van sups coolant.. no trace of it

[slowcoach]

hi,

my 1984 DH sups away at the coolant it seems. i have to keep topping up my expansion tank ( behind license flap) every 250 miles or so, by adding in about third of a litre maybe. i cant see any traces of a leak anywhere despite much searching under and over i havn't had the light come on in the dash yet- the header tank remains full to the brim and has never fallen. i don't have any over-heating issues and the temp needle sticks at half way- only rising a bit in stationary traffic, where the fan cuts in. basically it all behaves normally.

oil consumption is minimal. ive blue/green antifreeze in, and it looks clean with no gunk or anything evident.

if it were to need bleeding, it still wouldn't keep drinking it would it? ive had it about a year and half, and its always done it as far as i remember. i assume it shouldn't lose any!? are there any clues if it is getting into the combustion?
thanks!

[Ian Hulley]

It would show up on the emissions in the test. You'll have a slight weep somewhere, as said on another post park over some clean card overnight and see if there's any mark in the morning.

Ian

[slowcoach]

cheers ian-
it would show up in the MOT emissions test?

[kevtherev]

I had a leak ... and for weeks I could not find it, the coolant was going down albeit slowly , but disappearing non the less

turns out to be a leaking coolant sensor.
Only leaked when the system hot and pressurised.
then the coolant just evaporated away..

My point is your leak could be similarly hidden

[slowcoach]

My point is your leak could be similarly hidden

ah good point- i have not looked at the rad thermoswitch for example...

im going to spain next month, which will involve quite a lot of miles, so i dont want to constantly adding it all the time..

cheers fellas

[NicBeeee]

Hi
I have had a similar problem with my 1.9 DG. Looked everywhere both when system was pressurized and the dry carboard job. However whilst removing the spare wheel to start stripping down the gear linkage I found a drip coming from the long plastic hose where it connected to the radiator rubber hose. Jubilee clip was the wrong size.
Guess you never know. All I need to do now is to try and budge the gearbox filler screw. Doesnt want to shift for love nor money.

[Hacksawbob]

A couple of good ones are a leaking coolant resevior (in the engine bay). Mine weeped from a tiny stress fracture that developed when I tightened the dalek cap when it was warm, the plastic weakened around the shoulder to the cap. Also the frost prevention caps under the intake manifold caught me out for a while. Also the hot air switch again in the spare wheel area. one of which would leak while cold!

[gaz f]

A couple of good ones are a leaking coolant resevior (in the engine bay). Mine weeped from a tiny stress fracture

Mine was exactly the same, took ages to find it! My reservior had a stress fracture on the opposite side as you look at it from the rear and as mentioned only leaked when hot and at full pressure.

[skankyunderpants]

mine was the same, it only leaked when up to temp, went to the local auto shop, bought a tub of K-SEAL, in it went, left running for 10-15 mins, and hey presto, it does exactly what it says on the tin, perminatly fixes, and it has, £9.99, and not had a single drop since..... would recomend it highly, ive used it on 3 vehicles now,(mine,mrs and a friends) and everytime its done the job...................

[Cazz]

Ours had a slight leak, symptons the same as yours. It turned out to be the rear heater matrix, I know not all buses have them, but if your does it's another possibility.

[slowcoach]

thanks everyone, the search continues

might try this k-seal if i come up with nothing, seems like quite good stuff from background reading. not for major leaks, but weeping ones like this, maybe itll do the job...

[Mocki]

i know what others have said, but i would only use K seal as a real last resort, as it could cause more problems with sensors , switches and the rad......
another place to look for a weep is the connections onto the coolant distribution tower on the later cooling system, as its hidden in front of the engine bay baulk head, and often forgotten

[richhath]

Hi Kevtherev,
You mentioned that your coolant was leaking from the coolant sensor - I think I have the same problem, when I rev the engine up, the coolant level drops down in the main tank, when I release the accelerator cable, the coolant comes up again, but where the sensor is mounted, i get a leak. How did you fix your leak?
Thanks
Rich

[Ian Hulley]

Hi Rich, sounds like you have air in the system .... the coolant in the header tank shouldn't rise and fall like that. What engine do you have ?

Ian (also in Wirksworth)

[kevtherev]

Richard..
Follow baxters method of topping up and bleeding the cooling system.

http://www.brick-yard.co.uk/forum/bleed ... 29710.html

I changed the sensor, clip and O ring to stop the leak ..all available from Brickwerks.