vanishing coolant

[v8griffith]

Hi all
Can anyone advise---

I seem to be loosing coolant but I don't seem to have any leaks?
I am dong approx 80 mile per day in 2 40 mile trips to work and back at around 70mph
There is no overheating and the temp gauge doesn't move over 11 o'clock and there is no running or starting problems or unusual emissions?
I am having to fill my expansion tank about every 300 miles and it takes approx 1 litre to fill to 'full level'.
Does this mean that my head is damaged or the head gasket has failed? If so is there any way to tell without pulling it to bits? or could there be another cause for the disappearing coolant?

Many thanks in advance from a new owner and member

1995 2wd 2.5TD Auto Trans
180000 km
Auto Freetop

Ken n Moira

[wonkanoby]

some leaks like the water pump lower are very hard to spot

you can buy a uv dye and uv torch on ebay might help

[v8griffith]

Thanks for that suggestion I will give that a go.

[wonkanoby]

http://www.ebay.co.uk/itm/UV-Dye-UV-Tor ... 35b837e719

[Driver+Passengers]

Worth doing a pressure test.

Get a spare header tank cap, remove the lower seal/spring (damaging it) and then use a bike pump with pressure gauge to inflate the system, via the rubber overflow pipe coming out of the header tank, to around 10psi - I used an old bike inner tube for the valve and hose-clamped it into the end of the hose. If you see the pressure fall and you've got a leak somewhere. If you do have a leak and it's really hard to spot then if you can get somewhere quiet, dry and under cover, remove the undertrays, put some newspaper down and look for any drops reaching the ground.

[Northern Bongolow]

water pump at the bottom hole behind the crank pulley.

[v8griffith]

Thanks for the tip on how to pressure test the cooling system I will give that a go. Would you happen to know if the header tank cap is bongo specific or if you can get one from motor accessories stores?

Regards

[wonkanoby]

Just be sure its 1.1 bar

[haydn callow]

Shouldn't the caps be 1.1 on the rad and 0.9 on the header tank.....reason being you would want the tank cap to 'blow' first

[rita]

Shouldn't the caps be 1.1 on the rad and 0.9 on the header tank.....reason being you would want the tank cap to 'blow' first

Hi,both caps should be the same (value).

[haydn callow]

Not so sure about that.......if that was the case then the rad 'might' blow first....not what we want on a bongo or any other vehicle for that matter

[haydn callow]

I agree that on a rad without a outlet stub it makes no differance......however some rads do have stubs so it is best to safe as not everyone knows what is ment by stub and seal it off etc......

[rita]

Not so sure about that.......if that was the case then the rad 'might' blow first....not what we want on a bongo or any other vehicle for that matter

Its a fact as specified by Mazda.

[haydn callow]

If you have a Mazda rad in your bongo you only need a pressure cap on the ex tank.....any old thing will do on the rad