scottc

Hi guys,

I have a problem with my 91 XF ute, which has been happening for ages now, I am slowly losing coolant somewhere, and it has really got me stuffed where.

Basically I lose approx. 500ml every 450 kms. I have had my hoses replaced, new radiator and cap, had the head tested and also been keeping a look out for bubbles in the radiator, no sign of water in the oil. Every time I get a service I make sure to tell the mechanic about this problem, but they can never find anything.

I thought maybe there is a small crack in the cylinder block somewhere and the coolant is coming out the exhaust as steam??

I am pretty sure the water pump and heater core are ok because there is no sign of a leak when I drive on to a dry concrete driveway.

If anyone has any suggestions, I would love to hear them!

Cheers,
Scott.

RED_EL_XR8

Checked the radiator cap?

scottc

Yep, checked and replaced the cap.

RED_EL_XR8

Pressure test the heater core?

EBXR

What about running the overflow hose to a container - then you can see if that is where the water is going.

Sounds dodgy, but what about chucking in a can of Bars Stop leak...

__________________
'67 Mustang V8 4sp... what fun to drive!

scottc

I have done a pressure test, which came up ok.

The overflow bottle never fills or overflows, just stays around the 'cold' mark.

I have also thought about a can of bars leaks, but decided not to, would rather find the source of the problem.

RED_EL_XR8

An overdose of nice bright glycol wil show the location of any external leak real fast.

scottc

Yes, that is for sure.

Like i said, I have driven on to fresh dry concrete driveways, and cant find a drop of green coolant anywhere. I reckon it might be dissapearing somewhere inside the motor.

gordon451

If the overflow bottle never fills, this means you're not building pressure in the cooling system. It is possible you have a leak in the little hose between the filler and the bottle -- this often shows as overflow not being returned to the radiator. Check it anyway.

Another reason for not building pressure is lack of a working thermostat. Lots of silly people think the 'stat is a complete waste of money time and effort -- but it is absolutely necessary on almost every engine made -- overheating is a sign of poor maintenance, not poor design.

Have you checked the heater? Silly me! You just said so.

Try spending some money at your local radiator shop, have them pressure test the entire system -- they have the tools to find almost any leakage. Most service places don't have the knowledge or tools.

BTW -- ethylene glycol degrades with age, and breaks down in the system to form corrosive by-products, which is why they put anti-corrosion goop in with it. GLYCOL MUST BE CHANGED EVERY 6 OR 12 MONTHS depending on the brand.

Also, if you DO have a couple of pinholes in your heater, the glycol vapour can intoxicate you... Literally.

I recommend you change to the new non-glycol coolant additives -- follow Ford and Toyota. There's even one made in Australia (here in Perth) which has excellent results. Email me and I'll send you the details (I neither make nor sell it).

scottc

Hi gordon,

thanks for the detailed reply! I will check the hose to the overflow bottle, but i am sure there is enough pressure, as when I take the cap off, I get the sort of back pressure sound coming from the overflow, kind of like the coolant is rushing back to the bottle.

Funny you mention the thermostat, as I just replaced it last week, as well as flushing the radiator etc. And have nice new gylcol in the system.
I would love to know what the brand of non-glycol coolant you mentioned.

I have had the heater on a fair bit lately and have not had that radiator smell come through, so I pretty much discounted the heater core.

I will take your advice and get the whole system pressure tested at a cooling system place, good call there.

Thanks again,
Scott.