heeeeeeelp!

[tomalamix]

water disappearing and bad fuel consumption usually doesn't run away from the head gasket, head cracked, cylinder walls cracked or piston cracked..

[stephen1990]

water disappearing and bad fuel consumption usually doesn't run away from the head gasket, head cracked, cylinder walls cracked or piston cracked..

sh1t..............

[tomalamix]

how about the performance with the coil packs? its better ? the same (bad) ?

[stephen1990]

The coil packs just seem a little bit better, all 4 are now replaced. This really is starting to become a massive headache! I might just trade it in and get something better

[davelowe]

When you remove the oil filler cap, what does a) the cap look like, and b) can you see clean oil on the camshaft?

Lots of gloopy brown stuff is an indication of the oil mixing with water - which would be indicative of either very short term trips, or a bad head.

Odd ball thought: you have a coolant leak that is around the thermostat or elsewhere. Have you noticed any fluid on the ground where the car is stood for a period of time?

[stephen1990]

Well the bloke who did my coil packs said there's nothing wrong with the oil or the water/coolant because he was satisfied with the pressure of air that came out when he unscrewed the coolant cap, never noticed any patches when the cars been standing, just seems normal, just see what the guys say when I take it in on tuesday

[tomalamix]

you may have low pressure on the cap and that doesnt mean the system is ok, neither does the contrary.

What does he say about the water disappearing? did he made a pressure test on the cylinders? there is a problem, at least the problem of the water disappearing, and it goes somewhere...

[stephen1990]

Well after some much sleuthing online things point to either the thermostat or the coolant temperature sensor.

[tomalamix]

stuck thermostat or coolant temp sensor caput doesn't make the water disappear...its a closed loop with no input or output, the water cannot disappear without a leak

[davelowe]

There is the possibility that the cap vents steam when the coolant is boiling under low pressure (bad thermostat and cap design?)

Intrigued..

[stephen1990]

Well the diagnostics came back clean, nothing come up, he said that they had a megane in today and that was doing the same temperature reading as mine...... Hmm

[davelowe]

My thinking is that if the engine temperature sender is broken, it will report a high coolant temperature to the ECU (and gauge). The ECU might attempt to correct what it perceives as a lean mixture (hot engine flame) by additional fuelling (giving a richer mixture and cooler flame). This might explain things (fumes and bad mpg). Might be worth investigating?

[stephen1990]

Quite possibly, he did mention something about a sensor, I'll get it replaced and probably the thermostat (£5 from carparts4less.co.uk) hopefully be a cheapish fix. Their labour rates £40 an hour!

[tomalamix]

its really easy to swap it (temp sensor)if youre willing to do it....

and the ideai of wrong temp info is a good idea, it costs money to change the sensor but its a shot you can make..

[cockneycowboy]

hi there i had a similar problem with a vw polo i changed the thermostat and all was fine,the engine was not getting up to temperature and i think it was running on cold start plus and there was petrol fumes when stopped,the thermostat was stuck open when i changed it plus a diagnostic machine can't test the thermostat,good luck.