stuballs

Hi all

First post here and hoep someone can help.

Picked up a puma a couple of weeks ago. Ran fine but after having been sat for a few days covered in snow has devloped an overheating problem. The other half was driving when it happened and says the heaters went cold and the temp guage shot up past the red. She couldn't stop driving as she was on unlit country lanes at night so continued a couple of miles with it like that

When I checked it over i immediately saw that the expansion bottle was empty. I tipped about 5 litres of coolant/water in, expecting to see it pouring out of somewhere but nothing leaked. I bled it according to the correct procedure and it ran fine (heater working) until today when I had exactly the same thing (ironically on my way home from eurocarparts with everything i need for a full service!). I've been keeping an eye on the coolant level thinking it might have had a leak but it hadn' dropped at all. When I got it home once again all the coolant had gone. It seemed to be coming out of somewhere but by the time the time i jacked it up it had stopped. It looked like it had been coming out near the oil filter. Truly p****d off by this point I gingerly poured more water into the expansion bottle thinking surely now it'll pour out. But no!

So what is going on? No sign of head gasket failure. Expansion bottle cap seems to be holding pressure. I bled it properly and it ran fine for days with no coolant loss. So it must be an intermittent probelm (so not a leak and probably not the water pump). No loss in perfomance and no warning lights.

Could an (intermittently) faulty HCV cause overheating to such a degree that ALL the coolant pisses out?

Cheers

Stu

cos 4x4

Heater control valve mate.this happened to me on a zetec s fiesta changed that and problem solved

stuballs

Cheers mate. that was my first thought having done some research.

However, I've just changed teh HCV and filled it with coolant. Bled it. Fine. No leaks. Took it out for a drive. Came back. Massive leak underneath.

Seems to be coming from thermostat housing/block area but with the engine bay being what it is I can't actually see. It's definately below the alternator but above the air con pump.

Do these engine have core plugs? Could it be a cracked block? (just thinking about the few days it was sitting in sub-zero weather - I have no service history so could have been filled with water and no antifreeze for all I know) Or maybe just a cracked thermostat housing or even knackered thermostat body gasket?

help!

stuballs

OK so I have an update on this.

Got the thermostat housing off expecting to see it cracked. Something in that area has obviously been leaking for a while as you can see from the scaling but the body itself is fine. The gasket is clearly damaged.

Also, thermostat seemed to be stuck shut as put it in boiling water and didn't open. And the gasket on that was all baggy and knackered too.

Hoping that's the problem and there isn't somthing more sinister going on with the block. Pictures:

stuballs

Changed thermostat and housing today. Got it all back together but the radiator pipes and radiator are not even getting warm even with the rest of the system red hot! The rest of the pipework (for the heating) is getting hot and the heater is blowing nice and hot. So can't be the water pump - I had a feel of that when I did the thermostat and it felt absolutely fine.

What are the chances of getting a duff brand new thermostat?

Not relishing the thought of taking it all apart again. But think I might have to try another thermostat to rule that out. Or maybe chuck this new one in boiling water to see if it opens.

Could it be an air lock? Been trying to bleed it for ages with the proper method. The pipe that runs from the thermostat body to the bottom of the rad is just full of air with maybe a bit of water in there squelching when you squeeze it.

Getting really annoyed now.

melinamotor

I had this issue years ago, it was a duff core plug.

stuballs

Turned out just to be an air lock. After a couple of hours of bleeding it was all sorted.

Runs like a dream now!

melinamotor

Sorted