Cylinder Head Advice

[Blazerbob]

Hey folks, Blazerbob here- long time stalker, first time poster.
Despite having stalked on here for a while, i only came to own my bongo a couple of months ago but have done 300+ miles a week in it. It shows 94000 on the clock, not sure of km / mile split. No service history.

I got round to taking her in for a look over at the local bongo specialist, and it's come up with a cylinder head failure. I had a long chat with the mechanic who explained how they came to this conclusion; using a coloured dye in the coolant system which changes colour based on the presence of exhaust gases. So, there's some breach between combustion chamber and coolant channel, though we cant say to what degree.
I guess i'm the exception here in as much as i have had no overheating / coolant level issues. The engine runs smooth, starts up well, performance / efficiency seems okay. I have, however, noticed some leaky pipes & hoses, and more got flagged on the look over.

My theory is that there was a previously resolved coolant leak that caused this damage which up to now has been un-noticed. Another theory could be that the slightly perished hoses throughout gradually leached air in to the system which gathered in the cooling channels which have not been bled frequenttly enough or correctly. Would love to hear any other theories from y'all more experienced bongo-ers!
My current plan is to get all the work done to replace all the leaky pipes and hoses (possibly radiator as well) and then look to change the cylinder head myself. I'm a competant hobbyist but never done this job on any car. Any advice for this? I'm planning to also replace the waterpump & thermostat, cambelt (i already replaced this as soon as i bought, but worried i'll compromise it during this job). Anything else i should reaplce with cylinder head? How long do we think is safe to continue driving, if at all?

In the meantime I'm going monitor performance / efficiency very closely. I'll obviously monitor the coolant levels VERY VERY closely, check for creamy oil, check for steamy exhaust, drive only at low revs. Im also holding off an engine flush / oil change in case the crack is blocked with crud. Any other advice for me?

I love my bongo, and want to keep her running as best she can for as long as possible, i'm sure the knowledge out there in bongo land can make this possible

Cheers,

BB

[g8dhe]

Sounds a good approach, its very rare to see the coolant getting into the oil, the usual problem is crack in the head between the exhaust ports that allows exhaust into the coolant

[Ian]

I'm sure others will be along to give you some advice on this. But in the mean time it might be worth preparing the ground by watching BongoBonnie's multi part video about replacing the cylinder head at https://www.youtube.com/watch?v=HyCREtQPAFg&t=184s

Don't be tempted in going down the path of getting a cheap or reconditioned cylinder head. The best ones, which come fully prepared, with all accessories, can be obtained from https://mazdabongo.com/product/mazda-bo ... 5-onwards/

Out of interest, where are you based?

[Blazerbob]

thanks for the intel folks, and thanks for the recommendation for the cylinder head supplier, i forgot to ask that in the op but came to mind today.
I'm based in Bristol, i had my lookover done at ADS, and will likely get them to do the work on the coolant system.

[Bob]

ADS Are ok.

We're in Nailsea.