Thermostats in Bukh, Yanmar and Volvo

[vyv_cox]

Thanks to all contributors for their input to this thread. It seems to be clear now.

Loss of images was due to some problem with Photobucket, I am currently unable to log in to it, yet to be resolved, but the reposted images are now on public pages.

 

[West Coast]

I had a VP2002 that had low water flow and steamed quite a bit when hot.
I removed and cleaned the exhaust elbow and the small pipe leading to it (the one Vyv refers to with 3 bends in it) and removed the 'stat, I didn't remove the perforated head tube. I then filled up all the block with descaler and left it until it stopped fizzing.

After that the rate of water flow was enormously increased, both hot and cold, and steaming stopped.

You have a blockage somewhere for sure!

I believe post #6 is the right explanation of how it works.

PS I presume the subsequent MD20x0 and D1/D2 series will be quite different being really Perkins not Volvo.

Been reading this thread with interest, although my knowledge of diesels is very limited compared to those contributing and am trying to understand the explanations!

Article pilot, Troubadour, re your discussions regarding rescaling, are your VP engines direct or FW cooled? I have a FW cooled 2003, the FW pump failed this past season and when I dismantled it to replace the bearings etc, I found a moderate amount of white 'scale' on the internal surfaces of the pump, not sure if this is the scale you refer to or perhaps just corrosion of the pump body metal over the years (20 years old, first pump overhaul!)

But does this suggest that I should be thinking of descaling the whole FW circuit? And if so, how do I do this?

 

[Plevier]

Mine was raw water.

 

[TC Tuckton]

On an old seawater cooled Volvo, what would happen if I connected the drain clocks at the base of the cylinders to the drain cock at the after end of the exhaust manifold? Would this provide a better flow than thermosyphon through the cylinder block waterways?

 

[vyv_cox]

Been reading this thread with interest, although my knowledge of diesels is very limited compared to those contributing and am trying to understand the explanations!

Article pilot, Troubadour, re your discussions regarding rescaling, are your VP engines direct or FW cooled? I have a FW cooled 2003, the FW pump failed this past season and when I dismantled it to replace the bearings etc, I found a moderate amount of white 'scale' on the internal surfaces of the pump, not sure if this is the scale you refer to or perhaps just corrosion of the pump body metal over the years (20 years old, first pump overhaul!)

But does this suggest that I should be thinking of descaling the whole FW circuit? And if so, how do I do this?

Scale in indirectly cooled engines is often caused by deposits that were present in the water used as a coolant, indicating that the engine has been run without antifreeze for a time. Products such as Radflush from automotive shops will usually remove them. I did mine last week: the product seems to be more high-tech than it used to be, requiring a two-stage process with much flushing between. It does seem to have removed a lot of debris from my old engine.

 

[West Coast]

Scale in indirectly cooled engines is often caused by deposits that were present in the water used as a coolant, indicating that the engine has been run without antifreeze for a time. Products such as Radflush from automotive shops will usually remove them. I did mine last week: the product seems to be more high-tech than it used to be, requiring a two-stage process with much flushing between. It does seem to have removed a lot of debris from my old engine.

Vyv, many thanks, will look to do this in the spring when the boat is back in the water.