Bongo Fury

The garage has just suggested that my Bongo's head gasket has gone - I'm not so sure, especially after talking to Andy at AVA, so would welcome your thoughts. Head gaskest are new territory to me!

The story begins a fortnight ago when I (Hadyns alarm actually) noticed that the coolant level was low. I topped up with water, being what I had available, & drove half an hour to my mothers house. Checking under the drivers seat I found the top hose to be ballooning & dripping coolant. I drove the 100 miles home with a careful eye on the temperature gauge...

New hoses & a radiator were ordered - the radiator just because it seemed sensible to take the opportunity to put a nice clean unobstructed one in - and a slot at the local garage booked, due to lack of time, light & the foul weather forecast. The garage is one that I've used for a few things over the last 3 years & I've always been happy with their attitude and the fact that you deal with mechanics & not reception staff.

Having dropped the Bongo off this morning I called in during the afternoon to check on progress. The mechanic (not one I'd seen around before) was in the process of bleeding the system, using the factory procedure - he quoted the procedure, so I assumed that he was following it He then announced that my head gasket had gone & that this was why the hose had ballooned. Plausible enough, but he then pointed out the oil on the side of the engine as evidence. This has been there since I got the vehicle & I'm pretty certain is mainly, if not all, from the ECU. He then said that he'd found traces of oil in the top hose.

Andy at AVA wasn't convinced, when I phoned him to order the gold-plated gasket set & suggested that it was possible that the oil could come from gearbox oil, if there had been any leak into the radiator at that point. He suggested that it would be as well to keep an eye on things for the time being before investing in all the head work. Seems good advice to me.

Now.... When I collected the Bongo, the coolant alarm went into overdrive as soon as I turned the ignition on Thank you Hadyn, I honestly wouldn't have thought to check the tank after the garage signed it off. The tank was virtually dry. Drawing the mechanics attention to this, he told me to bring the Bongo inside & he'd top it up. I had some misgivings about the risk of gererating an airlock, but it was 5 to 5, so did as he asked. He topped the system up & I ran the engine until it was reasonably well warmed up. He was happy with that. I wasn't, but I took it for a good run getting the engine fully up to temperature ( 1o'clock - Mason Gauge fitted) with both heaters on. Everything seems ok & I'm sitting at work waiting for the system to cool down, so that I can check the coolant level before I go home -nowhere level to park at home!

Given the mechanics total lack of concern about the tank being virtually empty & the potential for airlocks, I'm forced to question the rest of his diagnosis. However, if coolant is being lost due to a failed head gasket pressurising the system, then I'm guessing that Hadyn's alarm won't give me a warning until the system has cooled & the level dropped Presumably the loss of coolant will lead to a rise in engine temperature, which I'd hope that the Mason alarm would give me sufficient warning of ,to prevent major damage

This mostly guesswork on my part, so I'd appreciate the thoughts of those with experience in this

Can't see why a head gasket leak would make the hose balloon - surely the pressure cap would let the pressure out first Like you, I'm suspicious as there's no reason the gasket would go unless the engine overheated.

Thanks John - reassuring comments are appreciated even more

In fairness to the garage I had a long chat with one of the other mechanics, who I know a bit better, while I was paying the bill & he agreed that there was no point in spending on work until I was certain that it was needed. He passed the Bongos MOT, so he must be a good guy Of course it could also mean that he skimps & doesn't do a thorough job......

Just checked the level after an hour & a half sitting & it seems to be fine so far, so I can go home . The tank was still warm & when I removed the cap & shone the torch in there seemed to be some tiny bubbles swirling around in the coolant. Would this be normal Hard to see properly by torchlight in a pitchy black car park, in the rain, with gale force winds sweeping in from the loch.

Now I did put that cap back on the expansion tank didn't I............

Well...I would find somone who knows how to bleed it properly before doing anything and get that done. If the tank was dry and they just filled it up you almost certainly have air in there and the little bubbles point to this. No reason as stated above why a failed gasket would cause the hose to ballon ...the cap would release the pressure. I don't think you have much to worry abour other than get it bled PROPERLY.

Now who was it said the alarms were best left unfitted in a drawer ???? Hmmmmm!!!

