Overheating Bongo... My Cup/Expansion Tank runneth over
Posted: Sat Apr 21, 2007 12:33 am
Hi Folks,
The great overheating debate seems to have died off a little but I need to resurrect the topic for a few minutes with a cautionary tale. I've had overheating problems in the last few weeks and have received excellent advice on this forum. Having had a few days away, I decided to get on with the suggested procedures to diagnose the problem.
My various one-man band garages in Blackburn didn't do dye-testing, but I managed to get a chap to do a pressure-test. He did the procedure there and then. There was no drop in pressure and he couldn't find leaks anywhere on the system despite a minute search with both seats up and torch underneath etc.
When I explained all the 'bleeding' problems we were having, he suggested we give it a quick try at bleeding the system whilst it was under pressure. I manned my marigolds and the bleedhose and he didn't bat an eyelid. Furthermore, he checked the water level in the expansion tank and repressurised the system when necessary. By the time we had bled, 'capped-off' and refilled four times, we were sending out liquid only, with no sign of any remaining air bubbles. I have to say I was very cynical and told him so. He said not to worry - if it didn't work I was to come back and he would use a vacumn process instead. I expected to return within the hour - but I am astounded to say that that was four days ago and the needle has read eleven o'clock whenever I've taken the beast for a spin up and down the hills of Lancashire.
The cautionary bit is as follows. When I was tackling my overheating problems a few weeks ago, I carefully followed all the bleeding procedures as per the manual and the forum - but - on reflection I may have made a fatal error. I was frantic to avoid re-introducing air into the system via the expansion tank when topping up after a satisfying bleed, so I may well have over-enthusiastically filled the expansion reservoir. At the time I rationalised that any excess liquid would simply drain off as the system became pressurised. Something tells me that by leaving little or no air in the expansion tank, I perpetuated the cycle of overheating. I blush to add that when I took the beast for test drives on those occasions, I stopped after every two or three mile 'up hill and down dale' loop, bled the system again, and filled the expansion tank to compensate for the loss at the other end...
What have I learned from this? I've just ordered a £2.37 Draper 1.8M Syphon Pump to syphon off excess water in the expansion tank when I attempt to top up in the future. I know real men 'suck and see' but I was traumatised at an early age whilst trying that technique with petrol... I have two lollipop sticks superglued together to create an eight inch dip stick with a min line and max line carefully drawn with a permanent marker. I never knew what 'anorak' and 'anal-retentive' meant until now... Also, being very impressed with the pressure tester, I popped on to E-Bay and managed to get my hands on one by leaping in with 10 seconds to go. There is no room for passengers in the Bongo - It's full of 5 litre bottles of water.
I am acutely aware that my investigations into the overheating problems with the Bongo are not over yet. I want that dye-test, and I want to have the radiator pressure tested. I've been at this point before, where I have managed to get back to full operational mode, only to fall foul of high temperatures a few weeks down the line. I'm interested to know whether pressure or vacumn bleeding is successful.
Well, there we have it, lollipop sticks and the highs and lows of an overheating Bongo. Who needs television.
Pat
The great overheating debate seems to have died off a little but I need to resurrect the topic for a few minutes with a cautionary tale. I've had overheating problems in the last few weeks and have received excellent advice on this forum. Having had a few days away, I decided to get on with the suggested procedures to diagnose the problem.
My various one-man band garages in Blackburn didn't do dye-testing, but I managed to get a chap to do a pressure-test. He did the procedure there and then. There was no drop in pressure and he couldn't find leaks anywhere on the system despite a minute search with both seats up and torch underneath etc.
When I explained all the 'bleeding' problems we were having, he suggested we give it a quick try at bleeding the system whilst it was under pressure. I manned my marigolds and the bleedhose and he didn't bat an eyelid. Furthermore, he checked the water level in the expansion tank and repressurised the system when necessary. By the time we had bled, 'capped-off' and refilled four times, we were sending out liquid only, with no sign of any remaining air bubbles. I have to say I was very cynical and told him so. He said not to worry - if it didn't work I was to come back and he would use a vacumn process instead. I expected to return within the hour - but I am astounded to say that that was four days ago and the needle has read eleven o'clock whenever I've taken the beast for a spin up and down the hills of Lancashire.
The cautionary bit is as follows. When I was tackling my overheating problems a few weeks ago, I carefully followed all the bleeding procedures as per the manual and the forum - but - on reflection I may have made a fatal error. I was frantic to avoid re-introducing air into the system via the expansion tank when topping up after a satisfying bleed, so I may well have over-enthusiastically filled the expansion reservoir. At the time I rationalised that any excess liquid would simply drain off as the system became pressurised. Something tells me that by leaving little or no air in the expansion tank, I perpetuated the cycle of overheating. I blush to add that when I took the beast for test drives on those occasions, I stopped after every two or three mile 'up hill and down dale' loop, bled the system again, and filled the expansion tank to compensate for the loss at the other end...
What have I learned from this? I've just ordered a £2.37 Draper 1.8M Syphon Pump to syphon off excess water in the expansion tank when I attempt to top up in the future. I know real men 'suck and see' but I was traumatised at an early age whilst trying that technique with petrol... I have two lollipop sticks superglued together to create an eight inch dip stick with a min line and max line carefully drawn with a permanent marker. I never knew what 'anorak' and 'anal-retentive' meant until now... Also, being very impressed with the pressure tester, I popped on to E-Bay and managed to get my hands on one by leaping in with 10 seconds to go. There is no room for passengers in the Bongo - It's full of 5 litre bottles of water.
I am acutely aware that my investigations into the overheating problems with the Bongo are not over yet. I want that dye-test, and I want to have the radiator pressure tested. I've been at this point before, where I have managed to get back to full operational mode, only to fall foul of high temperatures a few weeks down the line. I'm interested to know whether pressure or vacumn bleeding is successful.
Well, there we have it, lollipop sticks and the highs and lows of an overheating Bongo. Who needs television.
Pat
Was the lollypop sticks glued together a tongue in cheek comment pat? Why not just look at the header tank to see the level? Or am i missing something? 
I hope its sorted for you 
