Bongo Fury

Am worried about the coolant level in my 2.5 v6, van has been driving absolutely fine for the month I've had it and always sits just below half way on the temperature gauge, a couple of weeks ago as we were off in our first decent trip I tried to check the coolant level (mainly because every other post on here seems to be about issues if it drops) it's virtually impossible to see anything in the header tank but I thought at the time by rocking the van I could see something moving somewhere between low and max levels, tried again today and cannot see anything at all in there even when rocking the van, I put a thin stick in the cap and pushed it down at an angle and whilst this showed there was some liquid int there it didn't seem like much, I have topped it up with some coolant (God knows whether it's the same) and now the stick shows about 2 inches of liquid. At the top of the main part of the header tank is an overflow but this has no pipe on it, there is a pipe by the cap you undo but this is just clipped on the side of the header tank so would just overflow to the ground. I have seen absolutely no leaks anywhere of any sort so am a bit confused and to be honest now worried something is wrong even though the van has been driving fine, happy to take it to have the lot changed and a coolant alarm fitted (I have bought one but don't want to fit it until I know that the initial levels are right)and checked but have read lots of posts about garages not having a clue how to deal with the peculiarities of the bongo so really don't know what to do for the best??

Don't get worried!
If the tank is brown and you can't see thru it, either put a light behind it or when the coolant is cold, remove the cap and using a lollipop stick with a mark at 2cms on it use that as a dip vertically in.
If its less then 2cm fill it up a bit, if more don't worry!
I've always found on our V6 that if you do overfill it within a short time it will reduce to the halfway point, no doubt the cap releases some vapour when the system is pressurised as is intended and any excess will be lost safely.

Do you mean 2cms in the smaller right hand chamber I.e under the cap or the left hand side that drops far further down! If the right hand side there is no coolant in it at all

Vertically down the open filler cap.

really worried now, took the advice yesterday and topped the header tank up till there was 2cm vertically below the filler cap, drove the van about a mile and back all was well, left it to cool down gone back to the header tank and it is right back down to the low level with nothing below the filler cap. The van is due to go to a garage on wed for fixing the roof motor that is broke and having an mot done at the same time, garage is about a mile and a half away so sure I can top it up again before heading off but cannot understand where the coolant could be going, my drive is bone dry and the van has been sat on it unused all week, no smoke or anything out the exhaust, really not sure where to go from here ?

There are all sorts of places, especially when it squirts out of a small hole - pin hole - under pressure and evaporates, also top of radiator which you can't see without removing the air scoop, fails on the plastic to metal bond and dribbles down the radiator and evaporates, or leaks from the water pump underneath again when hot. There are all sorts of places to look!

g8dhe wrote:There are all sorts of places, especially when it squirts out of a small hole - pin hole - under pressure and evaporates, also top of radiator which you can't see without removing the air scoop, fails on the plastic to metal bond and dribbles down the radiator and evaporates, or leaks from the water pump underneath again when hot. There are all sorts of places to look!

Ok so would I be best to top it back up again, run the van and check all pipes to see if I can find the leak whilst it is running and under pressure?

Yes, look underneath over the top all places it may just be a fine mist, quite a lot of people use a UV dye in the coolant and then search for the tell tale streaks with a lamp - dye and lamps available from Ebay etc.

Ok so topped it back up again to 2cm level below filler cap, ran the van for 40mins checking everywhere I could get to, no leaks as far as I could see the level in the header tank went up to about 4cm below the filler cap I.e left hand side about 2cm above full mark, all pipes got hot but still no leaks (as far as the eye can see or hand feel) level stayed above the full mark, took the van for a drive, came back and checked level still at same level above full line. Have now left the van to cool down so I can check it when cool, could it be that it is at low when cold and full when warm and would that be normal? Think I will get it on to a specialist for a full service and coolant change and check for leaks as its now worrying me !

Here are images of my tank and results of dipping it;

Ok thanks ours is about 2cm above that red line when the engine is on but quite a bit lower when cold which is what is puzzling me

It will vary between the pressurised hot state and the cool state, the liquid expands when hot and it is this that creates the pressure increase to allow it heat up beyond 100°C, the diesels get to above 105°C and can go up to 120°C if required.
So when cool it will drop down, the concern comes if that level when cool changes by decreasing everytime.

Ok so maybe just monitor the high and low levels for a few days probably will still get a coolant change done at a specialist and get them to pressure test at the same time for peace of mind

I wouldn't worry about the high level when hot at all, it doesn't really mean a lot without other info. Just check each morning when its cold and provided it doesn't keep on decreasing then your OK at the 1-2cms level.

Get yourself a low coolant alarm for peace of mind especially if the header tank is not clear enough to see the level easily. Sometimes shining a torch down thru the top of the tank makes it easier to see.