I have been getting "normal height only" fault codes on my 07MY RRS. Codes U0416 (invalid data from vehicle dynamic control unit) and C1A20 (pressure increasing slowly).

It is the original Hitachi and yesterday I replaced the piston seals and the desiccant and filters.

Initially when reinstalled all was OK but after a while the faults were back. I cleaned out the air tank valve block and when reinstalled every thing was Ok for a while but again the codes were back.

So I guess I need to consider a new air compressor but which one?

Genuine AMK kits are very expensive but will obviously do the job.

You can get AMK style kits for less than half price but I do not know if they are any good.

I don't believe the OEM Hitachi is available but there are a number of knock-offs including Dunlops, Bearmach, Britpart and various no names on ebay.

Clearly the genuine AMK kits are the best and cost a bit but the other options are far cheaper but for me are of unknown quality.

So of the no name knockoffs - which are the best and where to buy.

Thanks

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

I had the same thing and the indie I use gave 2 options: Dunlop or a later unit that also require a software update. As you said he also said the original Hitachi one was no more. I went for the Dunlop and he said in fairness he doesn’t get any problems but ultimately it’s my choice. I’ve used him for years and trust what he says. It’s been on some 8 weeks, so still in the honeymoon period but no regrets.

Steve. 2006 2.7 TDV6 HSE in Cairns Blue.

Thanks Steve - so a thumbs up for the Dunlop - good to get a positive as I have seen a few negatives - mainly issues from new.

Would anyone risk this chinese no name copy of the Hitachi?
https://www.ebay.com.au/itm/For-Land-Rover...1438.l2649

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

I think anything Chinese you need to run very fast from. I have had the 'slow to build up pressure' fault a few times but it's not consistent, it just seems to throw the fault when it feels like it. I too have been looking at Compressors and as I may be changing the car soon, I am going to go for the Dunlop. If I was keeping it I would indoubtedly fit the AMK.

So you have experience with the the chinese built compressors?

Feedback I have on the Dunlop indicates they are worse than the Chinese versions - many fail on installation. Much to my surprise I have found that the original Hitachi compressors are still available so I might go that route.

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

I have had faulty Dunlop compressors out the box. It's a no from me

Fitted the AMK copies. Were OK for a while, but had 6 failures very recently, with one lasting barely 48 hours. Also a no

It may be expensive, but all I'll fit now is a genuine AMK, for piece of mind...

Thanks for that advice - good information. A genuine AMK and kit is just out of the price range at the moment so I NOS genuine Hitachi might be it is the knockoffs of both types are not up to scratch.
Cheers

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

how can you fit an amk when the car came originaly with the hitachi pump
i thought the plugs etc were different

Plugs are all the same, but needs a software update to work correctly

johnrambo wrote:

how can you fit an amk when the car came originaly with the hitachi pump
i thought the plugs etc were different

Just an update - I put a kit through my Hitachi, put on the metal desiccant cap and it still threw up the fault codes - hence looking for a new compressor.

Well one thing I had not replaced was the exhaust valve seals and spring. Well it would not undo and I over did things and ripped the hex head off it . The threaded plug was still in there and it was leaking air even when the compressor was running with no load. So I took the hammer and screwdriver to it to try and get the plug out without luck then a bit of heat without luck. So I need to get a new exhaust valve housing which is now on order.

Waiting for that delivery to arrive I needed to put the compressor back in as it will still top up the tank before its faults. However I need to stop the air leak in the broken off exhaust valve housing - only thing to hand was some superglue - so poured it all over the top of the plug and left for a few hours to dry - no air leak.

Put the compressor back in and guess what - no more faults - all fixed - all works as it should

My guess is that the corrosion in the exhaust valve area or maybe the white dust from the previously dead desiccant was keeping the exhaust valve open a little so air was escaping straight out the exhaust port. My bashing around has dislodged the obstruction and now the exhaust valve is opening and closing as requred.

The new exhaust valve housing will arrived next week so the decision is whether to just keep it as a spare if needed as long as the superglue continues to do its job, or do I take action now and drill out the housing plug still in the compressor and run the risk of stuffing things up - decisions, decisions.

Having now learnt these compressors inside out, with the exception of physical failure of something inside (burnt motor, conrod etc), with kits that are available there is really no need to replace the compressor.

garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

Do you have a link to the exhaust valve housing you have purchased please?

I slightly rounded the nut off on mine when I was trying to take it apart to clean inside. In the end I gave up because I didn't want to completely it up. Do you know if you can buy a new one? Kev

MY2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
MY2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Just the housing
https://www.ebay.com.au/itm/Land-Rover-Dis...1438.l2649

Housing and kit
https://www.ebay.com.au/itm/Discovery-3-Sp...1438.l2649

Just be aware that if you persist you will rip the hex head off it and then have to drill the remaining plug out and retap the tread.

The head in the socket

Click image to enlarge

Click image to enlarge

Brilliant! Thanks Garry! Kev

MY2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
MY2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey