i ll keep this short basically i have a n indy with 919 blade engine with blade gauges went out for a blast yesterday after moving the expansion bottle to a new position bled system fan runs as it should any way as im driving along the gauge goes upto beyond the max mark and stays there then will suddenly drop back down to normal then as the revs rise it goes mental and bouncing all over the shop but when you stop its not over heating rebled the system again tonight and the fan cuts in and out top hose warm no air lock what the hells going on any ideas welcome

Bad Earth? try running a temporary known good one

That's why I run capilary gauges!
Could be the sender or a voltage problem caused by a faulty regulator?

I'd go with the bad earth prognosis

you say..after moving the expansion bottle to a new position....,
Do u check if the bottle is over the entry of wather to the engine??. Because if bottle is too low , maybe the wather cant use gravity to go into the engine.
do u understand what i try to say??,

[Edited on 8/5/08 by Maradona]