HOW TO: Change your coolant temperature sensor

[Broon]

Most Fs , this will be the brown sensor, in later Fs and Tfs it is black.

The ECM uses engine temperature to calculate fuelling and ignition timing parameters during start up. It is also used to provide a temperature correction for fuelling and ignition timing when the engine is warming up, running normally or overheating. The ECT signal is used by the ECM to control the engine cooling fans.

If the sensor fails or becomes disconnected, the ECM will use a default value which is based on values from the engine oil temperature sensor. The driver may not notice that a fault is present although a fault code will be stored in the ECM which can be retrieved using TestBook. The default value will also include operation of the cooling fans in fast mode when the engine is running.

REMEMBER: DONT DO THIS WHEN COOLANT IS HOT!!

1. First, you need to remove the engine access panel (I have not covered that here). Then locate the sensor. Looking from above the engine bay, over the cylinder block, notice the coolant pipes at the rear (LHS on the photo).



2. Here is a close look. You can now easily see the sensor (black), and its even more obvious if you have a brown one



3. Remove the multiplug from the sensor. Easy on the later ones, just press the middle of the clip and then pull. I have heard the older ones are a bit more tricky? AT THIS POINT you can now check if your radiator fan works. With multiplug disconnected, start engine. Rad fan should come on immediatley if it is working OK.





4. When you remove the sensor, you WILL lose some coolant, so best to install some tissue/towels etc undserneath the sensor to catch spilled coolant



5. Now start to remove the sensor. I dont know the exact size, only that none of my sockets would fit over the connector block part, so I used an adjustable wrench.




6. Loosen the sensor A LITTLE BIT. Coolant will start to leak soon, and you need to be ready with the new sensor and a spare thumb to block the flow.
Remove the sensor by hand and once clear of the hole, plug with thumb.




7. There should be a little black gasket which goes round the sensor. KEEP this and repalce over the new sensor (mine has disappeared for some reason so I need to get a new one).

Simply screw in new sensor and tighten. Replace multiplug. Remove tissue/rags and then replace engine bay access cover.

[Petevick]

been busy today then Broon ......more links for me to add........

[Broon]

I could have added , how to test your cooalnt sensor is working, and how to test your TPS etc. BUt i never took photos

[Chris T]

Originally Posted by Broon

I could have added , how to test your cooalnt sensor is working, and how to test your TPS etc. BUt i never took photos

So close to greatness

[Broon]

Originally Posted by Chris T

So close to greatness

I also could have added, how to poke your fingers into your water pump area to see if its leaking. Now I DID take pictures of that


And it is

[Herbie]

Another great how-to (must spread around first Broon )

Don't be toooooooooo worried, I think changing your waterpump, cambelt etc. will sort it. Keep an eye to your expansion tank level. It's not loosing that much I guess.

Thanks for the finger, luckily I just finished my chili con carne

[Broon]

Originally Posted by Herbie

Another great how-to (must spread around first Broon )

Don't be toooooooooo worried, I think changing your waterpump, cambelt etc. will sort it. Keep an eye to your expansion tank level. It's not loosing that much I guess.

Whilst on subject, I checked the posisble HGF leak location s- alternator top and head/block join just above. This is them today....


Clearer than the Ukrainian Football Bosses next pay cheque

Amazing how shiny yhe engione block can be with a bit of degresatna nd a wire brush. Now there's a challenge for a rainly day

[Herbie]

Yeah very shiny and deffo a good starting point to watch

Mind you, I'll never clean my engine like that as no one can see it and it will be dirty again I promise

[Broon]

If I had the facilities, I am now tempted to remove the engine and clean all the alloy

[Herbie]

Originally Posted by Broon

If I had the facilities, I am now tempted to remove the engine and clean all the alloy

And put it into a vitrine ?????

Drive, drive, drive, drive, drive, drive ...... phew I'm exhausted now

But tbh I really know what you mean, once starting you can't get enough

[Broon]

:lo:

But surely a clean engine will be a healthy engine.

I am getting through my "Operation NO rusty bolts". Slowly replacing all bolts/nutes etc with spanking new OEM ones whenever I replace a part. ONe day , if I keep it long enough, mycar will be all new

[Herbie]

That sounds good, all for the long-term maintenance of value.
I'll be doing the same: failed original parts will be swapped to better built ones
(e.g. cat, zorst etc. etc.)

I think you are on the right way mate, Maggie will be thankful one day, e.g. when going toplesse throught the first December rain

[Broon]

Originally Posted by Herbie

That sounds good, all for the long-term maintenance of value.
I'll be doing the same: failed original parts will be swapped to better built ones
(e.g. cat, zorst etc. etc.)

I think you are on the right way mate, Maggie will be thankful one day, e.g. when going toplesse throught the first December rain

December rain? You dont know scotland