Bongo smoking from underneath

[newportbongo]

Hi,

Yesterday morning after driving my Bongo approx. 3 miles to work I parked in the work car park, got out and noticed the van was surrounded in white smoke/steam (which soon disappeared once I switched the engine off).

I drove home later than evening and no problem so put it down to it being a one off. However, exactly the same thing happened this morning but then again on my journey home in the evening so I figured something must be up.

I waited for her to cool down for a few hours before casting my eye over the engine and noticed that the coolant tank had pretty much run dry (even though no prior sign whatsoever from temp gauge that van was overheating) and then on further inspection I noticed a split in the main radiator hose of about 2-3 inches. Now the odd thing is that the smoke was not coming from the exhaust or the bonnet but actually underneath the van and does not happen on start up or really short journeys and only really when the van starts to warm up, so I figure it must be the coolant leaking onto something hot under the van (once she has had chance to warm up) and that is what is causing the smoke.

Up until yesterday morning she seemed absolutely fine (although I have only had her about 4 months). So... my question is, aside from obviously getting the coolant hose changed and the coolant tank bled and re-filled, what are the chances of any further damage having already been caused? I have read about split hoses and coolant loss leading to head gasket failure and so am a little concerned that I may have left it too late, are there any other tell tail signs that I should now be looking out for that would indicate this?

Finally, can anyone recommend a reliable garage in the Newport (South Wales) area that I can take her to for the repairs?

Thanks in advance for any advice!

[mikeonb4c]

Get the hose replaced, re-fill coolant and bleed system properly, and wait and see if all is ok (which it may well be). And fit a low coolant alarm in order to avoid a repeat. Good luck and keep us posted.

[Bob]

A and S in Caerphilly have recently been recommended in another thread, but if there is any hint of coolant leaking get it recovered there, don't drive it.

http://www.igmaynard.co.uk/bongo/forum/ ... 27&t=63594

And welcome to the Forum.

[newportbongo]

Thanks for the replies but unfortunately the saga continues.

Have now had the hose replaced and the coolant bleed and re-filled. Did not get the alarm fitted just yet as garage did not have time to order it and I wanted to get the repair done as soon as possible (perhaps a mistake in hindsight).

I collected the van on Monday and was assured by the garage was all running smoothly with no problems (spare for some advisories to replace the rest of the coolant hoses within 6 months as also showing sight of wear).

Drove the van to work yesterday (about 3 miles) with no issues at all. Then had a 140 miles drive in the evening which against my better judgement decided to risk due to the van 'seeming' fine. Got about 90 miles into the journey when suddenly the temp gauge shot up to max and the engine started smoking. Pulled over to side of the mptorway, popped bonnet and was header tank smoking and completely empty again. Left it about 40 mins to cool down before filling up with water, checked underneath the van and could not see anything leaking. I then drove it (at about 40mph) to a safe place to leave it overnight (about 15 miles away) keeping a close eye on the temp gauge which did fluctuate worringly close to maximum level at times but thankfully did not overheat. Did notice some knocking underneath at this point that I have never noticed previously but not sure if was me just being paranoid?

When I got to the resting point I checked the header tank again and it had appeared to have dropped again to almost empty. I am now in the process of arranging recovery back to a local garage but started to fear the worst!

Is there a chance this could be anything else other than the head gasket? Any advice most appreciated!

[Simon Jones]

I think it would help to establish if it's actually smoke, or steam that you are seeing. Steam would be what you'd expect to find when the hot coolant is exposed to the atmosphere. Smoke would be a completely different thing & would suggest significant engine failure. If you've had some issues with the pipework already, then that's the area I would investigate as being likely place where leak is coming from. It sounds like the system needs to undergo a pressure test to see where the leak is.

As a general rule for Bongos, head gasket failure in itself does not result in water being used, but combustion gases get into the coolant system which over-pressurises it & forces the coolant out the weakest point which is header tank cap, or a faulty pipe. It's a bit of a catch 22 situation: lack of coolant will result in increased temperature which can cause the head to crack, or a cracked head allows gases into the coolant which then gets forced out & the cycle starts from the other end. If you've had the (unmodified) temp gauge up to the top of the scale at motorway speed, then the chances of a cracked head are pretty high .

