Hi all

I have a 2002 r53 with the jcw package on. Only had it about 4 weeks but it overheated.

On first inspection it looked like the radiator tank so that was replaced.

It over heated again so on further inspection and because i had a bit of time I replaced the water pump, thermostat housing, thermostat, whole new radiator fan assembly.

I still have an issue and after doing further investigation, this is what I have found:

The 5amp radiator fan fuse blows when both the power steering fan and radiator fan are unplugged. The car will start run for a few seconds, then it sounds like the relay clicks over, then the fuse blows with no fans actually plugged in.

I have looked as some wiring diagrams and it looks like the 5amp fuse powers the coil in the relay to effectively switch the fans on when the wire from the ECU becomes active.

So, my questions are:
1. as the relay works for a short time (a few seconds to a minute) before blowing the fuse, it tells me that the temp sender is doing it's job and the fans are ok. Does this sound right?

2. As the 5amp fuse only appears to power the relay coil, would this suggest my relay is faulty?

3. would the 5amp fuse blow if there was a short on the sysyem by an old wire or something that goes to the fan. If so how do I even find that?

any help would be appreciated. I feel like in a short space I time I have got to know my mini well, but not sure about this one......

Thanks

 

Is your PS fan spinning freely? If it is seized or seizing, or shorted internally that will blow fuse 40 every time you replace it. Inspect your PS fan.

Does the car still overheat or is the fuse problem your only ongoing problem?

 

Check the P/S fan :

Check the fan if the gunk has built up on the back side between the fan blade and the motor itself. : Sometimes the fan can be cleaned and blown out in the gap between the fan and the motor itself, where rock and junk gather. If not see the below link.

https://www.northamericanmotoring.co...fan-issue.html

 

When I first picked up my '04 R53 m/c/s, the P/S fan was not operational.

After jacking up the car and trying to spin the blades with a screwdriver from underneath, I noticed the fan seemed to be somewhat seized up. I then checked the fuse and found it popped.

Before putting in a new fuse, I removed the fan and began to try and free it up by inverting it while carefully jiggling the fan blades. After a couple moments doing this, the blades were beginning to move with granules of dirt and sand falling out the more I moved it. I switched to compressed air and blew out the remainder of the dirt and/or sand that had accumulated inside over the years. After a couple minutes, the fan was spinning freely, and I shot a little light spray lube into it for good measure while turning the blades.

I reinstalled the fan, replaced the fuse, started the car and put on the AC. After a few moments the fan turned on, and has worked flawlessly ever since.

 

Hi All
Thanks for the reply. Yes, I have cleaned the fan and it appears to work well. To make sure I unplugged both the power steering fan and radiator fan from the car and started it up.

when I turned the AC on (to force the fans to come on) relay clicked, then the fuse blew. So it still blows when nothing is plugged in......

Thanks

 

I would look at that harness , if both the a/c fan and the p/s fan are unplugged and they blow the fuse , it most be the harness the plug on the harness side fried out and grounded itself.

 

so i have looked further into this and pulled out the fuse box and had a good look at all the wires. when i put the car back together i accidentially forgot to plug the temp sender back in and when i started the car the fuse continued to blow. what was interesting was that it blew even without the relay.

so i now think that it could be the temp sender. not 100% sure but it will be the next thing i try. The odd thing is that the gauge appears to work fine so it makes me think it may not be the sender but I can not find anything else.

any thoughts?

 

Yea, something is grounded, causing a fuse to blow. Its hard to find these line that make contact or that are torn or burnt, you have to examine it like scientist.

 

FOUND IT...... The power steering pump wires that go past the exhaust head shield had rubbed through causing the short. what an effort but at least it is now recorded in the forum if anyone has the same issue.

Thanks for your help.

 

You are welcome. I knew it was a short, but not where, glad you found it.

Do you need a new harness ?