Outer Limits 4x4 Board

Not on a 4x4, but hopefully somebody can suggest possible causes:

A mate of mine has Valiant Coupe with 6 cyl Hemi 245 on gas.

Only happens on longish trips, after about 40 minutes to an hour or so at 100kph, she starts to cough, splutter and die. Switch to petrol for a while and all is good. When he switches back to gas after running on petrol for a while she runs fine again for about 20 minutes before doing the same thing again.

Any suggestions gratefully appreciated.

Sounds like the converter (most likley) or the carb freezing.

Excuse my ignorance, what's the converter and what does it do?

Apparently happens more in warmer weather, and is fine on petrol. Any suggestions of it is freezing?

The converter is a heat exchanger that converts the liquid lpg into a gas by heating it, if you have an air lock or other cooling system problems the lpg freezes the converter stopping the flow. When it happens next get out and see if the converter is covered in ice.

if the rad level is low than it may cause the convertor to freeze up, my old mans did this just fill it up and away she goes

Awright, thanks guys, this is starting to make sense. He was having severe overheating problems recently and replaced water pump, fan, etc. and cleaned cooling system. It's only started having this problem since the colling system problems were sorted.

I used to get the same problems with my Valiant, it was the convertor freezing up. Had to replace one of the hoses and clean out all the crap from the lines. Had the radiator flushed as wel and everything was good again.

I miss my Valiant

AJFeroza wrote:Awright, thanks guys, this is starting to make sense. He was having severe overheating problems recently and replaced water pump, fan, etc. and cleaned cooling system. It's only started having this problem since the colling system problems were sorted.

Hi AJ, I recently went through similar drama on my GQ and the gas convertor was the problemon mine. I had it replaced with a new one because my old one was close to 15 years old and it would have cost the same to rebuild the old one.
The convertor was $250 from the Gasman at alexandria.

Cheers, Rod

Cheers guys. I knew I'd find an answer here

How're things anyway Rod? (Maybe should pm?)

AJFeroza wrote: How're things anyway Rod? (Maybe should pm?)

PM sent.

Loanrangie wrote:The converter is a heat exchanger that converts the liquid lpg into a gas by heating it, if you have an air lock or other cooling system problems the lpg freezes the converter stopping the flow. When it happens next get out and see if the converter is covered in ice.

Position of the converter is often critical in the older cars......

Make sure that the converter is mounted LOWER than the highest point that the water reaches prior to the converter being fitted.
High mounted converters will suffer from freezing far more often than others that are located lower down in the engine bay.

Other thing to check is the thermostat ....... make sure it has one fitted and that its working.


Kingy

Thanks Kingy. The car recently had new water pump, thermostat, radiator flush, new fan, etc.

I'll catch up with my mate on the weekend and have a look at where the converter is located.

V8Patrol wrote:

Loanrangie wrote:The converter is a heat exchanger that converts the liquid lpg into a gas by heating it, if you have an air lock or other cooling system problems the lpg freezes the converter stopping the flow. When it happens next get out and see if the converter is covered in ice.

Position of the converter is often critical in the older cars......

Make sure that the converter is mounted LOWER than the highest point that the water reaches prior to the converter being fitted.
High mounted converters will suffer from freezing far more often than others that are located lower down in the engine bay.

Other thing to check is the thermostat ....... make sure it has one fitted and that its working.


Kingy

In my rangie the converter was mounted higher than the engine/ rad on the inner guard and i never had probs with freezing, its only if you have cooling system issues or let the level drop that it becomes a problem.
All the air has to be released from the system to prevent airlocks etc, but yes lower is better.