Maxim X Radiator Fan Switch Modification (UPDATE)

Great post! I have been riding my maxim x since I bought it in November. Sitting in traffic the eng warms up and I can hear the fan kick on but only when the gauge reaches near the red zone. Very uncomfortable feeling! I will be working on this mod very soon. Thanks for posting this! Here in NC it's been fairly cool but I know it's going to get warmer soon and I just want to make sure my bike will run just a little bit cooler. Again, thanks for taking time to post your experiences!
Ride safe!!

 

Getting ready to do this mod myself, and wanted to provide a tip for all here.

I had tried to source the switch (Wells SW537) for the '88 Nissan Sentra through the local NAPA store. They wanted $67. ??? and it had to be ordered.

So being that I buy a lot of parts from RockAuto.com for all of my other vehicles, I decided to check there. What I found by using their drop down list for the 1988 Sentra / Electrical / Switches & Relays / Radiator Fan Switch = the equivalent switch for under $11. Of course you'll have to add the shipping cost to wherever you located.

Hope this helps.

Tony

 

WOW they must have heard it was multi-application and raised the price!

Just to clarify something from above, it doesn't matter which way the switch is connected, all it does in effect is short one wire to the other & allow current to flow.

 

I mentioned earlier that this looked like a good project, but I am a little put off by the cost of the mailing/shipping charges. I went to the Rockauto.com (thanks Tony) to check it out and for the costs to ship to a Michigan Zip was about 1 tenth the cost to Canada! The Fed Ex and UPS were a bit cheaper but using couriers can add more at the pick up point for brokerage fees (only happened once, never again) which can be rediculous.
Here's a "snip" for the U.S. costs


Here's one for the Canadian

 

What, they charge more for the same part too? 10.80 Vs 11.09 8O


And that shipping is just crazy, surely it'd be cheaper for a member to buy it in the US & then "send a gift to a friend in Canada"?

 

I'm sure there are other manufacturers making the same switch for cheaper (doesn't help with the shipping problem for sure!). I got the Wells at Autozone (I just asked for an '88 Nissan Sentra switch and it's what they had, ~20 bucks last fall). What is important is the temperature setpoint and the thread gauge; which should be consistent across manufacturers provided the switch is designed for the '88 Nissan Sentra. Also, due to the tight clearances I mentioned, make sure it fits first before you cut any of the leads.

Thanks for the feedback, and please keep posting any pictures, improvments, lessons learned to help others.

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(I went back and read Tony's post more carefully and saw that he found a switch for $11 + shipping. Nicely done)

 

Exchange rate

 

Duh of course! so US $ are diff to Canada $ lol, I'll play the "limey card" on that one k-moe

 

The exchange rate is a given, but the bit that burns my arse is the tenfold increase for shipping. I may just do the same thing as before and plan a road trip to make purchases. I'm only about an hour and a half (less on a bike ) from Port Huron so a bit of ME time on the bike combined with cheaper prices, plus the shipping alone would more than cover the cost of fuel and maybe McDonalds. A win-win all 'round!

 

I did the switch mod and it does kick in the fan just past the mid mark on the temp gauge.

However, the new switch was reluctant to shut the fan off until it reached the middle of the cold area on the gauge. Then it came back on just before it reached the middle (white) mark as the temp creeped back up.

Keep in mind that it's 35 degrees today (and snowing?) and at that point the fan just kept running while I had it idling? So I decided to let the bike cool down and than tested again. Did about the same thing. I suppose that I may have a switch that has a wider temp range for the ON/OFF switching.

So I did a little more research to see if there were any other options, and I found another switch that requires no mods. It has the same temp range as the SW537, which is ON at 203 and OFF at 194 Fahrenheit (95/90 Celsius).
For reference, the original switch has a range of 221 and 208 (105/98)

The Wells # is SW519 and I found it available through the local AutoZone.
http://www.autozone.com/autozone/parts/ ... fier=45306

Hope this helps anyone interested in doing this mod, and may save you guys north of the border a few bucks.

Tony

 

I also wanted to mention that the O-ring that came on the new switch was too large for our application. You will need to swap over your original one, or better yet, use a smaller and thinner new one.

The picture shows the original switch and O-ring on the left and the New switch on the right with the "Manly" sized O-ring that's too large.

 

Wow! Nice find; the SW519 looks nice and stubby, that will make reinstalling the thermostat housing a snap. The bulky SW537 made reassembly like solving a Chinese ring puzzle. Not having to make any modifications is a bonus too.

