Bongo Fury

Hi Guys: the saga of the van continued, new head, new radiator, cooling system stripped and checked all by local garage, system prezzurized, the garage tells me it runs well until revved slight knock appears, dumps water as original fault.
It is now nearly three months in garage, had head skimmed, lasted 30 mile, new head fitted and all other work done, no water in oil, garage now stumped.
any ideas out there. loadsa money spent, pot getting empty
Merry xmas?

Don't these have a water cooled turbo? Could be that.

Shouldn't they have done some basic diagnostic test by now? I cant remember what all these are but any competent garage should know. They are intended to discover:

Is there evidence that combustion materials are getting into the coolant (i.e. leaking head gasket). Does one check oil for water content too?

Is there combustion gas blowing into the coolant system i.e. head gasket problem.

Engine compression test. Not sure if this is relevant but ?cracked head

Is there good unobstructed flow around the coolant system. I hear flowtest of main radiator discussed on here but what about the rest of the system?

it seems pointless to keep racking up your bill without proper diagnostic tests to identify the heart of the problem.

V sorry to hear of your troubles - cant think what else to say

Hi Bonewage,

Sorry to hear of all your problems. A year ago I also had problems with my cooling system. There was a very long thread on these at the time.

I changed my radiator, tried two new thermostats, changed my water pump, drained and bled the system maybe ten times, maybe more.

I also hosed out the cooling system every possible way with a garden hose. I do not believe there was any possibility of a blockage in the cooling system but every time I drove it, it overheated.

All this after putting a new head on it.

In the end the only way I could get it not to overheat was by fitting a thermostat with some 3mm holes drilled in it. I do not believe for a moment that I bought two faulty thermostats, and I do not believe the thermostat could not or would not open. It always opened while bleeding because the lower radiator hose always heated up eventually. They also opened correctly when tested in a pot of water on the kitchen stove.

I first tried eight 3mm holes but with eight holes the temp guage really would not register. I currently have four 3mm holes in it. It never overheats and when on short or non demanding runs the temp guage either does not register or it registers low. When run hard for a distance or under load the guage comes up to the normal position.

I fixed my Bongo in March 2007. During the cold weather of the last few weeks my heater has not been as warm as I would like, so maybe four holes are too many.

I know my engine will be running a little cool but think this is unlikely to cause any lasting damage, and I drive it with any easy mind.

I am aware from other threads that others seem to do the same. I am fairly sure others have suggested that when they have worked on their engines they have no thermostat fitted or bits cut off.

I do not know if this will help you but you could try a holey thermostat.
It certainly would be cheap to try it.

In the last ten months I have probably driven 15,000 Km and the Bongo has less than 70,000 Km on the clock.

Good luck.

I can only say that by drilling holes in a thermostat you are bypassing a inherent problem which is still there waiting to get you.
99.9% (approx guess) of Bongos are driving around without this mod and they do NOT overheat.
You must have a restriction somewhere in system.
Sorry for the doom and gloom but thats the way I see it.

Stupid question but is it possible to fit the thermostat
upside down? and had you? if the stat was upside down
the wax cartridge or what ever opens the stat would be in
cool water the holes you drilled would maybe allow enough
hot water through to open it.
Looking at the engine diagram the stat sits with the wax
cartridge or bellows what ever activates it facing up the
opposite of most engines you never know it could be as simple as that.

Don't think it will go in upside down. But a good thought

haydn callow wrote:Don't think it will go in upside down. But a good thought

In theory it won't but if I'm being honest I failed to pay proper attention when fitting a new one in mine and just happened to notice as I was about to bolt things up that it had to be fitted the right way (by luck I'd done that anyway). It may be possible to put it in upside down and damage it whilst tightening bolts 'forces' it into place. Anyway you've now been warned - no excuse!

I have fitted / refitted the thermostat on numerous occasions.
It definitely will not go in upside down. It is almost certainly designed to be impossible to fit upside down. Pretty sensible if you ask me.

I understand that making holes in the thermostat may be masking some other problem, but since my Bongo runs fine that way it does not bother me.

It was only a suggestion which worked for me. It could work for others.

But wouldn't you like to know why you have had to drill holes in your thermostat to prevent cooling problems. I think you can assume you have no engine damage so the fault must lie in the cooling system. It really shouldn't be to difficult to start eliminating each section of the system.
I know what you are saying but if things suddenly go wrong it could be very expensive.
Each to his own I suppose.
After a long run ...how hot is your bottom hose??