Classic cars forum & vehicle restoration.

[Miken]

I removed the fan from my A40 truck and have been driving around for the last week without it.
It is now noticeably quieter in the 50-55mph range which I like (strangely it's made no difference in the 40-50 range which is what I wanted).
So now I want to keep it like this and fit an electric fan. There is loads of space in front of the radiator.
There are lots on eBay at surprisingly cheap prices.
Any recommendations or advice on what to look for when choosing?
Thanks

[Ray White]

I had a problem with my original fan so opted for an electric one. I searched for one that would fit my TC and eventually bought an Aeroline from Bad Boy Classics. You can fit it either behind or in front of the radiator to suit your needs and will run on either positive or negative earth.

I can't vouch for it's efficiency as I haven't got the engine running yet but what I can say is that I had no problems fitting it and BB classics were helpful.

[Miken]

Thanks Ray,
Is it best to buy the biggest one that will fit the radiator?
Or maybe smaller so as not to obstruct it so much when it's not running?

[Ray White]

[Miken]

I shall do as you suggest and give BBC A call tomorrow.
But thinking about it, my original 13" metal 2 blade fan is adequate so fitting a larger diameter more efficient multi blade device is surely going to be unesseasry. I would think a slightly smaller unit would sufffice.
They do a 12" and a 9" . Maybe the 12" would suffice to be on the safe side.
I will see what they say.

[Bitumen Boy]

I think it's a pretty safe bet that the electric fan will be turning a lot faster and moving a deal more air when you actually need it than the mechanical fan ever will. Something else to think about...

[MikeEdwards]

I've recently bought a small electric fan for my Sportshatch, but I only intend to use it as a supplementary fan to help out when necessary, so I'm leaving it manually controlled. Unfortunately the gap in the front panel and around that end of the nosecone means that a 7" fan is as big as I can fit, and even then I'll have to cut the frame down a little bit. If I was prepared to get rid of the standard viscous fan I could fit it behind and use a bigger one, but I'd prefer not to.

Hopefully it will do the job, though - I went to one show last year where it seemed like they were having a 2 minute conversation with every car in the queue in front of me (why do classic show organisers think it's a good idea to hold up a load of old cars on a hot day?) and the gauge was getting a little too high for my liking.
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1976 Vauxhall HP Firenza, 1976 Vauxhall Sportshatch (x2), 1986 Audi coupe quattro, 2000 Audi TT

[badhuis]

In the first 17 or so years in my possession, one always needed to keep an eye on the temp gauge in my TR4. It would touch the red in heavy traffic and hills though it never really overheated. Tried the usual suspects, changed the radiator core into one with an extra row, upgraded water pump, bellow type of thermostat, made sure the cowling in front of the radiator was such that air had to go through the radiator instead of passing by the sides, ignition timing correct. Even fitted a front electric fan with manual override switch. This electric fan was needed more and more. I wanted to make a trip into the Alps in mid summer and feared overheating, so I took the decision to remove the mechanical fan. Fitted a large electric fan behind the radiator which switches on automatically.
Although I am all in favour in keeping cars as original as possible, this was possible the best upgrade I have done for the car. Never fear of overheating anymore, even with high temps and heavy traffic or mountains.

British cars in my opinion usually have a very frugal cooling system. It works but only if all components are 100%, there is almost no margin. In the record hot summers we have in the last few years, combined with heavier traffic, the standard cooling system has a very difficult task to keep the engine cool.
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a car stops being fun when it becomes an investment

[Miken]

I rang BBC but they didn't really know what size I need, they just said measure the radiator and buy one that fits(whatever that means).
Anyway, I've bought a 12" diameter kit with thermostat switch.

When I rebuilt my engine the other year I spent several days digging out cruddy debris from the water gallery and I fitted a radiator with an extra row.
I fitted a digital temperature gauge to the cylinder head. The head temperature rarely goes over 80 degrees. Maybe 82 on a long incline in the summer. So I doubt my electric fan is going to get much use.

[Ray White]

[alastairq]

Has consideration been given to the amount of electricity the fan will need when running?
Will the charging circuit be up to the task?

The biggest heat issue will stem from today's petrol.
It will affect old engine designs by increasing the temperature of the exhaust.

[This leads to the commonplace, today, hot-start problem]
There is an issue recognised that, with an old-design of engine, sat in a traffic jam, cooking..that an electric fan will suck cool air from outside, through the hot radiator, and blast it all over the already sweating engine.

It has been suggested [by the MG expert,I've quoted before]...that an electric fan could have a DPDT switch so that, in the event of being stuck in a jam, the fan direction could be reversed, to suck the hot engine bay air outwards, for the duration?

Not sure how the car in front would take to having hot oily stinky air blown in via their sunroof, however?

The fan size should really match the radiator core dimensions. Or, near enough.

Shrouding is important as well.
Personally, I 'd also be looking at electric water pumps for the cooling system as well.
This allows the coolant to continue to be circulated at a better rate than the engine water pump can achieve at tickover.
Also allows the coolant to continue circulating after the engine has been turned off.

MAny modern cars have small pumps to achieve this, so it must be a recognised issue in today's road environetmn?
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Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[Penman]

Ray
It's the toppin up from the streams that does it cobber.

Incidentally, I notice a some of us appear to be still on BST, including me.
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Bristols should always come in pairs.

Any 2 from:-
Straight 6
V8 V10

[alastairq]

[Miken]

[Ray White]

How I see it fitting an electric fan is a win win. There are several disadvantages with a mechanical fan; firstly, the fan is pulling in cold air when the engine is cold thus slowing the warm up time.

Secondly, the fan will be running relative to engine speed so when driving flat out it is pulling air through the rad when the force of the air alone is enough to cool the engine... so a fan is just a waste of power.

Perhaps the most obvious down side to a mechanical fan is when the car is moving slowly or stationary in traffic. Then the fan is not running fast enough to cool the engine and it can overheat.

If you fit an electric fan it is thermostatically controlled so will only operate when needed and will keep the temperature within a pre determined range best suited to the engine regardless of driving speed and conditions. By eliminating the energy sapping fan belt your engine should become more efficient and save fuel.

Then there is the fact that most electric fans can either push or pull air through the radiator and do so at a far greater volume than a mechanical fan.

Then there are safety considerations. I don't know how may deaths or serious injuries have been caused by a broken metal blade.

The big debate, however, is where best to fit the temperature sender. Most say fit in the top hose... but there is an argument for fitting in the bottom hose.

The top of the radiator is obviously the hottest point but what I have read is that it is the temperature of the cooling water that is more useful. The reasoning is that the water temperature in a non pressurised system cannot exceed 100 degrees before it boils so knowing the temperature of the water entering the engine is more informative.