Excitable Temperature Guage On Mk3 Ls400

[jeastham]

Searched the forum, and not come across anything similar, so here goes......

My temperature guage requires an exorcism. It will steadily climb up, almost to the red, and then drop like a stone to the mid-point on the guage.

If I'm stationary in traffic, and the needle starts to climb up, then turning the ignition on and off sets the needle close to the midpoint.

The car is LPG converted, so there is a coolant hose running over the top of the engine (to supply coolant to/from the Vaporiser, to stop it icing up).

I'm thinking :

1) Air-lock somewhere in the coolant system, but then surely any trapped air would get pumped around with the water, and end up in the expansion tank ?

2) Dodgy coolant temperature sender - Any ideas as to where it lives, and how much of a 2nd mortgage I need to buy one from Lexus ?

3) Dodgy temperature guage; never had this happen before.

I welcome any advice. I might pop down to Lexus tomorrow, and enquire as to the cost of a sender and guage

TIA

Justin

[simontaylor]

I would guess at an air lock, but this should be easily bled out.

On the other hand, has the problem just started or did it start after the LPG was fitted?