Outer Limits 4x4 Board

Hi All,

First time since I had any problems LPG related since I bought my truck a few months ago.

234K on the clock.

Recently I noticed that when the truck is running on LPG the temperature needle would hit just below the over heat mark on the temp gauge, I then would need to switch it over to petrol and drive it and the temperature will slowly but surely go back down to normal.

I did run a tank of petrol ( 75L ) dry before reverting to use LPG since I was told I needed to run a full tank of petrol every 4th LPG tank.

Yesterday I came into an intersection about 10mins from starting her up from cold and she stalled for no reason and would not start on LPG so I had to sit there trying to crank it over on petrol and luckily she turned over. Before I switched it over to petrol I did notice the temp needle sitting on the overheat mark.

I drove home on petrol and turned her off for about 30mins and then started her up on petrol to run all the remaining petrol out of the carby. Once the truck stalled due to lack of petrol I switched it onto LPG and she started first go.

Can anyone explain why this is happening on LPG? or anything in particular I need to check?

At this stage Im hoping its the thermostat, I will get this replaced first thing. Might just be a coincidence that it happened twice on LPG.

I have flushed and filled the radiator with the correct coolant and its only been around 2500km since the last service. I changed oil, oil filter, spark plugs, spark plug leads, fuel filter and air filter.

Had the same problem with my MK, started doing it last tuesday, ran ok wednesday and then on thursday morning going to work it did it again, temp was right up to the high mark, I pulled into a servo and she just stopped, it wouldn't start on either gas or petrol.

I pulled the bonnet open and the converter was frozen along with thefeed line to the carby. All the coolant hoses were as hot as except for the two flow lines to the converter, they were cold.

I can only put it down to one of 3 things:

1. Water pump has crapped itself, if so why the cold hoses to the converter.

2. Thermostst has given up the ghost

3.The gas converter is blocked, hence no flow which would lead to the feed line being cold.

I have checked the hoses for blockages and they are fine.

My GQ has 250 000kms on the clock just had new water pump and similar thing, the missus kept telling me it was getting hot, i would have to put about a litre of water in every week. I warmed it up took off the cap and sure enough little bubbles, of the combustion gas type.
I did however stick some of the alluminium filing head repair stuff in and this has stoped the getting hot and water loss but by no means a long term solution. Tommorow im pulling of the head and i hope its just a failed head gasket. GQ's do however split heads right down the centre, LPG being a contributing factor as it does burn hotter than ULP. Hope this helps and with some luck it will be somthing cheep to fix.
cheers Brunsy