From a point at sea, to the circles of your mind, this is Dave
Wheatley:

There are 2 issues I have- spluttering when running gas & the coolant one.
Would the problems caused by a bad gasket be evident on both gas and
petrol though, rather than just the gas. Is the timing/compression etc
more critical when not using petrol thus causing the misfiring?

It does seem that the two things may not be related. If the vapouriser
is hot when it starts to splutter then it is not freezing due to
coolant loss.

A car running on LPG does give the ignition a harder time - the LPG
mixture is more resistant to letting a spark pass through it than a
pertol mix. If your high tension ignition components are not in good
condition then the spark can try to find its way home via other
routes. This often involves backfires in the inlet manifold, but can
involve rough running. On my Volvo I had to replace everything, the
plugs, the coil, the ditributor cap and rotor arm, and the HT leads.
But it did have a very destructive backfire habbit.

Does your answer above imply that you only lose coolant when running
on LPG? If so, maybe you have an overheating problem caused by poor
setup.


--

Stewart Hargrave

A lot faster than public transport


For email, replace 'SpamOnlyToHere' with my name