I was going to replace the coolant temp sensor on SWMBO's 1.4mpi Fabia, but after reading up it seemed that it made sense to replace the thermometer housing also. So on saturday i went and got the part, but due to the fabulous weather i have been unable to do it so far.

I have read ap0gee's guide on how to change the sensor, and had a good read of my haynes so im pretty confident. But im a very amateur mechanic, ive done oil and filter changes before but thats it, so is there anything i need to be aware of?

I know i will need to bleed and top up the coolant as there may be a little loss, from what i have read this is done by squeezing the bottom radiator hose? and running the car at idle for a few mins after to re-circ and top up.

Any help would be appreciated as i would never live it down if i break her car doing a relatively simple job

If you already have the Haynes, you should be OK - just follow the instructions for replacing the coolant, which are pretty much what you've listed already. Since the housing as at the 'top' of the circuit as mentioned in my guide, you should be able to disconnect the hoses either side and get an assistant to hold the open ends up, which will mean you'll only lose a smidgen. In fact, the best way to avoid an airlock might be to remove the sensor once everything's connected and top up through that - although I've not tried that myself so it might be worth seeing if any of the other members have any thoughts before you go off and do it...

HTH

Yeah Haynes mentions removing the sensor when topping up/replacing coolant as when bubbles stop coming through the hole the system is filled again. I wasn't planning to replace the coolant, but that might be an idea too, its been topped up with so many different brands over the years that it could probably do with replacing. Only problem is the only jack i have access to is the one with the car, and i dont fancy getting under the car to empty the coolant when its only jacked up like that. Think ill just top it up and get it replaced when its in for service. How much is the recommended G12 coolant? think i need about 6ltrs.

ISTR I bought a bottle of concentrate from the local VAG garage for 7 or 8 quid. You'll need a load of demineralised water to make it up, but this is pretty easy to get hold of. Whether it's not cheaper to get a big bottle of the ready-mix stuff from Halfords etc. I'm not sure - I can't remember what they call it, but it's the pinky/orangey stuff...

So the halfords stuff is ok then? Thats grand then, i wondered if using mixed coolant of not the recommended stuff might have aided the degredation of the sensor and stat but i suppose not, i suppose its 'recommended' because you have to buy it from them.

Well, the pinky/orangey stuff is what's in my wife's MPi - I'm pretty sure it's approved for VAG engines, but the MPi engine is a lot less sensitive to these things than my PD anyway - for instance boggo Castrol GTX is OK for it, and is again what's in SWMBO's car...

Brilliant, i needed to nip to Halfrauds anyway.

Brilliant, i needed to nip to Halfrauds anyway.

Go for the G12 plus chap, it's really good stuff.

Halfords coolant wont meet G12 plus spec.

G12 plus is superceding soon to G12 plus plus which is like a lifetime fill coolant, might be worth a look.

Go for the G12 plus chap, it's really good stuff.

Halfords coolant wont meet G12 plus spec.

G12 plus is superceding soon to G12 plus plus which is like a lifetime fill coolant, might be worth a look.

I'm pretty sure their orange stuff does, actually. It's their cheapo green(?) stuff that doesn't. But if in doubt give the label a thorough read and decide for yourself...

And you should be replacing it every two years whatever the spec, as it's hygroscopic like brake fluid, and so will absorb moisture and rust your engine from the inside out if you keep it in too long... :(

I'm pretty sure their orange stuff does, actually. It's their cheapo green(?) stuff that doesn't. But if in doubt give the label a thorough read and decide for yourself...

And you should be replacing it every two years whatever the spec, as it's hygroscopic like brake fluid, and so will absorb moisture and rust your engine from the inside out if you keep it in too long... :(

G12 plus is pretty high spec stuff, even vag own brand quantum red longlife coolant doesn't meet G12 spec and says so on the bottle so i seriously doubt whether halfrauds own brand coolant will. G12 plus needs to be changed every 5 years not 2.

G12 plus plus is the new coolant and is lifetime fill and says so on the bottle.

regards

wonkey

G12 plus is pretty high spec stuff, even vag own brand quantum red longlife coolant doesn't meet G12 spec and says so on the bottle so i seriously doubt whether halfrauds own brand coolant will. G12 plus needs to be changed every 5 years not 2.

G12 plus plus is the new coolant and is lifetime fill and says so on the bottle.

regards

wonkey

Well maybe, and to be fair, I wouldn't put it in my vRS (!) Although the relative standards for oil between mine and my wife's mean that I'm comfortable putting non-G12 coolant in my wife's MPi-engined car. Especially as the engine was probably designed to be cooled by salty water or ox urine or something!

As it happens, my wife's is due for a new thermostat soon, so watch this space for pics!

Well i replaced the temp sensor last thurs evening and all seems well so far, and the housing is going to be replaced next weekend when the car is in for a service.

Just to add my own experiences, I tried to see if there was any way I could cut back on the Haynes method, and apart from clamping the drain from the expansion tank and draining the coolant between it and the 'stat housing but placing a funnel and an empty bottle under the hose that connects to the radiator, I couldn't really find any ways of making the process any easier. :ne_nau: I didn't like how firm the nuts holding the houding onto the cylinder head were, but I got there in the end. Sure enough, one of the little brackets holding the 'stat plunger spring had snapped off, making it stay open. I couldn't find the bit that had snapped off, though! :(

Anyway, to cut a long story short, there's not really anything I can recommend that will give any real benefit over the Haynes method - and for once, the method in Haynes is pretty good!

Just to update, as ISTR it was discussed here, the Halfrauds red long-life coolant is TL774D, which is G12 by another name. G12 and G12+ (what a dealer will sell you now) are supposedly freely mixable, and I gather the dilution of the concentrated stuff is fairly flexible (something like 2:1 either way)

You should have just done the housing if thats what it needs as it comes with new sensor!!!!!!! would have saved you a few quid!

You should have just done the housing if thats what it needs as it comes with new sensor!!!!!!! would have saved you a few quid!

:confused:

That's what he did???