Head gaskets somtimes do "just go" they just get old and give up eventually.

Head gaskets somtimes do "just go" they just get old and give up eventually.

And you were being so encouraging up to that point Hadyn

I'll be over at my mothers later in the week, and she has a nice flat drive, so I'll bleed it properly over there. Just the small matter of having to drive 100 miles to get there, with my eye glued to the temperature gauge.. The gauge is sitting fairly steady tonight & both heaters are blowing hot air, so hopefully there is no major air in the system.

Could we have Cause and Effect backwards? Maybe the hose was faulty and allowed coolant loss/overheating.

I do think it would be much cheaper and easier to get the problem solved where you are rather than risk a 100 mile trip if you think there could be a problem.

Many tales of blown head gaskets start with knowledge of underlying problems which weren't addressed.

Good luck Rhod.

The top hose was definitely leaking & the amount of coolant lost over time consistent with the degree of leak. The engine has definitely not overheated during the last 11000 miles (Mason alarm means I can be sure of that), though I can't be sure what it's pre-import history is.

I hear the sense in bleeding the system properly before driving any distance. I think that i may need to delay my trip east for a day until I've had the chance to carry out the bleeding. Something of a shortage of garages here & I don't trust the one who just did the bleeding to do it again properly!

Am I correct in thinking that I can use the factory bleeding procedure effectively without having to drain & re-fill the system?

Rhod wrote:The top hose was definitely leaking & the amount of coolant lost over time consistent with the degree of leak. The engine has definitely not overheated during the last 11000 miles (Mason alarm means I can be sure of that), though I can't be sure what it's pre-import history is.

I hear the sense in bleeding the system properly before driving any distance. I think that i may need to delay my trip east for a day until I've had the chance to carry out the bleeding. Something of a shortage of garages here & I don't trust the one who just did the bleeding to do it again properly!

Am I correct in thinking that I can use the factory bleeding procedure effectively without having to drain & re-fill the system?

If yer mannie in the garage has a 4 gas exhaust analyser get him to pass the probe over the vapour from the expansion tank with the engine hot. Any CO2 (carbon dioxide) means there's exhaust gas present.

Sound advice Dandy

Thanks for the tip Dandy

Well just had my first attempt at bleeding the Bongo, using the factory method...
All seemed to go well, except that I wasn't expecting coolant to start flowing from the bleed pipe quite so copiously Just as well I used a bucket for my collecting container. By the time I'd realised what was happening, panicked for a second or two, & raced into the house for the bottle of ready-mixed coolant (0 marks for preparation ), the reservoir was almost certainly empty. I topped the system up & finished the bleeding process. Temperature gauge behaving fine, heaters blowing nice hot air & I am left with the same amount of coolant left over as the extra that I added, if you follow me, so hopefully no air in the system. Or the same amount of air that I started with, of course.

Obviously I'm going to have to bleed the system again, just as soon as it's cooled down, to be sure however.

Questions:
1) Is it normal for coolant to flow so copiously once the engine heats up? Or is it symptomatic of a problem
2) After running the engine at 2500rpm for the requisite 6 minutes, plus a minute or so, the lower radiator hose was only slightly cooler than the upper one. i.e there really wasn't all that much difference in temperature. Bearing in mind that all this is done with a stationary vehicle & the Mason adjusted gauge didn't rise too far, is this unusual I expected a more significant difference. I heard the cooling fans come on, but am not sure which one since I was too busy running around between reservoir & temp gauge, muttering "Don't panic, Don't panic" to take time out to peer behind the radiator with a torch! Since both hoses were hot & the heaters were both hot I assume that coolant is flowing through the system ok
3) If I'm right in thinking that there are 2 cooling fans, plus the scavenger fan, where exactly is the second fan? I can see the one on the rear left-hand side of the radiator (looking from front) but can't spot the other amongst the shadows form torchlight.

Rhod

Continued here - http://www.igmaynard.co.uk/bongo/forum/ ... 28#p247328 - as the same question has been asked by Rhod on a new thread. I'll lock this thread to avoid duplication & confusion, give me a shout if anyone wants it opened again