[newportbongo]

I think it would help to establish if it's actually smoke, or steam that you are seeing. Steam would be what you'd expect to find when the hot coolant is exposed to the atmosphere. Smoke would be a completely different thing & would suggest significant engine failure. If you've had some issues with the pipework already, then that's the area I would investigate as being likely place where leak is coming from. It sounds like the system needs to undergo a pressure test to see where the leak is.

As a general rule for Bongos, head gasket failure in itself does not result in water being used, but combustion gases get into the coolant system which over-pressurises it & forces the coolant out the weakest point which is header tank cap, or a faulty pipe. It's a bit of a catch 22 situation: lack of coolant will result in increased temperature which can cause the head to crack, or a cracked head allows gases into the coolant which then gets forced out & the cycle starts from the other end. If you've had the (unmodified) temp gauge up to the top of the scale at motorway speed, then the chances of a cracked head are pretty high .

Thanks for the swift reply. The initial smoke coming from underneath the van was white smoke being caused by the coolant leaking from the hose onto the exhaust manifold (when hot) and burning off into smoke.

On side of the motorway it was steam coming from the under the hood and was coming direct from underneath the header tank - not from the cap. I suspect the cracked head is pretty inevitable now but my question would be, considering that the engine had not previously overheated (the initial leak was identified within a day through the leak under the van and then repair) once I had that repair what is likely to have caused the repeat issue in overheating and loss in coolant?

[Velocette]

I think it would help to establish if it's actually smoke, or steam that you are seeing. Steam would be what you'd expect to find when the hot coolant is exposed to the atmosphere. Smoke would be a completely different thing & would suggest significant engine failure. If you've had some issues with the pipework already, then that's the area I would investigate as being likely place where leak is coming from. It sounds like the system needs to undergo a pressure test to see where the leak is.

As a general rule for Bongos, head gasket failure in itself does not result in water being used, but combustion gases get into the coolant system which over-pressurises it & forces the coolant out the weakest point which is header tank cap, or a faulty pipe. It's a bit of a catch 22 situation: lack of coolant will result in increased temperature which can cause the head to crack, or a cracked head allows gases into the coolant which then gets forced out & the cycle starts from the other end. If you've had the (unmodified) temp gauge up to the top of the scale at motorway speed, then the chances of a cracked head are pretty high .

Thanks for the swift reply. The initial smoke coming from underneath the van was white smoke being caused by the coolant leaking from the hose onto the exhaust manifold (when hot) and burning off into smoke.

On side of the motorway it was steam coming from the under the hood and was coming direct from underneath the header tank - not from the cap. I suspect the cracked head is pretty inevitable now but my question would be, considering that the engine had not previously overheated (the initial leak was identified within a day through the leak under the van and then repair) once I had that repair what is likely to have caused the repeat issue in overheating and loss in coolant?

If, when you had the initial water loss from the hose splitting, a dry spot occurred in the water jacket surrounding the head, this could have caused distortion, cracks or even a hole in the combustion chamber. The whole engine doesn't need to overheat for this to happen the hotspot could be local to one cylinder or in any case, away from the temperature sender. If the combustion chamber is heating an air pocket it is not ransferring the heat to the coolant as I see it.

[newportbongo]

So is that more likely to have caused the second overheating that say, the coolant not being bled and re-filled correctly?

[Velocette]

So is that more likely to have caused the second overheating that say, the coolant not being bled and re-filled correctly?

The damage could have been done by the initial coolant loss or it could have been done after refilling. I don't know how you would prove it one way or another if you haven't had a test of some sort done in between, but if you don't stop immediately after a coolant loss there is a very great danger of head damage.

Given the circumstances the garage should have done a pressure test and ideally a good long road test. If they did a pressure test and it was clear you could argue that they didn't bleed it properly, but even then head cracks don't always show up straight away.

I am only talking from my own experience and limited knowledge, you really need someone more qualified than me. I have had a head job done by ADS and they won't replace a head gasket without replacing the head because they reckon once it has overheated it can't be relied on again.

[newportbongo]

So is that more likely to have caused the second overheating that say, the coolant not being bled and re-filled correctly?

