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MG MGB GT V8 Factory Originals Technical - V8 electric fan thermostatic switch

Does anyone know where I can get hold of a replacement thermostatic fan switch for a standard MGB GT V8 ? Can't seem to find anybody that does one.

Many Thanks, Tony Hobbs
Tony Hobbs

Tony,
Try Burlen Fuel Systems in Salisbury, the company that is making all the SU carb parts. They have a direct replacement for the original thermo switch. I bought one last year, but have not installed it yet (car is undergoing full restoration).

The only problem with the switch is that it doesn't say "Otter" on it!

Cheers,
Paul Kile
1974 Factory MGB-GT V-8 (Teal Blue 889)
Paul Kile

Thanks Paul

I contacted Burlen Fuel Systems and they can provide the part.

I owe you one.

If anyone else is interested, contact details are:

Burlen Fuel Systems, Castle Street, Salisbury, UK.
07000 287536
Part no BHA 5252 £26.64 + VAT.

Thanks again,
Tony Hobbs
Tony Hobbs

Clive Wheatley now has them as well, but dearer than Burlen.

Incidentally 1: These remanufactured items use a thermistor instead of a bi-metal strip, but that looks like an original part number. Shouldn't have that unless it is either OE or manufactured to the OE spec and approved by Rover.

Incidentally 2: These items have a lower switch-on point than the original MG item which is no bad thing. Also be aware that the Rover P6 item which is physically identical (but has a different part No.) has a *higher* switch-on point than the MG item, which is not good.

PaulH.
Paul Hunt

Paul H.,

I'm not sure if the Burlen part actually carries the BL part number, or whether the packaging said "SU part number XXXX - to suit BHA 5252" or some such. Unfortunately, I installed the switch a couple of weeks ago in the engine and have thrown away the packaging.

If what I recall is correct, then Burlen has gotten around the Rover part number issue by not actually stamping their unit with the BL part #.

Hmmm....thermistor type switch....sounds less reliable than a good old bimetallic strip. I should probably lay in a spare for the touring kit, although I can get around it with the bypass switch I am installing under the dash.

By the way, I am off to Hawaii with my wife for two weeks, and won't be able to work on the car during that time - I'm already anticipating withdrawal symptoms!

Cheers,
Paul K.
Paul Kile

Those V8 thermostatic switches are fixable guys, try opening one. I believe David Smith wrote a note about it a while ago.
robert pulleyblank

Paul,
>>>>'and have thrown away the packaging. '
that'll teach you - I thought we agreed the other weekend that one could make a good case for never throwing anything away !
Bob and others - modesty prevents me claiming any knowledge of the innards of the Otter switch - I merely reproduced a 15-year old Technical note from the MGCC V8 Register for a couple of guys that were interested.
David Smith

Touche', David!! Although one has to draw the line somewhere.

Awhile back I looked into an unmarked box high on one of my shelves (can't understand why it was unmarked - you've seen my garage!) and what should I find but all of the original packaging for all the parts used in my MGA engine rebuild from 1993. No parts, just the packaging. Of course I relinquished the MGA in 1998, so all this was useless. I dumped it all into the trash bin, but felt a slight uneasiness as I did so - what if I should need to reference the stuff someday...?

Time to commit me to the Home for the Incurably Anal.

Cheers,
Paul Kile

Paul Kile

Paul,
ROFL !
David Smith

Paul - the original part did not carry a BL part No. as it is a proprietary item owned by Otter. Otter are still in business, last I heard, but wanted an order for 5000 switches before they would make any. Burlen (or whoever) have got round the patent by using a thermistor instead of the bi-metal contact as the OE part does, although I have also been told that a Patent runs out after 15 years anyway. One of the MG magazines some years back had an article describing the difference between 'OE', 'remanufactured', 'copy', 'passing-off', 'fake' and so on and said that it was illegal for a parts supplier to use the OE part No. in their own parts lists if it was not an OE or OE approved item, but should prefix it with a character of their own, likewise any part Nos. on the item itself or its packaging. An old Moss Europe parts catalogue I have does precisely this. Some years ago I nearly bought some rear springs from a very well known supplier in the Midlands, they were listed and stencilled with the OE part No., but I noticed they didn't have any interleaving. When I queried it they sheepishly admitted they were copies, or in this case, fakes. Caveat Emptor.

PaulH.
Paul Hunt

Having received and fitted the Burlen unit I pass on the following.

Since installing it I note that the switch-on point is noticeably lower than the lower white dot on the dial, and the switch-off point is closer to the switch-on than with the Otter. My old Otter had drifted noticeably above the upper dot and was flickering the relay, hence the replacement. Robert P has said before that they are openable and cleanable, but I didn't want to risk wrecking the switch on my daily driver without a replacement.

The new switch maintains a lower temperature (and slightly higher idling oil pressure), and the fans come on more frequently for a shorter period when going from moving traffic to stationary traffic than before. So far so good.

However the different internals (thermistor as opposed to bi-metal strip) seem to have a drawback in that if I switch off a hot engine, let it cool to below the switch-on point, and switch on again the fans start up and keep running until I start moving. What is worse is that if I do this in traffic the fans lower the temp until the needle is touching the N but keep running until I finally start moving. I suspect that the thermistor is operating to the heat of the spade terminal, which when stationary will be pretty hot.

Clive Wheatley is *cheaper* than Burlen (even though he buys his from them). Clive always quotes prices *including* VAT whereas Burlen (and many others) don't.

The switch came with an invoice for product code BHA 5252 i.e. the original BL part No. The SU bag containing the switch has a sticker on it with 'BHA 5252 Fan Switch' and 'GRN:80081'. The bag contains a slip of paper (and switch and gasket) titled 'Otter type switch', 'BHA 5252' and 'C18559'.

The pukka Otter switch has the following reverse-moulded into the central plastic part 'Otter Buxton England Patented' on one side of the spade and 'V60' below it. The replacement switch is plain. My Otter also has the spade positioned such that one face is directly in line with the nearest fixing hole, whereas the replacement has the spade pointing nowhere in particular (I'll be looking out for that, PaulK).

PaulH.
Paul Hunt

Good info on the switch, Paul H. Now does anyone out there have an original Otter switch I can get for those Concours events?

Cheers,
Paul Kile
Paul Kile

Having seen the innards of an Otter, and if the new switch contains a wire-ended component, I can imagine being able to remove the old bi-metal strip (if it is beyond repair) and solder the new innards to the Otter. Of course, you could end up with two scrap switches.

I'll see if Clive has an old Otter lying around.

PaulH.
Paul Hunt

This thread was discussed between 02/05/2000 and 24/05/2000

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