Another chapter in the quest for cool 8) . I've also wondered if it's getting too cool; but I keep going back to the statement in the owner's manual "...if the needle points to the red zone or higher, stop your motorcycle and let the engine cool..." Before the mod, the needle routinely 'pointed to the red' which couldn't have been good. That being said, we are guinea pigs here; so watch things closely and please continue post any observations.

 

As you can see in the previous picture, I had trimmed the lead wires back and unsoldered the wires. Made the install a bit easier, as the two connectors on the original jumper harness went right on to the switch terminals.

I actually swapped the switch over without removing the thermostat housing, saving some time there as well.

My biggest concern is not having the engine run cooler than before, that has to be a big plus for longevity. But having the fan running while idling in traffic draining the battery. We'll just have to make sure the battery and charging systems are operating at peak efficiency.

 

Good point. Leave it to me to not think through all the unintended consequences. I'm going to keep running like this and see how it goes; especially this summer when we get consecutive weeks at 95+. Nice thing is that the mod is not permanent and one could always go back to the stock setup. No such thing as a free lunch; nearly overheating engine OR tacky manual switch OR battery drain risk OR ...

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Nice work on doing the change out without removing the thermostat housing! I couldn't seem to get the right angle and was afraid I'd strip it.

 

I have been following this thread since it started and I just remembered something that may impact the running temps of these bikes, and probably others, is how clean the rad is inside. I removed the plastic drain plug and was surprised to see how much crud had acumlated in the bottom part of the rad. I could actually see that a few of the bottom flow holes were plugged as I was getting concerned about how hot it was getting. I think it's because these rads are unlike a cars radiator that it's easy to "Not see it, so don't worry about it". So next time you flush the system it might be worth having a look.
Just a thought.

 

That o-ring in the pic looks just plain too big for the switch anyway, looks like it'd squash out the side in whatever application it was used in. maybe the wrong one was put in with the switch?

 

It was a pretty nice day today (52 degrees, partly cloudy, no wind) so I tried an experiment. I took the bike out for about 30 minutes and had it nice and warmed up, then took it into the garage and let it idle. The fan comes on just a smidge past 12:00 high and runs for about 1 min 15 sec before shutting off. It stays off for about 2 min 10 sec and then repeats the cycle. I did this with a stopwatch for a few cycles and it was pretty consistent. ~ 1min on ... ~2min off.... repeat. When I was riding, I looked down a couple of times while at a light and the fan was off. I never timed the intervals with the stock switch, so I can't compare directly; but it doesn't appear that I'm getting the "fan always running" issue.

Maxim-X makes an excellent point regarding radiator cleanliness. Because I pulled the thermostat housing to swap the switch, I had drained and flushed the radiator. It definitely spewed out a lot of gunk, pretty brown actually. Considering the bike is 28 years old and the service manual says to flush the radiator every 24 months, it's no surprise that a flush was badly needed.

 

Yeah Pickax, I honestly think I got a bum switch. I'm waiting for the weather to get back up to normal temps and I'll report after I do my testing.

When I did the bike over last year I had the radiator off and flushed it out with a hose. Lots of gunk came out, so I think that it's working efficiently now.

As Bloke noted, the O-ring that they installed was probably not the correct one for the switch. I just wanted to point out the need to have a properly sized one in place before installing the switch.

 

Ive decided to finally do this. Hows it going for you that have? Did we decide the sw519 is the best candidate?

 

The SW519 looks to be a better geometric fit for sure. The setpoints for the SW537 (what I installed) and the SW519 are different; as shown in the following specs:

SW537 Cooling Fan Switch
Normally Open, Closes at 193°F-205°F, Opens at 184°F, M16 x 1.5 Thd., 2 Male Blade Terminals

SW519 Cooling Fan Switch
Normally Open, Closes at 194ºF-212ºF, Opens at 185°F-203°F, M16 x 1.5 Metric Thd, 2 Male Blade Terminals

The SW519 Open/Close ranges overlap; the SW537 do not. I have no idea how these setpoint differences will effect things; I didn't look into these details when I made the mod; I simply followed a recommendation I found in the VMAX forum.

Today was a great day for another test; it was 97 degrees! I rode for 25 miles and then parked in the sun while idling. The fan kicked on; but unlike earlier this spring (see previous test above); it stayed on and held the temp just past 12 oclock (I took a pic). I then rode up and down the block at 35 mph for a bit, stopped and checked the fan; it was off and stayed off for about 45 seconds and then kicked on and held the temp steady as before. So I conclude that in very hot weather, with my SW537 at least, the fan is primarily off while moving but will run constantly if it comes on while idling. I'm OK with this.