The damage could have been done by the initial coolant loss or it could have been done after refilling. I don't know how you would prove it one way or another if you haven't had a test of some sort done in between, but if you don't stop immediately after a coolant loss there is a very great danger of head damage.

Given the circumstances the garage should have done a pressure test and ideally a good long road test. If they did a pressure test and it was clear you could argue that they didn't bleed it properly, but even then head cracks don't always show up straight away.

I am only talking from my own experience and limited knowledge, you really need someone more qualified than me. I have had a head job done by ADS and they won't replace a head gasket without replacing the head because they reckon once it has overheated it can't be relied on again.

Ok thanks. Guess a case of just getting it back to the garage, doing a pressure test and hoping for the best (although expecting the worse!).

[Velocette]

So is that more likely to have caused the second overheating that say, the coolant not being bled and re-filled correctly?

The damage could have been done by the initial coolant loss or it could have been done after refilling. I don't know how you would prove it one way or another if you haven't had a test of some sort done in between, but if you don't stop immediately after a coolant loss there is a very great danger of head damage.

Given the circumstances the garage should have done a pressure test and ideally a good long road test. If they did a pressure test and it was clear you could argue that they didn't bleed it properly, but even then head cracks don't always show up straight away.

I am only talking from my own experience and limited knowledge, you really need someone more qualified than me. I have had a head job done by ADS and they won't replace a head gasket without replacing the head because they reckon once it has overheated it can't be relied on again.

Ok thanks. Guess a case of just getting it back to the garage, doing a pressure test and hoping for the best (although expecting the worse!).

Hope it is OK , it is a horrible feeling. I take it the garage are Bongo experienced?

[newportbongo]

Not exactly but as I took it to them the first time I would rather take it back to the same place as I am hoping they might be be able identify the problem having looked at it before rather than someone completely blind to it.

They assured me that it was re-filled and bled correctly so don't really have any reason to doubt them.

It would be helpful if someone could explain to how air in the system might lead to the coolant leaking out/evaporating though just for my own understanding?

[Velocette]

Not exactly but as I took it to them the first time I would rather take it back to the same place as I am hoping they might be be able identify the problem having looked at it before rather than someone completely blind to it.

They assured me that it was re-filled and bled correctly so don't really have any reason to doubt them.

It would be helpful if someone could explain to how air in the system might lead to the coolant leaking out/evaporating though just for my own understanding?

Air in the system if it gets to the head can cause distortion and or failure of the gasket because of a concentration of heat that the head is not designed to withstand. (Think of an aluminium milk pan that has boiled dry) The head gasket a highly stressed component and if the head expands out of spec especially in one place it is done for. This would allow coolant to escape under pressure either to the atmosphere or internally into the combustion chambers or oil system.. It is common for the expansion/degas tank to pressurise and blow coolant out when the head gasket has gone.

Either that or you could have had another hose fail which would just be that, a hose failure.

Ask them if they bled it at up to normal running temperature because the air usually sits under the thermostat from what I have read on here and elsewhere and that is where people often go wrong. If the thermostat doesn't open during the bleeding process the air just goes straight to the head when it does eventually open and then stays there.

can someone who has done a bleed themselves confirm this please?

[Northern Bongolow]

any leak in the system from a hose, water pump, rad leak, pipe, or anywhere may drop water when running, and let air IN when cooling, this air gathers around the highest spots around the system, usually the front heater, or the cylinder head, if it gathers into a significant sized pocket, it stops coolant flow, this causes rapid temp increase inside the engine. it gathers here because the coolant flows down hill on exit from these 2 items, air trapped here does not want to be pushed down hill so it collects.

[newportbongo]

any leak in the system from a hose, water pump, rad leak, pipe, or anywhere may drop water when running, and let air IN when cooling, this air gathers around the highest spots around the system, usually the front heater, or the cylinder head, if it gathers into a significant sized pocket, it stops coolant flow, this causes rapid temp increase inside the engine. it gathers here because the coolant flows down hill on exit from these 2 items, air trapped here does not want to be pushed down hill so it collects.

And so I guess if unless the system is bled and refilled correctly once the leak is repair the air will remain around the head and cause the overheating?