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Cooling fan control issue?


johnnyboy

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Hi Guys.

 

Anybody know why the engine management system on my 2006 350z has started asking for both cooling fans to come on full ("mode 3"), whatever the input?

 

Until recently the RH fan came on slow ("mode 1") with the aircon switch, the LH fan came on slow ("mode 2") when the engine got up to temperature and they both came on full ("mode 3") when the coolant temperature got over 100 degrees C.

 

To confuse the issue I have just put some Mishimoto fans on, and I understand (from Mishimoto support) that although Mishimoto fans are now "plug and play" and require no wiring changes they are only single speed fans (I was not amused at this definition of "OEM compatible"...). However, they say there is no reason for the fans to have caused this "both or nothing" scenario (anybody out there with Mishimoto fans got any ideas?).

 

I have taken it to a "Nissan High Performance Centre" who billed me £87 for plugging in a scanner and telling me that the fans were doing exactly what the controller was telling them to do and that there were no fault codes, and suggesting that I paid them a further £240 to check the wiring (but agreed that they could not think of any possible wiring fault that would cause this scenario....).

 

Any thoughts on a next step?

Edited by johnnyboy
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This might help you:

 

http://www.350z-uk.c...rs-youtube-vid/

 

Too Late! (The old ones were binned :bang: ).

 

It all seemed so simple... Nissan wanted £560 for a new fan (ie. each, and I think not including VAT). I did think of trying to refurb the old ones but didn't find the link you have.... and I saw elsewhere on here that people were giving good reports of Mishimoto replacements. At £171 for a pair (with shroud), it seemed a no-brainer. I should have known better.

 

But thanks anyway - I should maybe get some Nissan fans (and a shroud...) from a breaker and give it a go...

Edited by johnnyboy
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From what I've heard and seen from another member both the fans run together.

 

Do you mean with Nissan fans or with Mishimoto? (with a scanner and the Nissan fans installed, I am sure I saw it cycle through the "modes" as described above - it was just that the LH fan would stick sometimes until you gave it a tap)

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f***ing noisy.

 

have you ever heard the mishimotos?

 

Exactly...

 

Particularly bad when you are going slow with the aircon on on a warm, damp, day - in fact today!

 

(Noisy fans when you are desperate to cool the thing down on a hot day at 5000 revs is OK. On tickover round town is less so.)

 

Also, I am finding that the engine keeps getting too cold! The fans are so effective that they drop the radiator below "normal" operating temperature and cycle off...

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I'm currently playing with the idea of upgrading my fans or taking apart the old ones to clean the brushes and motor up. Are the misimoto fans not worth the hassle buying then?

 

I've just contacted them to see if they have stock lol!

 

I was quite happy with them until I heard the noise and then found out they were single speed. Then not so much

 

If you decide to get any can I have your old ones?.

Edited by johnnyboy
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Are they just noisy when you sit in traffic with no air moving over the rad? Or are the noisy all the time?

 

Has anyone else had any issues with the Mishimoto fans?

 

At high revs / high speed you don't notice it (as much...).

 

It is in traffic (but with a cool engine, when you would expect a single fan on slow...) that you really notice it. It is louder than the engine. Mishimoto tell be it is because they are "straight bladed fans for efficiency an slim profile"

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Are they just noisy when you sit in traffic with no air moving over the rad? Or are the noisy all the time?

 

Has anyone else had any issues with the Mishimoto fans?

 

At high revs / high speed you don't notice it (as much...).

 

It is in traffic (but with a cool engine, when you would expect a single fan on slow...) that you really notice it. It is louder than the engine. Mishimoto tell be it is because they are "straight bladed fans for efficiency an slim profile"

 

To be honest, I'm sort of relieved to hear cooling fans kicking in when stuck in traffic. Good sign they're working! lol :D

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Are they just noisy when you sit in traffic with no air moving over the rad? Or are the noisy all the time?

 

Has anyone else had any issues with the Mishimoto fans?

 

At high revs / high speed you don't notice it (as much...).

 

It is in traffic (but with a cool engine, when you would expect a single fan on slow...) that you really notice it. It is louder than the engine. Mishimoto tell be it is because they are "straight bladed fans for efficiency an slim profile"

 

To be honest, I'm sort of relieved to hear cooling fans kicking in when stuck in traffic. Good sign they're working! lol :D

 

In practice they are on all the time... and remember they are on all the time you have the AC on... and I like to be able to hear the radio...

