Empty Expansion tank

[andyjohn3]

Morning all - First post from me, but I've been a long time lurker! I wished my first post was on a brighter note, but I'm afraid we have an issue! We picked up our first Bongo a couple of weeks ago after a month or so in the garage. With a lot of cleaning and sorting we're just at the stage we're we're planning to go out for a camping trip. I checked the expansion tank yesterday and it seems to be completely empty!

The Bongo came from my sister who had owned it for 6 or 7 years, so we know the history well. It's always had overheating issues, but they were very good at identifying the signs, pulling over, letting the engine cool down then refilling the expansion tank.

The first thing we asked our garage to do when we bought it was to bleed the system properly and do a pressure test on the cooling system. This was done and the results seemed positive. Since then, we haven't experienced any kind of overheating issues (we've clocked up 300 odd km's - a mixture of town & motorway driving, and the dial hasn't once gone beyond 11 O'Clock). We bought this Bongo with our eyes open, so knew we could be in for a cylinder head replacement, but there was a week or two when we thought that my sister had been experiencing air pockets.

It was only when I was under the bonnet yesterday checking out the batteries that I noticed the expansion tank was empty. I couldn't see too well as the tank is a dirty yellow colour so hard to see. But putting a lolly pop stick down revealed the worst. I know I should have been checking this beforehand, but because it had been given the all clear, I was complacent. I had the Hadyn alarm on my shopping list (below an alarm and leisure battery conversion), but looks as though it should have been a top priority!

I've checked the youtube videos out, so I'm going to refill and bleed the system, but over the next week or so, could anyone tell me the signs I should be looking out for to try and identify the problem? I've heard I should look for white smoke, especially on start up, and check for any leaks before and after a journey, but are there any other tell tale signs? Milky residue in the oil filler cap for example?

At least then I can give the garage a good idea of where they should be concentrating their efforts. I'm beginning to fear the worst, but hoping for the best!

Thanks a lot, and apologies for the long post. Any suggestions would be appreciated - Andy

[Steptoe]

I am keeping a very close eye on mine, as the coolant level seems to drop a little sometimes (not always, and not much when it does). I have already fitted a PW electrics coolant alarm (only £14.99) which seems to work fine, and have had the system pressure-tested (twice) and the coolant analysed for combustion gases (negative). I have carried out a 'proper' bleed (took best part of an hour on my own).

I keep a couple of litres of water handy in case the alarm sounds whilst driving. I'd be interested to know if you find anything out with yours.

[g8dhe]

One that comes up frequently is a pinhole in one of the pipes, when the system is hot and under pressure then a fine jet of coolant develops, then when the system cools down air is sucked back in. So after a few journeys more and more air gets in until you get a serious problem and overheat. However tracking down that pinhole can be a difficult job as it only appears under both temperature and pressure. Maybe the UV Dye solution to locating the pinhole will be the best way ?

[dobby]

If the bongo has been standing for a bit it might be the water pump leaking, easy one for the garage to spot. Happened to mine a few years ago.

[andyjohn3]

Thanks for all the ideas folks. I've spoken to my garage, who advised me to fill the expansion tank back up, re-bleed the system, then have a good look over the next few weeks on the levels before and after trips, making a note of when the level actually drops. A Hadyn coolant alarm has just been ordered!

I opened the radiator cap yesterday and that was brimming with coolant, so I'm hoping I caught this one in time. Lucky really, as we were planning on camping last weekend and talked ourselves out of it, giving me the time to play with a few things which lead to me spotting the empty tank!

[Driver+Passengers]

Thanks for all the ideas folks. I've spoken to my garage, who advised me to fill the expansion tank back up, re-bleed the system, then have a good look over the next few weeks on the levels before and after trips, making a note of when the level actually drops. A Hadyn coolant alarm has just been ordered!

I opened the radiator cap yesterday and that was brimming with coolant, so I'm hoping I caught this one in time. Lucky really, as we were planning on camping last weekend and talked ourselves out of it, giving me the time to play with a few things which lead to me spotting the empty tank!

