The aux cooler exit always wants to be at the top to avoid an air pocket that would never go away otherwise.

 

That makes perfect sense and with both orientations the B & M shows in the directions, the exit is at the top.

 

With the current setup, what is the heat rejection capability of the B&M cooler? It might very well be - the B&M cooler is not able to reject any more heat than the trans radiator end tank heat exchanger and therefore you have not added any heat rejection capacity with the current set-up and perhaps the opposite has occured.

The issue to evaluate with adding the B&M air to oil heat exchanger after the radiator end tank heat exchanger is running too cool on cold days. However since you live in a relatively warm climate this perhaps not a concern for you. Also I would make sure the B&M is a low restriction or low pressure drop so not to reduce the ATF cooler flow from the transmission which will work against the efforts to increase heat rejection.

 

I think my car is proof that that cooler is more than enough to keep the trans cool. I never tried it through the rad but I cant really see how running the trans fluid alongside 200 degree coolant will help make it cooler when bypassing the rad I am seeing temps of average around 160-170.
In my opinion the first thing the op needs to try is changing the orientation of the cooler so that it is installed properly. If that doesn't work, then look at other options. I am betting this will fix the issue.

 

I agree. I had a chance to pull the fender well cover and take a look at the cooler. It looks to me that switching the orientation will also put the cooler directly in the path of air from the brake cooling duct hole (which I believe is useless on the base car anyway...the passenger side looks to be capped off.) I figure it may be beneficial to add some ducting to it to direct all the air possible to the cooler.

I think I'm going to have the shop plumb the radiator back in with a 140 tstat or something. I was on the interstate this weekend and in 90* temps the tranny was running 139-145 the whole time I was cruising (once it cooled down from the 180 that it was BEFORE I got on the highway). I would imagine that the temps will be too low during the winter. As this is a DD and my only car, it has to work hot, cold, warm, whatever. I don't have time to go swapping fittings based on the season.

When they do all this, I'll also have them flush the tranny/rad/cooler and re-fill with Redline D6, along with a fresh fill of mobil 1 oil/filter. I probably have a while before the DRM shocks come in, so keep the ideas flowing!

EDIT: Here's a shot of the cooler and the vent holes drilled behind it.

 

Those holes look like enough venting. I don't have a picture but the reason I put a louvered vent was to prevent crap from being thrown off the tire back at the cooler. Got a 5 dollar piece from home depot and riveted it to the liner. Once painted black its not noticeable at all.

Was something like this one. http://www.homedepot.ca/product/10-i...t-cover/990517

 

Apparently your installer didn't do the math to provide enough direct air flow. Assuming there are 28 holes 3/4" dia. in the pic, that's about 12.5 sq in of free area. The specs on the cooler (10 x 7.5 = 75 sq in) with a 7" fan. If the fan motor is 3.5" dia., the remaining free area is 28 sq in. So the bottom line is that when the trans coolant exceeds the 175* to activate the fan, you've reduced the fan efficiency to 45% of capacity at the time you need it most.

I'm guessing realcanuk's grill has far more free area than the minimum required.

If you can't, or don't want to, increase the airflow where you currently have the cooler mounted, then relocate it to the front of the condenser like dennis50nj said and eliminate the fan in the process.

Routing the cooler return through the OEM radiator will keep the trans fluid from being too cold in the winter. You could alternatively use a 180* inline t-stat and have better upside control.

For proper shifting, the A6 needs to be above 150*. For durability about 175* is the normal recommendation.

 

Dennis, those are great temps especially considering how hard you drive your car. Do you use 50/50 coolant or water/water wetter for cooling?

 

Well, the fan thermostat is bypassed, so the fan is on whenever the ignition is. You're still correct with everything else though.

I think one of the main issues is that even though there are holes for air to flow out of, there's nothing forcing the fan to blow out of them. I think, due to the small area of venting, that the majority of fan output is just recirculating within the fender well and contributing to the heat issue. Maybe if I modified the setup to have a duct around the fan that forced air out of the holes, that would alleviate some of it.

Alternatively, I could just cut out the entire section behind the fan/cooler and rivet on mesh or a vent like realcanuk suggested.

 

I use pre mixed Dex cool, my trans cooler is separate from the trans, I have the Cartek fan module, have had it since 2005, it ties into the main pcm wiring in the passenger fender, it allows the fans to come on at 181 100%, with hp tuners you cant set that low or that high of a fan %, I believe that is the main reason my car runs faster each pass, as the water stays cool the trans and the oil are all independent of each other, so I need a few passes to get the oil at the right temp and trans fluid

 

My best pass is rarely my first, but most likely the last or close to last. People look at me and wonder why I have the engine running for long periods in the staging lanes. I want the oil 210-220, engine coolant 180-190, and trans 165-175, before I get to the water box. Using up a little bit of excess fuel weight is a side benefit.

