any way to adjust fan speed at idle?

810 Views 18 Replies 7 Participants Last post by pboglio, 18 d ago

statera

Discussion Starter · 20 d ago

so as we all know the juke isn’t very good at idling, but i noticed mine tends to get really hot when it idles for a while, say if i’m waiting for something in my car.

when parked the radiator fan often does not run, despite the space around the car and the hood being noticeably hot to the touch. it doesn’t seem to bother the ecu but i’m noticing the alternator going through what seems like a power surge fluctuation when this happens. i tested the fans using cvtz50’s service functions and they do work as expected at high medium and low speeds.

basically what i’m asking is; is there any way i could adjust the fan curves like i would on a computer? i know fan speed is computer controlled, but it feels like the computer wants to cook my poor engine alive.

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Bargeld

· #2 · 20 d ago

Sounds like there is another root cause to your issue. I would try to fix the overheating problem. Are you leaking coolant, have you tried to flush it or have it flushed? Any odd behavior other than just "it runs hot"?

It's not supposed to run hot.

Macgyver

· #3 · 20 d ago

Not user able to and I dont think Nissan Consult can do it either.

When you say Hot. Cars get Hot while idling. Your hood will get hot.

What is the temp of the coolant when you say its hot ? Do the fans turn on when the AC is on ?

statera

Discussion Starter · #4 · 20 d ago

3

Macgyver said:
Not user able to and I dont think Nissan Consult can do it either.

When you say Hot. Cars get Hot while idling. Your hood will get hot.

What is the temp of the coolant when you say its hot ? Do the fans turn on when the AC is on ?

the fans don't go past low when parked, with the AC on it sits around 85 but when i turn the AC off the temps go up as hot as 98c before going back down to 95. occasionally i do notice coolant going missing (but i don't smell/see it burning or notice it leaking) but the coolant only seems to go missing when it's been idling for a while.

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Bargeld

· #5 · 20 d ago

That's the CVT temp, not the engine temp? The fans won't do anything to that temp in its OEM form. If you mount an external cooler and put the rad up front, then those fans might have an effect.

As it says, engine temp of 98^ is OK in he right in green. It's the CVT reporting HOT.

pboglio

· #6 · 20 d ago (Edited)

98*C engine, 92*C CVT.

From the datalog traces, your vehicle isn't overheating. The service manual has the different temperature fan actuation points. Nothing about 98*C says to me it's overheating at idle regardless of what you feel. What temperature you feel underneath the vehicle or hood is not just the coolant temp. It's a combination of the extreme exhaust heat and fan jet wash and can be highly exaggerated in warmer conditions.

I don't believe the ECM can be reprogrammed without some type of reflash. My other vehicle I believe I can alter the fan actuation temps as you're requesting here but I have full control of the aftermarket ECM flash software on that vehicle. Not sure if ECUTek or UPRev even allow it on the Juke, let alone the Consult.

FastReligion

· #7 · 20 d ago

98*c is 208*F. That's too hot. During idle, the coolant temp should not go much over 180-190*, even on a really hot day. Even beating the snot out of these you shouldn't see over 200*F. AC running will bump the temp up, but again, should not go much past 180-190. Thermostats are wide open at that point.

only way to change fan speeds is to get a ecu tune. ECUtek and Uprev both allow for modification of fan speed at certain temps.

Jaxxa

· #8 · 20 d ago

Sounds like what you need is some passive cooling, just hack a bunch of holes in your hood like I did to let the hot air vent out the top!
Seems to be a good option when I'm out offroading at low speeds.

Also it's showing CVT in red because it has logged a transmission error, you can check and clear the CVT codes with the same app

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pboglio

· #9 · 19 d ago (Edited)

Look at the datalog. The temps peak at 98*C then the fan kicks and draws it down in under 1 min. My other vehicles a 206*F at idle is the threshold limit for the fans to kick on as stated in the service manual, then they pull the temps down to about 186*F rating of the thermostat. Then it rises again and the fans cut-in. This is normal.

I have never seen in my life a vehicle that could hold the thermostat temperature rating at idle indefinitely without the fans at full blast to draw it down. It's possible to wire them that way but it's not even required. The OP has complete and total thermal control, there is no thermal runaway as the datalog clearly shows it stair stepping downwards once it hits 98*C it starts drawing down quickly. The ECM is commanding this anyway.

Generally, you are wasting your time on the cooling system unless you can't "cruise" at the stock thermostat setting, then I would start looking into it.

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FastReligion

· #10 · 19 d ago

3

Once again, comparing different vehicles. Even with the water control valve closed, coolant still moves through the system. At an idle, not moving or revving, the coolant flow through the cylinder head keeps all of the coolant in the engine cool. The water control valve does not even open unless things are getting really hot. The coolant in the head flow directly through the block. The thermostat controls coolant temp. The water control valve is there to open IF temps get too high. It is just a means of flowing more coolant through the system than normal. On V2 MR16DDT's the water control valve is electronically controlled, and during heavy load situations (and certain emissions situations), it opens to ensure maximum coolant flow to PREVENT the engine from reaching temps that would otherwise have opened the valve.

