Hi Everyone,

Just noticed the cooling fans have stopped working on my 97 XK8, they used to operate correctly and run after switching engine off, but now they dont seam to run at all.

can anyone advise what to check first. Im going to do a little research but if someone can point me in the right direction it would be much appreciated.

many thanks

Steveeasy

update
after reading a few past threads I ran the engine with ac on and the fans worked as before. so it seams with the ac on the cooling fans work, but not with the AC off. any idears?

thanks

 

The first thought that comes to mind is that the fans are not needed without use of the AC. They function as needed directed by temperature readings and other inputs provided by the various parts of the coolant system to the ECM.

Understanding that the temp gauge has no value are there any other indications that the engine is operating at above normal temp?

The Summer weather has broken where I live and coolant system operation should change accordingly.

 

See if you can get a 100 ohm resistor with wire leads (any wattage). Unplug the coolant temperature sensor (gray two pin connector, front and center on the top of the engine). With the ignition fully on, and engine off, 'plug' the resistor into the contacts on the harness side of the connector. If the fans start, all is well with the fan circuit and controls.

If you have an OBDII reader, also read the coolant temperature cold and warm and see if cold is ambient and warm is about 85-100C. This will check the temperature sensor.

 

White XKR... you are a wealth of knowledge on these cars! Amazing.

 

Hi
thanks for the help. in reality during the summer the fans operated fine it seams. now having turned the AC off, A short drive round the block and the engine was extremely hot, no fans operating.

Any suggestions on a reader that will monitor coolant temp ?.

many thanks

Steveeasy

 

You may be worrying unnecessarily. Emphasis on the MAY!

Temperatures in Lincolnshire at the moment are much the same as they are here 200 miles further north. My cooling fans are not operating during or after short drives of less than 5 miles whereas they would kick in a month or so ago. My earlier 2001 XK8 behaved similarly.

That being said, any excess coolant pressure or temperature should be investigated as overheating seriously affects the V8 very quickly.

You really only have two options for monitoring:

1. scantool such as AutoEnginuity which will allow you to monitor coolant temperature
2. fit WhiteXKR's RealGauge to make the temp gauge read correctly

A less costly but less informative approach is irreversible temperature sensitive strips as used in the medical and food processing sectors.

Graham

 

Hi Graham,
thanks for your response. I think you MAY be right. I clearly need to check the pump and thermostat now. and consider the temperature switch. I do need a code reader and if this will show coolant temperatures this will be very helpful

what confuses me is how the AC being on, can influence the operation of the fans.

I wonder if I have a combination of issues here, say a tired water pump, As the engine clearly seamed to get far too hot on what was a 4 mile trip. the fans did not operate but as I was moving the radiator should have had sufficient air flow.

Clearly im a bit behind the times as im used to only dealing with a pulley operated fan, and thermostat. Still these issues are part of the challenge

thanks
stephen

 

Search 'ELM327' on ebay. You will finder readers from China that work with your PC through the USB port for well under $20 that will work just fine. Use the attached software download, not the junk they send on the little CD.

 

Hi,
for that price its worth a go. thanks for helping.

Stephen

 

Hi whiteXKR,
I searched ebay and purchased the hardware for £12, downloaded the software, magic, it must be the cheapest way to access error codes and engine data. thanks for pointing me in this direction.

ill have a better idear now of what im dealing with.

thanks

stephen

 

You are welcome. Except for some auto parts stores that might offer a free code read, that is about as inexpensive as it gets.

Do consider ReaGauge though to keep an eye out for cooling system and oil pressure problems on a daily basis, which may pay off in the long run on an older car.

 

Hi,
Yes ive been considering realgauge for a while. sounds a great product.

many thanks

stephen