Lower temperature fan switch on AJ16
 

Hi gents;

Per some archived posts I went ahead and replaced the aux fan switch in my AJ16 with a lower temp WAHLER 6010 82D fan switch that comes on at 180 and goes of at 170. It fits in place of the original and I reused the OEM original copper washer with it. I modified the OEM connector to two spades, I made it extra long because my original thought was to use a push in connector thru the radiator fins, but decided against that idea. As usual I was able to clean wherever my hand and some degreaser could reach

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After I do something like this, however, some paranoia sets in.

If anyone else has converted to a lower, or this particular lower temp switch

1- did you just use the OEM washer and did your new switch leak?

2- does it matter what prong I attached the positive and negative cables to on the new switch?

3- This switch comes on at 180/of at 170. Will the fan be running too long after the car is shut down?

1- copper crush washers are intended to be one time use but iv re-used many over the years without issues as long as there not damaged, if it leaks your just have to replace it if not i wouldn't worry about it.

2- should not matter what prong the electricity flows threw it the switch just completes or brakes a circuit. wont be polarity sensitive.

3- should be fine, normally if the fans run after the engine is shut off its normally a timer controlled by the ecm anyway. not 100% sure on that with jag though. even if it is 100% controlled by the switch with the engine off should drop the temp to 160 in a reasonable enough amount of time your battery's should be fine, get it up to full operating temp and shut it off and see how long it takes for the fans to shut off.

Thanks for your reply. If I would have looked at the diagrams I would have figured out there was a washer there. I do hope this one seals properly. It’s not hard to change, but I already got everything closed up, I don’t want to take it apart again

It is rare that the electric fan is on anyway as the mechanical fan does a good job of maintaining temps. At the rare occasion that the fan is on when you actually shut down, I am not positive that the fan circuit is on the hot bus, so not sure it would be on when you shut down anyway.

Ok, Yes, I see that the fan relay is on the Hot bat, so if the temp switch met the turn-on temp even with ignition off, it would turn the fan on.
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If a copper washer leaks, it can be heated with a torch to regain its original shape and function. That's an old trick from the days of copper washers on spark plugs.

So the new aux fan switch is not leaking, works as intended, fits great ETC.......but it stays on for a LONG time after I shut down the car........At least it seemed like an eternity to me. Probably about 10 minutes.

Its a Wahler 6010.82D as mentioned

its coming on at 180F and coming of at 170F

Some internet and archive browsing reflects that any Wahler 6010 series switch will fit


1-the 6010.85 turns on the fan at 185F and of at 176F
2-the 6010.88 turns on the fan at 190F and of at 181F
3-the 6010.92 turns on the fan at 197F and of at 188F

should I stick with the one I have or get another one? I really like the idea of the fan staying on on a hot day to cool things down, but 10 minutes may be excessive. Which one would you guys pick?

I have been using a 6010.82D for years on my '96 and have been happy with it. I had first tried an .92 but didn't like how hot it let the car get before switching on. I didn't know about the ones in between; maybe they weren't available yet in 2012 when I first made the switch. Personally I think cooler is better and even the .82 doesn't come on until past N so I like it. And as many have noted it pretty much only comes on if one is using AC and driving in traffic.

-mB

Thanks Mike- but surely yours stays on after shut down on a hot day as well? They don’t close until 170 so it takes several minutes (I counted about 10) you have not had any battery drain issues?

I went ahead and ordered the 6010.88 to try it (open 190 shut down 180) since the car reaches 195 typically. it will probably stay on to cool it to 180.

because the fan switch is on the ground side of the coil on the relay you could re pin the positive side of the coil to a key on power source rather than bat + and then it will only switch when key on power is supplied fan won't continue to run after the engine is shut off

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Well, I do want the aux fan staying on after shut down on a hot day to cool the car down....but 10 minutes to bring the coolant down to 170 seems like way too long. My friend says his mini’s fan stays in for 10-12 minutes after shut down and he’s never had issues. It’s just sort of unnerving to leave my XJS behind with the fan running.

Yes, my fan will run after the car is shut down, but I'm pretty sure that is intentional. A lot of cars do that because temperatures actually spike just after shutting a hot car down (suddenly there's no more air, water or oil circulating). I've never had a battery go flat because of that. Sounds like you are giving a middling temp switch a try on yours, and that's about all you can do is try it and see if you are happy with the range it stays in. I've never been able to find out just what the range of the original switch was.

