Coolant temp gauge shoots to max.
 

Hiya All.
I have been a happy 440 owner for 2 weeks and the daily commute has become the highlight of the day.
A problem has arisen with the coolant temperature system.
When I turn the ignition on (without starting the engine) the coolant temperature needle shoots straight to maximum.
I am replacing the temperature sensor but if it was faulty I suspect the temperature would indicate low.
Any thoughts.
Regards, Robin.

I can't comment on 440s in particular, but it's my understanding most cars would have the temperature gauge behaving like that when there's an open circuit to the earth. Either a duff switch, or chafed wiring allowing the circuit to be completed.

If you remove the wire on the temp sender, and it does the same, its probably chafed wiring. If you remove the wire and the temp gauge then reads 0, it's probably the sender unit.

Many thanks indeed.
 

Many thanks indeed to Tofufi.

I replaced the sender today and no change so wiring it is....sigh.

Is it possible to disconnect the wire at the speedometer end (without disconnecting the others) to test that the gauge itself isn't faulty? I'd imagine not, but it could be possible.

As I said above, I've no 440 experience at all so only going on general principles. Good luck!

Coolant temp sender to dashboard needed. Volvo 440
 

Many thanks for the previous reply. It seems there are two coolant sensors on the 440. The one I changed is for the fan only.
I went to a Volvo specialist who isolated the fault to the temperature (to dashboard) sender but that, it seems, was the easy part. Getting hold of a Volvo one is the hard bit.
The local Volvo Specialist advised against using an aftermarket item as they think it could burn out the dashboard dials.
Has anyone any ideas?

Weight loss problem.
 

As the car has no temperature gauge I am running the heater at Maximum to (hopefully) detect problems through reduction of heater air temperature.
It takes an hour to get to work each day and I am losing about a stone a week in my sauna-car. If I cannot find a sensor in the next 12 weeks I will...vanish.:speechless-smiley-5

Temp problem
 

Hi, if you look back at some old threads you will see lots of information on temp problems with gauges.
Had the same problem twice with my 460 over the last 18years, and it proved to be the little brass spacers between the pcb and gauge,as these carry the earth through, slight white powder between the brass and solder of the pcb the cause.
Volvo used to say it was the pcb on the back of the gauge failing and first time I changed the pcb it fixed problem, but failed again after 10 years.
I bought a pcb from a scrap car that I new worked but found cleaning the spacers got the gauge working again.
Not saying this is your problem but it might help checking.
This is a post I put up about 10 years ago and sold the car about 5 years ago.

Many thanks.
 

Many thanks Jeff.
I am hoping the local Volvo specialists are right when they point to the sensor but will take your advice if things need to go further.
Sincerely.

Something is causing a ground to earth through the positive lead. Either the sensor or wiring.