fitting an electric fan to replace viscous

[solarman216]

Thoughts on a related issue:

I've had a Kenlow fan fitted in place of the normal fan for 3 years (3L auto). This was originally fitted because the viscous unit was faulty & it was much cheaper than buying & fitting a water pump/viscous unit.
However during the recent hot spell (LOL, 2 days at 25deg+ !) towing my 1.6t 'van the temperature gauge went round to 2/3rds for the first time ever. This occurred at 30/35mph, on a gradual long climb, so natural air flow was low but the electric fan quickly reduced it after selecting manual (maybe the temp. sensor has failed again?).

& my point is: Despite my use of the manual override after a towing session I have serious doubts regarding the cooling of the turbo prior to shutting off, & the oil cooler rad for the auto fluid, for that matter.

The original viscous fan would appear to me to be better at general engine cooling than is an electric, despite being less efficient with fuel. As my water pump will need changing soon (slight leak) I'm thinking of re-fitting the original fan (during the summer only......if we have one LOL) but removing it otherwise (& moving the electric fan to the front of the rad as a back-up). This will entail removing the aircon rad but that doesn’t work either LOL.

My main concern is the turbo & auto fluid temps, any thoughts?

There is no question that the water pump fan shifts far more air than electric ones, you only have to hear the roar when it is running, the problem is reliability, they are actually very reliable, and if they leak the viscous fluid this can not only be seen but the start up roar will not occur so you are, or should be aware of its failure, but if the small spindle in the middle gets seized, or the bi metal coil spring breaks or comes loose, you will have no warning, and there is no reliable way that I know of, of testing this part of the operation, other than visual check that all is in order, but to do this the rad has to come out for access, the only other issue as I see it is if your engine is working hard at low revs then the fan may not be drawing as much air as a twin electric set up, so as one that has experienced viscous failure when towing and wrecked a head, I would go for electric, at the moment both my motors retain the viscous but any hint of a problem they will go electric, Rick

 

[solarman216]

Micktheshead, having re read your post if the temp went so high then either your sensor has failed or it is in the wrong place, it should be in the bottom hose or on the lower part of the rad, the fact the temp came down when you over rode it testifies to the effectiveness of your fans, and if after a long hard tow you let it idle for a couple of mins with your fans on you will benefit your turbo and the auto box, Rick

 

[Madmark]

Battery don't run the viscous it's mechanical.

Yeah rather than put a electric fan in ill just replace the viscous as my battery has enough to do. 2led light bars. Heated seats. Sound system. Let alone the normal running. Not so bad this time of year but come winter months in sure the battery won't wanna run anything more lol

 

[solarman216]

Yeah rather than put a electric fan in ill just replace the viscous as my battery has enough to do. 2led light bars. Heated seats. Sound system. Let alone the normal running. Not so bad this time of year but come winter months in sure the battery won't wanna run anything more lol

electric fans cos they do not come on often pull very little from your alternator, your battery is only there to start the motor, and in the winter are much less likely to do so, Rick

 

[elty001]

As rick says they don't kick in that much.
I had the override more for when off road at low speeds and hard engine work.
Tbh I never really needed it though.
I just thought I would give it a try more for squeezing a few more mpg out of the old thing.

 

[micktheshed]

Micktheshead, having re read your post if the temp went so high then either your sensor has failed or it is in the wrong place, it should be in the bottom hose or on the lower part of the rad, the fact the temp came down when you over rode it testifies to the effectiveness of your fans, and if after a long hard tow you let it idle for a couple of mins with your fans on you will benefit your turbo and the auto box, Rick

Good news: Kenlow are replacing the auto switch assy & sensor for free.
Bad news: this is the second time in 3 years, first one put fan on permanently after 18 months use, this one no longer puts fan on at all.
Good news: replacement is of a 'more basic & more reliable' type. I certainly hope so. Considering the few times the fan has needed to be on this does not bode well.
Have now become somewhat paranoid watching temp. gauge as it either reads 1/3 (normal) or moves suddenly when temp. has reached danger level. It dosen't serve any real purpose, IMHO, as the reading is not linear or remotely accurate (in common with the +20% speado. & poor quality oil pressure sensors etc.). A true 'operator pacifying gauge' if ever there was one. I'm used to instruments that actually read correctly.

Sensor is fitted through rad. near top hose: as per Kenlow's instructions.

