Cooling/Fan issues

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Beau254

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1st of all, hello! Im a new member to the forum. Ok boys & girls: I have a ZL1000 that the fan quit working on me. I diagnosed it & seemed I had a popped relay. I ordered & replaced both. (Just to be safe) Also, according to the recommendations on here, I jumpered both temp sensor wires. Worked great for a couple days, then fan quit working again while riding, but comes on & goes off after u kill it like its supposed to. Think I may have a bad temp sensor? May have popped another relay? Rad cap has been replaced & looks near new. Tried bleeding the 2 air bleed bolts also & no hissing. One thing I did notice is the oil temp sensor wire-lead is not hooked up. Can't even find the wire. Not sure if sensor went bad, or if it is even worth worrying about? Im thinking of wiring a manual fan switch just in case, but would like to get it working correctly. Any suggestions?
 
Hi, welcome to the forum. Glad you found us.

On to your issues; first, there is a write up in the tech section that explains most of it:

http://www.zl-oa.com/community/threads/Cooling-system-info-for-GPZ-ZL900.6246

Also, here is a second article where the diagrams may be a bit clearer [or not]:

http://www.zl-oa.com/down_loads/Fan%20Circuit.zip

The oil temperature switch needs to be hooked up for the circuit to run correctly; it's what provides the ground path for the fan switch relay that selects between the 97 and 110 degree temp switches. It was probably defaulting to the 97 degree switch [the one that controls the fan with the ignition switch off], and that may be what was working. Since you replaced the relays [hopefully you saved the old ones, they're probably ok], the first thing to do is fix the missing connection for the oil temp switch. Next, sit down next to the bike with your favorite cold beverage and clean each and every connection on the bike, starting at the taillight and going to the headlight. Apply dielectric grease to the connections as you go to seal out water. This cures and/or prevents numerous issues with these bikes. Once those two things are done; see if the fan is working correctly. If not, with the bike running, disconnect the wires going to both temp switches and connect the relay side of the 110 degree switch [not the wire going into the temp switch itself] to ground. This should force the fan on. If this works, then everything else in the circuit is correct, if not, disconnect the wire from the oil temp switch and ground it. If the fan engages, then the oil temp switch is bad; if not, we need to check the rest of the fan circuit. Unground the oil temp switch wire, and take the wire you disconnected from the 97 degree and ground it. If the fan comes on, the fan circuit itself is good and we have to figure out the problem with the fan switch relay control circuit. Try this stuff [once you start, it will make more sense and you can do it all in 10 minutes] and post the results. A word of advice, the main cause of failure of the temp switch is NOT the bimetallic element inside them; rather the wire that is epoxied into the top of the switch has had the insulation broken and the wire corroded. You can fix this fairly easily by cleaning the epoxy out with a dremel, strip the wire back to where it's good [or replace if needed] and solder it onto the pin terminal sticking up in the middle of where the epoxy was. Then mix up some two part weatherproof epoxy and refill the switch. Once the epoxy hardens, it should be ready to go. Good luck and keep us posted.
 
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Very good explanation Bob and very helpful! I do have some used sensors in case you're in need of some.
 
Thanks for the info. Very helpful! I 2nd what your saying about the oil temp sensor. I noticed it was a grounded circuit for the relays. Not sure why they dis-connected it? Sensor may have went bad? Can't even find the old lead. I ordered a new $7 lead along with the relays off the parts breakdown online, but they refunded it & said it was just dis-continued. I guess I'll have to fab & splice in a new wire. I did save my old relays, but it worked for a couple days after replacing them. I bought an extra set too. I took all the sensor/relay harness wiring connections apart previously & ckd them & they all showed to be clean as a whistle. No corrosion. Bike is very clean for it's age. Has been garaged most of its life. Has only 8300 original miles on it. Only bad thing is, u know what happens when they just sit around & aren't ridden. Little issues like this popp up...
 
Where does the black wire of the 6 pin connector of the fan switch relay go to? Did they permanently ground it to bypass the oil temp switch?
 
Can't really tell w/o taking the whole wire loom apart to trace it. Not a lot of room in there. Didn't really want to cause a big mess that I can't get all back together. I hate messing with wiring gremlins. They suck! The oil temp sensor lead is the only thing I can tell that is not hooked up though. The lead leaves the 5 pin connector thru the main loom harness like it's supposed to, but can't tell on the bottom end where it's hooked up. Everything else looks as original. Guess I'll have to try & do some further snooping. Is that blk lead the only ground to the 5 wire relay circuit?
 
What factory temp thermostat do they run in these? Do u think it would hurt to put a 160 deg. Thermo in it? Even with everything working they still seem to run hotter than usual. Also, do u think I did more harm than good bridging the 2 sensor relays?
 
Beau254 said:
What factory temp thermostat do they run in these? Do u think it would hurt to put a 160 deg. Thermo in it? Even with everything working they still seem to run hotter than usual. Also, do u think I did more harm than good bridging the 2 sensor relays?
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Although I've yet to implement "engine ice" it's supposed to be a great coolant. Others have used this with good success. Also, watch out about putting too low a thermostat. Past experience with putting too low a thermostat in one of my cars, made it run "funny". Can't elaborate, but once I switched back to factory spec thermo, it ran much better.....I'm sure we will get some feedback on this.

You can also install the MUZZY SS fan, the one Bachus has @ the ZLSTORE.COM. Anyone install one of these? I put a super high flow flex fan on my 69 Camaro. Made big diff. ZLSTORE is my new WALMART. :notworthy:

Also, if you do buy a new thermostat...put it in water and boil it to make sure it opens. Made the mistake of thinking a new part was functional only to have to rip it all apart again, cuz it was froze closed.
 
