fixed it in 2017 I did 2 oil analyses & no water no sodium in the oil & wear metals came way down.
That boiling of AF in the recovery tank was the classic symptom of blown HGs on the Subaru EJ2.5 engines, we had one (a 1998 Outback), it did this 2x, first time we fixed it (109,000 miles) second time we sold it (186,000 miles). These would put combustion gas in the cooling system & overheat but didn’t put AF in the motor oil.

 

[tpenfield]

Thanks for the advice @Lou C

I ordered an exhaust gas testing kit, just in case the easy stuff does not prove to be the issue.

I’m also thinking that the exhaust gasses would end up in the heat exchanger and bubble to the top, and not really force water out as much, but hard to tell.

The temperature on the engine went a little high 171F during my last outing, but then came down on its own 165F.

My plan for this week is to check the cap, check the oil consistency, and maybe do the exhaust gas test. I got the better kit with the radiator cap attachments.

I really need the boat to be operational for the month of July, as we have lots of friends and family visiting

 

[Lou C]

That’s really not overheating though & when our Subaru overheated both times it pegged hot on the gauge.
My boat even when the HGs were leaking never really overheated, it really depends on where the HG failure is.

 

[tpenfield]

Yup . . . The temperature blip was just a bit odd, since I rarely see anything in the 170˚F range. Mostly 163-165.

I'll be working on the boat on Wednesday, just hoping for a good outcome.

 

[Lou C]

I could see if the pressure cap is allowing enough coolant out that you could wind up with a small amount of air in the cooling system that alone could cause the slight increase in running temp.

 

[tpenfield]

Yup, the nice thing about a closed cooling system is that they are relatively easy to pressure test . . . if it comes to that.

 

[tpenfield]

Update . . .

I spent some time out on the boat (at the mooring) today to take a further look at the cooling system.

The starboard engine's reservoir was quite full, so not much, if any coolant got sucked back into the HE as the engine cooled down from last week's outing.
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So, I drained it back into the HE. I still needed to add about a quart of coolant to get it back to full. The cap seemed to be on correctly, but maybe it is malfunctioning.

The port engine was fine . . . HE was full to the top.
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One thing I did notice was that there is too much coolant in the reservoirs.
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drained them down to the 'Cold' level.
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Here is the 'radiator cap' . . . I'll have to cross reference that to a generic P/N.
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I swapped the caps between engines to see if the overflow problem follows the cap.

I ran the engines up to temperature, but could not put a load on them, since I was at the mooring and a bit too stinky out in the bay to take the boat for a spin.
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The port engine had a bit more coolant rise in the reservoir than the starboard engine . . . so, maybe it is the cap.

I probed both engines with the IR thermometer, and the temperatures were very consistent side-to-side and engine-to-engine.

So, looks like the next thing to do is to take it out for a run (maybe tomorrow) and see what things look like under load.
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View attachment IMG_4822.MOV

 

[flashback]

I'm thinking the cap is your gremlin and a run under load will reveal it.. that said I wish I had the space around my motor that you do.. but don't want the COMPUTER! It would drive me crazy..

 

[tpenfield]

I'm thinking the cap is your gremlin and a run under load will reveal it.. that said I wish I had the space around my motor that you do.. but don't want the COMPUTER! It would drive me crazy..

Yup, I might order a couple new caps. I'm hoping to get some of the batteries out of the way with the LiFePO upgrade.

 

[Dubed]

Oh to have a problem that's as simple as a rad cap!

 

[tpenfield]

Oh to have a problem that's as simple as a rad cap!

I guess it would make sense if during each outing the engine discharged about a half quart of coolant and did not retrieve it back. We shall see.

 

[Lou C]

this is a great gadget for getting air out of cooling systems without making a mess, especially nice in a boat. Don't want to have the bilge pump kick on and discharge AF in the water!
A few years ago I had a P/S actuator leaking and that was a constant worry till I fixed it!

Lisle Radiator Funnel, comes with a set of adapters that fit most rad cap fittings. Here it is on my Hemi powered Jeep after I replaced a leaky thermostat assembly about 10 years ago.

 

[Scott Danforth]

Get new cap. OEM on the Champ HXs are stant.

Same puke bottle is used on everything from the ill-fated vaser to big blocks. If you add too much coolant, it spits into the bilge

 

[tpenfield]

Get new cap. OEM on the Champ HXs are stant.

Same puke bottle is used on everything from the ill-fated vaser to big blocks. If you add too much coolant, it spits into the bilge

Yes, it does . . .

BTW - I am on a couple Cruisers Yacht FB groups . . . There was recently some pictures of your boat (IIRC).

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[Scott Danforth]

It's a 1988 Rogue 2400 or 2420. Looks to have been repainted. Newer decal.

 

[tpenfield]

Cooling system update. . .

I went to pump the poop (out) and pump the gasoline (in) . . . about a 14 mile round trip journey up a couple of harbors from me.

The cooling system was fine . . . nothing extra in the overflow tanks. . . So, it must have been a slightly loose cap.
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Gasoline was $5.08/gallon !!!

I only got 40 gallons, and probably will be schlepping fuel in jugs out to the boat @ $3.50/gallon

I think I mentioned a few posts ago that as soon as I fix one problem another one takes its place. Sure enough . . . when I got gas, I noticed a lot of pressure/vacuum relief from the gas cap when I opened it. I don't remember it doing such last year. Wondering if I have a venting problem. . I checked it again when I got back to my harbor. . . more pressure relief.

Anyway, it was a nice day to be out in the boat . . .
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[alldodge]

87 here is 4.90 so not a lot better

 

[tpenfield]

87 here is 4.90 so not a lot better

Marina prices. . .

AD, what fuel mileage are you getting with the Chappy?