I have a couple of questions regarding the thermostat housing on my Ford Focus Mk1, I purchased an 88oC thermostat from euro car parts a couple of days ago and fitted it, thankfully I didn't have to remove the whole housing to do this, just 3 bolts off the front of the housing and a couple of pipes, upon refilling the system with coolant, it start leaking out of the housing all over the place, I soon realised that the thermostat, although it came with the seal, wasn't as tight a fit and the original one, and wasn't locking into place, I could rotate it easily in the housing, so I refitted the original one, hey presto, leak gone.

now this brings me onto a slightly different subject, to make life easier for myself, I'm going to take the parts back to euro car parts and just buy a whole new housing with stat and seals from ebay, however also in my car and have a radiator fan switch with a fuse which is strapped to the battery box, its a mod by ford themselves, very strange, however I thought I would try a different modification myself, The focus ST170 and also Mondeo MK1 (same engine as mine), comes with a housing with a whole in it to screw a radiator fan switch into so that its immersed in the coolant and actually monitors the water temp.

The reason for my worry is ive never seen my temp gauge raise above halfway even in the heat wave we just had, and also never seen the fans come on, I know they work as ive recently changed them and also if I remove the fan switch and short the terminals, they come on.

ive added some pictures below of my housing and fan switch that I mentioned earlier and also the replacement housing which I'm looking at purchasing, you can see from the picture where the hole is for the fan switch to screw into. the pipe layout of the new housing looks exactly the same as mine, even where it screws to the engine bay looks the same, its just screw hole positioning I'm not too sure about.

The switch is not for the fan that's ecu controlled the switch as you call it I a sensor to monitor under bonnet temps if its too high it switches the fan on so IDE leave that alone unless you want issues

I'm just concerned as ive never heard or seen the fans come on, temp gauge once warmed up always sits in the middle, on a very dry very hot day, sometimes you can open the bonnet and "smell the heat" as I like to call it, smells like the radiators in your home when you first switch them on after months without using them, coming off the engine, and the pipes are almost too hot to touch.

well a bit of relief today, went back to euro car parts and had a bit of an argument with the manager who was refusing to give me a refund for the leaking 88oC T-stat I brought from them "because I fitted it" my response was, of course I fitted it otherwise how would I have known it was the wrong one, and leaking, you sold me the wrong part, I got my refund and exchanged it for the other one that they do for my car which is a 92oC stat.

I took it out of the box in front of him, quite clearly a different size to the 88oC one, different length and slightly larger diameter, I told him, he needs to remove the other from the focus mk1 listings and he said, "maybe that is also for your model of car" I stated it cant be as both were coming up on their page with my registration number, yet the other one quite clearly leaks from the housing, new one is fine by the way.

Fitted it and bled the system, I then discovered you can enter a diag mode on the dashboard, so I went into the temperature setting and drove the car around for a little while, I got the temp up to 80oC and then pulled over and held the revs at 3000rpm, the temperature rose quite quickly and the fans which ive been worrying about kicked in at 98oC, they quickly cooled the car down to 94oC, and then switched back off again, I did notice however there was no slow speed fan, just full on or full off, I guess this just needs the fan speed resistor replacing, does anyone know where I can purchase one of these from ?