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Autobox oil cooler(s)?

860 views 11 replies 7 participants last post by  Si 
#1 ·
Is there more than one try of autobox oil cooler? I imagined it would be similar to the engine oil cooler on a turbo but i got hold of one over the weekend and it's completely different, this one sits in the coolant return hose from the radiator, i wondered if it helped regulate the oil temp better than a radiator style cooler?



 
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#2 ·
Yeah- there are two versions of the trans oil cooler. As I just learned, the air/oil cooler is very similar to the engine air/oil cooler,lives on the opposite side of the car and has different fittings. wich ones better? I guess that depends on where you live.
 
#3 ·
Yes there are two different types - the pictured one is the 'in-line' version that mounts under the intake manifold and forms part of the lower radiator hose going to the water-pump. The other type is an oil cooler style of fitting that mounts on the right-hand side of the engine-bay directly underneath the right-side headlight with a special mounting to direct air from floorpan level through the cooler.

My 81 turbo and 83 900S both have the inline-type of ATF cooler, but my 85 900i and 89 16V hatchback both have the later style of ATF cooler.

I guess Saab must have changed away from the inline type because of how difficult is was to service them! However, I guess the other reason was that the inline ATF coolers don't work as effectively after the engine is warmed up as the coolant is hot.

However on the flip-side, direct conduction cooling of heat from the ATF through a seperating layer of metal into engine coolant has merits too as water-based liquid solutions are many times better at conducting heat away than air coolers, so each has good and bad points.

air cooling the AFT requires a significant airflow but outside air is almost always going to be a lot colder in comparison with hot coolant mixture, so it's a trade-off.

Craig.
 
#6 ·
The cooler mounted in the lower hose ensures that the fluid is neither too hot nor too cold. The air cooled device used to have a thermostat to prevent overcooling (an alien concept to many, cooler is not better) but they proved troublesome and most were removed.
Given the choice, I'd take the lower hose cooler.
 
#7 ·
Do you think it helps regulate the oil temp more so than cool it?

I'll most likley tap in a temp sender into the gearbox or use the drain pug if there is one availiable, will have to figure out what the optimum GB oil temp is, and then see if i can run the cooler permanantly or if it needs to be switched.
Would be interesting to see if it helps maintain the oil temp within a certain preferable range, rather than with the air cooler & thermostat.
 
#8 ·
Jim Mesthene said:
The cooler mounted in the lower hose ensures that the fluid is neither too hot nor too cold. The air cooled device used to have a thermostat to prevent overcooling (an alien concept to many, cooler is not better) but they proved troublesome and most were removed.
Given the choice, I'd take the lower hose cooler.
Perhaps if people thought about their own muscles and how they work once they get some heat into them as opposed to sprinting a 1/4 mile on cold muscles.
 
#9 ·
Si said:
Do you think it helps regulate the oil temp more so than cool it?
I think "regulate" is too fancy a word for it.
The oil temperature wants to be over 180 and under 300 degrees. The lower hose cooler will help with the minimum and prevent the maximum.
Air cooler thermostats worked fine but leaked, and on a cold morning, did nothing at all.
Perhaps if people thought about their own muscles and how they work once they get some heat into them as opposed to sprinting a 1/4 mile on cold muscles.
I like that analogy.
 
#11 ·
Jim Mesthene said:
I think "regulate" is too fancy a word for it.
The oil temperature wants to be over 180 and under 300 degrees. The lower hose cooler will help with the minimum and prevent the maximum.
Air cooler thermostats worked fine but leaked, and on a cold morning, did nothing at all.
I like that analogy.
.

Here's something totally unrelated I just learned while taking some hockey coaching certification. The last three major studies have shown that stretching prior to exercise does nothing towards preventing injury. It may loosen you up a bit, or focus you mentally, but does nothing for your body. Doubly so if you stretch cold. The only time stretching does anything beneficial is after a hard workout to help with lactic acid build up.
They were teaching us not to put the kids on the ice and run them through a bunch of stretches as its a waste of their precious ice time.
 
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