Temp guage and sender issue

[pedro B]

Hi guys, I am new to the forum and am after a little advice. I have a 2.0 E AUDI cabriolet 1996

The guage was reading intermittently so I changed both the blue square two pin sender and also the grey 3 pin sender.

The guage then began to read. Yippi all is well.

No......the guage now goes up to 110 when hot (seems high) when it goes above the 2nd dot on the guage the red light flashes, the fans come on and it goes off eventually.

The water pump still has the belt on it so it is pumping.

my guess is either

1 the thermostat is not opening properly because the passenger compartment get hot quick

2 the water pump is dead and not pumping water around the engine fast enough.
3 the new sender is crap and I need to fit another
4 may not have enough concentration of coolant in engine?

[scotty33]

I think the electric fan is operated by a temperature switch on the radiator. If so, the fan operation is independant of the gauge sender (grey). The gauge reading, cooling fan operation and overtemp alarm all seem to suggest that it actually is getting very hot.
I guess it is possible there is a blockage or airlock affecting coolant flow, but it seems more likely the thermostat is not opening. If a new stat does not help, look at the waterpump, if that's ok, it must be a blockage?

[pedro B]

I was thinking about it and that seems to make sence. gonna buy a stat and then play hunt the stat. thanks for the help......will keep posted

[scotty33]

The stat is located under the 'flange' where the bottom radiator hose connects to the engine(water pump housing).

[Dox]

If the cars not actually over heating then I'd take the new sender back.

There will also be an earth tag to the engine block somewhere near the sender, make sure its clean secure, connected and not broken internally.

[pedro B]

fitted new stat,

still going to top on needle, but engine is cool near the stat. put old sender in and Old sender seems to work occasionally, possible earth fault?