Is it OK to run a fan blade with electric fan??

[Moto]

I'm just toying with an idea to run both a standard fan blade together with an electric fan mounted in front of the radiator.

Presumably the standard fan 'sucks' and the electric fan 'blows', so they should help each other and increase air flow and therefore cooling?

I realise there will be a small drop in power but realistically I'm guessing it's not a lot.

Why I hear! Well the electric fan currently keeps the engine cool perfectly well on it's own. Although it is manually switched on/off inside the car. I like it manual so that I can turn it off when starting the engine so as not to stress the battery. Also I don't turn it on unless the water temperature gets above 90 - often it never does unless sitting stationary in traffic. Occaissionaly I forget to turn it on soon enough though and notice it at 120+, when the electric fan then struggles to get it back down in stationary traffic.

OK, it's probably a dumb idea but don't hold back telling me why....

Moto

[Moto]

OK - so I hadn't considered the need for a shroud. I also think a thermostat is a sensible solution but whilst keeping a manual over ride. But if an electrical gremlin (in a TVR, surely not) enters the electric fan wiring it would be nice to still get home OK.

Has anyone got a photo of such a shroud?

Moto

[Moto]

I had presumed it's all original, however as there's no shroud, maybe not.



Moto

[Moto]

Thanks all - decision made. Scrap the standard fan blade idea and fit an automatic water temp switch.

Moto

[Moto]

I've sourced myself a thermostat cover pre-drilled 3/8" bsp for a thermostat switch. However I can't find anyone who supplies these. I can find suppliers for M14, M22 and 3/8" NPT, but not what I need. Can anyone point me in the right direction.

Thx

[Moto]

ATE399J said:

How about here...

http://www.revotec.com/acatalog/Electronic-Fan-Con...

Third one down.

Thx Phil. I had looked at the Revotec but it's a lot of money at over £70 when a std brass switch is less than a fiver.

http://www.ebay.co.uk/itm/152068542089?_trksid=p20...

Also a more messy installation. Nice idea to be able to adjust the temp setting though.

Moto

[Moto]

New thermostat housing fitted with an 80-85 deg switch. Single wire from the switch to the relay to 'dash switch' wire. Job done so I thought and started the engine. The fan didn't come on so when the dash gauge read 120 I switched off. The top rad hose was still cold so I presumed the new 82 deg thermostat I fitted wasn't opening. I took it out and tried again. This time all perfect, fan came on automatically as the dash gauge hit 90.

So I tested the thermostat in a pan on the stove and it works fine? Put it back in (yes - correct way up), but same problem, it didn't open so at 120 I turned the engine off again.

I'm now scratching my head - any ideas?

Moto

[Moto]

alanbarker said:

drill small hole in thermostat 3 mm dia to act as a bleed
Alan

Thx Alan.

I've just tried this and the fan now starts up when the dash gauge reads approx. 100 deg. It's definitely much better but still doesn't seem right. Gut feel is the bleed hole allows hot water through to the thermostat switch - hence why it now starts up sooner. But I still don't think the thermostat is opening as when I take it out, the fan starts up at 90 deg. I can't think of any way to know this for sure and it works fine in a pan on the stove. It's very odd - or is it just the flow is much less through an open thermostat compared to no thermostat?

I can always run without a thermostat fitted (as it's been for the 6 years I've had the car). The only downside I assume is taking longer to reach normal operating temperature?

Moto

[Moto]

[quote=Dollyman1850]

Change the stat for a very good quality one, drill a bleed hole again.
I have seen stats be OK when tested but then get ever so slightly twisted when bolted down enough to prevent them from opening.
Where are you taking the water temp reading from?
I would also consider a lower temp stat I think you can get 82's and 88's
Pic of your cooling system would help?

And how do you know your gauge is accurate??
I would boil your stat in the pan slowly with a thermometer so you can accurately see when it begins to open and when it is fully open..

The other favourite on cooling systems is the potential for short cut circuits via the heater matrix which rob flow from the rad??

N.

How do I know if it's a good quality one? The one I purchased is a First Line from Burton Power and is 82 deg.
The water temp reading is taken from the sender in the block, LHS front, 6" below the thermostat housing.
I don't know the gauge is accurate but it has always (no thermostat fitted) sat on 90 deg on hot days and slightly lower on cooler days.

I'll try the pan test again with a thermometer to get an accurate opening temp.

Photo of setup below. You'll see there is no expansion tank. Also the thermostat housing is the high point so I'm thinking possible air lock around the thermostat, so will also try bleeding.

[Moto]

V6Pushfit said:

Try one of these and put a blanking cap on the old filler. It can be filled to the high point and you can take to top off to see the thermostat working. Your temperature sender can then go into the side of the head where it should be.

In hindsight I think this would have been the better way to go.

Anyway did the pan test with a thermometer and it started to open at 93 deg fully open at 99 deg. So not the 82 deg as stated. This ties with the gauge reading.

So I contacted the manufacturer who said that pan tests in boiling water don't work as the heat is not uniform. It needs to be done in an oil bath. On the basis her indoors would probably be displeased at the idea I've just ordered a 74 deg thermostat with a hole and jiggle pin.

Hey ho

Moto