 

Any restriction that reduces the free area after the fan exit, will create backpressure that limits flow volume and velocity. If you duct from the fan to the current holes, the fan will reduce the volume to compensate for the lack of free area and most likely overheat or self-destruct. You just simply need more space for the air to exit in a relatively direct line with the fans output.

 

I went ahead and cut out the entire area that had holes drilled and also a little extra, then attached some steel mesh which I then plasti-dipped. I also added a piece of tube to the brake duct inlet to direct airflow at the cooler. It feels like there is significantly more airflow.

I'll know how effective this was tomorrow. I took it out for 45 minutes tonight and temps seemed to stabilize at 180, but it's only in the low 80's outside right now and there's no sunlight on the pavement, so that's not necessarily any relevant information.

One note: It seems like the fog light really impedes a lot of intake of air into the cooler. Has anyone done anything to get around this issue? I was thinking about throwing a PC fan into the brake duct tube that I added to try and increase the amount of air that gets into the area, but then I started thinking about potential water damage, etc...

 

I cant tell from the picture the exact placement of everything but something doesn't make sense. Like I said, on mine the little duct that was for the brakes aims directly on my cooler and there is tons of air flow. I did nothing extra other than put the cooler there and wire the fan to run all the time and my temps almost never get near 180, even on a 90 degree day here. I am pretty sure the drivers side and passenger side are the same and that wouldn't make a difference. One thing to possibly check is that the tranny lines are not touching the exhaust. I doubt it but I don't understand why similar we have similar installs and yours runs so much hotter. Also maybe check the fluid level to be sure its full.

 

I have same B&M cooler mounted in series with stock radiator. Mine's also mounted in the passenger side wheel well and fan is on with ignition (I had wired it with the thermostat but it quit working). The brake duct puts plenty of fresh air to the cooler and I didn't vent the wheel well because there's a cutout where the brake duct used to pass through. Takes mine a while to get up to temp and very rarely gets above 180, even in stop and go traffic in 90+ degree weather. It's usually in the 165-174 range.

 

same here

 

It looks like your cooler is mounted a bit lower than mine, as well as being oriented with the fittings up. The way mine is mounted, very little airflow from the duct would ever hit the cooler.

Also, I'm guessing you're using SS lines based on the fittings you have. You're probably not using 90 degree fittings either. I am.

What kind of annoys me is that I wasn't asked anything like, "do you want to bypass the radiator" or "do you want to use the rubber lines and 90 degree brass fittings that come with the cooler or do you want to use SS lines and 45* -an fittings"...That's why I had the shop do it...so that I didn't have to worry about any of this crap lol. They're gonna get a little talking to and I'm gonna push for them to make the changes to the cooling system for free since I've already paid for the cooler, install, etc. and it's still hot, and since I'm paying them to put on shocks, etc.

As above, how's your cooler mounted (orientation wise)? What type of fittings and hoses are you running?

I feel like this whole stock radiator thing is what's causing the problem. I spoke with Chuck CoW yesterday and ordered my Booster and AutoCal tune and he felt very strongly that I needed to utilize the factory heat exchanger in series with the aftermarket cooler for proper operation of the transmission as a system. It's gonna happen, just don't feel like making multiple trips to the shop over the next few weeks.

 

excuse the double post.

Took the car out for a drive today. Ambient temps were between 93* and 98* F. I let the tranny get up to 150 then drove for about an hour. Temps peaked at 192 and took the full hour to get there. About 45 minutes to get to 180. A couple of days ago I hit 200 in less than 30 minutes in similar conditions so I think messing with the fender definitely did some good. Driving was mostly traffic around town with probably 20 1st or 2nd gear pulls down some back roads.

It's still a bit hot for my liking, but I'm not worried about it around town any more. I'm sure once I get out on track it will be a different story though...

 

My cooler is mounted exactly how realcanuk's is. Inlet and outlet on top. I used brass 90 degree fitting and rubber transmission hose. I didn't cut any of the trans lines. I bought a fitting that went into radiator and clamped hose on other end. Then slid other hose over the stock trans line that came out do the radiator. Simple, clean, and it works great.

 

I am using stainless lines all the way to the trans. 90 degree or more fittings are not an issue. I never really was clear on which way you lines are pointing. I kind of get the feeling from you other post they are pointing down. If so, it could be your whole problem.