How bad is it.... - PeachParts Mercedes-Benz Forum

mobetta · #1 10-20-2008, 10:37 PM

to run an Air-Air transmission cooler and NOT the radiator unit?

I threw a belt 2 weeks ago- I know, bad preventive maintenance- I cant believe its already been 40 K miles- and afterwords I was leaking atf more than usual.

so I went and dusted off the new cooler lines I had on the shelf and installed them.
well- two days later, the darn nuts which seal the radiator tank to the cooler failed- split into pieces, and I was leaking coolant everywhere. so I managed to fab up new "nuts" using 5/8 washers, orings and I sliced an eighth inch off each end of an old cooler line, as a jamb nut type thing.

so I stopped the coolant leak, all's well there. but then the ATF leak got worse- either I chooched the fitting on the radiator, or line?( i did try the old one, just as bad) but it was a steady stream- not drip- coming out this AM when I first tested it out. so I was in need of the car- I installed an air to air cooler from the PNP which I got off an explorer. it is like 12"x 6", parallel flow- not a tube and fin.
I did have to extract the aux fan to get it in a decent position. but I dont have AC, and dont recall the fan ever turning on, especially not in winter. so I am not concerned with that at this point.

I ran it about 50 miles today, everything seemed fine. but of course, How would you know if it wasnt- not until you had a burned up tranny.

I live in MN, so at this time of year I am almost more concerned about the tranny not getting warmed up from the coolant in the radiator as I am about overheating.

what is all you all's opinion on this??

should I park it until I can get another radiator? how much of a cooler is actually in the radiator? i dissected the old radiator from the wifes volvo 940, and it was like 18" of tubing in there- not much.

On the flip side, I do have a spare tranny

not that I want to use it....

Brian Carlton · #2 10-20-2008, 10:50 PM

I'm sure you're ad-hoc cooler will be perfectly adequate for unlimited use. You'll get more cooling from 50F. air than you will from 115F. coolant.

kerry · #3 10-20-2008, 10:52 PM

I would drive it. Wouldn't it be an air to liquid cooler?

fdanielson · #4 10-21-2008, 10:41 AM

The companies that sell aftermarket transmission coolers also sell an inline thermostat that bypasses the cooler until the fluid gets warmed up. Install one of those and you'll be fine.

A Derale 13011 or Hayden 163 should be what you're looking for- http://store.summitracing.com/partdetail.asp?autofilter=1&part=DER-13011&N=700+-124017+115&autoview=sku

mobetta · #5 10-21-2008, 11:24 AM

Quote:

Originally Posted by kerry

I would drive it. Wouldn't it be an air to liquid cooler?

Duh- thinking too much about an intercooler....

on the thermostat- good idea- but that is also $70 towards a new radiator- which, mine being original, I should probably be thinking about replacing sooner than later. And is it bad to run too cool?

I had a thought to add in a temp gauge, so I can monitor that. but I have no baseline to compare it to. anyone have average temps for our trannies???

I had been wanting to add this cooler, as I do tow a bit, but the never ending leak finally motivated me to just do it.

Graplr · #6 10-21-2008, 11:36 AM

Mo,
I don't know if it will work but I have the radiator I pulled off of the 116 that I can sell to you.
-Ryan

2.5Turbo · #7 10-21-2008, 12:12 PM

I would think a cooler immersed in coolant in the radiator would work much better in a high temperature situation. The mean temperature of the ATF will be higher, but when you get into a situation where your tranny is working hard, the liquid cooled cooler will be more efficient.

For everyday use the air cooler would work fine, in fact better due to the cooler mean temperature, but when you get into an extreme situation where the ATF is getting really hot, the more efficient heat transfer to coolant would help keep things within the safe operating area.

SD Blue · #8 10-21-2008, 12:12 PM

Actually, the radiator "cooler" not only cools in summer, but also warms in winter. With that in mind, you might have some less than desirable shifts before the transmission warms up. Which, with the air-type cooler will take a little longer but probably won't have any harmful effects.

Flounder · #9 10-21-2008, 06:46 PM

I have an aftermarket trans cooler on my '81. (had to bypass the one in the bottom of the radiator) I had it on all last winter and didn't have any problems with shifting.

Hatterasguy · #10 10-21-2008, 09:07 PM

I don't see why you couldn't put a different cooler on the trans, it shouldn't bother anything. If I towed a trailer with my car I would probably bypass the one in the bottom of the radiator and mount a larger aftermarket cooler in front of the radiator.

iwrock · #11 10-21-2008, 09:15 PM

I know another forum member, SirNik84 has an additional trannie cooler (so stock+additional) and hes gone like 380k on the original transmission build. Fluids been changed though.

Cervan · #12 10-21-2008, 09:34 PM

Quote:

Originally Posted by mobetta

Duh- thinking too much about an intercooler....

on the thermostat- good idea- but that is also $70 towards a new radiator- which, mine being original, I should probably be thinking about replacing sooner than later. And is it bad to run too cool?

I had a thought to add in a temp gauge, so I can monitor that. but I have no baseline to compare it to. anyone have average temps for our trannies???

I had been wanting to add this cooler, as I do tow a bit, but the never ending leak finally motivated me to just do it.

yes it is bad to run too cool, transmission fluid needs to get to operating temperature just like engine oil.