vanishing water mystery??????/

[skankyunderpants]

hi all, hope your all well and got your busses ready for the next few months of lovely british weather????????
anyways, last winter, i noticed the bus was using abit of water, but just kept topping it up and thought nothing else of it, witth my usual, it'll sort its self out attitude, and anyways, as the weather got better, the less water it needed, happy days i thought, she's fixed her self, Well, as your all probably aware, the temp has dropped, and back again, the water just goes, its not leaking, as i fiiled it up on saturday, drove a couple of miles yeasterday, used a bit, done another 20 miles today, and bingo, bone dry again, so, my theory was, as the only thing im doing different is using the heater, then that must be the issue, but ive been told that if its the heater, then there would be water in the cab, but theres not, bone dry?? its not loosing any power, and pulls through the gears very well, if anything better than usual, probably the calm before the storm knowing my luck , any ideas anybody, they would be very gratefull, thanks again for your knowledge guys, im just not mechanicaly minded..........

the skankyundies guy...........

[andisnewsyncro]

Have a look at this thread, perhaps not exactly the same problem as yours but I reckon the root cause could be the same.... How does your temp guge read?

Replace the pressure cap, then do a lot of reading & bleeding. That would be my 1st actions anyway.

[..lee..]

does the windscreen mist up ??

[skankyunderpants]

thanks for your fast replys, firstly lee, the screen doesnt seem to steam up yet,and also the temp gauge reads fine, but thanks anyways, but the expansion tank idea of the thread you sent andi seems to be intresting and shall get it checked asap, just one thing, were is the expansion tank?????????? oh yeah, i really am that usless, and the bleeding What the blithering heck? im going to have to take it the garage arn't i? i was just concerned that it was'nt the head gasket like my brother sugested? he said that would be a big job, how can i rule this out? thanks guys.....

[protexblue]

Expansion tank behind number plate flap.
headgasket symptoms can be water in oil, white smoke / steam out of exhaust.

[kevtherev]

WBX engines don't have head gaskets in the conventional sense.
They have a metal shim at the joint of the head and barrel, with a two water sealing rings at either end of the barrel.
It is extremely unlikely that oil can ingress into the coolant via this way as the oil is not under any pressure here.
however water can get into the oil (via the sump and (oil cooler 2.1) if the bottom seal breaks as it is under pressure.
The water jacket has a seal on the outside of the engine.
Generally if the "head gasket" fails it pressurises the cooling system with combustion gas.

[kevtherev]

as you can see here there's a lot of joints and other gaskets here to check before we think the worst.
I had a leak at the cylinder head.. but no drips as the hot engine evapped it away



Late system shown (post '86)

[skankyunderpants]

now i am confused, so, its the expansion tank that is behind the number plate? well in that case, that is the one ive been filling and has been emptying? so, what does that mean? is that normal? and how do i now check my header tank? were is that? , im sooooo sorry, now i feal like a right t#@T

[peasant]

Do you have a second heater under the rear bench? If so, that is also most likely leaking (and possibly the cause for your potential air bubble circulating through the cooling system)

The thing is, leaking coolant from that heater comes out where you wouldn't suspect it ... through the sills at the side, in front of the rear wheels and looks just like rain or spray from a wet road when leaving a puddle behind.

Check under the rear seat and under the heater cover there first before you explore anything else

[skankyunderpants]

ok, im all over that, i'll check it and let you know the morrow, thanks for your help guys.........

[andisnewsyncro]

Here is a very easy to understand description of your cooling system, courtesy of Mr Baxter. What he doesn't know about VW engines is not worth knowing.

You'd have found that out for yourself soon enough, but I thought I'd push you in the right direction

Coupled with Kev's diagram it should make some sense.

[Ralf85]

Mine loses more coolant in winter too. It comes from a slight leak at the front of the van. It seems to relate to the heater control being switched on. It does not leak when I am driving along but only when the pipework has cooled down and contracted. It sounds like you have a similar problem.
Patrick

[gaz f]

Strange... I was just about to post up a similar issue with mine!

My bus doesn't seem to like having water in the expansion tank. Whenever I put water in it over a couple of days it will empty and as my drive is on a slope leading to the road it runs off of the undertray when I drive down the slope, leaving a tell tale dribble. Strange thing is, if I leave it empty there is no sign of a leak and the header remains full. Longest test I did was for a full week, keeping an eye on the temp guage (just below half all the time) and then checked the header tank after the week, first when hot (you can just see inside it with a torch stuck against it) and then when it had fully cooled down by removing the cap (which is new as I though that might be the problem). Header tank full! I even ran the engine with the cap off and revved it to see if it pulled the level down significantly, it pulled the level down but not by much. Fill the expansion tank back up to the max level when cold.... next day, it leaks again!

The thing is doing my nut in !!!

[gaz f]

Aren't those plastic expansion tanks known for getting hairline cracks in them?

HarryMann you are a genius! I just spent 1 hour with a torch and 2 cups of coffee with the bus running looking everywhere for the leak... and guess where it started to drip from? Only when very nice and warm though... Right around the edge of not the expansion tank but the header tank! Looks like when it's fully warmed and pressurised up it's leaking from the centre moulding of the tank. Only when right up to temperature though, there was nothing when it was colder. That would have been the last place I would have expected a leak from!

[gaz f]

Just in case others are needing one too Brickwerks have the header tanks as do Gunzl over here in Germany.

Gunzl are (as usual) a bit pricey at 41 euros delivered but I need it in a hurry.