Extra fan!

[Mr Tank]

Hi

Well the car has been on the road for over four weeks now after the rebuild, with out any major worries apart from the temp gauge going up over 100 in traffic queue's (Mainly while waitiing in the take away queue!!!!!)

As I have replaced all the pipes the rad etc, and there are no air locks I was thinking on fitting an additionaly fan on the front of the rad which I can manually switch on!

What's the opinon off people on this etc!

Andy

[350zwelgje]

Have a wedge with an override switch on the standard fan. Queing, out on the track I switch it on manually/permenantly. Never had those levels of high temperature you are mentioning, maximum 95° but on our wedges this depens on the earths and all other stuff. Seems that the single fan and rad on mine are able to handle the heat under those circumstances. Once even got stuck for over an hour in a nearly non-moving traffic jam, with close to 30° Celsius outside temp and all was ok. Checked once on the side of the road but all was fine. This is a standard 350i with single kenlowe fan. Although I must mention that I have the heater on hot with the interiour fan off to have more coolant flowing as a precaution.

Back to your question (finally): you can add a fan without a problem, but probably you need a standard two fan setup and not just add one.... As a single fan will limit what you can install or you need to move it.

Rob

[Mr Tank]

Rob

I have a twin fan set up at present, both work well! My idea is just a back up! We all have done the heater fan on in our time, but that can be a bit much in the height of summer so an extra fan rad fan was my idea round that!

Andy

[rev-erend]

A 350i has the same rad as 390/400/450/ and all SEAC's ..

So - I believe you have a fault that needs to be found.

Could be -

Fan not working
Temp guage incorrect (use a lazer temp guage to check it)
Otter (fan) switch
Mixture far too lean

Cant think of any others..

[wombat172a]

Similar problem here, I've got a single fan with override switch on my 350i. It cools fine when it's moving, but the fan just can't do the job. During it's MOT test last week where it was sitting stationary for some time, I stopped the test once I noticed steam coming out everywhere.

Steam started coming out of the exhaust, so I'm going to do a compression check once I've got it back to make sure it hasn't blown a gasket/warped a head.

I'm quite certain that it's just a case that the fan is quite old, noisy, and simply doesn't spin fast enough anymore for it to cool properly.

[rev-erend]

I added an extra 14 inch fan - to the front of my rad .. and moved the existing fan over to the opposite side ..

The 14 incher is huge and flows twice as much air as the 12 incher.

[CarbonWedge]

If not allready done a lower rated thermostat will help.

[350zwelgje]

CarbonWedge said:

If not allready done a lower rated thermostat will help.

Only temporary (like a couple of minutes), as I think if the engine is hot the thermostat is fully open and as such independent of its rating as 95° is over 82° or 78° for example.... Fully open is fully open. The rating only defines how quick or slow the fully open state achieved.
If the engine then gets too hot, with this fully open thermostat) the cooling capacity is not enough. Can be caused by a airlocks, too much antifreeze, waterpump not up to the job (belt or worn),design error or wrong rad/problems with the rad.

Rob

[GV]

If you want peace of mind opt for a rad re-core going one up of the factory spec. Can't remember if the factory spec was 3 core etc. I went this route getting an extra core fittted on my original rad spec which allows more water to get cooled by whatever fan set up you have. I have a single fan and provided you fill the car up correctly you should have no troubles. My car is at a constant 85 on the run and will drop down to 90 when the fan is on in traffic and will stay there. I also got rid of the otter switch and turn the fan on and off manually.

I've tested the temp with an infrared gauge at the stat housing which shows the car a shade cooler than the temp gauge when idling - so this can be another factor to consider hence the need to check your connections etc. My car also doesn't have Efi which stores a lot of heat which is another factor. Having said all that - a rad re-core will make a vast difference all the same...

[Mr Tank]

Hi

Thanks for all your coments.

My rad is new, the termostat is new, the water pump is new, fan belt is new, otter switch is new, fans have been rebuilt, one is a little noisy. All the earths are like new!
Tonight the car was in a photo session for two hours and the temp gauge sat between 95 - 100 but the car was OK. It occasionaly pinks so I am going to stop using Tesco's 95 and use super unleaded and see if that helps. But I think for peace of mind I will also fit a fan in front of the rad!

