D1-30 still overheating - try without thermostat?

[DownWest]

I posted this before, but a similar prob on an older VP/Perkins three pot was due to the vent from just under the filler cap to the header tank, becoming blocked. Kept air in the circuit that caused it to over heat.

 

[amcrittenden]

I had the expansion tank on my new D1-13 raised after 12 months of intermittent problems. I found that motorsailing on a port tack will definitely make it overheat, motorsailing on a starboard tack will definitely clear the overheat and on the flat, anything could happen. Try that and you will know whether you need to raise the tank.

I'm happy to have stumbled onto this discussion. My D1-13 has also been overheating intermittently and unpredictably for most of the time that I've owned it. There seems to be a bleed screw on top of the freshwater pump, but it only bled coolant when I opened it. I'll try raising the expansion tank and see what happens.

 

[Refueler]

First is that many engines do not like to have Thermostat removed - when removed - cooling water can then just flow via the bypass with little going through engine.
If the Thermostat is too high rated - such as using a car thermostat - then it may not be opening early enough and engine is running too hot.

Personally I prefer to run a colder opening Thermostat so it opens a little lower temp to what book says - this does two things .. 1 : engine gets its cooling 2 : you don't start depositing salts etc. in the waterways from engine running hot ...

I think my first action would be swap out the thermostat for a lower temp rated .... then run descaler through the engine to clear out all the crap that has probably collected because of your 'hot runs' ... Keep de-scaling until things appear better ... You can even run de-scaler into the engine - then shut off engine and let de-scaler sit for a while - then run and flush out.

Just example from the Perkins blurb (many Volvos are rebadged) ... Raw water cooling not to exceed 60 C ..... closed circuit Heat Exchanger between 65 C and max 93C ..... (I would be wary of the 93C as it leaves little margin) ... Temps measured at Cylinder Head outlet .... I would be happier with about 70C Thermostat

That's my view anyway ..

 

[Slowtack]

My D1 30 pumps about 10 litres per minute at idle revs... Hope that's of some use....

 

[TonyMills]

Good point - I'm definitely raising the expansion tank on Arpeggio this winter.

I put together a blog page about my investigations here, which people might find useful. I think I've got the permissions correct on the page so that it's publicly readable!

Hi, I'm having issues with my D1-30. Steam coming from the wet exhaust and obvious bubbles in the raw water pipe work. I'd like to read your blog page but the link isn't working? Thanks Tony

 

[jlavery]

Unfortunately the blog site is no longer active - sorry!

If you've got steam coming from the exhaust, sounds like not enough water getting through the raw water side of the heat exchanger. Bubbles in the raw water pipework could well be linked. How much water is coming out of the exhaust? Should be regular gushes of good flow.

 

[TonyMills]

Unfortunately the blog site is no longer active - sorry!

If you've got steam coming from the exhaust, sounds like not enough water getting through the raw water side of the heat exchanger. Bubbles in the raw water pipework could well be linked. How much water is coming out of the exhaust? Should be regular gushes of good flow.

Thanks, I've just posted a forum entry on the issue including links to videos which show the bubbles and the water flow. I don't think I'm getting as good flow in the exhaust as I used to, particularly when the engine is pushed over 2500 revs.
Links:
Bubbles
Exhaust

 

[jlavery]

How hot is the water coming out of the exhaust, if you reach down and feel it with your hand?

Could there be a leak in the raw water side which is allowing air into the system?