V6 Prv Radiator Fan Cut-in Temperatures, changes in 1991

[jorgy9]

Hi all

since I just mentioned this on Tim's thread I though I'll also post it under a more relevant heading for the interested parties to see.

So was recently reading the french "Revue Technique" publications dedicated to the V6 PRVs (12+24v) engines, and by chance noticed that the temperatures for radiator fan cut-in have been modified. This happened in 6/91, concerns both 12v+24v, autos and manuals, and coincides with the revision of certain components for the over-heating 24v PRVs.

till 6/91:
1st fan speed 95>90 degrees C
2nd speed 100>95
thermostat: 87C

After 6/91:
1st 88>83
2nd 95>90
thermostat:78
so a much cooler engine overall!!

I immediately realised my fans clearly cut in at the 100+95 setting, although my car is a 1994! Don't know how this hapenned but, before summer comes for good, I'll get an appropriate fan switch -have found the part in Cit and it's the right post-91 spec-. Shame cos all these years my cooling system has operated under higher-than-necessary pressures-.

cheers
George

ps. will take a photo of and post here the relevant page, but later this month.

[aengus-xmv6]

hi George,

Guessing that my V6 will have the higher settings too then,
what does the temp gauge read when running?

Mine sits around 80-85, never more expect when you restart shortly after a fast run, when you see 90+ and sometimes get the overheat warning, which goes quickly after the fans have done their bit.

Sure it's not helped by the fact that the fans never run on after the keys have been removed, so the heat just site there in the system with nowhere to go.

regards
Dave

[citroenxm]

My V6 temp sits at 80-85 too, with fans on or off....

That was after I put a new thermostat in ..

I prefer that, as I think 95 to 100 (boiling point) is too hot for an engine..


Rgds

C

[jorgy9]

Thanks for the info guys, your cars look similar between them, and different to mine, which helps alot to know.

My temp seats steady at exactly 87 when going steady on the motorway. If I approach the rear of a lorry nearer than 2-3 cars' length, it starts rising. Entering the city, it quickly climbs to 95 -if I'm between traffic lights- and then towards 100 sometimes, where 2nd speed brings it down. This behavior doesn't exhibit great difference between summer/winter (Scotland).

Looks like either my car has received an old exchange engine, or, thermostat and fan switch have been taken from an older engine, or, my thermostat is bad and my fan switching is the older style. Who knows. The first thing I'll do though is put the updated switch.

BTW I'm informed the XM got the after-leaving-the-car "fans on" feature after around 1997. It needs a different Bitron box, fan switch, and cabling has differences also.

Often I see 110+ if I come back to the car 5mins after leaving it. I always thought this car's temperature tends to rise a bit too high, too quickly.

G

[citroenxm]

George,

Check your Air Con Rad also, if this is all bunged up with years of crap it will also reduce air flow through the rads..

The Air con rad sits in front of the rad, and on mine I found it all bunged up, when I converted the car to R134a gas and swapped the air con rad for the newer one, this is when I also found the temp setadying at 85 is. It NEVER goes over 90 now!!


Rgds

C

[jorgy9]

I'll do, thanks for info!

G