Using water with no noticeable symptoms

[Dodgey]

My trusty Bongo has started using water. She used about a litre a year to start with. No big deal.

Then after a long trip (2700k) she needed 1.5 litres. Now, after a 5 hour trip towing a heavy trailer she needed another 1.5-1.8 litres of water.

It never runs low (to set the alarm off) when I'm driving, it's after. They next day I put the keys in and the low coolant alarm stays on. I then find the header tank to be pretty much empty. It takes a full kettle to get her full again, which is around 1.7 litres.

If I carry on pottering about, I'll prob have to top her up again some time in a couple of months at the soonest, but it does seem to be getting worse.

I have no symptoms at all. Runs fine, not hot, no water on my drive that I've noticed.

I'm assuming either the water is being consumed and then when it eventually gets low enough, when the water cools, it contracts and drops below the alarm threshold - hence I discover it in the morning. Or, it's leaking somehwhere "invisible" and evapourating, and it drips below the alarm threshold when I'm parked.

Any obvious things to look for/at?

p.s. the previous owner had the head replaced etc, all new hoses and rad, and it's been a gem so far. TM2, LCA, Modified temp gauge etc.

[BigPanzer]

Hi Dodgey,

Don't know much about Bongo cooling systems because its something I've not had a problem with (yet!)
However based on the posts I read, the first suspects could be the water pump or the rear heater.
As the hoses have been replaced, were the proper wire clips used? There might be a jubilee clip working loose somewhere.

Good luck

Peter

[mikeonb4c]

Maybe start by putting u/v dye in the coolant and buying a u/v torch? Hmmm, wonder if the dye would survive combustion chamber and coat inside of exhaust pipe, in case it's that.

[helen&tony]

Hi
First job, check your Cap on the plastic header/ degassing tank...I'd put a new one on. Next - how old are your hoses? Check along the rim of the radiator if it's the original. The water pump is a hard one to spot. The usual place is the hole underneath, and it will drip straight down. I found that only an intensely bright torch will spot the wee droplet on the pulley area...I tried with a host of other torches/ maglights (genuine), and only the brightest found it for me. If you have red coolant in, a UV light can sometimes pick up the leak without dye, BUT you need a high-power UV light (240 volt)...I have the UV torches...not much good, even with dye.
Having tried that lot, then it's down to checking the metal pipes, and hose clips. Jubilee clips are a waste of space...only use Mikalor spring clips like the original Mazda ones...Last , but not least, check under the plastic header/ degasser tank...they have been known to split underneath.
Regarding the heater matrices...yes, they do go, but usually (not always) catastrophically, and dump your coolant such that when the LCA goes off, you stop on the spot!...usually with no damage.
If it's the head, you would have most likely heard/ smelled something , but, again, not always
There...your weekend's busy, now!...best of luck...I hope you find it!...(I'm sure you will), and I hope it's not pricey!
Cheers
Helen

[jimmo62]

I worked out that mine is losing water via the expansion cap - by putting the end of the overflow hose into an old coke bottle - when I put the water I caught back into the expansion tank it went back up to the original level. Could indicate a faulty cap or pressurisation of the water system due to gas leaking in the head

[haydn callow]

You say the tank was pretty much empty......BE VERY CAREFUL ..if the level drops down to the 2 pipes that enter/exit the bottom of the tank ...you WILL get air in with expensive results.....you cannot simply top it back up.......read up about bleeding the system and watch the YouTube videos.

[helen&tony]

Hi
Ah, yes...
Haydn is 300% correct...If you're losing coolant at that rate, it does seem that you might be a bit near to a "below the hoses" mark!...how far did it go down?
Cheers
Helen

[Dodgey]

Cheers. It's hard to tell how low as my bottle/tank is old and cloudy and I can't really see.

Put it this way, the alarm doesn't go off when driving so I assume I park up with a fairly decent level that then finally drops below the coolant sensor level. It takes weeks, so I have to assume the loss is gradual.

This time I took notice of the amount of water (1.7l according to my kettle). I don't know the capacity of the Bongo header tank.

I'll do a coolant flush soon as I've probably topped it up three times like this in the 3 years I've owned her so there is around 4-5 litres of pure water that has gone in over that time. But in the mean time I'll look at some of the areas you've all mentioned above.

My TM2 tells me I'm still getting a steady 88-90 on the cylinder head, as I've always done.

[New Forest Terrier]

I had exactly those symptoms with a leak in the rear heater matrix. Not catastrophic at all. Just a slow water loss with no sign anywhere of a leak. I finally spotted some glossy blue coolant on the drive behind the drivers door. It passed two pressure tests at Discount Trucks, hot and cold. There was no visible leak that Fred could find, but he bypassed the rear heater matrix and the leak stopped. The coolant leak looks just like the water from the air conditioning, so it easy to miss.

[Northern Bongolow]

try this mate.

http://www.igmaynard.co.uk/bongo/forum/ ... =0#p482224

[Dodgey]

Today I noticed a had a sooty puddle of water in the drive. I'd reversed so could not pin point where from, but most probably the front. It's dried now and left this:



Bear in mind it was a puddle before it dried.

I've looked under that side of the bonnet and can see evidence of water on pipes.



I think the top pipe is a little oily, the lower, out of focus ones are water, most definitely.

I'm not sure what pipe is what yet.

Whilst under the van I noticed this



Notice the soot at the top of the can.

And...



Look slike a new rear exhaust section.... (I'm also going to pinpoint where the next sooty puddle is. Perhaps it's from the exhaust holes - water dripping out when it cools - hope not....

Incidentally, this is my head. Never worried about a small amount of oil ...

[haydn callow]

That bit of oil is not a problem.....
When you put 1.7 litres in how full is it.....not to the brim I hope.....get a dry stick...when cold dip the tank vertically down the neck....it should show 2cms on the stick

[Dodgey]

I did nearly brim it......

[haydn callow]

If you did then you will lose loads of coolant and over pressure the system....there is nowhere for it to expand .......get it to the correct level as above post and see how it goes.

[Dodgey]

Will do.

Also, seems the zorst is not particularly expensive = phew!