LPG is a big thing in Australia, people pay thousands to get their cars converted or fitted with an additional tank, most times Fords and Holdens.
I can't imagine it on a 2.2 JTS but? Have read about this engine being sensitive to fuels and can confirm it with my own experience as sometimes it idles poorly or doesn't start first time when using a full tank of Premium 98, there's a few threads on this.
Apart from the heat issue you noted in first post, how is the 2.2 with LPG?
look, as written before, I can not judge exactly how was the Autogas on my previous 2.2JTS for few reasons. the main one is that the company (mechanic) which did it here for me was doing so poor technically job that I had other problems then working system per se.
first example, when I had my car installed with autogas, came the day to pick it up. I went there and during the take-over, I smelled gas in cabin. ok, back in waiting room for few hours, problem sorted out. this things should not be happening!
second example, mechanic installed hot water lines in the very narrow space between engine and the car's body, plus adding one joint with the Schelne (metal strap). so guess what, when engine was running, there was relative movement between the parts, Schelne started eating the rubber, hot water under pressure found its way out and I got indication of engine overheating.
in few more areas the pipe routing was so poorly done, that other mechanic in AR service was asking was I doing this job or some other amateur!?!?!? after several iterations on complaints and repairs under guarantee, last time I went there the boss told me that they fired their mechanic, because lately they were mostly doing repairs of the installations than the installations themself.
back to autogas itself. on highways I have noticed that oil temp goes bit up, but nothing that would worry me. on gasoline, it would normally staying at 90 deg C, while on autogas was running at around 100 deg C.
but in the city it was able to heat up quicker, especially if you are in the stop and go in fully congested streets. again, that should be normally corrected with the fan operating, but due to the bad installation, guess that hot water under pressure found its way out!
for that reason I thought that adding additional radiator or increasing the capacity of the current one would have done the job.
since I made 100k KM on that car, both guarantees expired, I knew that I had troublesome installation and got chance to get the current baby, I decided to sell that car!
still think that some bit more educated mechanic with experience could have tuned the system good.
the system on the car was BRS sequent, meaning that it was 1 of 4 or 1 of 5 injections still done with gasoline (to run fuel through direct injectors) and the rest was done using Autogas with extra injectors.
but, both BRC and Vialle have developed now fully direct injection systems, using most of the parts from original gasoline system. The only change is, of course beside the new tank and additional ECU, flange on the low pressure fuel pump on the gasoline reservoir. everything else is OEM from the car. the problem is that JTS engines are not any more in production and are for the cars that stoped producing in 2011. so, no business case for BRC and Vialle if they need to give guarantee on their products
since system is so small impact on the car fuel system, ECU is more less standard, programmable unit and even pump is standard (Bosch?) part, one just need to spend some time tuning the program!
that is why I said that we should mollest the Vialle and BRC demanding that they tune their systems for our cars, since still lot of them on the streets, meaning lot of money waiting to be collected.