Volvo Penta D1-20 Overheating

[Danny_Labrador]

So a mate of mine has a problem with his Volvo Penta its been fine since new in 2014 and has 2,400 hours on the clock.

However during the last few months its started to run hot and regularly sounds the overheat alarm. So far the sensor has been changed as has the exhaust elbow. Also the water reservoir has been raised a little to see it his helped. Also checks has been made to see if an airlock is present with no luck.

The sea water flow rate has been checked as have the inlets and outlets.

The domestic hot water supply after the engine has been run for some time does seem much hotter then I remember generally hot water on boats being.

Can anyone suggest a reason or other checks that could be made please.

 

[Rafiki]

Almost the same post on the PBO forum, with quite a few answers. Likely to be the heat exchanger needs cleaning.

 

[Danny_Labrador]

Almost the same post on the PBO forum, with quite a few answers. Likely to be the heat exchanger needs cleaning.

Thanks for that - do you have a link please ?

 

[RichardS]

Thermostat?

Richard

 

[WalshamUK]

I agree with others that the most likely cause is that the heat exchanger needs to be cleaned. Especially after doing 2400 engine hours in only 5 years. My Volvo Penta 2030's heat exchanger had 25 out of 32 tubes blocked when I cleaned it, after being used for under 1000 engine hours. Keith

 

[Frank Holden]

I had a few overheating issues with my MD17D over the last year and into this year..
Checked the usual stuff .. SW impeller, thermostat, filter on raw water intake....belt tension for FW circ pump...
Would be OK at low revs... overheat at high...
Anyway... hauled boat for all the usual reasons...
Replaced all hoses, replaced 35 yo Volvo raw water filter with new Vetus one. Checked heat exchanger... all good.
Drained and flushed all FW galleries in the engine.
Engine tested OK at low power on the hard... splashed boat...
On way to fuel dock maybe a mile away.... blowing steam on high revs and in the red.....

Happened to have a mate with me... 'I had this problem' sez he....
'Check the cover plate on the raw water pump.....'

Now this isn't a 35 year old cover plate but a maybe 10 year old speedseal one....

Showed wear,,, centre 10mm standing proud of the bits opposite the impeller... almost 1mm... obvious when you know what to look for... letting water bleed past the impeller at high revs... ie reduced efficiency.

Machined smooth... problem solved
Also solved the problem of losing prime sometimes when rolling heavily.... I had not linked the two....

Hope this helps...