Large radiator fan not spinning

I'm working on getting the AC working again on a 2006 Jetta TDI wagon (MK4, same as 2005).

Looks like all my fuses are ok. When I turn on the AC, the small fan turns, but the large fan does not.

The large fan does not free spin when moving by hand. It's mostly stuck. I can force it to turn by hand, but no amount of physical effort will make it spin.

Can I assume that this fan is toast if this is the case?

Is it also safe to say that if this fan doesn't work, neither will the AC?

You need a new fan.

Your A/C *should* still come on, but it will not work very well with that dead fan. However if it has been driven that way for a while, it may have taxed the compressor beyond its limits, and ruined it.

User "DanG144" has some excellent A/C and fan troubleshooting guides you can search for here and make use of if you like.

Alright, I'll try to find a fan tonight and give it a go.


Hopefully the compressor isn't bad. I still have 100psi in the system.

The problem with running A/C with the driver side fan dead for any length of time is that the unit will overheat, the oil will coke in the compressor, and once that starts it's a progressive thing and ultimately will destroy the compressor.

Fix the fan, but if it's been dead for a while expect trouble a year or so down the road even if all appears to be ok now.

I'll try to yank a compressor as well then from the scrap yard.

You are getting ahead of yourself.

If the A/C does not work, meaning, the compressor does not engage, the fan isn't going to fix anything.

oilhammer, you are right, the compressor does not ever engage.


Heres' what I've done:
1. Checked all fuses, including check conductivity in the above battery fuse box
2. Checked the fans, big ones is sorta seized, small one is not.
3. Checked the pressure in the system, it's at 100psi
4. Checked the compressor, it never engages no matter what.


What's my next step? Try to engage the compressor manually with a jumper wire?

oilhammer said:

You need a new fan.
Your A/C *should* still come on, but it will not work very well with that dead fan. However if it has been driven that way for a while, it may have taxed the compressor beyond its limits, and ruined it.
User "DanG144" has some excellent A/C and fan troubleshooting guides you can search for here and make use of if you like.

Click to expand...

Start there.

What oilhammer said.

HOWEVER, fix the fan now. There's another problem obviously if the clutch does not pull in, but that which you find and is obviously broken needs fixed anyway, especially when not fixing it can and will cause future collateral damage, so fix it.

encoad said:

What's my next step?

Click to expand...

Read this entire thread: http://forums.tdiclub.com/showthread.php?t=242699


Yes, the whole thing. Print it out at work. 3-hole punch it, put it in a binder, take it with you to the bathroom to study while you excremeditate. Highlight, add notes in the margins, etc...

1,897 posts, mostly asking the same questions answered in the first part.
That's a great AC troubleshooter for more than just fans. Post #1 and it's links contain the meat. Some additional info in say the first 20 posts.

encoad said:

What's my next step? Try to engage the compressor manually with a jumper wire?

Click to expand...

You might get lucky and find the compressor clutch coil has gone open circuit. It should measure around 3-4 ohms, and can be replaced without opening the system.

I'm not sure how long mine ran with a bad large fan. It was working when checked in the spring, AC failed mid-August. New fan and compressor clutch coil fixed it, that was 2 years ago.

Simon

I ran my car for a year before replacing the big fan. No problems with the A/C. That said, my car is run on the highway, Monday through Friday. What clued me in, was got stuck in traffic, and the A/C did not feel as cold. New fan, all back to normal.

So I've made some progress. The big fan was not spinning, so I replaced it with a used one and it works great. I tried to replace the control box under the battery, but discovered that it's wires were corroded. So I replaced the harness section and kept the same control box. Still no engagement fromt he AC clutch.

I've now tested the AC clutch and discovered it is giving an open circuit instead of 3.7ohms of resistance, so this is the next thing that I'll replace. I tested as per this video and will try to replace it like he does as well: https://www.youtube.com/watch?v=x7PHH5a8JK8

encoad said:

I've now tested the AC clutch and discovered it is giving an open circuit instead of 3.7ohms of resistance, so this is the next thing that I'll replace. I tested as per this video and will try to replace it like he does as well: https://www.youtube.com/watch?v=x7PHH5a8JK8

Click to expand...

Much easier to do this job from underneath, just unbolt the compressor, lower and support it while you change the coil. No need to remove the belt tensioner or alternator.

Simon