B&M Transmission Cooler; Location & Size & Orientation

UTEP

UTEP

New member
Hi,

I know this has been discussed to death, as I have read pretty much everything on this an YT and other forums. One thing that seems to be ignored is location and orientation. I also put size in my title as my concerns there are part of it.

Location:
Most seem to use the spacers and leave the recommended 1/8" gap. There is plenty of room on my 2000 Limited to get a 70268, the 3/4" 13k btu model, more than an inch away. BUT does it need to be closer so the fan can draw air through it?

Orientation:
Vertical or horizontal? Vertical with hoses above and below on the passenger side seems the best idea but more people seem to mount horizontal with the inlet/outlet both on top. I'm not sure how the tranny circulates fluid but guess it's a lower pressure system. With that in mind the vertical will be able to use gravity on the return...

Size:
Seems most folks in the desert SW use the 70264 model for greater cooling. This is rated at ~14k btu. It has a smaller footprint but is thicker. 2x as thick. My thinking is the thinner should be more effective. I'm probably messing up my physics but it seems a larger flatter/thinner object would cool more effectively than a smaller fatter/thicker surface. I know the 70264,smaller fatter/thicker surface, has more over all surface area but unsure if it is that big of a deal....


I've been accused of over thinking some things...

Warren
 
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BTW.

I have not found the B&M 70266 as an option but the above linked spec sheet states:

Typically the smallest cooler you should consider when not using the radiator provision would be the B&M #70266 or #70272 Universal SuperCooler.

B&M rates the coolers in conjunction with routing through the radiator. Since we are not do this to eliminate the "stawberry milkshake" I wonder why no one seems to choose the 70266?

Off to search...

Warren
 
I went with this sure some will say it's overkill but I didn't want to re-attack this project again (bypassed radiator). Scan gauge avgs 120-130 and I've seen it as high as 170 off-road. Good luck.
 
After obsessing about this all evening I think the best approach is a new KOYO radiator and run the smaller B&M THROUGH the new radiator.

Still at risk for the strawberry milkshake but not for quite a while at best. Since the issue seemed to be restricted to 3rd gen 4R's perhaps it was more of a bad run or radiators. I mean I have owned vehicles with AT's and never had this strawberry milkshake issue.

Are the new Koyo's working out?

I'm actually seeing them as rebranded or vis versa TYC radiators that get a lot of complaints. I know in the world of manufacturing there just aren't that many radiator plants and neither Koyo TYC or any name brand else actual makes them.

BTW thoughts on Denso radiators? Seem to be a good compromise $111 1-day ship from Amazon or Koyo $158 and a week out....

Thanks,

Warren
 
AFAIK Denso is an OEM supplier for many Toyota parts, specifically on our trucks, so I would not hesitate to use them. I installed a new Koyo nearly 1 year ago (still running inline cooler) and so far, knock on wood, all is well. I plan on installing the largest external cooler I can soon and completely bypassing the radiator as I really rarely see temps below freezing, and we have tons of hills and traffic so heat can be a concern even in this soggy climate. I do go into the mountains, but even up there temps hardly ever fall below 25*f, the "snow" is more like heavy rain up here near Seattle, even in the mountains.
 
I push my 4runner pretty hard and the 70266 keeps my transmission cool even during slow crawling out here in the desert.
 
I've heard that the B&M's are fine for cooling but is there any concern with the lack of heating transmission fluid up to operating levels (Assuming cold weather like we get in CO Winters)? I've read before that the Radiator helps in that process... which obv you wouldn't have with a bypass.
 
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The B&M coolers have a low temp bypass. The transmission should heat up the fluid plenty fast. Then the temp bypass opens up and the cooler cools.
 
I have the 70264, it's mounted on the passenger side about 5" off of the AC condenser. It did it by bending those metal brackets into sort of a lightning bolt shape and using existing bolt holes. I mounted it like that so I could put a Derale 16505 315cfm puller fan behind it. In order to mount the fan I had to drill 2 holes in the 70264's flange because the plastic string clip deals won't pass through the cooler itself very well. Had it in there a couple months and so far so good.

I also have the cooler mounted with the ports facing horizontally, with the transmission send line going to the top port in the cooler and the return line coming out the bottom. I did it this way because heat rises, so if hot fluid is going in the bottom line then it's following the fluid up to the top line and going back to the trans. Maybe it's over thinking but whateva, it works fine.
 
