Cooling Help Please! At the end of my tether :{

[Manxda]

Curious thing is why it's not going the whole hog with the gauge setting at 1 o'clock, anymore. Cheers.

Sometimes the force of the boiling is sufficient to force the trapped air along and out, and hence the temperature varies wildly!

Yep, sounds plausible. Me and the missus going to do a coolant bleed again tomorrow (she hates it!). Took us 2 hours last time. Thanks.

[haydn callow]

Not much help but I was in the I o m 2 weeks ago.
Bongo heads need to be fitted by peeps who know what they are doing.....was the engine block face 'decked' ? (Made level) if not and it is untrue (warped)then the heads will suffer. Without Expert Bongo help you are going to struggle.

[cmm303]

Given the overheat and persistent, albeit sporadic inclination to ditch its coolant a sniff test could save you a lot of effort by ruling in or out the elephant in the room.

So we've got newish pump, thermostat, radiator and caps. Sounds like all the coolant pipes (17 of 'em) could do with inspection and perhaps replacement. Also check the condition of the metal pipes especially running between the rear heater hoses and the front. Looking for the smallest pinhole.

Has the coolant been replaced recently and/or changed to a different type of coolant?

I appreciate this is after the event, but it sounds like you could do with a head temperature gauge or, if funds are tight modify the temp gauge for pence so you have more warning of overheating than the standard gauge gives you. Many consider that by the time the standard gauge reacts it is often too late.

[haydn callow]

Sniff tests are not conclusive. A negative test does NOT mean all is well. Cracks in the head can be very difficult to suss out

[Bob]

This could be cheaper than paying a garage:

http://www.ebay.co.uk/itm/like/33171824 ... 4071953993

[mikeonb4c]

I was at my mechanic Adrian at Japandirect in Bury a few years back. He was dealing with a Bongo that had crudded up radiators and he was replacing both main and front heater radiators. I also recall people on here doing research on the Bongo coolant system and determining that the front heater radiator was an important part of the circuit. Seems a strange idea to me but I'm sure Adrian wouldn't mind you calling him on 0161-763-3003 to ask him what he thinks. He's a Bongo expert of many years standing. Of course if channels in the engine block are crudded I'm not sure what you do. I wonder whether one bodge might be an engine block temp gauge and either link rad fans to activate from the temp gauge or else with a manual override switch. Not fixing the cause but might prevent system going critical.

[haydn callow]

If the coolant is being 'blown'out of the header tank it is probably because the system is being over pressurised by exhaust gasses entering the system via the cylinder head cracks.

[haydn callow]

Reguarding the front ( or rear) heater rads, I don't really see how they can cause to much of a problem......rearones are often by passed, and when I had a leaky front one I bypassed it for a couple of weeks until I Got back from holiday and fitted a new one. The main coolant flow does not depend on the heater rads.

[rita]

This could be cheaper than paying a garage:

http://www.ebay.co.uk/itm/like/33171824 ... 4071953993

This is a Chemical block test kit, the Sniffer test is using a Gas Analyser over the expansion/header tank to take a Sniff (sample) which will or not confirm the presence of combustion gasses in the coolant.

Good Luck

[mikeonb4c]

Reguarding the front ( or rear) heater rads, I don't really see how they can cause to much of a problem......rearones are often by passed, and when I had a leaky front one I bypassed it for a couple of weeks until I Got back from holiday and fitted a new one. The main coolant flow does not depend on the heater rads.

I'm inclined to agree, but I mention it because I seem to recall a great big BF think-tank some years back (Widdowson et al) suggesting the front heater radiator was important. Adrian might just be able to comment since he sees and deals with the beasties.

[cmm303]

I don't know about the front heater but on the only journey I had the rear heater running the Bongo ran a few degrees HOTTER than normal. Explain that!!

[teenmal]

Reguarding the front ( or rear) heater rads, I don't really see how they can cause to much of a problem......rearones are often by passed, and when I had a leaky front one I bypassed it for a couple of weeks until I Got back from holiday and fitted a new one. The main coolant flow does not depend on the heater rads.

The fact that you by-passed and did not blank the flow/return should answer your question?.

[Northern Bongolow]

it would be best to pressure test the whole system before you bleed it again, it will not bleed up right if it has a leak somewhere.
get an old rad cap and cut through the bottom seal and disc so that it does not seal against the bottom seal point in the exp tank but still seals at the top seal at the neck.
attach a 2 bar pressure gauge and pipe to the expansion tank over flow pipe then fit an old car tyre valve into the end, this will allow you to inflate the whole system to no more than 1 bar with a bike pump, remove the pump, the valve will hold pressure and watch the gauge either hold pressure for a min or two or slowly drop pressure, if it drops you have a leak somewhere so you should see it leak with 1 bar of pressure pushing out the coolant. if no leak is found but pressure is dropping suspect a crack in the head.
to make sure its the head remove the glow plugs on cylinders 2 and 3 then get a few dry strips of paper from your paper shredder and dip them into the cylinders to see if they get wet.
shout if you need more how to make stuff info.

[mikeonb4c]

Reguarding the front ( or rear) heater rads, I don't really see how they can cause to much of a problem......rearones are often by passed, and when I had a leaky front one I bypassed it for a couple of weeks until I Got back from holiday and fitted a new one. The main coolant flow does not depend on the heater rads.

The fact that you by-passed and did not blank the flow/return should answer your question?.

It's a good point. Bypassing is not the same as obstructing the circuit with a blocked radiator. However.......

[Manxda]

Given the overheat and persistent, albeit sporadic inclination to ditch its coolant a sniff test could save you a lot of effort by ruling in or out the elephant in the room.

So we've got newish pump, thermostat, radiator and caps. Sounds like all the coolant pipes (17 of 'em) could do with inspection and perhaps replacement. Also check the condition of the metal pipes especially running between the rear heater hoses and the front. Looking for the smallest pinhole.

Has the coolant been replaced recently and/or changed to a different type of coolant?

I appreciate this is after the event, but it sounds like you could do with a head temperature gauge or, if funds are tight modify the temp gauge for pence so you have more warning of overheating than the standard gauge gives you. Many consider that by the time the standard gauge reacts it is often too late.

Many thanks.