I'm an x350 owner, but have a question for the x300 group. I recall reading some old thread over in this section about your radiator fans running a minute or two after shutdown in hot weather. Is this true? Does the ECM keep your fan on to eliminate heat soak issues?

My x350 does has done this for a few years in summer ever since the ECM was updated at the dealer (was told this programming change was done to fix a hot restart issue on some vehicles). Even the owner's manual says that fan run-on will occur under certain conditions. It has never been an issue, but I do worry if I make a lot of short trips it will run the battery down. Fortunately I almost always drive more than 5 miles on any given trip.

Thanks,
-Michael

 

I shouldn't worry about it Michael, there is supposed to be a thermostat involved somewhere (inter cooler water temperature?) The X300 XJR only does it after a caning and in hot (admittedly by UK standards!) conditions. Short journeys shouldn't set it off, all other things being equal, unless you are in an extremely hot climate.

 

My X306 XJR runs fans after shutdown regularly in summer, and I live in New England. I don't remember my normally aspirated X300 doing it, but it may be due to my bad memory.

 

I should have been clearer. I believe Juha is correct, and it is only the XJR which had a fan that can run on. The normally aspirated cars do not as far as I know.

 

My car usually doesn't run the fan after I stop it, even after a long run, even if it is around 90 degrees. However If I stop first at the store or something for ten or fifteen minutes then drive the couple miles home it will run a bit after I stop . I think that a "heat soak" condition warms the motor up more that usual on the second stop.

 

Thank you all for the replies!

Understood that it's an XJR specific action, that makes sense since I'm sure the S/C engine runs hotter than N/A. I was more curious the effect of the fan running on regardless.

Most x350s do not run the fan after shutdown (mine didn't for the first 7 years). There was a specific TSB that the dealer did to update the software. Only after the ECM flash did mine start doing it, and several Jag techs told me this is by design. I did a lot of troubleshooting thinking it was a problem, but it turns out Jag just redesigned the software so that whenever fuel temperature is above 90C it runs the fan for 3 mins after shutdown. I can make it stop by faking out the fuel temp sensor, but that defeats the purpose.

On my car, any time the ambient is above ~85 F it will run the fan if I've driven in city traffic or stopped any idled for any amount of time. If I drive on the highway, pull off, and shut down, the fan won't run because the engine bay is cooler. If I drive 3 miles in the city during summer, it will run the fan.

I was mostly curious whether the battery can handle multiple short trips. I'm sure the ECM monitors battery voltage and will not run it if below a certain threshold, but still. If I drove to the store, started and drove across the parking lot, then started and drove to another store, it would have run the fan for 12 minutes in total. But based on juha_teuvonnen's comment, I guess I won't worry too much. I do realize the fan doesn't consume much current once it's up to speed. And my fan runs at low speed, not full blast.

 

My X300, the mighty 3.2ltr engined beast had the Efans of course.

IF, and I mean IF, I pulled up and the Efan was running, it would continue to run after engine shutdown until a predetermined temp at the radiator sensor was reached.

IF the Efan was NOT on when I shut the engine down, then it did NOT start up and do anything.

Same with all my V12 cars for too many years.

If the Efan is ON at engine shutdown, it will stay on as designed.

 

Here in the desert of British Columbia, Canada, my beautiful beast runs fans after semi -mountainous trips at ambients of +35°C, quite frequently.
Runs for maybe one minute + after shutdown ;...note that I've never seen the gauge over normal during any driving conditions, including stop/start in heavy traffic at similar temperatures.
Sounds OK to this OF!!

 

My normally aspirated XJ6 fans will run after the ignition is turned off.

I live in Vegas and its been 105F for quite a while here.

 

Same here.

 

Thank you all!

I feel better now about my x350 running the fan. Not even noticeable when parked outside, but when I pull in my garage then I can hear the fan run. More of an annoyance to me than anything else. I will live with it for the summer months!

 

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