The only place for a coil spring is up Zebedee's arse
111 posts

I fitted the zebra connector a couple of years ago and all was fine. Last winter, however, the display started to lose a few segments but recovered quickly as the car warmed up. Unfortunately, the problem gradually worsened so a month or so ago I decided to disassemble the HEVAC unit to see what could be done. I discovered two problems:

  1. The two screws immediately under the display unit that holds the internals all together and provide most of the clamping force for the connector were loose and the threads in the plastic housing had stripped - I was probably a bit overzealous in the previous reassembly in trying to ensure a good contact. The application of a few drops of fibreglass resin into the holes sorted that problem out.

  2. The display connection strips on the board (not the display itself) were very discoloured. They had been cleaned when I first installed the zebra connector but I was very gentle. Probably too gentle. This time I used a plastic scraper (a clean spare small glue spreader in my case - definitely non metallic) to firmly but carefully scrape away all the discolouration using contact cleaner as ‘lubrication’. This took some time to get all the strips looking brand new. I also carefully recleaned the contacts on the screen itself for good measure even though they looked OK.

Once reassembled the HEVAC display has been back to rude health at all times . . . . . so far.

I’ve never had much success using adhesives as keeping the seal in the correct position whilst the adhesive cures has always proved tricky to impossible. I now use double sided tape but it has to be the 3M variety which does stick instantly and holds really well - have to spend a little time making sure both surfaces are absolutely clean though.

May drift even further! For the first time I can hear the blend motors struggling - they currently still do the business but are now making their presence clearly known. The front trim on the dash (twixt dash and windscreen) has also come adrift on the driver’s side. These together with the O ring leakage now has me considering complete dash removal to ‘cure’ all these ills. This may also escalate to a change of the heater matrix itself to remove the O ring problem once and for all.

And plenty of anti-seize on the threads of the new sensors (they came with plenty already applied) and not overtightening the crush washer will make them easy to remove next time . . . hopefully . . . if there is a next time . . . who am I kidding, of course there will be a next time - this is a P38!

Seal removal and replacement is straight forward as per most other oils seals. If you get the old seal out without mangling it you can use it when tapping the new seal into place. I would recommend changing the flange as well as the seal - the flange may well have some wear marks from the old seal which will not match the new seal or may end up prematurely wearing it.

Not spectacularly cold but the ambient temperatures here in the UK move around quite a bit from day to day with >10C movements quite common. We recently moved from +17C day temperatures (way above normal for this time of year) to low single figures in a couple of days and then warmed up again. I suspect the O rings are getting past their best after 12 years and the temperature fluctuations are testing them out and they are beginning to struggle a bit.

Both sensors now changed.

The offside sensor easily unscrewed and the connector pulled apart fairly easily, except it left part of the male connector insert inside the female connector (connector on the vehicle harness). This took a mere hour to extract as it was firmly lodged in so what could have taken 10 minutes took over an hour. Grrrr.

The near side sensor also easily unscrewed. The connector is, however, in a really inaccessible location high up on the side of the gearbox with the pipes in the way (which is why I couldn’t initially see it on my quick inspection). This was compounded by the connector absolutely refusing to come of its locating lug and disconnecting it was impossible in situ. Again, an hour coaxing and cajoling the connector and it finally yielded its position - it’s locating lug was rather bent which was why it was jammed on it. At least the connector halves came apart without incident and installation of the replacement went smoothly. Another, what could have been a,10 minute job again took over an hour. Grrr again.

Nearly two and half hours to do what should have been a twenty minute job - don’t you just love theses vehicles!

The good news is that all the vehicle wiring looked OK and NanoCom tells me all is now well.

BTW Richard, a ring spanner will not fit over the sensor connector on the Thor version, happily the open ended spanner readily shifted both.

A couple of days ago I mopped up the (very) few drips of coolant and then inserted an old towel together with kitchen paper underneath the joint to at least soak up any leakage until I get round to tackling the job. Had Rangie out for family trip yesterday so a few miles put under its belt. This morning I remove the towel/paper and . . . nothing!!!! Dry as a bone.

