Thirsty van drinking coolant!

[Emz]

Hi,

I have a 1986 water cooled T25 and was wondering if anyone could help me with a coolant problem! I had to refill my coolant (I used a 50/50 mix of coolant and water) on Thursday, since then I've done about 100 miles in the van, and it has used all the coolant again - the container is completely dry! I hadnt noticed a problem prior to this, but the first time I was aware of it was when my coolant light came on. Its still driving beautifully, just seems quite thirsty!

Can anyone suggest problems/solutions please?
Thanks in advance!

[mm289]

Hi Emz,

could be a number of things really - hard to tell from a distance, but would include:

- any signs of water leaks around engine pipework, front to rear pipes under van, radiator etc. Look when vehicle is parked for a while for damp patches underneath and also when it is running and temp gauge is at normal temp (cooling system is pressurised) - most likely/easy to fix

- any signs of leaks from the rubber seal around the cylinder heads - particularly at the back of the engine - a small leak is often difficult to spot as it evaporates on a hot engine but look for tell tale signs/stains - common problem/harder to fix

- any "mayonnaise"/white residue in oil filler cap or tube (water leak into sump/oilways through cylinder liner bottom gasket or cracked head) - unlikely/engine stripdown needed

- any associated lack of power or misfire (seal failed on top of cylinder liner) - unlikely/engine stripdown needed

That would be my starter for 10, any other associated probs such as overheating etc? Next step after carefully checking for evidence of leaks would be to pressure test cooling system and compression/leak down test cylinders.

Quite a few posts on hear about water leaks if you search around as well.

HTH

MM

[Emz]

Hi,

Thanks for your response! I've had a look around and cant see any obvious leaks - I will have a proper look in the morning, as I know exactly how much coolant is in there right now. There's also no associated misfiring/loss of power. I will work my way through your other list of suggestions tomorrow, fingers crossed its nothing too serious!

Thanks again!

[StuM]

Hi,

Are you checking the main coolant tank or the expansion tank behind the pull down flap, out of interest?

[Emz]

I'm checking the pull down flap - is there somewhere else I should be checking to? (I'm new to all of this!)

Thanks!

[Ian Hulley]

That's the top-up tank, the header tank is on your left inside the engine bay. This must be full to the top and the top-up tank on 'Max'.

Ian

[Mocki]

ok, how the system works!

There are two coolant tanks, one inside the engine bay, infront of your left knee as you stand looking in the engine bay, and the one behind your numberplate flap.....

the one behind the numberplate flap is known as the top up tank, the other one is your header tank.

As said above, the header tank should be full to the brim at all times (only check when cold)
the top up tank should be full to the MAX mark when the engine is cold, but may be fuller than this when the engine is warm.....

When the engine is up to running temperature the coolant expands, and is pushed out of the header tank into the top up tank, where it will stay untill the engine cools, when the engine cools, the coolant contracts, and the header tank sucks the excess coolant back into the header tank from the top up tank.....

so, if your header tanks wasnt full to the brim, it sucked all it could out of the top up tank, and emptied it.... you filled it, it drank it again..... so if you are lucky, you dont have a problem, just low coolant level.

did that make sense?
i hope so..... but if not shout and ill try again!!!!

[Emz]

I think that makes sense! Thank-you! I refilled the coolant, and went for another trip in it, and the level seemed ok, I'll check the other tank though! It'd be brilliant if it wasnt an expensive problem! Thanks for all your help!!!