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Right...

 

Put my Zed through the Autotest to see if the fans were working at all. Ran it twice, so 6 times the vehicle went through the process and the fans didn't kick in once!

 

Tested the fuse / Relay, all working fine so out with the old fan shroud. :rant:

 

In with the new Mishimoto fans, and boom put it all back together works a treat. Ran autotest and they fired straight up, got it up to running temp and 1 kicked in, put A/C on and both came on.

 

Personally, I highly recomend the Mishimoto fans I don't think their too loud at all. In fact I think they sound too healthy! Plus with my stereo booming and my Invidia Dual exhaust I would struggle hearing them anyway.

 

Gone back into my garage today to have full silicone Mishimoto hoses and new thermostat fitted, then full coolant bleed!

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Right...

 

Put my Zed through the Autotest to see if the fans were working at all. Ran it twice, so 6 times the vehicle went through the process and the fans didn't kick in once!

 

Tested the fuse / Relay, all working fine so out with the old fan shroud. :rant:

 

In with the new Mishimoto fans, and boom put it all back together works a treat. Ran autotest and they fired straight up, got it up to running temp and 1 kicked in, put A/C on and both came on.

 

Personally, I highly recomend the Mishimoto fans I don't think their too loud at all. In fact I think they sound too healthy! Plus with my stereo booming and my Invidia Dual exhaust I would struggle hearing them anyway.

 

Gone back into my garage today to have full silicone Mishimoto hoses and new thermostat fitted, then full coolant bleed!

 

Can I have your old Cowl and fans then please?

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Right...

 

"got it up to running temp and 1 kicked in, put A/C on and both came on".

 

 

That's good information... I think it shows that I have a (separate) problem with the IPDM/ECU.... remember mine now both come on full at normal operating temperature (with no AC), and again both on full when I turn on the AC (with a cold engine).

 

Looking through every post I can find, some people refer to both fans being on all the time with Mishimoto's. with single running only being available with OEM fans - which sounds illogical now I come to think of it...

 

Anybody got practical experience of fixing a "lack of single running" issue? What did you do? (in fact, what is going on?)

 

(and Rich, I mean it about buying your old stuff if you want to get rid of it)

 

John

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Right...

 

"got it up to running temp and 1 kicked in, put A/C on and both came on".

 

 

That's good information... I think it shows that I have a (separate) problem with the IPDM/ECU.... remember mine now both come on full at normal operating temperature (with no AC), and again both on full when I turn on the AC (with a cold engine).

 

Looking through every post I can find, some people refer to both fans being on all the time with Mishimoto's. with single running only being available with OEM fans - which sounds illogical now I come to think of it...

 

Anybody got practical experience of fixing a "lack of single running" issue? What did you do? (in fact, what is going on?)

 

(and Rich, I mean it about buying your old stuff if you want to get rid of it)

 

John

 

Hmm, could be a different ongoing issure you have then.. Yea I havent even had time to to clear all the crap away from when I changed it on the weekend so as soon as I'm sorted and got em ready to sell or whatever, I'll PM you Johnny

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Like Johnnyboy I am confused. Mine boiled during last hot Sunday. Neither fan working. Connected battery directly to fan motor terminals. Drivers side both terminals worked. Near side only one worked. Replaced nearside motor and now, on the car, nearside comes on but not drivers side. Put AC on and still only nearside works. Should OEM's both come on together ? Do I have a separate problem with drivers side fan ,(relay ?) because it works when direct to battery. HELP !

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Like Johnnyboy I am confused. Mine boiled during last hot Sunday. Neither fan working. Connected battery directly to fan motor terminals. Drivers side both terminals worked. Near side only one worked. Replaced nearside motor and now, on the car, nearside comes on but not drivers side. Put AC on and still only nearside works. Should OEM's both come on together ? Do I have a separate problem with drivers side fan ,(relay ?) because it works when direct to battery. HELP !

 

Both sides should come on when AC is on. Probably the same issue everyone else gets where the contacts in the motor are too clogged up. My advice would be take the motor apart and clean up like others have before, then reconnect it all and see what happens?

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