I have a 56 plate Fiesta MK6 Zetec S, done 99k and hasn't let me down yet, untill recently. I first had a problem arriving at work after a 26 mile commute, noticed steam coming out of the bonnet so lifted it up to find there was NO coolant in it what so ever after being serviced 2 weeks before.

so i topped it up and kept an eye on it. 2 months later after everything seemed fine, i was on the same commute and my engine temp rose from 90 to 120 in around 45 seconds while idleing in traffic, so i pulled over as there was luckily a petrol station right next to me and filled it up with coolant, then resumed on my way home, checked in the morning and all semmed fine, got to work this morning, checked again straight away, all seemed fine, checked an hour later after explaining my problem to a colleauge and it had dropped to basically 1/4 of the amount i had put in?! but the car had not moved, there are no puddles and no "mayonaise" in the engine oil.

any advice would be appreciated on this as its doing my head in.

thanks

Chris.

My 206 started off like this, sometimes there will be a minute crack in the head gasket that will only expand when the engine gets warm enough so you may find that you have a lot of condensation coming out of the exhaust, hence the coolant maybe mixing in the combustion chamber.

It did take a few months for the mayonnaise effect to appear in my oil.

It may be that it dropped to 1/4 of the original amount after the air had worked it's way out of the system hence no puddle. I'd double check the oil

hi steve,

i dont notice any condensation from the exhaust at all, only the usual when i first start it up on a cold morning.

My 206 started off like this, sometimes there will be a minute crack in the head gasket that will only expand when the engine gets warm enough so you may find that you have a lot of condensation coming out of the exhaust, hence the coolant maybe mixing in the combustion chamber.

It did take a few months for the mayonnaise effect to appear in my oil.

It may be that it dropped to 1/4 of the original amount after the air had worked it's way out of the system hence no puddle. I'd double check the oil

hi steve,

i dont notice any condenstion coming from the exhaust at all, only the usual on a cold morning. the strange part of it is that i was fine for months and just happened again. must be a crack/leak somwhere just cant see where.

thanks for the reply.

Try the water pump. I had one from there on my old fiesta, very small, but it was there.

There are only a few places where the coolant could be dissapearing:-

1: A leak from somewhere but as you've stated there are no puddles.

2: Mixing with the oil but as you've stated there is no mayonnaise mixture.

3: Getting burnt off in the combustion process as steam.

If it is a minute fracture it will be very difficult to spot. Get the engine up to operating temperature and then see if you have a leak.

Is the engine mis-firing? as this would point to head gasket failure as coolant doesn't combust.

Look for the tell tale signs of pink or green crusty gunk around the engine hoses, if you spot any then you have a leak coming from that hose

Normally its thermostat housing or water pump or both.

Did both on a fiesta last week