Show whole topic
Dec 12, 2007 8:57 am
Dec 12, 2007 8:57 am
Subject: V12 Boiling
When I started with my V12 it was boiling after I did some uphill driving and stopped or slowed down at the top. But the indicated water temperature was below 80 Celsius and this was confirmed with a separate temperature measurement.
My theory is that there are two problems: the motor block and especially the head is full of corrosion and limestone. And the water pump is corroded and delivering much less water than inteded to, especially at low revs.
I had cleaned the block by removing the sideplates (found about 1l of debris, I had expected even more). But after that it was the same problem. Then I tried a rather short and soft acid cleaning of the cooling system (citric acid, about 10%, pumped with an external pum through the block, running motor, heating up) but only for about 30minutes. (Ask Eckhard, F2 on a more thorough cleaning of detached heads with higher acid concentration and longer, with very good result)
Next I was looking to improve the water flow. I found an electric water pump From Davies Craig Pty Ltd. (Australia), I mailed to Richard Davies, received all detailed information and ordered a pump type 8005 for a mere 100AUD. It is small enough to fit it between the bottom of the radiator and the inlet of the original water pump. I have a switch on my dashboard to start it when needed (e.g. strong uphill, at least before the top). When it is switched off the water simply flows through it, when it is running it presses more water through the normal pump. This helps and when the rest of the motor is correct (especially ignition) then it cures the boiling.
It is only a fix - the real solution would be to clean the cylinder heads and check the original pump - but it is cheap can be removed and helps.
Attachments:
When I started with my V12 it was boiling after I did some uphill driving and stopped or slowed down at the top. But the indicated water temperature was below 80 Celsius and this was confirmed with a separate temperature measurement.
My theory is that there are two problems: the motor block and especially the head is full of corrosion and limestone. And the water pump is corroded and delivering much less water than inteded to, especially at low revs.
I had cleaned the block by removing the sideplates (found about 1l of debris, I had expected even more). But after that it was the same problem. Then I tried a rather short and soft acid cleaning of the cooling system (citric acid, about 10%, pumped with an external pum through the block, running motor, heating up) but only for about 30minutes. (Ask Eckhard, F2 on a more thorough cleaning of detached heads with higher acid concentration and longer, with very good result)
Next I was looking to improve the water flow. I found an electric water pump From Davies Craig Pty Ltd. (Australia), I mailed to Richard Davies, received all detailed information and ordered a pump type 8005 for a mere 100AUD. It is small enough to fit it between the bottom of the radiator and the inlet of the original water pump. I have a switch on my dashboard to start it when needed (e.g. strong uphill, at least before the top). When it is switched off the water simply flows through it, when it is running it presses more water through the normal pump. This helps and when the rest of the motor is correct (especially ignition) then it cures the boiling.
It is only a fix - the real solution would be to clean the cylinder heads and check the original pump - but it is cheap can be removed and helps.
Attachments: