Water loss

[Karensmyth]

After driving for a while the expansion tank can be heard spitting out water, yesterday four times during a 80 mile trip. Is this a faulty cap, airlock or something worse.

[g8dhe]

It could be a faulty cap, there have been a few reported, but much more common is an airlock problem!
Which engine is it ? Has there been any work done in the last couple of months ? Have any pipes been replaced in the past ?

[Karensmyth]

It is a 2.5 td that has had no work done on the pipes. We have to top it up every time we take it out because of this. Engine runs fine with no smoke or overheating, although the fans are wired to a switch to run continuously to help keep it cool

[mikeonb4c]

Hmmm. Why does it need fans on continuously to run cool. How was it discovered it was running hot. Sounds a bit dodgy to me. Does the header tank have any signs of rust staining? Could system be blocked or pressurisung?

[Karensmyth]

The fans running constantly was set up to prevent over heating, something which we have used on other older vehicles that have a tendency to over heat. There are no rust stains in the water bottle, no obvious leaks anywhere, only the spitting out of water. The system is a pressurised one

[Bob]

There's something wrong here.

You definitely shouldn't have to top up coolant regularly so I recon you have an air lock.

Personaly I'd get it recovered to a Bongo Friendly garage for a cooling system check and bleed before driving it.

If you've looked around on here you'll be aware this is the exact kind of problem which can cause the head to fail so let's hope you catch it in time.

[Karensmyth]

Don't know of bongo friendly garages in Northern Ireland. My husband works on all our vehicles so will have a look at bleeding the system( as shown on the video) and see if that solves the problem

[g8dhe]

IF its no easy visible leak then possibly a pin hole leak that squirts coolant out when hot and under pressure, and then when it cools it draws in air. Over a few heating cycles this air builds up until you have an airlock and then an overheating event, which will in the end kill your head!!! Get is seen too NOW, use UV dye to help locate the leak etc. but if you leave it and hope it goes away it will, the entire van to the scrap heap once the head is damaged

[Karensmyth]

The water is being lost out the expansion cap, we hear it spit it out when driving

[mikeonb4c]

The fans running constantly was set up to prevent over heating, something which we have used on other older vehicles that have a tendency to over heat. There are no rust stains in the water bottle, no obvious leaks anywhere, only the spitting out of water. The system is a pressurised one

Sorry, should have been clearer, I meant over-pressurising, as can happen if the head gasket/head is compromised and blowing gases into the coolant system. My expert Bongo mechanic Adrian often feels the top hose to try and decided if it is too rigid (with pressure).

Running fans constantly as an aid for older vehicles is an interesting idea, and I can see the sense of it. But I'd want to identify the underlying cause and fix it if possible. One of the more obvious ones on an old Bongo is an inefficiently working radiator (well actually, two as the front heater radiator is said to play a significant part in the Bongo cooling system). People whose Bongos have engine block temp gauges fitted have reported significantly cooler running engines after fitting a new radiator.

I'd be tempted towards a cooling system overhaul, with a new (good quality - plenty of cooling power) main radiator, new thermostart and new water pump. All pipes (especially metal ones, for corrosion) to be checked also. And I'd fit an engine temp gauge like the TM2. Then I'd try putting the fans back to either sensor driven or manual driven control and see how often I had to resort to them (I have a manual over-ride on my scavenger fan and use the TM2 as a guide as to when to put it on). I assume you've got a low coolant alarm already fitted? Essential piece of kit going forward, though it may not work properly until header tank bubbling over problem is sorted.

Before all that though, and as others have said, investigation of airlock might be sensible, in case its that.

Of course, if there is a problem with the head gasket/head, then we're into a whole new area of spend. But if there is a problem there, quite likely a chronically hot running engine is what caused it, and the investment in overhauled coolant system will be money well spent anyway.

Good luck, keep us posted.

[cmm303]

The water is being lost out the expansion cap, we hear it spit it out when driving

this is most likely a symptom of another cooling problem. If it still happens after fitting a new cap then (or even straight away) the coolant can be tested for evidence of combustion gases. That will help point you at whether there is an underlying problem or just a cooling issue.

Or as others suggest, bleed it and see how you get on. Once it has boiled, it probably would need bleeding again as part of the top up. Means the top up will take several hours by the time you have allowed it to cool, then top up and bleed.

The radiator fans rarely come on in our climate unless you get stuck in a lot of traffic jams without the aircon on. So always-on fans are definitely masking a problem.

[haydn callow]

Whereabouts are you in N Ireland? I spend a lot of time in Castlerock. But if I'm not there I have a friend near Castlerock who knows his way round the cooling system. He has a Bongo.