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Heater o-ring replacement full procedure & new shortcuts

The technical forum for the P38a/second generation Range Rover 1995-2002

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Heater o-ring replacement full procedure & new shortcuts

Postby paul.adshead » Wed Jan 10, 2007 7:53 pm

SOURCING THE REPLACEMENT O-RINGS
I searched the RR.net main site and found here, that the Landrover part number is STC3262 (and you need two of them). I phoned the local LR dealer, they wanted NZ$9.94+tax each - total NZ$22.37.
I then searched the RR.net forums and found a post from Jos Geuze, where he lists the o-ring size as "22mm inner diameter and 2.5mm thickness". I went to the local auto store (- Repco) and they had loads of different sizes of o-rings. I bought 2 of the size specified by Jos, for $2 each = $$'s saved.

ACCESSING THE O-RINGS
I'd read from the main RR.net site, that accessing the o-rings to replace them, was a bit of a nightmare. Forum posts of 12 hours and $1000 labour to remove/reinstall the dash sounded horrific. I thought there has got to be a better way, (which I subsequently found)! Credit where it's due, to the contributions of others along the way and from the main site.

The entire difficulty in accessing the o-rings, comes from the one HEVAC duct that passes in front of the o-ring connection and feeds air to the rear passengers' RH face vent. If you take this duct out of the mix, then access is pretty good. The unfortunate thing is, that it is really quite difficult to remove this duct (intact) without removing the dash. So what about removing the duct in two pieces....

PROCEDURE TO CHANGE THE O-RINGS (ON A RHD)
1, Remove RH footwell-light panel above brake/accelerator pedals. Secured with 3 plastic screws/connectors. Disconnect footwell light connector.

2, Remove lower fascia-panel under steering wheel. Secured with four large and two small crosshead screws.

3, Remove upper instrument-panel cover above steering wheel. Secured with four small crosshead screws.

4, Remove instrument-cluster. Secured with four crosshead screws. :!: Make sure ignition is fully switched off when disconnecting any wiring connector to the instrument cluster! It must remain switched off, any time either connector is not present! :!: Disconnect airbag and instrument wiring connectors.

5, Remove LH instrument-cluster mount-bracket. Secured with two crosshead screws, going into the rear of the dash.

6, Remove the duct that feeds the far right dash vent. Slide the 'gate' to the right to release from the lower HEVAC duct; push the duct's right hand end forward to disengage; retrieve the duct through the hole in the dash.

Image
(Picture from RR.net)

Image
(Picture from RR.net)

At this point you should be looking something like this:
Image
Note, that this picture shows the top HEVAC motor also disconnected (- 2 screws and pull out the motor), but this is probably unnecessary.

7, Slide RH front seat, fully rearwards.

8, Remove windows/sunroof switchpack. Secured with two crosshead screws. Screws are accessed from top front edge, of the open cubby-box lid. Disconnect switch pack connector.

9, Remove RH centre-console side-panel. Secured with two crosshead screws. Refer to these two videos of the side view (9.9MB) and rear view (4.1MB) for the 'nack' to release this panel. As long as you have released the rear of the panel upwards and outwards, you can be quite brutal to release the clip at the front.

10, Remove the RH heater floor vents.
Outer vent.
Image
(Picture from RR.net)
Inner vent.
Image
(Picture from RR.net)

11, Drill 10mm access hole in side panel. Make sure that you stop as soon as the drill is through the panel (- other components are not far underneath). Don't worry about leaving a visible hole, this hole is covered by the side panel removed in step 9.
Image
(Picture from RR.net)

12, Remove the ducting retention screws. Using access hole drilled in step 11 and another screw lower down. These screws and duct are numbered "6" in the RAVE picture below.

Side view showing the aluminium heater water pipes and the HEVAC duct causing the access issues.
Image

Rear view showing where the heater water pipes connect to the HEVAC box (- on the far right hand side).
Image

Photo of the o-ring connector.
Image
(Picture from RR.net)

Photo showing the o-ring screw (at the top).
Image
(Picture from RR.net)

13, Disconnect the upper and lower ends of the problematic HEVAC duct from where they connect to the HEVAC box and rear ductwork.

