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(13 May 2021, 17:25)Chris Williams Wrote: To be fair and the purist will hate it. I detest the OE fan switch with a passion despite my love of all things BL. IMHO best thing you can do is throw it away and replace it with the one in part developed by our own ChrisP now sold on D-Go.
But as mentioned above you need to find out why they are on all the time. Most likely is the wires have been bridged at the otterstat (as mentioned bottom pic) Remember the fans will be on if your A/C is on and working.
Very, very unlikely to be the thermistor at fault, they are a non failure part. The temp sender is on the R/H cylinder head (looking from the rear) right at the back/inner side of the valley. The connection has been known to come off. It's really difficult to see from above. Picture attached.
Sometimes the gauge (or more likely) the printed circuit board at the back may have failed.
Lol! Having bought a car in the 'wrong' colour, I guess it's too late for me to be a purist now!
Thanks for the pics, that's really helpful. Always much easier to know what you're looking for if one has a piccie for reference!
Cheers!
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Otterstat failure..?
I think I posted about this somewhere earlier. My fans are constantly 'on' from key on.
Someone suggested that some previous owner may have simply shorted across the otterstat as a crude fix.
I had a look. That's not seemingly the case, but testing the otterstat with my trusty multimeter (cold), there is a zero ohm reading across the terminals (with the wires disconnected).
To my mind, that's a failure - if I understand this correctly, the otterstat should be 'open circuit' when cold, then close the circuit when at the 'correct' high temperature. So, closed circuit (no resistance) across the otterstat terminals when cold means otterstat failure.
Anyone care to confirm (or deny!) that this is the (or a) usual failure mode of the otterstat..?
Just checking!
Thanks all,
Ivan.
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I'll take a look at mine, hang on....
Richard Hanlon
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ps: many thanks for previous answers to my temp gauge problem.
Amusingly, I found a couple of threads which suggested the old 'wriggle a bit of wire through the gap round the reset button in the instrument panel and touch the needle, it might move it round and get it going again' technique..
Nothing to lose, thinks I - lo and behold, I now appear to have a working temperature gauge!
:-D
Still need just to check it's properly reading a correct temperature, but it's certainly better than just pointing straight down and not moving at all!
(24 Jun 2021, 17:50)Rich Hanlon Wrote: I'll take a look at mine, hang on....
Ooh, thank you!
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Quote:My fans are constantly 'on' from key on.
IIRC that also happens if your A/C is switched on so may be worth checking that's off (or I could have made this up)
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(24 Jun 2021, 18:15)Chris Williams Wrote: Quote:My fans are constantly 'on' from key on.
IIRC that also happens if your A/C is switched on so may be worth checking that's off (or I could have made this up)
Thanks, Chris - A/C off on switch-on. Or the dial is set to 'off' at least, so hopefully that's what it means! If A/C is on anyway, that's a whole new set of investigations!! :-D
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(24 Jun 2021, 17:51)lordivanhoe Wrote: ps: many thanks for previous answers to my temp gauge problem.
Amusingly, I found a couple of threads which suggested the old 'wriggle a bit of wire through the gap round the reset button in the instrument panel and touch the needle, it might move it round and get it going again' technique..
Nothing to lose, thinks I - lo and behold, I now appear to have a working temperature gauge!
:-D
Still need just to check it's properly reading a correct temperature, but it's certainly better than just pointing straight down and not moving at all!
(24 Jun 2021, 17:50)Rich Hanlon Wrote: I'll take a look at mine, hang on....
Ooh, thank you!
I have several spares but no means of testing them - just discovered I'd left my multimeter switched on. Totally flat and takes weird batteries. Can send you a spare for cost of postage though? They were known good when I stashed them!
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On another thought...... if the A/C is off then the fans should not run if cold so it would not harm to have them plugged in or not to the otterstat. It's not un-common for owners to wire in a by-pass switch to over-ride the otterstat in case of failure or to keep the temp down. Often this is done by running an extra cable to each otterstat connector so would be worth looking at that, or may have been wired in somewhere else or may be something else!
Chris
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One thing you DEFINITELY need is a working temperature gauge.....don't leave the garage before that is fixed!!
I speak from long experience.......my latest one was last night at 19.40.
I was stranded for 5 hours ( waiting for the AA ....who never arrived) , ETA 8.45.....they finally arrived at 23.45, by which time I'd hired a tow truck!!). Unfortunately I'd not spotted that my alternator had moved....loosening the fan belt completely....hence overheating. The engine was so hot, I just didn't notice that the fan belt....which was obviously still in position and not broken..was very very loose. 
I think Chris W had previously recommended the new screw-in otterstat switch, from D-Go...I helped develop that after my old one blew out....and left me stranded .....AGAIN!
If you really BOIL these engines..it will wreck them.
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(24 Jun 2021, 17:48)lordivanhoe Wrote: Otterstat failure..?
I think I posted about this somewhere earlier. My fans are constantly 'on' from key on.
Someone suggested that some previous owner may have simply shorted across the otterstat as a crude fix.
I had a look. That's not seemingly the case, but testing the otterstat with my trusty multimeter (cold), there is a zero ohm reading across the terminals (with the wires disconnected).
To my mind, that's a failure - if I understand this correctly, the otterstat should be 'open circuit' when cold, then close the circuit when at the 'correct' high temperature. So, closed circuit (no resistance) across the otterstat terminals when cold means otterstat failure.
Anyone care to confirm (or deny!) that this is the (or a) usual failure mode of the otterstat..?
Just checking!
Thanks all,
Ivan.
A good Otterstat should be open circuit when cold (no ohms) and very low to no ohms at all when hot. If yours is cold, but giving conductivity between the terminals with next to no ohms, and definitely not open circuit, then i'd say it's goosed and needs replacing.
Unless you want to update to a screw in type like Chris P suggests (needs a new pipe section to accommodate) then this is the replacement type you want. https://www.ebay.co.uk/itm/334016480982?...SwwyJgr3EC
Rissy
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All;
Thanks very much for all the info and suggestions.
I'm deffo in the camp of wanting to know temperature at all times, I've had my fill of overheating problems with older cars in my time!! 
So - I'd already ordered a new otterstat from DGo, on the basis that even if I didn't need it now it'd be useful to keep in reserve - I assume that'll do the job. I'll plan to upgrade to the screw-in version with pipe at next service, I think - which might also be the time at which I renew all the old rubber pipes anyway. Long term update/upgrade list an' all that..!! 
I will also fit a fan override switch in the meantime, though (and to use up my 'spare' console button!).
Additionally, for now, I've decided to add a couple of extra in-line temp sensors to my system*, which I'll run to a couple of digital gauges in the cab, just for additional readings/security and so I can see what's happening in the system. If she consistently runs well I can always then disconnect the additional gauges and hide the wires away in due course. Until then I should be able to keep an eye on things. 
(I really, really don't want to overheat. Chris P, so sorry to hear of your incident!  ).
I'll keep y'all posted and maybe see if I can work out how to get some pics on here when I'm done!
Cheers!
Ivan.
*one in the feed pipe to the pump, one in the pipe from the thermostat.. should enable me to spot when the thermostat opens, too, I hope..!
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