1.8T Radiator Fan

[kully]

Evening,

I've spent a good couple of hours reading all about fans and I am quite confused.

My May '03 manufactured 75 1.8T appears to have a three-speed fan (I checked for the resistor but it is not present), however, the fan only comes on thus:

> At 105C fan comes on until the temp goes below 97C (actually, I've realised I've been tardy, I'll time the switch-on to switch-off time as it may be time instead of temp based).
> A/C on - fan speed on at same speed as above.

I had thought that the fan would come on at a lower speed if the coolant temp reached 98C ( I checked and the blades were stationary).

A lot of the posts are for KV6, M47 and K4 NASP engines, is the K4T engine a peculiarity in its behaviour?

This all started when I noticed the fan seemed to be noisier than when I used A/C in the cooler months.

Any thoughts would be appreciated.

[Jules]

If the fan doesn't come on as soon as Aircon selected, there may be a speed missing.

[T-Cut]

At 105C fan comes on until the temp goes below 97C (actually, I've realised I've been tardy, I'll time the switch-on to switch-off time as it may be time instead of temp based).

For engine cooling, that sounds normal for the 1.8. Mine has a 2-speed system and the fan starts at 107C and stops again at 97C. I believe a 3-speed system runs at slightly lower temperatures. The fan operation is temperature controlled not timed.

A/C on - fan speed on at same speed as above.

Is this with the engine hot or cool? It should run with a cold engine.

I had thought that the fan would come on at a lower speed if the coolant temp reached 98C

There's bound to be a small tolerance. For engine cooling, it seems normal to me.

is the K4T engine a peculiarity in its behaviour?

I don't think so.

TC

[Jules]

Agree with Tcut

Fan should be running even with a cold engine.(AC ON)
Without cooling the condensor & AC compressor will overheat (overpressurise) in about 20 seconds flat

The Small High pressure pipe gets sizzling hot & will burn your fingers if touched with no fan operation.

[kully]

Thanks for the replies T-Cut and Jules.

Jules, I am going to test both speeds of the fan with the method you described in another thread (air-con on and disconnecting coolant temp sensor) as the 'normal' speed seems very loud.

[SMC Trading]

I always thought the 1.8T only ever had the 2 speed fan, different to the standard 1.8 but still 2 speed? :shrug:

[kully]

From what I am seeing, it does seem to be a two-speed fan, but there is no resistor visible. Mmm...

Jules, did you figure out this procedure: http://www.the75andztclub.co.uk/forum/showthread.php?t=35567

For the non M47 engines?

[T-Cut]

From what I am seeing, it does seem to be a two-speed fan, but there is no resistor visible. Mmm...

Thinking about it more, I believe the 1.8/1.8T models only ever had a 2-speed system irrespective of year. The pre-resistor models use brush selection to adjust the speed. The 1.8 has a 250 watt motor, the 1.8T a 350 watt and all other earlier models (3-speed) use a 450 watt motor. Another read of Keith's fan dossier should confirm. Can't remember what the power of the current 2-speed is, but it's used in all models.

TC

[kully]

I think we need to update the radiator sticky in this sub-forum wrt. the K1.8

http://www.the75andztclub.co.uk/forum/showpost.php?p=13169&postcount=2

[jcwatrichmond]

Kully, my 1.8T registered on 30.06.03 seems to operate exactly the same as your description of fans and temperatures.

John Wright