Still think re-installing the viscous fan (only for the summer towing season) is the best way. But what a cost......!

I'm in the habit of opening the bonnet after a long tow, to cool things down before switching off. Comes from using wing-mounted towing mirrors years ago, then realising that the (petrol) car started better afterwards (fuel was maybe boiling off?). I think it's beneficial to the head gasket's life also. In any case it can't do any harm though I do get some funny looks & comments LOL.

 

[solarman216]

Sensor is fitted through rad. near top hose: as per Kenlow's instructions.

Still think re-installing the viscous fan (only for the summer towing season) is the best way. But what a cost......!

I'm in the habit of opening the bonnet after a long tow, to cool things down before switching off. .

Fitting the sensor near the top of the rad is so so wrong, it will require a very small hysteresis stat that has to react quickly, ie a rise of 5 C must switch instantly, this leads to a high tech expensive unit, that is in the harsh car environment likely to fail, if it is situated around halfway down the rad and set correctly you will be looking at a much greater hysteresis of around 15-20 C and at a lower temperature, so if there is any kind of delay there is much less margin for going over temp, on my off roader I use a capillary tube stat set at about 10 C above the normal RETURN temp on the return pipe in the engine bay, return pipe is normally cool to the touch, it rarely brings the fans on full, (they are running slow just to take away residual heat as they are in the rear door so do not get normal airflow).

Re opening the bonnet, madness, just use your over ride switch for 2 mins before shutting of your engine, and it will be normal idle temp and so will your turbo, Rick

 

[micktheshed]

Just received new switch assy. from Kenlow (give them some credit for rapid 24 hr. supply). This one is of the older type that I had fitted to a Viva about 30 years ago. I only hope the new one is as reliable as that was.
Instructions state sensor is to be fitted into the top hose. I have to assume they know what they're on about.

Still intend re-fitting viscous fan for next years 'summer' towing use. After 2 failiers I have lost faith in sensor operated switches.

Will also continue to raise bonnet after a long run (been doing it too long to stop now!) if only because I enjoy the puzzled looks on peoples' faces LOL.

 

[AlexD333]

I guess even with this manual override it will never compare to the viscous fan as it's running all the time and is already stronger.. I suggest just replacing it and!! Keeping the electric fan too :sly

 

[solarman216]

I guess even with this manual override it will never compare to the viscous fan as it's running all the time and is already stronger.. I suggest just replacing it and!! Keeping the electric fan too :sly

Ignore this post as on Alexis own admission knows nothing about mechanic's, Rick

 

[elty001]

Just received new switch assy. from Kenlow (give them some credit for rapid 24 hr. supply). This one is of the older type that I had fitted to a Viva about 30 years ago. I only hope the new one is as reliable as that was.
Instructions state sensor is to be fitted into the top hose. I have to assume they know what they're on about.

Still intend re-fitting viscous fan for next years 'summer' towing use. After 2 failiers I have lost faith in sensor operated switches.

Will also continue to raise bonnet after a long run (been doing it too long to stop now!) if only because I enjoy the puzzled looks on peoples' faces LOL.

The unit I bought also said to fit the sensor into the top radiator hose .
As for having your bonnet up just tell people you don't want to feel left out as all the landrover owners seem to do it all the time :lol

 

[solarman216]

The unit I bought also said to fit the sensor into the top radiator hose .

Absolute rubbish, what on earth are these people on about, the top hose is regulated at thermostat temperature (say 88 C) so a stat with a hysteresis of 5 deg C should cut in at 93 C but by the time 93 is seen at the top hose the bottom hose will be at around 80 C cos this will be the reason for the 93 at the top, so if the fans are a little delayed a few seconds off hard driving will push it over the limits, total rubbish, now if you look at a properly operating viscous fan as the rad heats up lower down the hotter air drawn in by the idling fan kicks the fan into full speed, so lower down rad temp is the trigger, I rest my case, Rick

 

[elty001]

The unit I had was adjustable so you could set it to come in at what ever temp You wanted.
I set mine to come on went temp gauge read halfway.

 

[micktheshed]

The unit I bought also said to fit the sensor into the top radiator hose .
As for having your bonnet up just tell people you don't want to feel left out as all the landrover owners seem to do it all the time :lol

Kenlow have always (1st one fitted 1975!) specified top hose. What do I know to tell them different?

You've got a point there! Daughters Disco always seems to have something (expensive) wrong with it.