DIY: Troubleshooting radiator fan failure, and replacing fans

My Symptom:

In my case, one day I noticed that my A/C compressor clutch was clicking on and off rapidly, and the A/C wasn’t cooling very well.

 

Initial Diagnosis:

I quickly noticed that the radiator fan on the driver’s side wasn’t turning on like it should when the A/C is on. It should turn on even though the engine is still well below normal operating temp if the A/C is running.

 

Troubleshooting the radiator fan failure:

You should start with checking the condition of the radiator fan fuses in the compartment behind the driver’s seat. The panel comes off with 3 Allen keys under the storage lid, and 3 Phillips screws under the edge of the carpet. It is much easier to work in this area with the driver’s seat taken out, but you can still work with the seat pushed all the way forward and the back tilted as far forward as possible.

 

You can use a multimeter (they are around $10 on Amazon if you don’t own one), to check continuity across each fuse. If you are not familiar with doing this with a multimeter, you can find YouTube videos, so I won’t reinvent the wheel here.

 

The fuses for the fan are not labeled on the back of the fuse panel cover like the rest of the engine management fuses, and I couldn’t find anything in the manual to show which fuse is which, but if you check them all, and one is bad, then you know you found the right one. I found out that the driver side radiator fan fuse is connected to the wire with the number 6 on its yellow label.

 

You can buy the “strip” 50amp fuses from the Volkswagen dealership, or online, for about $5. The good news is that if you need one now, the fuse on the very bottom of the fuse box is a spare fuse ready to be put into service. I bought a couple of spares to have them ready if mine blew again.

 

Once I replaced the fuse, the fan started working, which is great for me, but since fuses blow for a reason, I took some additional troubleshooting measures to isolate the problem.

 

In addition to replacing the fuse, I took out the fan to examine it. It’s only 4 screws to release the grill, and then disconnect 1 electrical connector, and then loosen the 4 retaining bolts. You don’t need to completely remove the bolts because once you loosen them, the fan rotates clockwise to release it from the mount, and it’s out.

 

(Lambo really screwed up by making it so easy to change the radiator fans! I hope they fired the responsible engineer because Lambo is not about accessibility!)

 

I found the bearing to be a little noisy when I hand spun the fan, so I went ahead and swapped the fans left to right, and I also swapped the relays left to right so I could isolate the wiring to make sure something wasn’t wrong with the wiring causing a short to ground.

 

The relays are the 100 amp relays in the same fuse box, and the two for the fans are the ones on opposite ends of the string of 4 big relays. If the relay is bad in your case, it’s an easy fix. Mine were just fine.

 

I ran the car and everything was good, but I wanted to replace the aging fan with the noisy bearing as it was clear that it was no longer pulling as much air as the other fan, and that extra motor resistance was probably the cause of the blown fuse.

 

A new radiator fan is around $400 from the normal Lambo suppliers, but it is a common SPAL brand. I found in another Lambo model forum that the following SPAL fan was found to be a match on all the dimensions, number of blades, mounting method, air flow, and wattage.

 

SPAL part number 30103202

http://www.amazon.com/gp/product/B009OBP5A...ailpage_o09_s00

 

For wattage, this fan is a good match to the fuse because the specs show this fan drawing 25 amps at the low end and 36 amps max, so it’s well within the 50amp fuse range.

 

I put the new fan in after cutting off the connector and soldering it on to the new fan (it comes with a different connector naturally), and it fit right it.

 

The new fan has been working flawlessly for a week now of regular driving, and it feels like it’s pulling the same amount of air as the good old fan, so it’s a good match. It does have a bigger motor, but since it’s pulling the same air and fits the amperage, it’s good and the extra motor size does not cause a mounting clearance issue at all.

 

So $130 for this fan versus $400 for the Lambo sourced one is a nice savings.

 

If your fan fails, your situation may be different. So if your fuse is not blown, next try swapping the relays to see if the other fan comes on. If it doesn’t, try swapping the fans to see if that makes a difference. If that doesn’t make a difference, than you either have a wiring issue, or something is wrong with the ECU telling the fan to run based on either the engine temperature, or A/C system pressure. That gets tricky to troubleshoot, so hopefully you will have fixed your issue by changing the fuse, relay, or fan before you have to examine the wiring or dig into the fan ECU management.

 

The wires for the fan do run next to the muffler, so they do get some heat. You can get to the wires pretty easily by removing the rear deck lid, and then the carbon fiber panels on the left side of the engine bay.

I will add that the new SPAL fan is rated VLL (very long life) and it's a sealed unit. The original fan is not VLL ant it must be mounted in a certain orientation to have the water drain holes down. So the replacement fan seems to be a nice upgrade.

Thanks for the info

What a great and useful DIY! I deeply thank you for explanation and sharing pictures.

Please keep on doing similar DIYs in the future.

Cheers Stimpy... I also enjoy wrenching on my cars so good to see

You're welcome.

 

I already have a DIY for ballast replacement on the head lights coming. And I'll show how you reduce the dealers $8000 quote to repair this problem down to $29.

Great info. Fan failure is a common problem on the early Murci (could be LP too, I just haven't heard much).

You're welcome.

 

I already have a DIY for ballast replacement on the head lights coming. And I'll show how you reduce the dealers $8000 quote to repair this problem down to $29.

 

Wow 8k down to 29 bucks? That's 99.9% of saving, this is awesome. You are quite competent for sure. Thank you for contributing the DIY.

 

 

Wow 8k down to 29 bucks? That's 99.9% of saving, this is awesome. You are quite competent for sure. Thank you for contributing the DIY.

 

Yea, I read somewhere that the dealers don't want to repair a headlight, just replace it. It's a $7000 part, so after install and taxes -- ouch for just a bad ballast!

 

And I read somewhere that one guy had a simple problem with their radiator fan, like I did, and the dealer bill was $2000.

Great write up. Awesome.

Thank you.

Thank you Stimpy for the very useful information and write up. Keep the DIY posts going.

Stimpy -- you're awesome! You're meticulous like I am, except I don't have the skills and tools you do. I wish there was a way to add a sub-category on this forum for all your DIY repairs, so they're all in one place. They're such a tremendous resource. I guess I'll make a Word file with links instead...

Just a quick update that 3 months and much warmer weather later with regular weekly driving, the new Spal fan is doing great and I haven't blown a fuse again.

Just a quick update that 3 months and much warmer weather later with regular weekly driving, the new Spal fan is doing great and I haven't blown a fuse again.

 

 

How does one check if a relay is working properly?

NVM, just found a video on youtube.

Great stuff as always, thank you!