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Riderman

Pathfinder AC cooling Tip

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Posted (edited)

Hope this helps somebody.

 

We just put a "new" JDM motor/Trans/front differential/Xfer case in my daughters 98 pathfinder a few weeks ago.  I replaced all seals, gaskets, etc in each piece.  I replaced both Idler pulleys and the fan clutch with new ones  I then decided to replace her AC comp/ Expansion valve, dryer, etc. I recharged her AC by wieghing in the exact charge.  Her AC was OK driving around town, not bad, not great @ around 80-90 degrees.  I purchased some 1/2" rubber HVAC pipe insulation from Lowes for less than $6.00.  It comes in 6 foot lengths.  I cut it in half, right down the center so I had two 6' pieces.  I installed/stuffed it around the outer edge/gap between the radiator and condenser, the top, and both sides.  This directs more air thru the condenser at low rpm's, like when it's needed while driving around town.  

 

I wish I measured the before/after evaporator temp when I did this, but by seat of the pants feelings, it is MUCH better.

 

My daughter said, "MY AC is Kicking."  She told me tonight that her friend stated, "your AC is colder, did you do something to it?"

 

I'll let you know how it works around town in the upper nineties.  :)

 

 

 

Edited by Riderman
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I insulated the low pressure lines in mine as well and I can tell a difference. I don’t care what anyone says to the contrary, that big aluminum plumbing absorbs heat energy that has to be removed by the condenser and insulating it makes a difference.

 

Someone could calculate the surface area of the plumbing and approximate the ambient heat load inside the engine bay (especially the section that is clamped behind the belt tensioner) to see exactly how much it helps. I have seen a couple degreesF lower temps at the vents (w/ fan on high).

 

I’ll tell you what makes a giant difference, a high CFM electric radiator fan. Night and day!

 

The condenser is undersized though and no matter what it’s not gonna compare to other cars that were designed better.

 

I’ve been kicking around the idea of a atomized water spray system built with a window washer pump and reservoir from the junk yard and some jets from McMastercarr for the situations that still need improvement, ie 95degF ambient temps in a drive thru line..

 

 

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I'm hoping to get my aircon going for this summer, I'll have to take a look at the lines and the foam under the condenser. I think there was foam under it originally but I'll be surprised if it's still there and doing something.
 

On 6/21/2020 at 6:46 PM, onespiritbrain said:

I’ve been kicking around the idea of a atomized water spray system built with a window washer pump and reservoir from the junk yard and some jets from McMastercarr for the situations that still need improvement, ie 95degF ambient temps in a drive thru line..

 

MCM used a pump-up bug sprayer to spray an intercooler, might be good enough for a test run before committing to a proper setup.

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When my youngest son was tiny my ac wasn’t cold enough to provide any relief from the summer heat and I used to slowly pour water bottles over the condenser haha


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If your ac is not working well at idle and you have all good components, you have an airflow issue. The clutch fan when fully locked will pull more air than any electric. Like OP did with the pipe insulation, there was some sort of foam @!*% there from the factory, but it degrades over the years and falls out.

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Well I did replace the fan clutch, but it was with a part from the junk yard so it’s possible that I did have an air flow issue but now I can feel a large amount of air being pulled across the condenser when I couldn’t before.

 

The mechanical fan would blow a huge amount of air toward the engine— more than the electric fan for sure, and it had to be coming from somewhere, but I know for sure there’s a lot more air coming across the condenser with the electric fan.

 

Maybe it’s how close the electric fan is (increased air speed at the condenser) to the radiator surface, and subsequently the condenser, that causes more air to be drawn across the condenser.

 

Maybe there was some sort of OEM baffle that had been removed that forces the air to be pulled across the condenser instead of drawing air in from the open space between the radiator and condenser. Edit: I think this is what you were saying with the foam that degrades and falls out.

 

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Yep, originally the condenser and radiator had foam seals around the edges to control air flow through both. The splash pan on the bottom is also part of the air flow control. 

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My 1995 still has them, surprisingly, I did replace the bad parts with some new stuff when I replaced the condenser. With a new fan clutch she blows 40 degree air at idle and that is on a 90+ day with humidity. It's colder than most of my friends/coworkers cars feel at idle. Then again when I pulled a vacuum, I went for lunch and left it running for almost 2 hours by accident lol.

