Inspiron 3670, CPU cooler, case fan, upgrade compatibility?

For the case fan get the biggest one that will fit in any space available, it's all you can do.

The fan faces down because its sitting at the top and heat rises.

It sits directly over the CPU and takes heat up and out.

Many of the units like this  have an air vent near the slots down low to allow air to be drawn in from the bottom.

This is standard Micro BTX and has been for over 10 years.

The other issue with 3670 and Optiplex 9020 is the proprietary 8 pin power supply that is only 290W.  I didn't want to use an adapter so I got the 7VK45  365W power supply.

DELL BTX

Dell does not use standard wiring or Pinouts on their fan headers.

For 3 wire they reverse 12v and tach. 

Black Red White not

Black White Red

DELL 3 PIN

This can lead to self destruction for a dell fan on standard motherboard or the other way round.

https://www.amazon.com/Dedicated-Adapter-Conversion-Cable-Dell/dp/B07F7CTMVZ

 https://www.walmart.com/ip/48729225

This is the CPU FAN for Example.

https://www.amazon.com/Dell-Optiplex-Processor-Aluminum-Heatsink/dp/B079YVX6HC

DELL FAN WIRING

 So if I understand correctly, I need special adapters for both the case fan and cpu cooler fan? Which one is for the 3 to 3 pin and 5 to 4 pin?

As you can see in my setup in the picture below, it's different in comparison to yours where my power supply is faced down located at the bottom while yours is also faced down but located at the top. Your explanation for why your setup is the way it is makes a lot of sense, which is why I was befuddled at first when I saw my psu could only be bolted face down toward the bottom of the case especially when there's no ventilation down there. My guess is that this desktop setup is simply poor design and psu upgrades weren't expected to be made.

So why does my Arctic pwm case fan work perfectly? It's connected to the top fan header and the top fan is connected to the pigtail coming from the connecter. 

Wow, that's a lot of psu for an Inspiron, does everything else benefit from it?

The PSU is mostly just for the GPU.. both parts were swapped from my old computer.

Can anyone confirm if a case fan or a cpu cooler like a CRYORIG H7 Tower Cooler or Cooler Master Hyper RR-212E could be installed into this system as long as I get one of those special 3 to 3 pin and 5 to 4 pin connectors as mentioned in a few posts above?

I also physically measured the one area where a case fan could be placed as seems to be around 75-85mm, so maybe 80mm is the choice since it's more commonly found, unless an exact case fit size is needed.

I'm in the same situation, trying to power my GTX 970. There's no way to power the 970 without upgrading the psu, right? I suppose there's no adapter cable that could split to the 8 pin on the motherboard and the 6 pin on the 970?

Thanks.

No an exact case fit isn't needed, you can always cut some duct tape to take up extra space around the fan so air doesn't get misdirected. Also, I mount my fans with weather stripping tape to keep the noise down. I had a very noisy HDD in a cage, took it out, and mounted it on 3/8" weather stripping and it was dead quiet.

i frankensteined a cryorig R1 ultimate heatsink into a dell inspiron 3670

and used the regular to dell fan pin adapter 

i updated the BIOS;

it still won’t boot if the fan’s cable is plugged in.

when troubleshooting at BIOS screen, if i plug it in it doesn’t do anything 

https://imgur.com/a/rij5Zhs

i don’t know what to do

Re: used the regular to dell fan pin adapter

some Dell bios is picky of the fan rpm when motherboard senses tach feedback. Aftermarket fan does not have similar resistance load as stock fan and will draw different current, spin at different speed, and feedback different rpm. All these may contribute to bios startup firmware test error, or fail power on test.

using adapter for Dell does not solve problem above.

PS sad angry tired Snoopy in picture will be smiling with Dell stock fan.

Hello all. I wanted to share my current setup with the Inspiron 3670. As you can see in the pictures the only thing stock is the i5-8400! (I would love a i7-9700)  I watched a great video on YouTube by "Shane C". He used a giant circle bit and drilled a giant hole in the bottom of the case for a new PSU ventilation. I decided on a bunch of smaller holes. I also added (2) 80mm Kingwin fans to the rear exhaust area. The case has that exact size already there. I added a third 80mm fan on the side of the case and it acts as an intake. I powered all three from the PSU by molex connector. The Corsair CX750M does the job just fine. I had a CX550M but got a great deal on the 750 so couldn't pass it up. I scored the 2x16gb HyperX Fury 2666 from Mercari for under $100, the Zotac GTX 1070 Mini 8gb for under $200 on Mercari (before GPU prices went crazy), the Crucial P5 NVME M.2 500gb drive for $50 from a sale on crucial.com. Lastly I recently pulled the plastic fan shroud off the CPU fan. It's running a lot cooler now since the hot air can escape faster. I have Speccy showing some idle temps. Its weird that it does not recognize the Kingston HyperX Fury ram or the fact the GTX 1070 is an 8gb card not 4gb. The last picture shows the Mercari purchases, yea I like Corsair. Of course what setup is complete without the Two-Time Back to Back, 6ft 8 gaming great. 37 inch vertical leap, with that mustache aka Slick Daddy, the name is Dr.....Dis....Respect...spect...spect.. SORRY!  Thanks for checking it out. 

https://imgur.com/f4Q0AnT

https://imgur.com/YEdBOPm

https://imgur.com/8a0C8Z4

https://imgur.com/FpBO0mM

https://imgur.com/3jNVaXP

https://imgur.com/ZhuZf3r

https://imgur.com/zvXpioY

Hey again! I wanted to update you on a cpu cooler. I just installed the Vetroo V5 tower cooler. It plugs right into the cpu fan port. All I had to do was assemble the included intel brackets to the bottom of the cooler, apply your paste and screw down. No access to the back of the motherboard needed. It’s dropped my 15 degrees or more.  My i5-8400 was idling around 29c.  A stress test and benchmarking got it to 60c.   The only downside is…it’s a little too tall for the side panel. However it’s right on the grill part. I simply cut away a rectangular section which allowed the tops of the heat pipes to come through. The side panel fits right back on.   Lastly  I am awaiting  an i7-8700k. That will test the cooler for sure.