My campervan has been off the road road and in pieces for the last few weeks,  but there’s been something “not quite right” with it for much longer than that (as you’ll know if you follow the ramblings of @campervanning on twitter). The problems started last summer at the start of our first big camping trip – 10 days in various spots around Cornwall. During the 400+ mile journey to Looe the water pump died. The water pump is essential for keeping the coolant flowing through the radiator to prevent the engine from overheating. Eventually over time the bearing in the pump wears out and as a result the water leaks out. Owners of classic VWs will be rubbing their hands with glee at this (I’m looking at you Sarah & Paul!) because their 30+ year old vans are air cooled so this is one problem that they can’t be afflicted with. We hoped that we’d stopped in time before the overheating did any damage to the engine. Once the repair was complete, everything was looking good: the van behaved perfectly for the rest of our holiday and did the 400+ mile journey home without missing a beat.


After a breakdown like this you tend to be a bit paranoid though, and so I started obsessing over the temperature gauge. I also got into the habit of popping open the bonnet and checking the coolant level before every single journey no matter how long or short. Toward the end of the summer just as my confidence was beginning to be restored, I noticed that the coolant level had dropped a couple of inches. I topped it up, and it was fine for a few weeks. But then it dropped again and took a full litre to bring it back up to the normal level. Something wasn’t right.

After a breakdown like this you tend to be a bit paranoid

I took it to my local garage where they pressure tested the cooling system and reported small leaks from just about every hose and joint! I had them replace a bunch of hoses and all the jubilee clips that fasten them on, but there was a corroded metal cooling pipe that they couldn’t source a replacement for. They managed to patch it up, but told me it would really need replacing if I could find a part. I collected the van and drove it the 5mile journey home, but when I got home I checked the coolant level (did I mention that I’d become paranoid?): it had already dropped below the minimum line!

I called the garage and they took it back for another look. I managed to find a replacement for the metal pipe, which they fitted for me and that seemed to cure the problem… for a couple of weeks.


After reading countless pages of forum threads on the owners club website I decided that it was time to get someone with a bit of specialist knowledge to take a look. The problem is that my van is a 15 year old Mazda Bongo that was never sold by Mazda in the UK, so every one of them has been imported from Japan with very little service history and the average mechanic may never have worked on one before. To complicate things further they have two separate heater systems (one for the front and one for the rear) and as the engine is mid-mounted under the front seats but the radiator is in the normal position at the front of the van, there are a lot of unusually long pipes and hoses to connect everything together. All of this ends up meaning that the Mazda Bongo has a notoriously complicated and fragile cooling system.

Also over this time the van started spitting out a lot of white smoke when it was first started. Usually (but not always) when it had been sat for a couple of weeks without being driven. This just threw more possible causes into the mix: was it just one issue, or two? did the glow plugs need replacing? Was a dodgy sensor causing the fuel and air to be mixed incorrectly?

I found a local mobile mechanic, Chris,  who is originally from South Africa where he tells me they use Bongos as taxis so he had worked on them before. He came and tested the cooling system with a special liquid that changes colour if oxygen is detected in the system (which normally indicates either a blown head gasket (bad news, but could be worse), or a cracked cylinder head (about as bad as it gets). He connected up a little tube of dark blue liquid and started up the engine. Over the next 10 minutes the liquid slowly and subtly changed to a dark green. Chris told me that often the liquid changes to a bright green within seconds so mine wasn’t a very bad leak and probably only a blown gasket. This would explain the dropping coolant levels and also the billowing white smoke as traces of coolant liquid could leak into the cylinders and collect on the piston heads until it gets burned off when the engine is next started. I ordered a whole new gasket and Chris took the van away to fit it. It’s quite a big job involving removing the cylinder head and then sending it to a workshop to have fractions of a millimetre skimmed off the surface to make sure it’s perfectly flat and will make a good seal with the engine block. They also pressure test the head (by submerging it in water) to check that it’s not cracked.

Cracking up

Shiny new cylinder head

The engineering workshop originally thought that there was a small crack, but after further testing decided that there wasn’t (not exactly as conclusive as I’d have liked!). They then had to strip out the old bolts (which aren’t reusable) and when they did this they found that the head was in fact cracked – the crack had been in one of the bolt holes so had been blocked by the bolt which is why it was difficult to detect. So the only course of action was a new head.

…they found that the head was in fact cracked

This whole process took a couple of weeks, but although the news got progressively worse, I was relieved that we were actually making positive progress toward identifying the real problem and then actually fixing it rather than just randomly changing parts and hoping it got better.

New for old

Engine back in one piece

So, after replacing the cylinder head, head gasket, inlet manifold gasket, exhaust manifold gasket, turbo gasket, all the head bolts, the manifold studs and refilling & bleeding the cooling system, I got word from Chris that the van was back in one piece and had started first time. I got it back last week and so far, touch wood, it’s running better than ever.  The engine runs a little smoother and it seems a little quieter. I’m hoping that I might even get a couple more miles per gallon. I think I’ll be watching that temperature dial and listening for strange noises even more intently than ever though!

It’s almost as exiting as getting a whole new van!

VN:F [1.7.8_1020]
Tell us what you think by adding your own rating:
Rating: 4.8/5 (5 votes cast)


Paul · March 29, 2011 at 11:14

Warning: count(): Parameter must be an array or an object that implements Countable in /home/happycam/public_html/wp-content/plugins/gd-star-rating/code/blg/frontend.php on line 543

air cooled our VW bus may be, but they are reknowned for setting on fire because of it.

UN:F [1.7.8_1020]
Rating: 0 (from 0 votes)

Tom · March 30, 2011 at 10:43

Warning: count(): Parameter must be an array or an object that implements Countable in /home/happycam/public_html/wp-content/plugins/gd-star-rating/code/blg/frontend.php on line 543

So it’s a choice between sitting at the side of the road with rivers of coolant flowing out of the van, or sitting at the side of the road with flames lapping up from the engine bay?

Remind me again why we do this?

UA:F [1.7.8_1020]
Rating: 0 (from 0 votes)

Comments are closed.