Urgent Advice needed - Temp gauge - Please help

[tacoma]

Hi guys it is with some sadness that i report that i have sold my car yesterday; albeit i think it is going to a very good home.

I haven't been using the car for the last 3 months or so and when i took it out on the test drive for the new owner the temp gauge in the car was reading 120!!!! We were almost home after quite a short, moderately paced run so i pressed on to home. There were seemingly no ill effects. And the guy bought the car and will collect it next weekend

I went out to the car this morning, having read Steve Heath's chapter on the cooling system. I was a little low on oil but the anti-freeze/ water levels were fine and the radiator was full on opening the bleed valve. I turned the car to pre-ignition and the temp gauge went straight to 120, the engine had not been run for 24 hours! I want to sort this before the new owner picks up the car. Is the gauge 'failing safe' by giving a maximal reading, is this something simple that i can fix or is it garage time or worse still 'expensive TVR Specialist' time?

Please help, i think it only fair to sort this before handing the car over to another PistonHeader.

Mike

[cmr2payne]

have you bleed the radiator, it says in the steve heath guide how to. I had this problem ones and it was an airlock

[chassis 33]

I'll just pop outside and see what happens when I disconnect the sender, it may be that the wire has popped off or such like.

Give me 10mins!

Regards
Iain

[chassis 33]

Right, it's the opposite to what I said, shorting the sender wire out to earth gives a maxed out reading, disconnecting the wire gives minimum reading. You need to check for a chaffed wire or the like. The sender is in one of two positions, either just next to the coolant temp sender for the ECU, or underneath the inlet manifold behind the dizzy...and is a BASTID to get at, I'm now back off to fight this one out

Regards
Iain

[tacoma]

chassis 33 said:

Right, it's the opposite to what I said, shorting the sender wire out to earth gives a maxed out reading, disconnecting the wire gives minimum reading. You need to check for a chaffed wire or the like. The sender is in one of two positions, either just next to the coolant temp sender for the ECU, or underneath the inlet manifold behind the dizzy...and is a BASTID to get at, I'm now back off to fight this one out

Regards
Iain

Thanks Iain, would you mind if i gave you a call so that you could talk me through finding it? My number is 01939 270361 if you call me i will call you right back. Really appreciate this....

m

[frankgilbert]

Apparently there are 3 temp readers on the V8.1 behind the dizzy at the front and on top of the r.h.V bank,with a 2 pin connector this feeds the ecu.The second is either on the swill pot or rad ,this operates the fan and the 3rd sits in the V of the engine above the water pump and behind the dizzy a ba----- to get at but can I am informed be done without stripping the front down .it is this little b----- that runs to the temp gauge. Best of luck,P.P.of Melton Mowbury told me this is the case in regard to my 96 chim.

[Paulathome]

Hi Mike, sounds like temp sensor has failed which is fairly common.
The part is available from most TVR dealers/suppliers and cost about 15 quid.
Just had a look on clever trevors web site and he has them. Part No N0125.
Cost £13.21.
There are often 2 seperate sensors fitted on the inlet manifold, one of which is
not connected to anything but is just fitted to block the hole in the water jacket.
This will not have any wires fitted to it. The sensor you need to replace is the one
with a single spade connector wire going to it.
Best undone with a ring spanner if you can get one on and don't forget to change the
copper washer at the same time.
Hope this helps
Paul.

[david beer]

If you have the "spare" sender you can use this one,saves removing the old one and risking air locks etc. Normally a 120 ohm resistor is needed but if you go a variable 200 ohm you can set it up correctly.