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UTEP said:
I've been accused of over thinking some things...

Warren
Click to expand...

You are over thinking it, just follow the B&M instructions, so either both on top, or sideways with the inlet on bottom, outlet on top.

amalik said:
I've heard that the B&M's are fine for cooling but is there any concern with the lack of heating transmission fluid up to operating levels (Assuming cold weather like we get in CO Winters)? I've read before that the Radiator helps in that process... which obv you wouldn't have with a bypass.
Click to expand...

No, there is no concern about heat up without the radiator. The tranny warms itself up pretty fast anyway, possibly faster than waiting for the engine to warm up enough the trip the thermostat and actually heat up the entire radiator. Someone actually measured this once, and very little heat is transferred from the coolant to the tranny fluid. Warm up time difference was negligible.

Boom Headshot said:
I also have the cooler mounted with the ports facing horizontally, with the transmission send line going to the top port in the cooler and the return line coming out the bottom. I did it this way because heat rises, so if hot fluid is going in the bottom line then it's following the fluid up to the top line and going back to the trans. Maybe it's over thinking but whateva, it works fine.
Click to expand...

Heat doesn't rise. Hot air rises above cold air because air is a gas and expands alot with temperature, so the densities are pretty different between hot and cold. Fluids don't change densities with temperature nearly as much as gas (especially as a ratio of density change to viscosity), so you only really see temp change driving fluid flow in pretty static systems. In an actively flowing system like the tranny, density differential has no effect.

The reason you want fluid entering the cooler from the bottom is so that the cooler fills completely as fluid flows in. If you mount the cooler empty, then only flow fluid into the top and out the bottom, then you aren't actually filling the cooler, but letting gravity drive the fluid down the cooler, leaving tons of air inside. Unfilled cooler area = poor efficiency. You effectively have a smaller cooler.
 
UTEP said:
How has it worked out since the thread?

Have you pushed the 4R? Or still just a grocery getter?

Thanks, Great write up!

Warren
Click to expand...

I've pushed her with lots of low range hill climbing and long border line-ups in hot weather. Never have had a problem with it. Always stays nice and cool.:thumb3:
 
Nelsonmd said:
Heat doesn't rise. Hot air rises above cold air because air is a gas and expands alot with temperature, so the densities are pretty different between hot and cold. Fluids don't change densities with temperature nearly as much as gas (especially as a ratio of density change to viscosity), so you only really see temp change driving fluid flow in pretty static systems. In an actively flowing system like the tranny, density differential has no effect.

The reason you want fluid entering the cooler from the bottom is so that the cooler fills completely as fluid flows in. If you mount the cooler empty, then only flow fluid into the top and out the bottom, then you aren't actually filling the cooler, but letting gravity drive the fluid down the cooler, leaving tons of air inside. Unfilled cooler area = poor efficiency. You effectively have a smaller cooler.
Click to expand...

Boom, headshot. That seemed to be the consensus by a few guys who know more than I do in one of the countless threads on this subject. What you're saying makes more sense though, so I stand corrected and a moran. :biggrin2:
 
Nelsonmd said:
You are over thinking it, just follow the B&M instructions, so either both on top, or sideways with the inlet on bottom, outlet on top.
Click to expand...

Thanks for all the above but I had seen more installations with inlet on top ;out let on bottom in a vertical mounting. Sure enough I called B&M and they recommend inlet top; outlet bottom.

Also as with the radiator cooler; there is no check valve and simply an open passage.

Thanks,

Warren
 
UTEP said:
Thanks for all the above but I had seen more installations with inlet on top ;out let on bottom in a vertical mounting. Sure enough I called B&M and they recommend inlet top; outlet bottom.

Also as with the radiator cooler; there is no check valve and simply an open passage.

Thanks,

Warren
Click to expand...

Hmmm, that's odd, since their instructions clearly state the cooler should fill from the bottom. Maybe there was a confusion of terms over the phone? Here's the link to their instructions. IMO, I'd trust their written instructions over the guy on the phone.

http://bmracing.com/wp-bnmcont/uploads/bm_cooler_techdoc.pdf

I think the guy on the phone might have been wrong, or was referring to the tranny inlet and outlet (which are opposite of the cooler inlet and outlet).
 
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