Electric fan conversion question

[Codym42]

Hey guys, I did an electric fan conversion a few months back using a 14" pusher from Ireland Engineering and an e36 temp switch (80/88 degree). I have noticed that it doesn't kick on until the temp gauge hits the 3/4 mark. Just wondering if that is normal. I get nervous when the gauge reads that high. Also, this is an m42 car. The cooling system was completely redone about three years ago and yes, I bled the system.

Thanks in advance!

[jeffnhiscars]

A couple of thoughts are that your gauge may not be accurate or you may have wired the fan to the high side of the switch. If you replaced your mechanical fan with this I would think you'd want a puller not a pusher and assuming you also deleted your shroud do you have a good tight fit against your radiator ?

Of course if this replaced your aux fan, ignore what I just said :)

[Codym42]

A couple of thoughts are that your gauge may not be accurate or you may have wired the fan to the high side of the switch. If you replaced your mechanical fan with this I would think you'd want a puller not a pusher and assuming you also deleted your shroud do you have a good tight fit against your radiator ?

Of course if this replaced your aux fan, ignore what I just said :)

Yeah, the pusher replaced the aux fan. The gauge reads dead center when I'm on the highway and only starts creeping up in traffic. I'm pretty sure my wiring is correct but I may check again. Any other thoughts?

I'm going to flush my coolant today and put in some Zerex g05 to replace the nasty green stuff and since I was running low last night.

[Codym42]

Good news. I drained the green coolant out and filled it up with the garden hose and let it warm up. The needle reached the half way point and the fan kicked in. Must have been air in the system or something. Now I've got to drain again and fill with zerex.

[jlevie]

The first check would be to see if the fan is coming on at low speed when the radiator temperature exceeds 80C. With the engine running you might not be able to tell is that is happening with the hood closed. You will almost certainly be able to hear the fan in high speed.

If the fan is running at both speeds, as it should be, I'd say the fan is just too small and moves too little air. Here in the south I've found that a 16" fan rated for at least 2000CFM is needed to dump the heat load from the engine when the car goes from driving at speed to stop and go traffic. Since you are using a pusher and have deleted the A/C and are using a pusher (the ideal) a full shroud will help.

[Codym42]

The first check would be to see if the fan is coming on at low speed when the radiator temperature exceeds 80C. With the engine running you might not be able to tell is that is happening with the hood closed. You will almost certainly be able to hear the fan in high speed.

If the fan is running at both speeds, as it should be, I'd say the fan is just too small and moves too little air. Here in the south I've found that a 16" fan rated for at least 2000CFM is needed to dump the heat load from the engine when the car goes from driving at speed to stop and go traffic. Since you are using a pusher and have deleted the A/C and are using a pusher (the ideal) a full shroud will help.

Like I said in the post above, it seems to be working a lot better after I flushed the coolant. After putting Zerex g05 coolant in, the fan does work at around the half way point and the needle only goes slightly over half way in traffic and stays in the center while driving. Of course, I probably still need to bleed it more.

And, I actually have not deleted the A/C although it does need a recharge. The fan is mounted in the stock position in front of the condenser.

Thanks for your input. I'll have to keep that in mind what you said about the 16". :)

[jeffnhiscars]

If you are counting on the aux fan to keep the engine at proper operating temp then something is wrong with your cooling system

[Codym42]

@jeffnhiscars This is my only fan. The mechanical fan has been removed and I have changed out the temp switch so that it kicks on at lower temps. Sorry if I wasn't clear on that.

[jeffnhiscars]

That was my next question. Id say you are under cooled by asking one fan to do the work or 2. When you bring your AC back that fan will be on 100% of the time which will over ride your temp switch and IMO not provide enough air.

Im not sure what the goal was and Im no m42 expert, but you really ought to put the stock fan back for this to work properly.

[nrubenstein]

A pusher in front of the condenser is not going to provide adequate cooling in all conditions. You need a puller as well.

[Codym42]

Hmm...I've seen people on here running just a pusher like me but I think most have removed their a/c. So if I have the ac button pressed does that disable the high speed part of the switch?

[nrubenstein]

Hmm...I've seen people on here running just a pusher like me but I think most have removed their a/c. So if I have the ac button pressed does that disable the high speed part of the switch?

No, it doesn't. And yes, people running just a pusher do not have a condenser. (Or they don't drive in traffic.)

Just feel how much air actually comes through the rad via the pusher. It isn't much.

[jlevie]

As stated above, if you want to use a pusher the A/C condenser must be deleted. It causes too much restriction of the airflow from the fan.