Bongo Fury

garage changed head and gaskets. gas still in cooling system after thorough bleeding.
Could there be any other possible cause other than a cracked block......please!
dave, stockport

Hi Dave, sorry to hear of your troubles. While it's not impossible that there is a crack in the block or one of the cylinder bores, I've only ever come across one owner who has had this happen. It seems the vast majority of problems are with the gasket or head.

Did the garage 'deck the block' where they use a fine abrasive on a flat heavy surface to take off any imperfections on the top of the block? If you fit a new / skimmed head to a distorted surface you wont be able to get a gas-tight seal. The other tip is to use WellSeal which is a head gasket sealing compound which will give the best chance of keeping the water & gas seperate.

Did you use a recommended Bongo garage......were good quality parts used ??

no - they are not bongo specialist but they have about 5 employees. what special considerations are there in replacing a bongo head rather than a similar diesel alloy head?

I'd check the cooling system has been bled properly. Good luck.

Were good quality parts used (not cheap China etc stuff) did they use the new correct head bolts...do they know how to refill/bleed the cooling system ????

I see your point about replacing one head must be like changing any other...However ..so many Bongos go to non Bongo garages and although the work is done in good faith...problems soon arise..

The Bongo cooling system needs to be bled according to a set of instructions...it is not stright forward...If not done properly....a new head could be destroyed.

You live in a area where there are some good Bongo garages...

As a thought...what caused the head to go in the first place and has whatever caused it been sorted....??? blocked radiator etc .

Sorry I carn't be more positive....At the end of the day if you have gas in the system ..it is going to have to be stripped down again...It's down to your garage to sort this for you.

Bob wrote:I'd check the cooling system has been bled properly. Good luck.

Bob...Stockportdave said " still GAS in the cooling system"

haydn callow wrote:

Bob wrote:I'd check the cooling system has been bled properly. Good luck.

Bob...Stockportdave said " still GAS in the cooling system"

True, and don't want to be pedantic but until he's had the coolant tested to confirm it is exhaust gas, then it is still just possible the gas is only unbled air. Could be what Bob is driving at?

Stockportdave - are you absolutely certain the garage followed the full instructions for funnel bleeding method to the letter, running the engine at something more than tickover speed for periods as Mazda recommend, and ensuring for example that the bottom hose was warm/hot, as part of the bleed process?

Yep, thanks Mike.

Hi all,
I've recently been in this very similar situation and i did use a very well respected bongo specialist as i allways have done The very frustrating end result was 3 different cylinder heads used and proper gaskets ect The block was checked as well several times.It was resolved when the head company inspected the block and put a block skimming machine on the head and it removed a very tiny amount of material Result The block was only being affected when the van was hot and under pressure This took 3 weeks to resolve and when the said specialist is struggling you know your in trouble.I'm glad i've allways used my man as i would have lost faith had it been any other garage You pays your money and takes your choice.Dave

davelou wrote:Hi all,
I've recently been in this very similar situation and i did use a very well respected bongo specialist as i allways have done The very frustrating end result was 3 different cylinder heads used and proper gaskets ect The block was checked as well several times.It was resolved when the head company inspected the block and put a block skimming machine on the head and it removed a very tiny amount of material Result The block was only being affected when the van was hot and under pressure This took 3 weeks to resolve and when the said specialist is struggling you know your in trouble.I'm glad i've allways used my man as i would have lost faith had it been any other garage You pays your money and takes your choice.Dave

How interesting. Simon Jones regularly issues this advice (about skimming/flatting the block). Yet more evidence to show his advice is sound

mikeonb4c wrote:
How interesting. Simon Jones regularly issues this advice (about skimming/flatting the block). Yet more evidence to show his advice is sound

Thanks Mike - I was just passing on the info that I was given by Bellhill Garage. Tom & Keith really know their stuff down there.

Thank you all. Am taking the bongo back to the garage today - I suspect that the block head was not prepared properly.
I bled the thing for about 30mins, engine hot (bottom pipe) eventually bubbles did stop coming out of the funnel attached to the bleeding hose - thought i had cracked it (no pun intended). There were tiny, tiny bubbles coming through but thought this was not significant. Bit of a mystery that.
thanks again bongonaughts.