Andy

[bbjonn]

Hi

I've got an early series1 350i and it behaves in pretty much the same way with the temperature seeming to be a 'bit' on the high side and sometimes heading off over 100 degrees. Does your car have the small saddle bag style expansion tank? I'm wondering if swapping to the later style would help.

I'd be careful fitting another big fan in front of the radiator it will block the flow of air through the radiator and when the fans turned off you might find your running temperature goes up!

cheers

Jon

[GV]

Of course - you are talking about my first wedge! I dug out the original bumpers you asked for. If you don't want them let me know.

My recollections was that car's temp fluctuated between the high 90's & 100 - but it never overheated. The car had the heads done early in its life and had a kenlowe overide when I got it with twin fans. It always ran hot in traffic even wth the fans on...

[Henry Harris]

Just to relate what is on my car. There is a rheostat to adjust the temperature reading to match expectation when the car is running in ‘normal’ conditions. The gauge, which looks like the original, does rise when the engine is hot and settles back to the expected reading when conditions allow. This works fine although I do not know why it is there in the first place.

[Mr Tank]

Jon

Thanks for that info!
I am now thinking it's in fact the cap on the expension tank. That's the only thing which I have not changed.
It looked nearly new, but I am still going to change it today!

Andy

[Mr Tank]

Hi

Well the cap on the expension tank was some of the problem, I found that it had been letting water/leaking out around its self.
I fitted a new one today, it felt better when being fitting than the old one.
This helped the temp a bit also no leak! But after a while the temp raised again when the car was stationary, the fans were on but they could not move enougth air to greatly reduce the temp! I put a house-hold fan in front of the car to give it's some extra air flow, like it was moving at around 5 mph and the temp whent down! So the twin fans can't move enougth air when the outside temp is high to cool the engine!

So a extra fan is going to be fitted for the rare occasion we get good weather!!!!!!!!!!

Andy

[TVRleigh_BBWR]

Mr Tank said:

Hi

Well the cap on the expension tank was some of the problem, I found that it had been letting water/leaking out around its self.
I fitted a new one today, it felt better when being fitting than the old one.
This helped the temp a bit also no leak! But after a while the temp raised again when the car was stationary, the fans were on but they could not move enougth air to greatly reduce the temp! I put a house-hold fan in front of the car to give it's some extra air flow, like it was moving at around 5 mph and the temp whent down! So the twin fans can't move enougth air when the outside temp is high to cool the engine!

So a extra fan is going to be fitted for the rare occasion we get good weather!!!!!!!!!!

Andy

I sure just a singe good quality one will do the Job, Fan can vary a lot on the amount of air they can move, it may be best to just fit a high flow SPAL fan.

[rev-erend]

Also worth checking .. the swan neck should have a plain cap (no pressure spring) and the header tank should have the pressure spring..

Seen a few where the owners have got confused and had them the wrong way round.

[redweapon]

Had similar problem with my wedge, In traffic and the temp was well up in the red 110-115. Checked the fan switch and it was rated at 246f or 118deg. No wonder it got hot and the fan cut off whilst the temp was still in the Red! . Ended up welding a m22 nut on the top swan neck and fitting a standard threaded switch with cuts in at 90-87. And fitted a new Spal 12" sucker fan as the kenlows bearings were buggered. Now it doesn't get above 90 when sat in traffic. Which is much more relaxing....

[TVRleigh_BBWR]

You have said you don't have any air locks but the wedge design can be very bad at hiding them, it took ages to get the last bit of air out of the Racer, was running at 110 on 1st test, even after we thought we got all the air out. but we tried again and managed to get some more out. and was then running at a solid 90oC at Rockingham for the whole of both races, and was fine sitting on idle also.

[rev-erend]

I find the best way to bleed them is :

Run engine, interior fan on, swan cap off or just not locked to let air to escape.. and pump the bottom hose with your hands .. this puts a lot of agitation into the rad and helps free any trapped air.