Electric fan turn on / off sensor switch issue

[dursleyman]

Just for information, this is the Revotec fan controller in my car.

[UKPhilTR7]

Looks nice but my main question is how would I retro fit that into my kenlow fan? What connections / wires do you get with it as I cannot see from the standard picture.

Also on my system now I have a manual override switch. Can the revotec system have a manual switch added?

[sonscar]

It uses a relay to switch the fan as the fan draws a fair current.Earthing the relay control earth via a separate switch overrides the thermostatic control and operates the fan.Google relay wiring if you are unsure.Steve..

[busheytrader]

It looks like the Rovotec item has a variable range that starts at 90c.

Id rather have one of those than my existing unit. It has one of those capillary probes that fits in to the top hose under the hose clip. It takes a while to get a 100% seal

I had to replace the radiator hoses and of course had trouble again getting a 100% seal around the capillary probe. On eBay I found some stuff described as "Marine Silicone Fire rubber high temp Pyrosil tape", wrapped it several times around the top hose inlet on the radiator and got a watertight seal first time around. It has enough give in it to accept the contour of the tube and hopefully being silicone it won't degrade.

Might help someone having the same issues.

[dursleyman]

I had the dreaded drip problem from the capilliary as well. Kenlowe did send me a couple of the new red "saddle" pieces that act as the seal in the top hose free of charge, but I was never entirely happy with it so changed to a Revotec unit which has proved an excellent piece of kit.

[simps]

@bushey... did you wind the tape around the outlet and put the tube on top or vice verse?

TIA

S

[busheytrader]

I wound the tape several times around the radiator pipe outlet (behind the swage line). It was probably about 1.5 - 2.0mm thick after I'd finished. It enabled the capillary tube to bed into it when the clip was tightened.

[simps]

Excellent, thanks, I’ll give it a go!

[Hasbeen]

I have 2, 16" fans in the 8, thermostatically controlled by the probe in the top radiator hose, one behind the radiator for engine cooling & one infront of the air conditioning condenser.

These work perfectly since fitted the new Haltech computer to control both ignition & mixture. It was always lean mixture at low revvs that caused overheating in the 4.6L Rover, it just took 4 years for us to learn that. I can now drive in stop start bumper to bumper traffic on 100F days in the comfort of my air conditioning, with a cool engine.

I had only one new problem. Although the engine cooling fan rarely ran in normal driving, after a stop say for petrol, the heat sink from the engine, would be enough to trigger both fans when wanting to start again. As the fans combined drew 35 amps, there was not enough capacity left to start the high compression 4.6L V8.

To over come this I fitted a cut out switch to isolate both fans. To avoid the possibility of some old goat turning the fans off, & not turning them on again, this is a spring loaded normally on, press to disconnect button. Other than fitting the air conditioning to the 7, this is the best thing have ever done.

Hasbeen

[busheytrader]

I like the idea of the cut out switch being spring loaded

[John_C]

I too changed to a Revotec sensor. But I did get around the Kenlowe drip, drip, drip for years by strapping the sensor to the outside of the top hose and adjusting the cut in/cut off point accordingly. This does work with the one side effect that after the engine has been turned off from operating temperature the sensor will respond to the underbonnet heat when the ignition is activated again within about half an hour. After about half a minute the fan goes off though so it's not a problem at all.

I have the Revotec sensor connected to the Kenlowe manual override switch too so nothing has really changed other than no more drip, drip, drip.

[saabfast]

I fitted an electric fan with capillary sensor some 10 years ago, can't remember the brand. I just used some sealant around the thin capillary line where it entered the hose and tightened up. Never had a leak since.

[skertonman]

Mine also has a Revotec fan conversion, but mine's worked from a sensor in the top of the Rad by the top hose connector. This sensor appears to be a factory fit type affair, proper bracket and rubber seal.

It's also wired in with a manual over ride switch fitted under the dash with a tell tale warning light to let me know when the fan is running, there is a fused relay in the wiring.

Fan seems to kick in when the temp gauge is on the 3/4 hot segment on the dash gauge, but couldn't tell you what precise temp it kicks in or out at.

Should I be worried

[Beans]

When I got my first TR7 many moons ago it was fitted with an electric fan.
It too would kick in around the ¾ mark and switch of around the ¼ mark.
It didn't take long before the head gasket blew.

I then retro fitted the original set up with the visco coupling and never looked back.
The temperature remains steady on the scale on both my cars (between ¼ and ½ of the scale).

I will probably fit an electronic fan to 't Kreng somewhere in the future ...
But it will be fitted with two sensors to keep the temperature at a constant level

[Hasbeen]

1 was a bit surprised to find, when checked my records, that 1 fitted the new engine to the 7 just a few days over 7 years ago. 1 fitted a new viscos fan & radiator as part of the mechanical overhaul. That system has worked beautifully ever since, allowing me to run the air conditioning, no matter how hot our summer may get, with out the needle ever getting above the quarter mark.

Hasbeen