If you don't need to drive it in the next day or two, I'd wait and fit the coolant alarm and then bleed - you'll get a warm fuzzy feeling every time it goes off when your funnel is full.

Good luck!

[g8dhe]

Bear in mind that it IS NOT an expansion tank, its a continuous part of the coolant flow! Which is why the radiator is always brimming, opening the radiator cap will cause the levels to drop if your not carefull.

[Diplomat]

Bear in mind that it IS NOT an expansion tank, its a continuous part of the coolant flow! Which is why the radiator is always brimming, opening the radiator cap will cause the levels to drop if your not carefull.

For good measure, I have stuck a red Dymo label next to the radiator cap saying 'DO NOT REMOVE'. As a third party is highly unlikely to be commissioned by me to to routine servicing, this is mainly meant as a reminder to me.

I have to put my hand up to taking the cap off for a quick look for nasties in the coolant when I first inspected the Bongo prior to purchase but at that point I didn't understand the layout. Old habits die hard, it's on my buyer's checklist which also includes insisting on viewing without the car warmed up or conveniently moved from its normal parking spot.


Frank

[andyjohn3]

Thanks again for all of your advice. I did leaving bleeding the system until after I had fitted the Haydn alarm (which went in no problems). We had our first attempt on Sunday night, but due to constant funnel issues (kept popping off the bleed pipe, spilling coolant all over me), we chose to abandon the job just as we were getting up to temp as I had a hissy fit and kicked my glove away!

Went for attempt number 2 last night, and found the Bongo with an empty expansion tank again (the alarm worked too, although, man, that noise is annoying!), suggesting that its leaking coolant somewhere even when not in use, so the bleed did feel a bit of a futile effort, but we carried on regardless. I kept my emotions in check more this time, and we did have a successful bleed. Got the van up to temp in about 30 minutes and really saw the difference once the thermostat opened up - bubbles galore! We then had to abandon it a minute or two earlier than I had hoped (the bubbling had just about stopped) as the funnel popped out again, but I feel as though we got most, if not all of the air out this time.

I checked the expansion tank a couple of hours later once it had a chance to cool down and the coolant level was up beyond the 'full line'. I checked again this morning and it had settled a bit more and dropped an inch or so. I'll keep an eye on it over the next few days to see where the level sits, and hopefully this will help in finding out the cause of the drop. I also put paper underneath the engine, hoping that it would highlight any coolant leak, but alas it rained all night so the paper was soaked anyway (no signs of dripping though).

Only other thing to note, my front heaters did not push out any hot air, only cold. And the rear heaters didn't push out anything, so more jobs to add to the list!

[mikeonb4c]

Heaters should be pushing out hot air. I'd get a specialist to look at it before driving further. Is there evidence of (rust) staining in the header tank?

[andyjohn3]

Heaters should be pushing out hot air. I'd get a specialist to look at it before driving further. Is there evidence of (rust) staining in the header tank?

Well the header tank is a dirty brown colour making it hard to see the level of coolant, but as mentioned in the youtube bleeding video, I was under the impression that pretty much all header tanks were the same!

[wonkanoby]

sounds like it meeds a good flush out and back flush on both heaters

[Driver+Passengers]

Only other thing to note, my front heaters did not push out any hot air, only cold. And the rear heaters didn't push out anything, so more jobs to add to the list!

There should be a switch in the front which electrically isolates the rear heater controls - ie make sure you're not trying to use the rear heater with this disabled. I don't know if you've got manual or electronic controls and I'm not sure of the anatomy of either, but check that the linkages controlling the front heater baffles are sound - ie setting to "hot" does in fact move something.

[andyjohn3]

Thanks D+P - I've got manual controls (its a 1995) and I don't recall there being a button/switch that isolates controls - something for me to go and have a look at

wonkaboy - would I need to rebleed the system if I were to do this? I've had a quick search online on what needs to be done, but any advice would be a help

[Driver+Passengers]

I don't recall there being a button/switch that isolates controls - something for me to go and have a look at

One of the standard black dash switches, not on the front heater controls themselves... a picture of a fan with the word "REAR" below it.