replacement cooling fan-wedge
Discussion
RubbishFettler said:
Hi all
The cooling fan is struggling to do it's job when my 350i is idling for any length of time. Has anybody recently fitted a replacement which performs better, or can anybody quote any data for the output of the standard fan to check against a potential upgrade?
Cheers
Steve
How do you know the cooling fan is not doing it's job? Is the car overheating? Are you loosing water? Or are you going by the fact that the temperature gauge is hitting red? It could be your temperature gauge needs calibrating against the sender.The cooling fan is struggling to do it's job when my 350i is idling for any length of time. Has anybody recently fitted a replacement which performs better, or can anybody quote any data for the output of the standard fan to check against a potential upgrade?
Cheers
Steve
Tony. TCB.
When you fit a new sender you should calibrate the gauge to the new sender or at least check that the two are calibrated.
This is what should happen. When cruising and fully warm the temprature could be anywhere between 50 to 80. In traffic it will creep up to around 90. Slightly above 90 the fan should come on and reduce the temperature back under 90, untill the car starts to move again and the temprature is reduced back to somewhere between 50 and 80.
Don't forget 90 on the gauge looks quite close to the red mark on the Wedge.
You could also check the true temperature of the engine with a suitable heat sensor.
Tony. TCB.
This is what should happen. When cruising and fully warm the temprature could be anywhere between 50 to 80. In traffic it will creep up to around 90. Slightly above 90 the fan should come on and reduce the temperature back under 90, untill the car starts to move again and the temprature is reduced back to somewhere between 50 and 80.
Don't forget 90 on the gauge looks quite close to the red mark on the Wedge.
You could also check the true temperature of the engine with a suitable heat sensor.
Tony. TCB.
The sender is the correct one for the gauge. I have actually fit a manual override for the fan, if i switch it on at rest when gauge shows 80, it soon rises above the 90 degrees. I take what you are saying about accuracy though, i will see if i can measure the temperature externally to be sure.
Steve
Steve
RubbishFettler said:
The sender is the correct one for the gauge. I have actually fit a manual override for the fan, if i switch it on at rest when gauge shows 80, it soon rises above the 90 degrees. I take what you are saying about accuracy though, i will see if i can measure the temperature externally to be sure.
Steve
I had a similar problem and in the end I had to fit a resistor to calibrate the gauge, and now I get a pretty accurate reading. However, the fan comes on and goes off by itself, indicating that it is actually cooling the engine.Steve
If you measure the temperature externally and find that the engine is not overheating, then a simple inline resistor of the correct resistance will cure your problem.
Tony. TCB.
On my SEAC i replaced the cooling fans with a twin fan setup and still had the engine temp creeping up in traffic and idle. I changed the expansion cap and after a trip over the forth road bridge the car temp was on the mark all the way over the forth as it took over 40mins to cross.
Worth a look first as it will be the cheapest option.
Worth a look first as it will be the cheapest option.
Just a thought, but if the fans have been adequate before and they are still running properly...
The radiator could be at the 'tipping point' where - with the ram effect of the air forced through at speed - there is sufficient cooling to keep things at temperature. But when it relies on just the suction from the fans it doesn't quite cut it and the heat slowly builds.
In the old days with cooler engines and more space in the engine bay it was said you only need the cooling from a mechanical fan when going under 35-45 MPH.
The radiator could be at the 'tipping point' where - with the ram effect of the air forced through at speed - there is sufficient cooling to keep things at temperature. But when it relies on just the suction from the fans it doesn't quite cut it and the heat slowly builds.
In the old days with cooler engines and more space in the engine bay it was said you only need the cooling from a mechanical fan when going under 35-45 MPH.
Yes I can see what you are saying about the efficiency without the ram air. Thanks for the data on the standard fan, that is useful. Presumably if I fit a replacement fan with a higher CFM, that may make the difference, especially as the original fan probably won't be as efficient as it was after 30 years.
Yes, it could be the fan, radiator, thermostat or anyting else, but before you make these changes make sure the car is actually running hot, otherwise you will be spending a lot of time and money on something not needed. Then, you WILL be living up to your forum name. The gauges on these cars are not accurate, just a word of advice.
Tony. TCB.
Tony. TCB.
Just realised I never posted a final update on this-bit rude I know! Checked temperature and readout was within a couple of degrees. Investigated further and realised the wiring to the fan did not look original or that substantial. I replaced with heavier gauge cable, now the fan cuts in just below it hits the red and manages to keep the temperature below. I am not that techy with electrics, but I can only assume the small cable was not allowing the fan to run at capable speed? I plan on fitting a small fan to one side on the rad and have that on a manual override, so in extreme conditions it can give the system a bit of extra oomph. Thought it was worth posting this in case someone else may have the same issue.
Thanks again for everybody's contributions.
Steve
Thanks again for everybody's contributions.
Steve
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Probably a good post to read alongside this one.
Probably a good post to read alongside this one.
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