Hi All,

Firstly thanks for taking the time to read my post.

So I have a MK5 2005, 1.9TDI Golf. For the last year or so I've been struggling (especially in the winter at -6C) with a heater/engine temperature fault on my car. So I've noticed that the engine temperature used to reach 90C quickly and stay there, and never move, however now its all over the place. The heater in the cabin is intermittent, so sometimes it's hot, sometimes it will not get hot even if I rag the engine to within an inch of its life to try and get it hot. What seems to happen is, the heater will either work immediately and the engine temp will stay at the lowest point, or the heater won't work, the engine temp will go up then drop as soon as I get any heat into the cabin.

I tested it today as it was mild but not freezing (7C) and the issue is still there after the summer. Does anyone have and idea why this is? the thermostat was replaced about 6 months ago and made not difference whatsoever!

Many thanks in advance,
F1Lane