My journeys are either around town or long distances towing a variety of trailers so I didn't really notice at first, but mine seems to be using less LPG now I have a complete new system with cats (admittedly much smaller than the originals) that with the gutted ones that were on it before. I also had the odd zingy noise but as it was only noticeable from outside (and I'm not usually outside), I ignored it. Now I just have a very pleasant hum.....

Most likely you have a small leak somewhere. A common place is where the hoses join the steel connecting pipes. The steel pipes start to rust so you get a leak at the join when it gets hot. As it is hot the coolant evaporates so there's nothing dripping out but the level will still drop slightly. Other common culprit is the water pump, again, the coolant evaporates so nothing drips but if you look at it very closely, you'll see the trails where the coolant has leaked.

Mine was plumbed in parallel when I first got it and noticed the heater dropped down to vaguely lukewarm while siting at idle waiting to get into a car park to do my Christmas shopping, but fine once the revs were up due to lack of flow at idle. The Classic I had before was also in parallel and that would ice up the vaporiser within a couple of hundred yards due to lack of flow through the vaporiser. Swapping both to series cured both problems and allowed the pipework to be a lot neater. As Simon says though it is going to depend on the car and how clogged up things are. Might be worth reverse flushing the heater and vaporiser and seeing how much water flows and how close to oxtail soup it looks.

As well as needing the unlock codes for other models for some you need a different cable too. Tried using mine of a Disco 3 and it didn't want to know. Checked with BBS and found that it will connect but only with the correct cable. Hardly anything can talk to the 2002-2010 L322.

No idea on the Audi core but on the original the flow goes in at the bottom and the return out of the top. I'm not much of a fan of the Audi core mod either. The original O rings lasted over 15 years and while being a bit of a pain aren't that difficult to change whereas to change the heater core involves either a dash out or butchery to the metalwork to allow it to be got out. As Sloth says, change the O rings every so often (although I'd say nearer every 10 years would be adequate) and leave things as they are.

Replace filters, check for leaks.

It shouldn't make a difference which way round the flow through the vaporiser is. In theory it should be inlet at the top but in practice it makes virtually no difference. With them plumbed in series, then you will get full flow through both. If they were in parallel I would say that was the problem as the coolant would take the easiest route but in series? How high up is the vaporiser mounted? If too high you could be getting an airlock in it or there may be too much restriction to the flow. What size hoses have you got going to the vaporiser? What vaporiser do you have? On both mine I've got the 19mm hose from the inlet manifold to a reducer down to 16mm, though the vaporiser and then another 16-19mm adapter to the heater and they are both working fine, even in this weather. The sensor will be reading a bit low if it is on a rubber hose rather than the original alloy pipe but I wouldn't have expected it to read that much lower. Do you have an infra red thermometer to check the temperatures of the flow and return hoses to the heater at the bulkhead? Mine read the same within a couple of degrees.

It's the one clipped to the inlet pipe next to where the O rings live. The clip can break so it falls off the pipe and just dangles so reads ambient temperature. I know it's been cold but I doubt it got that cold.......

Yes, it's open circuit.

James, did you get my PM with the part number for the bumper blanking plates?

Only the last one? I must have lost about 5 by leaving them on the bumper and forgetting to put them back on. I buy two at a time now so I've always got a spare.

Yes having to take the weight of the hose can be interesting. Standing there like a bloody scarecrow with one arm outstretched one way holding the hose and the other holding the button in on the pump.

I'll get mine too then. I've got the cup and Acme adapters in my centre cubby but I think I've only used the Acme one once or twice. Nearly as good as ours unlike the cup filler where you have to support the weight of the hose to stop the seal leaking on half the pumps I've found.

There's 4 different fillers, the bayonet type used in the UK and Holland, the Acme screw used in Germany and Ireland, the Euro filler used in Spain and Portugal and the Italian cup used virtually everywhere else. I've got the standard UK filler but it has a 22mm thread on the inside so I can screw in an adapter to any of the other types. Take off the cap, screw on the adapter and fill so no real problems as long as you have the adapter.

What filler have you got?

Depends what filler you have but if you have a look here https://tinleytech.co.uk/product-category/lpg-parts/filler-components/caps-and-housings/ you should find the right one.

All the tailgate wires are white as a security measure (so nobody can identify the wire that opens the tailgate if you ground it). Why not just turn the ignition on, put it in reverse and see which of the 4 wires is live?

Up a bit and to the right......

He said he's in Fife in the Radius Arms thread.

It's the same with other cars. Friend's son was trying to get insurance of a 1.1 Fiesta and getting stupid quotes. He had nothing going for him, 18 year old student with a driving licence that the ink was still wet on. Found that while the Fiesta was going to cost a fortune, he could get insurance on my friend's old Peugeot 405 diesel for sensible money. It's all done on risk, number of 18 year old students driving a Fiesta that make a claim versus number of 18 year old students driving a Peugeot 405 diesel that make a claim makes him look like a good risk. It'll be just the same with the Volvo, How many young drivers in Volvos make a claim? Not very many I suspect so statistically it looks a better risk but in reality it's because very few young drivers drive Volvos.

Mind you, getting back to the original question, how many claims have been made by young drivers in diesel Range Rovers? Again not many I suspect.

Nice little run then. The last couple of summer camps at Marty's have been over a weekend so some have stayed in a local hotel on the Saturday night with a beer or three in the evening to make it worthwhile. Morat's skills with the barbecue have to be sampled too.

Check for play, if none, replace the rubber, if there's play, bite the bullet and replace the joints. How is the rest of the restoration coming along?

My local motor factors sells assorted sized rubber boots so I'd be inclined to get one of the right size or even slightly larger, slit it, wrap it round and Superglue the ends together. Much the same as the universal CV joint boots that you can buy that even come with a tube of glue. Assuming there's no play in the actual joints, all you are doing is keeping the grease in and the wet out.