-mB

Hi Mike

the one thing that there is almost universal consensus on whenever the original AJ16 fan switch is discussed is that it’s pretty useless. It was designed to come on way pass 215, maybe even 220, and for someone like me, in Houston Texas, it’s pretty much not helpful.

Well, based on your experience I think I will go ahead and keep the switch I have, although I am still concerned about the fan running nearly 10 minutes to cool the car down. I am not sure if you are also in the Southern USA, but it’s guaranteed that my car will get hot enough for the fan to come on and stay on after shut down for 7 or 8 months of the year.....one thing is for sure, after sitting by the car for those ten minutes counting down for the aux to shut down, I restarted the car, and the A/C was able to blow cold air right away, do it did dissipate quite a bit of heat

have you had a chance to figure out how long your fan stays on after a long drive where the car reaches operating temps? Or perhaps you live in a cooler part of the country?

Houston weather 97 degrees. Drove XJS for an hour, some light traffic,lots of lights, but mainly a Friday 5th of July roads. Freezing A/C all the way from my garage .....gauge never passed the left of the N........After an hour of driving, I parked the car to get Starbucks, and the fan stayed on for 12 minutes. I stayed and counted. Went to get coffee (about 10 minutes) got back into the car, and when I turned her back on, the gauge had gone way way down, and A/C got comfortable/cool almost immediately. I guess the downside to this is that the aux fan life will be shortened, but I already replaced my stock aux fan with two spal pusher fans in front of the condenser anyway (running on the stock circuit) , so replacing them is not a big deal. I am concerned about the battery but I guess the benefit outweigh the down side.

Impressive results, and I'm sure the battery can handle ten minutes of fan.
Silly question, probably: how much would cooling the rad cool the rest of the coolant surrounding the engine? It's the heat from that, non-circulating, coolant that does the damage, right? Not the heat from the coolant safely in the rad.

I agree



Recently, either here or on J-L, a fellow did a lot of temperature graphing and concluded that the best after-cooling occurred by re-starting the car after a few minutes to circulate new (hotter) coolant into the radiator.

So, stop the engine. Cooling fan is already on or turns on. Let it cool the radiator for 5-6 minutes. Restart engine briefly (one minute? I can't remember) to circulate coolant from the engine to the radiator. Stop engine. Cooling fan runs (as expected) for another 5-6 minutes.

Whether of not a person is willing to go thru this drill on a regular basis is up to the individual.

Cheers
DD

What thermostat are you running?

Typical Jag thermostats are 82ºC (180ºF) or 88ºC (190ºF) so, by design, you're running temp will be at least 180º or 190ºF at all times.

Seems to me that what you're doing is turning the auxiliary fan into a full-time fan. But I'll have to do some mulling, taking location of the switch into consideration. And I'm on my first cup of coffee.

Cheers
DD

Which is a real 'plus' and, on that basis alone, makes the modification attractive

Cheers
DD

I run the 82 degree thermostat..... but in this weather the car will reach 190+ anyway.

I am tempted to see what the car does with the 88c switch (turning fan on at 190F and shutting it down at 180F).....I imagine the only difference in this extremely hot weather will be the amount of time it stays on afterwards will be cut down in half.


That certainly was a surprise. Looks like it’s able to cool the condenser considerably.

Actually it makes good sense for an auxiliary fan. Maybe a bit high, but if the fan works effectively, it isn't an unreasonable temperature.

Somebody figured that 220º was the point where A) the cooling system needed some help and B) post-shut down temps might begin to be an issue.

If you're running less than 220º (which you probably are) and shut down, the fan will come on at 220º to keep things in a more comfortable range.

If you're running 190-200ºF while driving, well, that's a perfectly normal-safe range. If you shut down at that temp it's unlikely the spike will reach anything dangerous. You shouldn't need the aux fan.

If you're consistently running more than 190-200 while driving then a lower-temp fan switch makes particularly good sense, as the cooling system obviously needs a bit of help.

But I fully understand the desire to build-in some buffer zone to a cooling system.

This is of interest to me, though, because I'd like my aux fan to come on less often. In my case it operates needlessly. The sources for various switches is helpful !

Cheers
DD