Replacement fan woes
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Intermediate
Joined: Oct 2007
Posts: 32
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From: '85 32v 5spd LSD - Vancouver, Canada
Replacement fan woes
I have a 928 Motorsports replacement main fan installed and I am having some woes keeping it operational. It is powered from the jump post, goes thru an inline 25A fuse to the fan itself, returns back thru the thermostat and grounds close by. (as per instructions that came with kit) Simple circuit right? I am blowing my 25A fuse constantly (and irregularly). I did have a relay in there that was supposed to turn off the fan with the ignition. Since I could not find an ignition wire it was redundant, Job #1 was to remove the relay from the circuit in case that was the problem. The fan dying was the root cause of my overheating problem I posted a while ago (ref: "coolant blowout").
I managed to measure an instantaneous 34 A once when the fan started, before blowing the fuse. I have wired it to a number of different grounds, thinking that might be the problem. Brand new fan. Turns nicely and is quiet. Pulls 18A when it does run and hasn't blown the fuse. The problem is not consistent. I have been thru many fuses thus far.
What is (perhaps) interesting is that this is a second fan - the first was not secured properly by the PO and ended up having a wobble. I melted the wires on that fan and put it down to the fan rubbing the rad and pulling too many amps. Now I am thinking it was the same problem all along and the wires melted due to a bigger fuse in there that may have been put in by the PO to overcome the same issue. Unfortunately I garbaged the fan without checking what fuse was in there. Old fan was a Zirgo - this one is a SPAL. As it is my second kit, there is a new thermostat switch in there also.
Appreciate any ideas to do some more detective work to solve the problem, I have the original clutch fan which could go back in, but would hate to give up on the electric.
Cheers
I managed to measure an instantaneous 34 A once when the fan started, before blowing the fuse. I have wired it to a number of different grounds, thinking that might be the problem. Brand new fan. Turns nicely and is quiet. Pulls 18A when it does run and hasn't blown the fuse. The problem is not consistent. I have been thru many fuses thus far.
What is (perhaps) interesting is that this is a second fan - the first was not secured properly by the PO and ended up having a wobble. I melted the wires on that fan and put it down to the fan rubbing the rad and pulling too many amps. Now I am thinking it was the same problem all along and the wires melted due to a bigger fuse in there that may have been put in by the PO to overcome the same issue. Unfortunately I garbaged the fan without checking what fuse was in there. Old fan was a Zirgo - this one is a SPAL. As it is my second kit, there is a new thermostat switch in there also.
Appreciate any ideas to do some more detective work to solve the problem, I have the original clutch fan which could go back in, but would hate to give up on the electric.
Cheers
Rennlist Member
Joined: Jun 2005
Posts: 3,261
Likes: 53
From: Park Ridge, IL (near Chicago)
It seems the fan should not draw that much current, ever. I think it's rated at 17 amps. I am afraid you may have a bad Spal fan. If under warranty, Carl may be able to help you. He's a good guy. I have a Spal fan that I got from him that wobbles and I will be returning to him. (I bought a spare one on the internet, as a backup, so I can keep driving the car.)