Its called a water control valve for a reason. A thermostat is called a thermostat for a reason.

Go take a look at the upper housing, then look at the coolant passages in the head and block, then go look at your coolant outlet for the water pump. The pump is fed from the block, not the head. So, even though primarily fluid flow is pushing through the head, a large amount of coolant in the block itself is being moved through the system anyway.

As the thermostat opens, cold coolant from the radiator gets pulled into the system. Now, if there where no means of circulating that coolant out of the radiator, there could be a vacuum. But there is not. There is enough free flowing passageways between the head and the upper radiator hose, that the coolant is able to freely circulate. This is why when people do suffer water control valve failures, they only witness rises in temp during highway (heavy load) driving, but low speed (low load) the car does not over heat as severely. As at low load (idling as the OP mentioned), there is enough circulation to keep the engine plenty cool.

idling with the AC on, that will cause enough heat to build up in the radiator that sitting still will cause temps to rise enough to kick the fans on to a higher speed and open the water control valve, yes. But. the AC being on is considered a high load situation when sitting still, as there's more than normal load on the engine and on the heating system and your RPM's are higher.

In fact, if you look at the diagnosis for the p1217 engine over temp code, it tells you to inspect/replace the thermostat BEFORE the water control valve, because the thermostat controls more heat transfer than the water control valve does.

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statera

Discussion Starter · #11 · 19 d ago

Jaxxa said:
Sounds like what you need is some passive cooling, just hack a bunch of holes in your hood like I did to let the hot air vent out the top!
Seems to be a good option when I'm out offroading at low speeds.

Also it's showing CVT in red because it has logged a transmission error, you can check and clear the CVT codes with the same app
View attachment 193583

i like the way you think

oh and i cleared the CVT code and it hasn't come back, no lights were on on the dash either which was weird.

Reactions: 1

pboglio

· #12 · 19 d ago

I'll say it again, the ECM is commanding to actuate the fans at 98*C, WELL below a critical temperature or the boiling temperature of coolant under rated pressure. The coolant cannot maintain thermostatic temperature without airflow as it's physically impossible. ALL gas engine vehicles without continuous fan airflow or airflow from vehicle speed will creep up temps at a stop. The radiator core efficiency drops immense without airflow. There is no need at idle load to require low coolant temps or basically the thermostat temp. There is no risk of engine knock as the ignition timing is already low and there is almost zero engine load. Boiling temps are going to be nearly 250*F and thus if you are below 212-220*F this would be the threshold limit typically on most cars for idle. Here it actually is about 208.4*F set by the factory. Please explain to me how this logic doesn't make sense? If the fan cannot draw the temps down there is a serious serious problem and the datalogs CLEARLY refute this. There is NOT a problem here, the fan actuated and temps immediately pulled down and would have pulled down to thermostat given enough time. I don't have the fan actuation temps for low-high speed and AC actuation, someone can dig into the service manual to find them.

Datalog on cruise conditions and report back. If you can hold thermostat temps at cruise then you are solid, you already did the idle test and it looks nominal for a gas 4-cyl engine. Some service manuals will even tell you at what coolant temp threshhold the ignition timing get's retarded and this would tell you the danger zone, I can't find it in the Juke service manual.

Beyond this, take it to the dealership and they will tell you exactly what I'm saying. I have a bunch of ECUTek datalogs including extended idle I can post up to illustrate what I'm talking about and I had ZERO problems with cooling.

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JukeAholic

· #13 · 19 d ago

pboglio said:
I'll say it again, the ECM is commanding to actuate the fans at 98*C, WELL below a critical temperature or the boiling temperature of coolant under rated pressure. The coolant cannot maintain thermostatic temperature without airflow as it's physically impossible. ALL gas engine vehicles without continuous fan airflow or airflow from vehicle speed will creep up temps at a stop. The radiator core efficiency drops immense without airflow. There is no need at idle load to require low coolant temps or basically the thermostat temp. There is no risk of engine knock as the ignition timing is already low and there is almost zero engine load. Boiling temps are going to be nearly 250*F and thus if you are below 212-220*F this would be the threshold limit typically on most cars for idle. Here it actually is about 208.4*F set by the factory. Please explain to me how this logic doesn't make sense? If the fan cannot draw the temps down there is a serious serious problem and the datalogs CLEARLY refute this. There is NOT a problem here, the fan actuated and temps immediately pulled down and would have pulled down to thermostat given enough time. I don't have the fan actuation temps for low-high speed and AC actuation, someone can dig into the service manual to find them.

Datalog on cruise conditions and report back. If you can hold thermostat temps at cruise then you are solid, you already did the idle test and it looks nominal for a gas 4-cyl engine. Some service manuals will even tell you at what coolant temp threshhold the ignition timing get's retarded and this would tell you the danger zone, I can't find it in the Juke service manual.

