Thread: D4 Aircon Compressor Replacement

Well then. I am chasing the same whine. Just replaced the Alternator because it had a crunchy bearing, but it sounds identical to yours from behind the wheel. I was hoping it was the compressor pulley.

On the 2.7 there's no magnetic clutch. The replacement is relatively straight forward. I've done a few pulley bearings on compressors with mag clutches over the years. Just need the manual for the compressor. Generally they can be done in-place, although I've had to make a tool before to hold the plate while undoing the nose bolt. Figure out how to wind the clutch plate off, then there's usually a circlip behind that holding the pulley in place. The pulley slides off the nose of the compressor. On older units I've replaced the bearing. On the D3 the pulley comes as a unit with the bearing. Don't know for yours.

Bitter experience says if you leave it too long the movement will trash the front bearing in the compressor and take out the seal necessitating replacement, so the earlier you can fix it the cheaper its going to be.

Thanks, there is magnetic plate on the discovery 4, but think I read it's not serviceable in D4. Would be happy to hear otherwise from the collective wisdom in group.

Originally Posted by BradC

Well then. I am chasing the same whine. Just replaced the Alternator because it had a crunchy bearing, but it sounds identical to yours from behind the wheel. I was hoping it was the compressor pulley.

On the 2.7 there's no magnetic clutch. The replacement is relatively straight forward. I've done a few pulley bearings on compressors with mag clutches over the years. Just need the manual for the compressor. Generally they can be done in-place, although I've had to make a tool before to hold the plate while undoing the nose bolt. Figure out how to wind the clutch plate off, then there's usually a circlip behind that holding the pulley in place. The pulley slides off the nose of the compressor. On older units I've replaced the bearing. On the D3 the pulley comes as a unit with the bearing. Don't know for yours.

Bitter experience says if you leave it too long the movement will trash the front bearing in the compressor and take out the seal necessitating replacement, so the earlier you can fix it the cheaper its going to be.

Suggest you take of belt and spin the pulley see whether smooth or noisy.

I did that a couple of weeks ago and everything felt smooth and quiet, which was frustrating.

I did the alternator because even though it felt smooth I knew it was becoming a problem. In the 2 weeks from test to replacement the alternator had become quite crunchy, so I'll have to re-assess the A/C pulley. I have found my mechanics stethoscope, so I'll take the opportunity to have a good listen to all the others while I'm in there.

Thankfully ever since I un-stuck the fan 8 years ago, it always goes back on with grease on the threads and it comes off with a crescent wrench and a gentle tap each time, so I'm getting quite quick at getting the belt on and off.

I always thought protocol was to replace the front condenser and dryer anytime you open it up.

Originally Posted by DiscoJeffster

I always thought protocol was to replace the front condenser and dryer anytime you open it up.

Some don't if Compressor hasn't grenades and sent swarf or dust through the System. It depends on how long open for and Vacuuming as soon as possible will remove air moisture from system.

I can get OEM dryer from Rimmers reasonable priced. Anyone any recommendations on the full condenser / dryer unit ?

Also should rest of system be flushed ? I think I read although some do it, shouldn't flush through the TX.

And if it should be flushed should that be done before or after replacement ?

Originally Posted by BradC

I did that a couple of weeks ago and everything felt smooth and quiet, which was frustrating.

I did the alternator because even though it felt smooth I knew it was becoming a problem. In the 2 weeks from test to replacement the alternator had become quite crunchy, so I'll have to re-assess the A/C pulley. I have found my mechanics stethoscope, so I'll take the opportunity to have a good listen to all the others while I'm in there.

Thankfully ever since I un-stuck the fan 8 years ago, it always goes back on with grease on the threads and it comes off with a crescent wrench and a gentle tap each time, so I'm getting quite quick at getting the belt on and off.

With the D3 if you search the Dico UK site you can also bypass the aircon with shorter belt, this will allow you to
1. Verify it is AC
2. Avoid risking damage to wider system until you get it replaced