I really hate these intermittent on/off faults. I can only conclude that the higher ambient temperature over the past few days together with a good heating from the coolant has sealed things up. However! I think I’ll change them anyway but it doesn’t appear to be the emergency job I was anticipating.

I think running the engine will heat the exhaust and sensor in equal measure so may have negligible effect. Externally heating the collar preferentially should yield better results.

I do almost all things myself* including plumbing for which crows foot spanners are invaluable for those tight spaces. Not sure of their utility for this job over and above a standard spanner with nice big bit of scaffold tube?

In an earlier post I did state that Stilsons are the tool of last resort. Not quite true . . . I have been known to undo the odd recalcitrant nut with a cold chisel and lump hammer!

*Apart from removing the gearbox/transfer box on the Rangie - without a suitable vehicle lift I considered this a job just that little bit too far for home DIY!

Stilsons: I always feel a bit disappointed like it’s a bit if a failure when I have to resort to the Stilsons but I have, all too often, had to apply them and they rarely fail . . . especially when I have my length of scaffold tube over the handle to give that increased and brutal mechanical advantage!

Heat: Yes, good point. I will take my blowtorch with me when I go grovelling and, if needed, hope I don’t set anything on fire . . . particularly me!

Thanks, I do not have the correct flare nut spanner. However, I have the correct open ended spanner and the correct ring spanner - the latter will be used if the former is looking flakey, the existing sensors are toast so I’ll just cut the wire and use it if necessary. I also have a length of pipe to wield if necessary! Stilsons will be the tool of last resort!!

New Bosch O2 sensors have turned up. I have never removed the sensors on this vehicle and assume it’s just a case of disconnecting the existing ones, unscrewing them and reverse for fitment of the new ones making sure not to touch the sensor end itself. However, I have heard stories of them being very difficult to unscrew so any tips on making this easier would be welcome before I get grovelling underneath.

Genuine LR O rings have turned up. Before I get working on replacing them does anyone have any additional tips, over and above the how to’s, on the procedure. I have done it before but it was so long ago I can’t remember everything I did - I don’t remember cutting/removing the duct just a vague recollection of disconnecting and manoeuvring it out of the way. I do still have the hole cut in the centre console panel - I see it every time I remove the outer trim panel!!

I just had a quick look under - one is easily visible, t’other not so. Once I get it up on its stilts and grovel properly underneath it will submit and reveal itself I’m sure.

Well that explains why three of them appear completely static which struck me as a bit strange! I have put 2 Bosch O2 sensors on order as I couldn’t be sure of the correct NTK ones - may as well change both of them as they are still the originals and the P0155 fault code is intermittent. I can cancel it but it eventually returns after a short while. The P0135 fault code just comes instantly back when cancelled.

Now have to locate one of the O2 sensor connectors - I know it’s up there somewhere but it’s playing hide and seek at the moment!

Genuine LR O rings on order with free delivery so ha to your LPG . . . . . although that is together with a couple of Bosch O2 sensors on the order!

Well spotted. That should be 0.4V, in fact one of the upstream O2 sensors and both downstream sensors are 'pinned' at 0.44V - the Bank A upstream sensor is wanging about at a range of readings 0.1V and 0.8V changing about 4 times a second!

Bosch it is - the OEM ones look to be a third of the price of the 'genuine' LR ones! Although before I go nap I'll check the price of the NTK ones.

BTW, Nanocom seems to use Bank A & B in its values but Bank 1 & 2 in description of fault codes . . . . . although A does correspond to 1 and B to 2 at least!

Thanks Richard. Slight problem is that with the Rangie running a bit rich - see other thread - the cost of fuel to go and collect them (nearest LR dealer is 20 miles away so 40 mile round trip) will probably dwarf postage cost!

During a regular test of the HEVAC system and running the blowers/distribution/blend motors through their paces I just felt a barely perceptible dampness down by the lower blower output an the drivers side and, yes, it's hardly anything but definitely the start of the O ring problem! Been replaced once before in 2009. I'm not going to do the 'replace the matrix job' but what are the best replacement O rings to get (and what to avoid), what size and where from? I'd like to get some that will last another nearly 13 years like the last ones (which I can't find the detail of!).