does yours do this

[menostig]

Now my temperature guage/sendor combo is accurate, I can see the following behaviour at the start of every drive:
- within 3 miles of urban driving it climbs visibly to 80 or 90
- then shoots down over a couple of seconds to 65
- then rises to about 80, then drops to 70 but both gradients much more gradual
- then settles at 60-80 depending if I'm cruising (60) or traffic-bound (80)
- from this point on it's well behaved

So it's just that initial rise where sometimes it approaches 90 which is a bit worrying. It is just like my earlier thread predicted about the lack of a rad bypass. Any other Sport or GTR owners see this ?

Does opening the heater valve make much odds - not experimented with this yet, it's too hot outside.

cheers
Roger

[gdr]

Used to do something similar, erratic and very rapid rise on gauge especially in traffic, sometimes if working it hard on track, then sudden drop off to low temp, eventually in cruise mode it would settle out 82 ish. I believe it was airlocking. Spent ages trying to bleed without success but eventually raised the swirl pot about 4 inches and problem has gone away.
Heater valve position might make a difference, worth enduring sauna for a bit with it open to try and flush air from system.
Also, where is your temp sender? 60 deg is a bit low I think, have you a thermostat in it?
Not just Ultima problem, had a TVR 350i many years ago would do same thing when heater valve partially open. Dealer unable to fix. Was a case of "they all do that" (ie part of the wonderful TVR owning experience).

Edited by gdr on Saturday 24th June 15:11

[bigmack]

I really don't see the problem? I wouldn't sweat it. I don't start worrying until my water temp hits 100-105!
Relax and have fun with the car. I'd be more interested in your oil being too cool.
Cheers!
-Mack

[peterpsg]

I appear to have a block mounted thermostat, or at least there a sensor comming off the side of the head and another by the dizzy (Oil Pressure I think), and when I'm driving normally the gauge sits at 80 and stays there...

I've had it up to 95/100 on a hot day at a slow crawl...

[stig]

I just replaced my fans and the car now holds a stead 85 when driving, rising to 100 in traffic, fans cut in, temps drop to indicated 95 (I reckon the Stack over-reads slightly having tested the temps at the rad with a thermal gun) and fans cut out again

That was in yesterday's high ambients too.

[menostig]

ok, cooling sussed. New fan switch sorted it. Now onto the electrics...