Hi all, Im new to the forum, Im Mark and Im in Co Down N Ireland, and my wife and I own a 2005 1.8 tdci silver 5 door focus.

I only drive the car at weekends, sometimes I don't get to drive it at all, which brings me to the problem, the temp needle is almost at the 12 o'clock position, my wife said the fan was running when she stopped the engine, so I checked the coolant level, and there was next to nothing in the expansion tank. I topped it up and checked it again this evening, and there is next to nothing in the tank again.

First thing I thought might be the problem was the thermostat, but I don't know where its located in the engine, or could there be something else causing the overheating.

Thanks in advance Mark

i would investigate any leakage to begin with...pour some water in and check for any drips or puddles under car...if none it will seem the fluid is evaporating out..

Thanks ill try that tomorrow cause its raining outside, could you tell me where the thermostat is please. Thanks Mark

from what i read on net:

Thanks for that, ill have a look when my wife comes back with the keys

I started the engine up and noticed water dripping from under the thermostat housing. New part ordered

I would say its the thermostat housing as mine was doing the same ,after being fixed she's running like a dream again.

Ive fitted the new thermostat housing, I haven't added the coolant yet, are there any things I need to know now about bleeding the system, are there any bleed valves in 1800 tdci engine. Or what is the best way to bleed the system.

According to etis to bleed the 1.8tdci you rev to 3k for some minutes and get someone to add coolant as it drops

Fill the coolant up, leave the expansion cap off and let it run for a few minutes and 'burp' the air out itself.

Ive left the cap and let the car tick over for 2 hrs. The coolant in the expansion tank has dropped s little. Im not sure if that's the air lock out.

When driving after about 4 miles the needle starts to rise. Then if I go fast the needle drops again. then If I take my foot off the accelerator pedal the needle starts to rise again and it sits at roughly the 12 o'clock position on the gauge. Would this suggedt there is still air in the system.

i know its abit too warm for this right now but run the car with the heaters on hot, this will let the coolant circulate around the entire system

The needle on the temp gauge should rise to half way point when the engine warms up, and stay there, should stay steady at the half way point for the majority of the driving, that's what I understand is considered to be normal operations for the engine.

If it goes over the half way mark, then better worry about engine overheating.

If it drops a bit and rise again and drops a bit, messing about, like you say it's doing on your car, and it is actually doing to mine as well, but as long as it is often below the halfway mark, then we've got coolant problem, coolant leak, and such, so you'll have to have the coolant system checked out and fixed.

I've got the same problem on my Mk 1 Focus. It seems to be always coolant problems.

i know its abit too warm for this right now but run the car with the heaters on hot, this will let the coolant circulate around the entire system

Won't that makes the coolant leak some more?

With the heater on hot the valve in the heater opens and lets the coolant through the internal 'radiator ' thus pushing all the excess air out of the system then the coolant completes its cycle returning to the header tank .