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Beau254 said:
Can't really tell w/o taking the whole wire loom apart to trace it. Not a lot of room in there. Didn't really want to cause a big mess that I can't get all back together. I hate messing with wiring gremlins. They suck! The oil temp sensor lead is the only thing I can tell that is not hooked up though. The lead leaves the 5 pin connector thru the main loom harness like it's supposed to, but can't tell on the bottom end where it's hooked up. Everything else looks as original. Guess I'll have to try & do some further snooping. Is that blk lead the only ground to the 5 wire relay circuit?
Click to expand...

It should be a 6 pin connector, with 5 wires coming out of it. Do you have an ohmmeter? If not, you can easily pick one up for under $10. Pull the fan switch relay and measure from where the black wire is in the connector to ground, should be <5 Ohms.

The black lead which goes to the oil temp switch is the only ground path for the armature [activating] side of the relay; both the yellow [97 degree switch] and white/green [110 degree switch] provide ground paths for the fan relay [the one that turns the fan on].

As Scooby noted, changing the operating temp of the motor can impact performance [and pollution standards], that seems to be the reason that Kaw did the whole multiple temp switch thing to start with; they wanted to keep the motor in a specific temperature range. With everything working correctly and something along the lines of Engine Ice, you should be okay. Biggest problems with cooling are failing to bleed all the air out of the system [one of the bolts on the water pump is also a bleeder], bad radiator caps and broken switch wires. Take care of those three things and everything should stay cool unless you're stopped in the desert or caught in ungodly traffic.
 
Does anyone know where there are any 110 degree sensors available now mama kaw is out?
 
Sorry, I meant 6 pin connector. I got that mixed up with the 5 wires. I just got in from wiring a manual fan switch for good measure. Probably going to flush rad. & try engine ice or water wetters also. I can understand the engine needing to come up to operating temp in order to run correctly, but The 97 & 110 deg. C temp sensors convert to 206.6 - 230 deg. F! To me that's way too hot. Anything over 200 deg. Is to much. They did this to help pass the California emissions test. However, I'm not to worried about emissions because I live in the great state of TX in an non-emissions county. Also, I don't know about you guys up there, but it is 110 deg. In the shade down here right now! That doesnt help any either. A 160 might be pushing it, but I bet a 180 would be ideal. Still not sure what temp they originally came with? If I had to guess, I'd say probably a 200 deg.
 
Beau254 said:
Probably going to flush rad. & try engine ice or water wetters also.
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Make sure to bleed the system, run 5 minutes, bleed again, run 5 minutes, bleed again. These guys tend to get air trapped in the system, and it can be a pain to get out. Air will definitely cause overheat issues; even with Engine Ice. Don't forget bleeder bolt at water pump.

Beau254 said:
I can understand the engine needing to come up to operating temp in order to run correctly, but The 97 & 110 deg. C temp sensors convert to 206.6 - 230 deg. F! To me that's way too hot. Anything over 200 deg. Is to much. They did this to help pass the California emissions test.
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Don't think it was specific to California, the actually did other things for bikes sold there [hence why there is a separate listing for CA bikes]. While 230 is hot, that's when the fan kicks on; not the temp they're trying to hold. Remember, the fan is a supplement to the airflow through the radiator; not the only controlling factor. If I was riding down the highway here [Where it's only in the high 90s and low 100s :)] the airflow through the radiator would provide sufficient cooling and the temp would never get high enough [110C] to turn on the fan.

Beau254 said:
A 160 might be pushing it, but I bet a 180 would be ideal. Still not sure what temp they originally came with? If I had to guess, I'd say probably a 200 deg.
Click to expand...

I believe the stock thermostat is 180...
 
golddrakul said:
Make sure to bleed the system, run 5 minutes, bleed again, run 5 minutes, bleed again. These guys tend to get air trapped in the system, and it can be a pain to get out. Air will definitely cause overheat issues; even with Engine Ice. Don't forget bleeder bolt at water pump.


Don't think it was specific to California, the actually did other things for bikes sold there [hence why there is a separate listing for CA bikes]. While 230 is hot, that's when the fan kicks on; not the temp they're trying to hold. Remember, the fan is a supplement to the airflow through the radiator; not the only controlling factor. If I was riding down the highway here [Where it's only in the high 90s and low 100s :)] the airflow through the radiator would provide sufficient cooling and the temp would never get high enough [110C] to turn on the fan.



I believe the stock thermostat is 180...
Click to expand...

Thanks Gold for putting the proper terminology into my explanation. Yea...putting too cold a thermostat will cause all sorts of kinds performance/emissions issues.
 
Ok guys. Get this: I wired a manual fan switch, like i mentioned earlier for reassurance & decided to take it for a spin. I left town & went down the hwy a few miles came back & did a little more in town driving. Both times in town (below 30-40 mph) I switched the fan on & left it on until I got out on the hwy. When I got back & was tooling residential back roads to the house (with the fan running the whole time) the damn red hi-temp warning light came on!!! Strolled in my driveway with it gurgling hot again. What the hell??? Doesn't make sense if the fans going??? I can't even leave far from the house in fear of this damn thing overheating. Starting to piss me off royally! Got to drive it a little further this time but geez!?! WTH?
 
you said "gurgling hot" which if I was a betting man the first thing I would do is replace the radiator cap with a new one. You may be surprised.
 
I,m with Furchin on this one, replace the radiator cap and bleed the cooling system before you do anything else.
 
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