940 radiator fan intermittent

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

James Sweet - 25 Oct 2005 22:56 GMT

A friend's 940 has been overheating occasionally for quite a while now
requiring the heat to be cranked up in all sorts of weather to keep it
out of the red. He eventually tracked it down to the electric radiator
fan occasionally not starting but I haven't had a chance to diagnose it
further. What's involved in the fan control? Is there anything other
than a relay and a temperature switch? My two main suspects at the
moment are a bad relay, and a bad winding on the motor armature causing
the fan to not start if it happens to stop on the dead winding. Is there
anything else I should check?

Reply to this Message

Peter K L Milnes - 26 Oct 2005 01:40 GMT

Where is the fan? if it is in front of the radiator (and aircon) then it is
meant to give a boost to the cooling if air con is on and car is stationary
or slow moving in traffic. I would check the mechanical fan for correct
operation (it is temperature dependant) and possibly refresh the refrigerant
in the air con as there are pressure switches involved in switching the
electric fan.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).

>A friend's 940 has been overheating occasionally for quite a while now
>requiring the heat to be cranked up in all sorts of weather to keep it out
[quoted text clipped - 5 lines]
>start if it happens to stop on the dead winding. Is there anything else I
>should check?

Reply to this Message

James Sweet - 26 Oct 2005 02:45 GMT

> Where is the fan? if it is in front of the radiator (and aircon) then it is
> meant to give a boost to the cooling if air con is on and car is stationary
> or slow moving in traffic. I would check the mechanical fan for correct
> operation (it is temperature dependant) and possibly refresh the refrigerant
> in the air con as there are pressure switches involved in switching the
> electric fan.

It's the primary fan behind the radiator, 940's never had mechanical
engine driven fans, at least not here.

Reply to this Message

User - 26 Oct 2005 06:24 GMT

> > Where is the fan? if it is in front of the radiator (and aircon) then it is
> > meant to give a boost to the cooling if air con is on and car is stationary
[quoted text clipped - 5 lines]
> It's the primary fan behind the radiator, 940's never had mechanical
> engine driven fans, at least not here.

IIRC the fan relay is a two speed type like the 850 and it sits low
where the battery can crap all over it.

Bob

Signature

The goal when driving is to miss the maximum number of objects.

Reply to this Message

Mike F - 26 Oct 2005 13:31 GMT

> IIRC the fan relay is a two speed type like the 850 and it sits low
> where the battery can crap all over it.
>
> Bob
> --
> The goal when driving is to miss the maximum number of objects.

And on Bosch FI the fan (relay) is controlled by the fuel computer,
which gets it's information from the engine temperature sensor. There's
no separate temp switch on the rad like you're used to on your 740.

940s with Regina fuel systems do have the separate temp sensor.

Signature

Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

Reply to this Message

James Sweet - 26 Oct 2005 18:36 GMT

>>IIRC the fan relay is a two speed type like the 850 and it sits low
>>where the battery can crap all over it.
[quoted text clipped - 8 lines]
>
> 940s with Regina fuel systems do have the separate temp sensor.

I'm pretty sure it's a Regina fuel system, been a while since I was
under the hood but I'm pretty sure it's the car I'm thinking of with no AMM.

Reply to this Message