 

If I put my hand in front of the condenser I feel a lot of air being moved, then again I replaced the radiator as well. The old one was very caked with mud and debris from over the years. I'm sure that prevented the air from the fan getting to the condenser. The other thing I don't like about e-fans is I have been on the trail where someone's has died after a water crossing. It's just my opinion that the original style fan is more reliable. But this is the r50 forum and I'm getting off topic so...

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I bring my fan clutch with me on long/tough trails and I really need a kill switch and a forced high speed switch for my efan. Right now at water crossings I end up running the ac before I get to the crossing so the engine temp is low enough that when I cut the ac off my efan cuts off as well. It’s annoying..

Then there’s 4wheeling transmission temps to worry about. I suspect that the trans gets hotter than normal with the efan since there are often periods of near zero air flow.. again I combat this by leaving the ac on or cycling the ac when I think about the trans getting to hot, which isn’t fun to worry about when your trying to have a good time.

I have to agree that the mechanical fan is a lot better off road in several regards. However, I don’t know if it was a worn out fan clutch or what but I have better control over engine temps with the efan.


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On 6/26/2020 at 5:00 AM, onespiritbrain said:


Then there’s 4wheeling transmission temps to worry about. I suspect that the trans gets hotter than normal with the efan since there are often periods of near zero air flow.. again I combat this by leaving the ac on or cycling the ac when I think about the trans getting to hot, which isn’t fun to worry about when your trying to have a good time.


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Another reason for a separately mounted external cooler

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And a reason NOT to delete the cooler inside the radiator.


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1 hour ago, onespiritbrain said:

And a reason NOT to delete the cooler inside the radiator.


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because of the no airflow?

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I have a big external cooler but I bypassed the internal radiator completely. Now the trans can heat up independently from the engine instead of sharing their heat loads, which is actually a good thing except in extreme cold and off-road situations.

I should’ve left the internal cooler in the circuit before the external cooler. I might valve the internal cooler back in and just have it where I can take it back out for normal summer daily driving.


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I have a big external cooler but I bypassed the internal radiator completely. Now the trans can heat up independently from the engine instead of sharing their heat loads, which is actually a good thing except in extreme cold and off-road situations.

I should’ve left the internal cooler in the circuit before the external cooler. I might valve the internal cooler back in and just have it where I can take it back out for normal summer daily driving.


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I’m a little lost, why it is bad to bypass for off-road situations?


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Near zero air flow when the fan isn’t running, and for my particular setup, only low fan speed unless the coolant temp is over 215.

 

It could be a non issue, I’ve never measured temps or anything. It’s just something I end up finagling with when off-roading because I worry about the trans getting too hot.

 

The internal radiator cooler causes trans temps to follow engine temps. When all you have is an external cooler then the engine temp could be normal while the trans is literally cooking itself. Again, this might never ever happen but for all I know while I’m off-roading, it’s occurring right then and there, so I end up worrying about it.

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Near zero air flow when the fan isn’t running, and for my particular setup, only low fan speed unless the coolant temp is over 215.

 

It could be a non issue, I’ve never measured temps or anything. It’s just something I end up finagling with when off-roading because I worry about the trans getting too hot.

 

The internal radiator cooler causes trans temps to follow engine temps. When all you have is an external cooler then the engine temp could be normal while the trans is literally cooking itself. Again, this might never ever happen but for all I know while I’m off-roading, it’s occurring right then and there, so I end up worrying about it.

 

I though it was the opposite of that. I have felt my externally-bypassed cooler while engine is idling. The temp is much lower than radiator. I have also touched the cooler with engine shut off within five mins after idling and temp is near cold.

 

 

Sent from my Pathfinder l

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I don’t think I’ve measured temps since installing the external cooler but I’d say my external cooler is only a little lower in temp than when I’ve felt my radiator at 185degF but is still hot to the touch after highway driving, and that’s with gobs of 70mph airflow. If I had to guess I’d say 150-160degF area.

I always forget to grab the temp gun before I hit the trails so


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Going by the trans temp gauge I installed years ago on mine, my trans runs cold most of the time. Yesterday I did manage to get it up to 200°f briefly, but ambiant air temp was 85+ and I was slow driving up a poorly maintained dirt road up a mountain. Normally my temp doesn't usually go over 185°f according to the gauge. Winter time with the temps near freezing, it takes a lot to get the trans over 150°f, and that causes the converter clutch to not lock up on the highway. My trans is running it's own dedicated cooler since the original cooler killed it about 17 years ago. 

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