Bypassing OEM transmission oil cooler,
 

I need to replace the oem radiator in my car ( 5AT ) because it's cracked and leaking pretty bad at the top plastic tank.

I was thinking about buying an all aluminum radiator like the koyo performance & buy a standalone transmission cooler like a setrab 19 or 25 row coolers, But i'm not sure if it will be sufficient enough !!!

Anyone ideas ?

unless youre running a big turbo build a OEM replacement will be fine. You may want to do a little research on the combined radiator transmission cooler. I'm sure a 19 or 25 row will be more than ample but cooler transmission fluid doesnt mean it'll lubricate better. I believe nissan combined the radiator and transmission cooler to keep the transmission fluid at the 200*-210* coolant temperature range as that they have determined the fluid lubricates best at this temp.

Do your research and see if this is correct - I would look for an aftermarket unit that combines the radiator and tranny cooler in one unit similar to how your OEM radiator is.

The size of the OEM cooler us actually about the size of the PS cooler, a small trans cooler will be fine.

I understand that the integrated cooler helps getting the transmission fluid up to temp quickly, But in a 110 : 120 degrees ambient temperature, I'm sure a bigger radiator will be a better investment.


The only aftermarket radiator with builtin trans cooler is from mishimoto, But it's the same size as the OEM one, And uses plastic tanks also.

A 19 or 25 rows cooler could be enough with the car moving, But my concern is city driving with a lot of stop and go traffic where the OEM cooler will benefit from the fans :dunno: !!!

fyi the mishimoto is more than 2x as thick as the oem radiator core and it is all aluminum. I have one on my car and it works great.

All aluminum with built-in transmission cooler :confused: ???, Any part # or Link please ?

This is the only one from mishimoto with trans cooler, link

Attachment 461141

youre on the wrong item. says OEM replacement.
they sell OEM and racing versions. I would call them to make sure it has the trans cooler though. I have a G35 and mine had it, but they make revisions so even mine was different from what they had shown but revised to be better.

edit: according to Z1's website it says no auto cooler for 350z model. I would say use a g35 radiator or add a trans cooler with inline thermostat to maintain the temp.

http://www.mishimoto.com/nissan-350z...diator-03.html

Do you think that a thermostat will still be needed even in such ambient temps ( i'm talking about 110 degrees most of the year ) ?

Only way to really know is use a gauge and monitor. Don't know if anyone has really done it on a stock car. Most of my experience is a FI car that was tracked and needed as much cooling as possible. With a large B&M cooler it would still overheat the trans in 5 laps at only 430 Hp. After the modded performance Barbie trans got cooked he swapped it to a stick.

its really up to you how you want to do it. the B&M trans coolers i believe have a thermostat built into it anyway. the cheaper ones will not. Im assuming youre not tracking the car. I had one installed inline with my 5at before I did a 6mt swap. worked great while I had it though I did not track the car or push it hard for long periods of time. I drove it about 1000 miles non-stop(except for gas) through vegas this summer in 116+ heat with no issue. I am also FI though, so you should be fine.

yes, you still need to run a thermostat...your car runs at an optimum temperature of 200 to 210 degrees...oil lubricates best at these temperature as does transmission fluid...so running your engine excessively cooler does more harm than good. You should stop worrying about your high ambient temp so much...yes, this is hot to you and I but to the engine it is nothing...the engine runs at double that temperature without issue.

Good answer. I agree but I'd like to know if the existing oem configuration includes it's own thermostatic temperature control? I would like to think it does. If it does & you use a separate cooler to run inline with the stock setup, another thermostatic control is a waste of $ and possibly cause some cross-mogination. Asked this question on 2 other threads tonight so hopefully someone is in the know.
That mishimoto rad. is nice & is double the thickness (2 rows) of the oem but the transmission cooler built within is no larger:icon22:. I called & spoke w/someone @ mishi a couple weeks back. Bummer.