Ian Vincent Posted November 11, 2016 Report Share Posted November 11, 2016 I was out in my TR3a yesterday and after returning it to the garage noticed that the electric fan was still operating. It turns out that the thermo switch has failed and is shorting to earth permanently. I have ordered a new switch from Moss but has anyone else had the same problem. Part of the fun of ordering the new switch was getting the correct temperature range. Up until it failed, I have been very happy with how the cooling system is operating, the engine warms up quickly and the fan only seems to come on in traffic. "Simples", I thought, buy another like the one I had. The only problem was that when I looked up the invoice for the original order back in 2010 it states: IM50090 - Thermoswitch for 88 - 79C And when I look at the current Moss catalogue it shows that part number as being for a 86 - 81C 'switch, and it's out of stock. So I ended up ordering IM50120 which is the current listing for the 88 to 79 deg C switch. Hopefully it will work as well as the old one did. Rgds Ian PS Considering the limited mileage that the car does, the original switch hasn't lasted very well. Quote Link to post Share on other sites
TriumphV8 Posted November 11, 2016 Report Share Posted November 11, 2016 It might help to put a relay between switch and fan to reduce the load on the switch. Anyway besides some additional work it can do no harm. Quote Link to post Share on other sites
Guest Posted November 11, 2016 Report Share Posted November 11, 2016 Good to read that in this case of faillure, the switch is 'on' providing cooling! M. Quote Link to post Share on other sites
stillp Posted November 11, 2016 Report Share Posted November 11, 2016 It might help to put a relay between switch and fan to reduce the load on the switch. Anyway besides some additional work it can do no harm. Adding a relay will add several more potential failure points! Pete Quote Link to post Share on other sites
Alec Pringle Posted November 11, 2016 Report Share Posted November 11, 2016 " but has anyone else had the same problem. " Damn right, as in just about every Kenlowe-equipped car I can recall owning over the past 50 years . . . . . Which is why I try and avoid Kenlowe. Cheers, Alec Quote Link to post Share on other sites
Ian Vincent Posted November 12, 2016 Author Report Share Posted November 12, 2016 " but has anyone else had the same problem. " Damn right, as in just about every Kenlowe-equipped car I can recall owning over the past 50 years . . . . . Which is why I try and avoid Kenlowe. Cheers, Alec It was the switch that failed not the fan. The switch was a stock item from Moss so I suspect it emanated from the PRC. Rgds Ian Quote Link to post Share on other sites
ChrisR-4A Posted November 12, 2016 Report Share Posted November 12, 2016 Doesn't the fan have its own relay in which case the thermoswitch should be on the low power activation side of the relay? Quote Link to post Share on other sites
Lebro Posted November 12, 2016 Report Share Posted November 12, 2016 I am assuming (always dangerous) that you had an "Otter switch" controlling your fan. All the Kenlow fans I have seen have had a variable controller which connects to the top hose via a capillary tube. Anyway, The Otter switches are usually pretty reliable, although I did have one fail on me a couple of years ago. I had replace my Revotec controller with an Otter switch when the former failed on me - causing the relay to chatter as soon as the cold engine was started. The first Otter switch failed in as much that it's operating temperature - which had been spot on previously - started to change so that the fan was coming on at much lower temperatures. The TR shop (where I bought it) sent me a new one, & that has been fine ever since. The one I use is rated at ON 92°C OFF 87°C I find this is just right, My car runs normally at around 183°F (sorry about the mixed units), & the fan stays off. In traffic it slowly rises (no mechanical fan) to around 195, the fan cuts in, & drops it down to around 185, then switches off. I think a relay in the circuit is a very good idea. Bob. Quote Link to post Share on other sites
Alec Pringle Posted November 12, 2016 Report Share Posted November 12, 2016 Hi Ian, I was referring to the standard issue Kenlowe switches, the originals that came with the fan. Cheers Alec Quote Link to post Share on other sites
stuart Posted November 12, 2016 Report Share Posted November 12, 2016 Nothing wrong with Kenlowes per se but the inline switches in the water pipes are often problematic and fail fairly regularly. Dont also be tempted with the newer Kenlowe type of switching that involves a thermocouple inserted between the fins of the rad. They dont last five minutes on a TR as they cant stand the vibrations. Stuart. Quote Link to post Share on other sites
Ian Vincent Posted November 12, 2016 Author Report Share Posted November 12, 2016 (edited) It was an in line switch in the water pipe that failed. It was fairly straightforward to replace and if I had been away from home it wouldn't have been a problem as I could just disconnect it and use the manual switch in the car instead. Picking up on Stuart's point it would seem to be not that unusual. Rgds Ian PS Bob, what is an Otter switch? Edited November 12, 2016 by Ian Vincent Quote Link to post Share on other sites
Lebro Posted November 13, 2016 Report Share Posted November 13, 2016 Ian. See this page from Moss catalogue, & Otter web page They work on the bi-metallic strip principal. http://www.moss-europe.co.uk/water-pipes-and-fan-switches.html http://www.ottercontrols.co.uk/y1-series.html Bob. Quote Link to post Share on other sites
Hamish Posted November 13, 2016 Report Share Posted November 13, 2016 (edited) Hi had that type of switch fail the day of the REDROSE august TR fest. It seemed to fail safe ie the fan on. I had to remove the fuse to turn it off. Easily fixed with new part tho. You learn something every day !! I thought an otter switch was the switch on a kettle - to make the water 'otter ...... (Sorry couldn't resist ????) Edited November 13, 2016 by Hamish Quote Link to post Share on other sites
stuart Posted November 13, 2016 Report Share Posted November 13, 2016 Jaguar Mk7/8/9/1/2 S type and Mk 10 electric choke is controlled by a switch in the water rail clearly marked "Otter" Stuart. Quote Link to post Share on other sites
Dic Doretti Posted November 15, 2016 Report Share Posted November 15, 2016 I had a switch fail recently and was told the electronic components could be damaged by interference from the coil and to keep the two as far apart as possible. This may be more applicable to electronic ignition coils. Cheers Richard Quote Link to post Share on other sites
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