Electric fan controller

[tomlongley]

I am looking to replace the defunct Kenlowe thermostat with a "variable electric fan control" from Europa Spares, or similar. I don't have access to the car right now, otherwise I'd go and check, but could someone tell me the internal diameter of the radiator's top hose?

Thank's in advance.

Tom

[eightofthem (Andy)]

Hi tom internal diameter is 35 mm external is 44.5mm

[tomlongley]

Thanks for your reply; that is the information I needed. I will go right ahead and order the part.

Many thanks,

Tom

[Smallfry]

A sensor for an electric fan is better off in the BOTTOM hose (or tank)

That way it is better at controlling a more consistant temperature without over cooling, which is bad for performance, and more importantly, engine wear

[tomlongley]

Thanks, Smallfry. I did not know that.

Regards,

Tom

[Welsh Warlock]

Tom,
may I suggest that instead of using the Kelowe item again, which in my opinion is ugly, unsightly and can give problems when the balloon that gous into the top hose fractures, that you have a look at the one from the MG Owners club that fits into the top hose (or you could put it in the bottom hose).

To fit it you simply cut the main hose and connect it either end of the thermostatic switch. There are a couple of wires and relay included. There is a miniature setting control hidden under a cover.

I had a quick look for the link on th MGOC site but I'm short of time right now and was unable to locate it.

Edited to add: Mine looks like this

Available from www.burtonpower.com/product_main.aspx?dets_product.aspx?PGrp=07012&PSet=98

[enigmas]

Not trying to confuse the issue too much, but what you really need to do is control the inlet temperature of the water to the engine block, i.e. fit a thermostat into the bottom hose controlled by a bypass hose feeding hot coolant over the thermostat capsule. In this manner metered quantities of coolant enter the bottom of the block reducing thermal shock and also ensuring a more even block temperature without the fluctuations evident in top mounted thermostats.

Here's an old link:
roverp5.proboards31.com/index.cgi?action=display&board=rover12&thread=2198&page=3

[Deleted]

I use the same controller as pictured above, nice bit of kit. mine is in the top hose but I think it may be better in the bottom hose, and I will probably put it there on my next hose replacement cycle.
Interestingly, I fitted this to a pretty new looking top hose, and it had a huge split in it i think hoses are pretty much annual replacement iitems now.

Ian

[Smallfry]

Mar 3, 2009 13:18:32 GMT enigmas said:

Not trying to confuse the issue too much, but what you really need to do is control the inlet temperature of the water to the engine block, i.e. fit a thermostat into the bottom hose controlled by a bypass hose feeding hot coolant over the thermostat capsule. In this manner metered quantities of coolant enter the bottom of the block reducing thermal shock and also ensuring a more even block tempratiure without the fluctuations evident in top mounted thermostats.

Its what I said !

Most modern cars have this type of system as it gives a more consistant temperature, which is good for the oil, and for economy and wear and tear.

Without blinding with science (I would get a headache anyway) think of it this way.................If the sensor is in the thermostat housing or the top hose, and it senses an overheat, it will turn on the fan/s and cool the water irrespective of the outside conditions.............not too bad on a hot summers day, but imagine the outside air temperature is minus 40 C (not likely but to illustate the point) the engine is going to get a mighty big thermal shock which will overcool the oil (not good) could cause head gasket failure, or to really extreme a cracked block or head/s.

Imagine being plunged into an ice cold bath ?

With the sensor in the bottom tank or hose, it senses that the "radiator is not coping" but only turns on the fan/s until the coolant ENTERING the engine is normal temperature. This keeps the whole engine and its oil at a much more consistant temperature which is much better all round. The only difference YOU will notice, is that the fan will stay on a bit longer, but your engine will thank you for it.

[Smallfry]

Mar 3, 2009 19:19:32 GMT @59fan said:

Interestingly, I fitted this to a pretty new looking top hose, and it had a huge split in it i think hoses are pretty much annual replacement iitems now.

Ian

A lot of modern replacement hoses for old/classic cars are what they call "Kevlar reinforced". Intead of the old fashioned fabric reinforcement, they have Kevlar fibres mixed in with the molten/liquid rubber. They are utter, utter rubbish. Make sure you get fabric reinforced ones. They will last years. You can tell by looking at the end of the hose. If you can see three distinct layers, then it is fabric reinforced. If it looks one piece and is soft and shiny, it will be Kevlar reinforced.............as you say, they only last about a year, and are prone to failure on the road.

Interestingly, I don't THINK you will find kevlar hoses on ANY new production car..............................

[tomlongley]

Thanks people, for all the replies.

I am relieved to be able to tell you that the replacement thermostat is not a Kenlowe model but is in fact the exact same one as in Smallfry's photograph (thanks for that). I obtained it from Europa Spares and it appears to be a good quality piece of kit. (The Kenlowe one has been consigned to the dustbin).

I have to confess that at the moment it is fitted in the top hose but I will move it to the bottom hose when I come to replace the hoses.

Regards,

Tom

[Welsh Warlock]

Mar 4, 2009 17:45:05 GMT tomlongley said:

......same one as in Smallfry's photograph (thanks for that). .......

Ahem :cough:

[tomlongley]

Oh yes, sorry, (doh!) it was indeed your post, eastmidsrep, so the thanks do in fact go to you.

And thanks of course, too, to all who responded.

Regards,

Tom

[enigmas]

Smallfry, You may find this of interest? Coolant needs to be controlled through a metering process. Switching the fan on or off at this point (bottom hose) does little to control the coolant inlet temperature to the block, as the process of heat exchange lags well behind the flow and volume of coolant that would pass into the block before the top mounted thermostat could react to the change in coolant temperature. Coolant needs to be held or processed through the radiator tubes for a given time for a heat exchange to occur. Too fast or too erratic leads to thermal shock within the engine block.

A bottom mounted thermostat (not thermo switch) designed with a bypass circuit feeding heated coolant (from the cyl heads) over the thermostat capsule reacts continuously to coolant temperature change and will effectively totally lock out/isolate the coolant in the radiator from entering the block at very low temperatures. It will also stabilise the temperature within the block more effectively...leading to more uniform combustion if other things are set up precisely.