NEW SHORTCUT!
14, Cut HEVAC the duct in two and remove. You will need a sharp hacksaw blade and about five minutes of elbow grease. The top portion is retrieved through the dash hole and the lower portion is slid out from below. The location of the cut can be seen from the photo below. When removed, clean up the 'fur' on the two edges, created by the hacksaw blade, using sandpaper or a small knife - don't make the gap any bigger though!

Image

This now gives you un-precedented access to the heater o-rings and the securing screw. Unfortunately I didn't take a picture at this stage, but you can imagine the access, given earlier photos and the RAVE diagrams above.

15, Drain some of the engine coolant. Remove the header tank cap. Place a clean bucket under the radiator in the engine bay. Using a 21mm socket, gently/slowly undo the drain valve in the centre of the base of the radiator. Be looking to take approx 3-5 litres of coolant out. Re-tighten the radiator drain valve!!

16, Remove the screw securing the heater o-rings. This screw often siezes in quite well - a few tips to remove it:
a, firstly, spray WD40/CRC on any exposed threads.
b, before trying to undo it, try to tighten the screw, slightly further - this often un-siezes the bolt, whilst not destroying the faces of the screw head, that are to be used to undo the screw.
As soon as the screw has started to turn be prepared to catch/ mop-up coolant in the footwell. Remove the screw.

OPTIONAL STEP
17, Remove the two aluminium pipes from the firewall. This is optional, as you can clean the ends of the pipes whilst still in-situ, but I chose to remove them from the car to clean them more throughly. To remove the pipes requires you to release the two coolant hoses from the within the engine bay. Make sure you note the orientation of which pipe goes where! It's your choice if you want to do this step or not.

18, Clean the two aluminium pipe connections. I carefully used an 'artificial wire wool' to remove all of the rubbish/ built up crud/ coolant residue. At this point I noticed some small amount of corrosion damage to the sealing surface on the end of the pipes. It was probably part of the reason for the leak originally. :-(

19, Using a small mirror, look under the dash and check the sealing surface on the heater matrix, that the new o-rings will be going back onto. Using a clean cloth thoroughly wipe this surface of any rubbish/ built up crud/ coolant residue. Do NOT leave any bits of cloth/rag behind.

20, O-ring connection re-assembly. If you removed the aluminium pipes, now put them back through the firewall, roughly in position. As the sealing surface of my own aluminium pipes was slightly pitted, I put some 'oil rated', 'form in place gasket' material on the end of the pipes. Then, put the new o-ring on the end of each pipe. Push the aluminum pipes back into place on the HEVAC box. Put the securing screw back in and tighten it up. I used a new screw, as the old screw-head was damaged during removal.

21, Go and have a coffee. If you used any 'form in place' gasket material then you need to leave it all be, without movement, for at least 15 minutes.

TESTING BEFORE FULL REASSEMBLY
22, Put the instrument-cluster loosely in place and (temporarily) re-connect the two multiplugs. :!: Remember ignition must be off any time either connector is not present! :!:

23, Reconnect the two coolant pipes in the engine bay, if you disconnected them earlier.

24, VERY carefully remove the breather line from the top right end of the radiator (- twist the pipe axially to release the seal). Pour the earlier drained coolant back into the header tank. When coolant appears at the breather port, replace the breather hose. Then pour more of the remaining coolant into the header tank, up to the mark on the side.

25, Run the engine at a fast idle, for 5 minutes. Briefly 'blip the throttle' to 3000 RPM, to flush through any air-locks. Pour any remaining coolant into the header tank and top up if necessary. Replace the header tank cap. Continue to run engine for 5-10 mins more and check for leaks.

REASSEMBLY
26, The HEVAC duct cut and removed earlier, is repaired in-situ using high strength duct tape, as per the photos below. There is enough space to get your hands around all of the sides of the duct.

Image

I then went a bit crazy with the tape, and put it over a few of the other joins too. :-)
Image

27, Re-trace your steps, to re-assemble the rest of the components removed.

JOB DONE

Not including coffee time and engine warm up, then with a good breakfast, it would take less than two hours to do this again.
:-)
Last edited by paul.adshead on Wed Jun 27, 2007 1:57 pm, edited 1 time in total.
Paul
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Postby wayne » Wed Jan 10, 2007 8:42 pm

Paul: Thanks for the detailed post on this greatly feared task. I don't have a problem yet, but I am certain it is in my future. Do you think there will be significant differences for a left hand drive??
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Postby jsp » Wed Jan 10, 2007 9:19 pm

umm I cut mine the same way, it allowed me to move the bottom portion out of the way but I couldn't get it out all together?

