[Mick Huestis]

Running out of things to check.

Wet exhaust was clear, like the day I built it.
Dry riser was perfect. No moisture. Working perfectly (thanks to Tony’s Tips 5 years ago).
Turbo exhaust was silky velvet soot, clearly no moisture leaking through exhaust manifold / header tank.
Engine oil lab test was good, zero water in crank case.
Gave coolant pump a spin today, seems to be flowing normally.
After cooler, totally clear, o rings still greased, all good (thanks to Tony’s Tips 5 years ago) regreased and ready to go again.
Checked coolant drains – all clear, flowing clear with no gel or sediment. No concern of heat exchanger being gelled up on coolant side.

Plan forward
– coolant side alkaline clean
– new coolant
– new thermostat
– New salt water impeller
– test run and see what is happening

Next things to check, in order
– salt water pump to come off for a look see, if that doesn’t find it;
– coolant pump to be pulled off for a look

I will find the heating issue!

Cheers

[Mick Huestis]

I still don’t know what my problem is, but some good news – today received back engine oil laboratory analysis.

No water in oil – no abnormal results.

Rules out the head gasket I think.

progress…

Got a coat of paint on the aftercooler, ready to go back together with new o-rings and plenty of grease.

No leak between salt water side and oil side of oil cooler.

back together and then coolant side flush out, replace thermostat, try again.

[Mick Huestis]

how do we measure the Yanmar sea water pump to determine if the OD and cam is worn too far?

some water I run in is silty, could be abrasive?

cheers
Mick

[Mick Huestis]

Hi Bill

The coolant is Fluro green. Now I’ve checked, It says to change every two years. It was recommended based on all different metal types in the system. Doesn’t say anything about silicates or phosphates. Unfortunately have gone 4 years on the coolant, didn’t realise it needed changing yet. Thought it was long life but was wrong.

Cheers

[Mick Huestis]

Hi Rob

Raw water Intake hose is 7 years old, steel wire reinforced industrial pump intake hose,

Coolant side. Water pump is original. Feels good to spin, no bearing issue and no mechanical seal leak. I have not removed for checking impeller clearances. do the coolant pump impellers wear?

Coolant. Has had Nulon Ultra Cool which says it is good for all metal types in the engine. Block was fully washed out 5 years ago when engine was removed to deal with an oil leak between block and bell housing (can shaft welsh plug). Will do coolant flush this weekend and will change thermostat.

What is involved in rebuilding the raw water pump? Never done that.

Cheers
Mick

[Mick Huestis]

Thanks Rob

is there somewhere a bit of data that says what the unrestricted flow rate should be directly off the raw water pump?

cheers
Mick

[Mick Huestis]

guys, another thing.

What flow rate should the sea water pump have? 4LHA-STP

when engine is cold I should be able to run at 1000 rpm for a minute with the sea water diverted into a bucket to measure flow rate.

[Mick Huestis]

Hi Rob

Thanks for the ideas.

I have a seacock with basket strainer.

The basket is clean.

I have put a hose down the seacock valve to the inlet grate and at full pressure the water all flows out the bottom.

I would have thought that if the inlet was blocked the hose would have backed up and overflowed the seacock.

I’ll try your idea of greasing the top plastic gasket – never done that before so will give it a try.

cheers

[Mick Huestis]

What is the best way to clean the engine block coolant cavities?

I’ll do that too.

is any cooling system cleaner ok, or is there a ‘best’ type?

[Mick Huestis]

After cooler came out last night. perfectly clean as expected. no rubber bits or any other bits any where. no blockages, tubes clean like all other coolers from the Barnacle Buster circuit flush.

Thermostat tested – all ok. rechecked new impellor in seawater pump, looks ok.

not the heat exchanger
not the gear cooler
not the after cooler
not the oil cooler

Something has happened very recently that is a totally new and additional problem to the gradual increase in temperature from the coolers getting dirty (which I have fixed). Now the coolers are perfectly clean, temperature should have gone down 5 degrees C. Instead, temp went up to 87 / 88 degrees C.

Next option, take off the wet exhaust (custom dry riser and wet exhaust nozzle) to see if any build up there blocking flow. If not that, sea water pump will come off for a good look on the bench.

All very puzzling. My gut tells me the problem is not in the salt water cooling circuit.

[Mick Huestis]

whole salt water system gets fully serviced every few years, never had trouble.

Aftercooler is just next this time around (this week), expect it is clean though and just needs check and new O ring plus greasing.

No impeller pieces anywhere, didn’t fail – was changed our preventive maintenance every year.

Salt water since 2004.

Normally just needs full salt side clean out to get temp back down, just didn’t happen this time.

Can see daylight through heat exchanger, oil cooler and gear cooler tubes.

Gear cooler and heat exchanger photo attached to show how clean my tubes are.

Salt water pump to come out next.

[Mick Huestis]

Hi Tony

The engine has as normal gone from 80 degrees C to 85 over about 3 years since last cooling system clean.
Last couple trips it was running hotter, to 87 at full noise so I just trolled to keep temp down.
Book says clean heat exchangers etc at 85 degrees C.
Reckon the issue is very recent.
I did a chemical recirculating clean using product commercially available for recirculating cleaning of the salt water side. (barnacle buster)
Did raw water pump impeller at the same time, just annual change out, came out in one piece as normal.
Took caps off heat exchanger and oil cooler to do annual gasket change.
Tubes all clear, no blockages or debris.
Only thing I haven’t opened yet is the air cooler which will need to come apart anyway to change the O Ring and regrease. But I expect that will be clear.
Hose runs freely through sea cock and out through intake.
Just pulling the thermostat now to test that.
Oil looks clean.
No oil in coolant.
No loss of coolant.
Annodes done every 3 months.
Don’t think it is the temp sender, everything felt a bit too hot.
Cheers
Mick

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