Dell Inspiron 13-7378 - vents

This link from the service manual should help. The small forward vents appear to be intake and the large vent (in the picture where the heat sink and fan are located) are exhaust.

https://www.dell.com/support/manuals/us/en/19/inspiron-13-7378-2-in-1-laptop/inspiron-13-7378-service-manual/procedure?guid=guid-8a343c56-0edf-41e6-bf4d-eff479697cd4&lang=en-us

OK, first off...smarter, not so much according to my wife. However after taking a good look at the 7378 pics try this. With the fan running, take a very light piece of Kleenex (facial tissue) and hold it up to the large rear vent. If the tissue is held there then it is an intake vent.  Looking at the rear of the 7378 system's case I see a long slot between the hinges (which you mentioned). That is the exhaust vent. On my 5575 the large bottom vent is intake and the exhaust is the slot between the hinges.The small vents near the front are just secondary intakes which pull additional air across the other components. Sorry if I led you astray on this one, the pics in the service manual were not very obvious as you stated.

Not sure what the differences are between 7378 and my 7368? the front two vents are actually left and right speakers. I only have 1 long rectangle if grid toward the back covering the area of the CPU heat pipes and heat sink and fan. Using the tissue test I found that the intake is the first 2" from right to left are drawing air in.  I assume the rest of the grid is exhausting, I say I assume because the tissue did not stick to the grid but the tissue but wasn't blown away from the grid as would be expected.

To ensure that my fan is running full blast I'm running "burn-in test" which is set up to run the CPU at 100% as well as the onboard GPU 2d and 3d at 100%. My temps were running in the high 80'c C

I moved a fan on my notebook cooler Coolmaster U2 with the 3 U3 fans. I moved the one fan to the top right corner and that dropped my temps into the low 70's C

So Now that I have done some checking around the hinges I find a definite exhaust from the right hinge nothing on the left hinge in or out. So I'm suspecting that air is coming in from the right side of the bottom plate same area that the fan is located and exhaust through the right hinge. This doesn't really make sense to me but I'm quite sure that Air is being sucked in through the right 2" of the bottom vent grill. I could not verify air flow either in or out through the rest of the vent crossing to the left-hand side. I am also quite sure I am getting exhaust through the right-hand hinge and no air movement noticeable on the left hinge either direction. Not really sure what I have actually discovered as it doesn't make sense to me that air would come in and out on the same corner of the notebook and what the other 8" of the vent on the bottom actually does. 

When I had the bottom off I did look to see if I could figure out the airflow and i couldn't All I saw was the fan heat pipes and heat sink all open the only crowling was around the fan Which was set up to draw air from the bottom of the case on the right side so maybe I just wasn't expecting a fan to exhaust out a hinge I'll have to have another look. If that is the case then any fans I put on that vent grid is going to force air across the CPU Heat sink and heat pipes. I'm still not getting my head wrapped around this yet.

100% sure as my 5575 has a similar vent configuration and I was able to prove that the bottom vents were intake. I also could put my hand across the slit between the hinges and actually feel the hot air being expelled.

I had a vacuum style cooler on my old Latitude and it worked like a charm. But as you stated, you have to have a side vent for that to work. A good cooling pad should make it pretty obvious quickly that the CPU is cooler.

And thanks for the kind words. My wife is not a techie in any measure of the word, To impress her usually means cleaning out the attic...:Zipit:

After reading your last post, I had another look at my 7386 And Yes I have vent holes that you can see with the screen open and the right one is definitely exhausting I can feel the heat coming out. the tissue paper definitely is affected by the flow. The left side appears to have the same holes but I can't detect and flow either way.

As to the Back, I have 4 narrow slots, 2 near the right hinge that is exhausting and two near the left hinge that neither exhaust or intake that I  can tell. The bottom remains the same for me two speakers under the trackpad frame out towards the left and right sides of the bottom and one  

I may not be  able to figure out the path to my laptop bath pict, then try this link.  If you use the enlarger, you can see the  wire mesh in the one of them and not in the  other. 

https://www.ebay.com/itm/Dell-Inspiron-13-7378-2-in-1-13-3-Genuine-Laptop-Bottom-Case-Cover-D69KX-ER-/282613106514

Clintlgm, I THINK we are saying the same thing.  I have no idea why I am not smart enough to attach a pict of the back of my laptop.  The speakers are the same except on my laptop they look like vents.  That leaves 2 more bottom vents on mine which would be the same place as your one long bottom vent.  I think we might have our rights and lefts mixed up. So does half of that long bottom vent have a wire mesh that you can see?  And the other half does not have that wire mesh?  

And your back 4 short vents is one long vent for me.  Do all 4 of your back vents have that same wire mesh?  My long vent back vent is all wire mesh.

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@Jerry1111 wrote:

Clintlgm, I THINK we are saying the same thing.  I have no idea why I am not smart enough to attach a pict of the back of my laptop.  The speakers are the same except on my laptop they look like vents.  That leaves 2 more bottom vents on mine which would be the same place as your one long bottom vent.  I think we might have our rights and lefts mixed up. So does half of that long bottom vent have a wire mesh that you can see?  And the other half does not have that wire mesh?  

 

And your back 4 short vents is one long vent for me.  Do all 4 of your back vents have that same wire mesh?  My long vent back vent is all wire mesh.

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Well, the 7378 is quite different from 7368 the front two speakers look like they would be vents, I read in the service manual that they were speakers and I listen to verify that.

the four vents across the back have no mesh at all they are all intended to exhaust I guess same with the Right hinge.

Left and right get mixed up whether you have the notebook in user mode or flipped over to work on the back side. I would guess that I may have gotten confused a couple of times. on mine, it appears that the exhaust is the right hinge and the back two slots next to that hinge. I could not detect any other exhaust and the screen bottom are is all screened so I am assuming that is all intake. So i have my cooler fans blowing up through there. Most likely putting a positive pressure in the notebook since there is so little exhaust area, I still see no exhaust from the left hinge or the two slots on that side.

As to posting Pictures. they have a limit in size, I used Snagit to reduce the size of my picture then click on the photo link above and a box appears that you can drag and drop the photos into then choose size and position and  upload them

Okay I tried drag and drop and copy and paste.  Nothing works.  My pict is probably too big.  Or I am just too stupid.

Guys, I think we have gotten as far as we can on this.  It was fun.  Thanks to you both. 

Jerry

Hey, if you see it, at least I succeed in sending a  pict.  The secret...  I had to first log on.   Haha.