Was a moot point in the end the dash came out for a new matrix :(
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Postby paul.adshead » Wed Jan 10, 2007 11:52 pm

wayne wrote:Paul: Thanks for the detailed post on this greatly feared task. I don't have a problem yet, but I am certain it is in my future. Do you think there will be significant differences for a left hand drive??

On a LHD, then removing the glove box may well give you near identical access as to that gained by steps 2-thru-6 inclusive and should allow you to cut the problem duct (- the top end of the duct may have to stay in place, but that is not a problem, you only need the bottom end out). Further, if you removed the passenger airbag, then I'm pretty sure this will give even more improved access - you might even be able to get the duct out in one piece! :-)
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Postby Lee-J » Sat Jan 13, 2007 6:24 am

Excellent work Paul, I shall be printing this out for reference due to the damp carpet that I knew spelled this task :(
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Postby Overfinched » Sat Jan 13, 2007 6:53 am

Very good report, Paul.





(Just remember to replace the duct for the right hand vent BEFORE you reassemble everything! I didn't and got a bit upset with my motor vehicle........when I saw it sat on the back seat ) :roll:
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Postby jcole21 » Sat Jan 13, 2007 8:03 am

Great write-up. Posts and knowledge like this are what make this website so valuable.
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Postby shupack » Sat Jan 13, 2007 10:13 am

does anyone know what size that screw is? (for the orings)
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Postby Max » Sat Jan 13, 2007 3:17 pm

The screw is an M5x0.8mm ISO coarse approx 15mm long.
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Postby paul.adshead » Sun Jan 14, 2007 2:18 pm

shupack wrote:does anyone know what size that screw is? (for the orings)

Why, are you going to expand upon your EAS business, to now include heater oring kits too? :-) :-)
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Postby shupack » Sun Jan 14, 2007 8:45 pm

orings are orings...the screw would be a good addition I think.
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Postby mattco » Tue Mar 06, 2007 8:08 pm

I started my o-ring replacement tonight and as it has been said before, this isn't for the faint of heart. I am pretty mechanically inclined, but getting that last screw out was a nightmare. I saw a tip saying to cut a hole in the side of the center console and I ended up doing that and getting the screw out just before I stripped it out completely.

I am picking up a new bolt tomorrow and putting it back together. I replaced the sensor while I was in there even though it really isn't that tough to get at in my opinion, maybe an hour of effort. I just hope this was all of the leak and the heater matrix wasn't leaking too.

I have some pictures of the screwdriver setup I used if anyone is interested and the hole I cut in the side of the center console. The best combination of screwdriver I found was a 1/4" driver with a 6" extension, then a universal joint, then another 6" extension with the bit on the end. This seemed to give me enough play to get where I needed to be the best for me.
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Postby Captnrangie » Tue Mar 06, 2007 10:46 pm

Hi Paul

Great post and discription, i have just printed it off and will study it tonight. I had a wet LH floor just before i came away, so just cleared the drain under the floor, and switched the A/C off and decided to forget about it till i get home next week. Now i will have the proceedure to find the problem and sort it, I'm sure i will have a few questions to ask you when we all meet in a few weeks time too!

keep on rovering, this is good stuff! :D

Ian
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Postby chrisall » Wed Mar 07, 2007 3:27 am

shupack wrote:orings are orings...the screw would be a good addition I think.


If you do then I would think about replacing the standard phillips screw with a stainless cap-head one. No corrosion and much easier to tighten (and remove if it fails again). Also, I would increase the length slightly, as I found it difficult to get the standard screw to start when I replaced mine.

Cheers,
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Postby MJSAUL01 » Wed Mar 07, 2007 3:58 am

Brilliant. This is why this is the best forum.
The cutting the duct is great also for the dreaded blend motors. I cut mine when I did the last set. All it needs is a little duct tape and jobs good, saves a lot of fiddling around.
Thanks Paul for taking the time and effort of posting your efforts.
TTFN
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