Fan clutch test

[whiskychaser]

Since I did some work on the car, the temp gauge is a needle's width higher. Viewed straight on its bang on 12 o'clock but I dont usually drive with my head a foot to the right:) So I decide to test the fan this morning:
Engine off and cold - Light resistance to turning fan by hand
Start engine -fan turns quickly
After 2 mins fan seems to have slowed a bit but engine is still on fast idle
After 4 mins normal idle but fan hasnt slowed any more
After 5 mins normal op temp and no change in fan speed
Turned off and got very light resistance to turning the fan.
Any thoughts?

[Ferret]

Since I did some work on the car, the temp gauge is a needle's width higher. Viewed straight on its bang on 12 o'clock but I dont usually drive with my head a foot to the right:) So I decide to test the fan this morning:
Engine off and cold - Light resistance to turning fan by hand
Start engine -fan turns quickly
After 2 mins fan seems to have slowed a bit but engine is still on fast idle
After 4 mins normal idle but fan hasnt slowed any more
After 5 mins normal op temp and no change in fan speed
Turned off and got very light resistance to turning the fan.
Any thoughts?

You can kinda tell if your fan has packed in, when the engine's cold and you rev it - you should hear the 'whooo' noise it makes until you hit a certain rpm and then it should disengage.

5 Minutes is no way long enough to get the thing to heat up, you'd probably need a good 15 minutes of traffic driving to bring it up to operating temp. When it's hit lockup temp, it should be quite stiff to turn by hand, as in it wont freewheel at all, regardless of the force you put into it.

This thread reminds me I still need to change my thermostat as it's gone lazy and makes the engine take forever warming up.

[whiskychaser]

It does take about 10 mins if I'm driving but standing still its quicker. I assume cos no cold air is rushing in through the front:) Needle goes no higher on the motorway. I'm just puzzled that the fan seems to slow down after a couple of mins. If anything I thought it should engage more and speed up as the car got warmer

So once the car is warm I shoudnt be able to turn the fan?

[Ferret]

So once the car is warm I shoudnt be able to turn the fan?

You should, but it should put up a bit of a fight...

[filip00]

it's important to warm up the car completely, then when you turn it off, you should feel a fair resistance when you try to turn the fan clutch.

it's really easy to see if it's working when the car is working, pop the hood, and simply rev the engine under the hood, and look at the fan...you will notice it's slipping instead of following the engine's rpms.

[whiskychaser]

You should, but it should put up a bit of a fight...
At op temp its easier to turn than when its cold. The needle doesnt go above 12 and its only 18 deg C outside so I'm wondering if its hot enough to lock the fan up. My car was built for S Africa so may have bigger fan blades anyway. And maybe I'm just being paranoid :)

[Ferret]

At op temp its easier to turn than when its cold. The needle doesnt go above 12 and its only 18 deg C outside so I'm wondering if its hot enough to lock the fan up. My car was built for S Africa so may have bigger fan blades anyway. And maybe I'm just being paranoid :)

Saaaaf Aaafrica?

It's amazingly warm here in Reading, considering the rest of the country's under water - glad I live on a hill! (Going out with the camera this evening - the thames is supposed to peak here at about 9 tonight :D )

The 12 o'clock mark on the temp guage has a massive damped region in it - so you could be running a little hotter than normal and wouldnt notice.

I'd expect the clutch to be a little stiffer when stone cold because of the fluid inside - but not by much really. I'll go out and play with mine when I get home later and report back.

[whiskychaser]

it's important to warm up the car completely, then when you turn it off, you should feel a fair resistance when you try to turn the fan clutch.

it's really easy to see if it's working when the car is working, pop the hood, and simply rev the engine under the hood, and look at the fan...you will notice it's slipping instead of following the engine's rpms.
I just went and tried that. Revved the engine and the fan did seem to slip but did increase in speed. When I let the throttle go the fan kept turning at a faster rate for a few minutes then slowed down. Second time I tried it, it didnt slow down fully again but I will swear the speed of the fan varied over the 5 mins or so I watched it. When I switched off I could move the fan easily. The temp gauge stayed rock solid throughout

[whiskychaser]

Saaaaf Aaafrica?

It's amazingly warm here in Reading, considering the rest of the country's under water - glad I live on a hill! (Going out with the camera this evening - the thames is supposed to peak here at about 9 tonight :D )

The 12 o'clock mark on the temp guage has a massive damped region in it - so you could be running a little hotter than normal and wouldnt notice.

I'd expect the clutch to be a little stiffer when stone cold because of the fluid inside - but not by much really. I'll go out and play with mine when I get home later and report back.
Thanks ! S Africa? Yep. Its for aircon, full leather and a blind in the back window:) Make sure you got your camera on a string round your neck-with your luck you will drop it in the water:)

[filip00]

I just went and tried that. Revved the engine and the fan did seem to slip but did increase in speed. When I let the throttle go the fan kept turning at a faster rate for a few minutes then slowed down. Second time I tried it, it didnt slow down fully again but I will swear the speed of the fan varied over the 5 mins or so I watched it. When I switched off I could move the fan easily. The temp gauge stayed rock solid throughout

it's working fine then, isn't it? the problem is, when the car is hot, and you rev it up, it slips all the time......that's the problem...

i remember when my fan clutch failed, you could really feel the less wind blowing towards the windshield than it should blow.

[whiskychaser]

when the car is hot, and you rev it up, it slips all the time......that's the problem...

Now I get it! My fan does actually speed up when I rev the engine and there is a definite increase in the amount of air its blowing. I was concerned about the lack of resistance to turning when you stop the engine but I dont suppose that matters. Looks like its working OK. Thanks for clearing that up:)

[filip00]

glad i could help :)