Beyond this, take it to the dealership and they will tell you exactly what I'm saying. I have a bunch of ECUTek datalogs including extended idle I can post up to illustrate what I'm talking about and I had ZERO problems with cooling.

I mean, your engine and CVT did both end up blowing up so maybe it was running too hot this whole time and you thought it was fine? Also, please post the applicable datalogs, I'm curious to see what they say, as my car running at 36PSI after multiple dyno power pulls didn't see past around 190ish*F.

Bargeld

· #14 · 19 d ago

Did you have large external shop fans blowing the radiator on the dyno?

Edit: Brevity. 190^ pfft. I was at -20F.

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FastReligion

· #15 · 19 d ago

Bargeld said:
Did you have large external shop fans blowing the radiator on the dyno?

Edit: Brevity. 190^ pfft. I was at -20F.
View attachment 193589

No. The fans we use are fairly small. The cooling systems in these cars are pretty robust. We used our shop test car at 450 whp over and over again for about 2 hours, then when we got off the dyno, noticed the fans werent even on. Car was fine. Good temps. Jukeaholics car went through a beating with just the small fans aimed at the intercooler only.

JukeAholic

· #16 · 19 d ago

Bargeld said:
Did you have large external shop fans blowing the radiator on the dyno?

Edit: Brevity. 190^ pfft. I was at -20F.
View attachment 193589

more like this size lol:

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pboglio

· #17 · 18 d ago (Edited)

Statera,

I re-read your post. Actually @Bargeld is correct here. The CVTz50 is flagging engine coolant temp of 98*C under these idle conditions as "OK" in GREEN. CVT coolant temps track with engine coolant temps as this is the CVT cooling system too. The CVT trans case & sump pan has decent cooling itself. If you are idling at 98*C then the CVT temp of 94*C isn't un-expected. With the engine cooling fans pulling the engine temps down to say 85*C I would recheck the CVT temps and I bet they drop accordingly. I'd double confirm everything at cruise.

The missing coolant after extended idling.....that isn't good if that is correct. But, if the temperature keeps rising at idle before the fans kick on, then the cooling system will keep pushing fluid out into the overflow tank, as it drops it would pull fluid back in. Make sense, it physically is designed with an internal check valve for siphon draw or thermal contraction, and the pressure cap for thermal expansion. Thus the cooling system and overflow are in constant "communication" with each other.

I actually don't see anything wrong other than a slightly hot CVT temp but I would check that again while cruising and try and keep in under 100*C. If not then maybe a beehive filter swap and CVT oil change would help.

Good luck.

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statera

Discussion Starter · #18 · 18 d ago

pboglio said:
Statera,

I re-read your post. Actually @Bargeld is correct here. The CVTz50 is flagging engine coolant temp of 98*C under these idle conditions as "OK" in GREEN. CVT coolant temps track with engine coolant temps as this is the CVT cooling system too. The CVT trans case & sump pan has decent cooling itself. If you are idling at 98*C then the CVT temp of 94*C isn't un-expected. With the engine cooling fans pulling the engine temps down to say 85*C I would recheck the CVT temps and I bet they drop accordingly. I'd double confirm everything at cruise.

The missing coolant after extended idling.....that isn't good if that is correct. But, if the temperature keeps rising at idle before the fans kick on, then the cooling system will keep pushing fluid out into the overflow tank, as it drops it would pull fluid back in. Make sense, it physically is designed with an internal check valve for siphon draw or thermal contraction, and the pressure cap for thermal expansion. Thus the cooling system and overflow are in constant "communication" with each other.

I actually don't see anything wrong other than a slightly hot CVT temp but I would check that again while cruising and try and keep in under 100*C. If not then maybe a beehive filter swap and CVT oil change would help.

Good luck.

so wait, i’m reading that and some things are starting to make sense.

the car used to lose coolant all the time but i figured that there was air in the system. i’ve been adding coolant each time it dips near empty. and it’s been happening increasingly less and less. the last time i have had to add coolant was probably about three weeks ago. for good measure i checked it just now after a spirited drive home and it hasn’t moved an inch.

my apologies, i should have mentioned that in my original post, i guess that’s what i get for primarily posting on the forum while also at work.

pboglio

· #19 · 18 d ago

statera said:
so wait, i’m reading that and some things are starting to make sense.

the car used to lose coolant all the time but i figured that there was air in the system. i’ve been adding coolant each time it dips near empty. and it’s been happening increasingly less and less. the last time i have had to add coolant was probably about three weeks ago. for good measure i checked it just now after a spirited drive home and it hasn’t moved an inch.

my apologies, i should have mentioned that in my original post, i guess that’s what i get for primarily posting on the forum while also at work.

OK, that is exactly what happened to my Juke. I think it was a factory problem when they filled it....maybe. Same as you and eventually I eliminated the air, pretty simple.
That's good, means you have pushed most air out.

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