Transmission oil coolers

[ari666]

I'll refer to a post I made here: Ari the air deflection isn't an issue with a decent stacked plate like the PWR, the thing is almost invisible.

ill think you will be surprise at the amount itll block off. we had temp problems with old turbo s13's and skylines when we used to put meshin over the bar openings. so a trans cooler hard up against a rad will effectively block off that area. if you had some kind of accurate reference (before and after temps, or a cfm fan behind the rad) id be more inclined to take your word, but ill just stick to what my radiator reconditioner, sales guys at VPW and the internet says.

also, coolant temps need to be stable, i.e. not too cold, not too hot. the info i have been given is that you feed the fluid back to the radiator to stabalise temps, not lower them further.

 

[Pollushon]

Yeah I should have taken before temps, but the way it stands now is the water and fluid temps are really solid/stable, over two months the tranny has continued to get a very consistent 80c, and warms up in time with the engine. It would be impossible to achieve this when the fluid runs back through the rad of a cooling system @ 135kpa, that's up to 115c (approx) in warmer weather. I will grab a CFM meter from work though and run a test, then post back results, but I get a strong notion the results will back up my sentiment that it's as if the cooler isn't there.

The one test I did do was using my mouth, blowing over the rad or rad with cooler resulted in no resistance I could notice. Whilst I have been called a big mouth and full of hot air, my lungs have nothing on moving air or a thermo fan, I think the trick is to ensure the rad/cooler fins are similar and aligned perfectly. Also the cooler quality really matter itself, of which the PWR quality amazed me when I got it. Josh the previous owner of my blower kit did the same thing (same cooler) without a hitch. I just added the thermal tape given I live in a really cold climate during winter.

 

[Immortality]

Mate, fit an external transmission cooler, fit it in-line, after the factory internal transmission cooler. Worst case the problem doesn't get any better.

What does the new fluid look like now? Although the transmission may have been flushed there may still have been a fair bit of build up inside the transmission that the new fluid has slowly loosed. If it's dirty again consider doing another flush. Use a white paper towel to check transmission fluid levels, good fluid should be almost pink in colour, by the time it's a dark red it should be changed. Also smell the fluid, it it smells burnt, change it.

 

[Calaber]

Immortality

It would be nice to be able to do as you suggest but guess what Captiva's don't have. Yep, a dipstick. Sealed trans, just like Falcon 6 speed autos and many others. After 30+k's, it probably wouldn't hurt to have the box flushed and refilled again ($330 last time - ouch!)

Regarding your comment about the placement of the cooler - you're saying have the trans oil go through the heat exchanger first, then through the cooler, and back to the trans. Correct?

 

[Immortality]

Ahhh, yes, I forgot about that. Farking rediculous, how would you know if you have a slow trans leak if it's not simple to check?

Your probably running that fancy/expensive synthetic transmission fluid but damn that's just silly.

Yep, after the factory cooler, Fairly damn sure that is how external cooler is in the VS. IF you have a look that this chart you'll see that transmission fluid temp has a direct effect on transmission life expectancy.

As mentioned before, with the standard engine operating temp the outlet temp of the radiator (will cooler than the engine temp) is generally still higher than what you would want the transmission fluid temp to be at so fitting the external cooler after the internal radiator transmission cooler makes sense.

I'm no expert, but from what I have been told, the fluid coming out of the transmission is basically coming out of the converter, the hottest part of the transmission.

 

[ari666]

Sealed trans

oh dear, so topping up the level required to fill the ex-cololer is gonna be impossible...


think this idea needs to be shelved.

 

[Immortality]

oh dear, so topping up the level required to fill the ex-cololer is gonna be impossible...


think this idea needs to be shelved.

Not impossible, just not straight forward. Really need to get it up in the air so you can access the filler plug, same way you have to check the transmission fluid level. Just like a manual trans really.

 

[ari666]

ah ok, so its not fully sealed.

we had a V35 skyline with a "sealed" box, but i found a tube that looked very much like a disptick tube but was sealed off on the end. undid the 10mm bolt and hey presto! a dipstick was in it!

cool story huh?

 

[Calaber]

Yeah, there is a filler under the car and from what I recall in an on-line workshop manual (which for some reason I can no longer access unless I speak Russian), it actually has a dipstick fitted. It just isn't the sort of thing you can access easily. I might consult the auto specialist about this one and see if they think the problem is something that cooler oil won't fix. Might get them to check the condition of the fluid while they're at it.

Thanks for the advice guys. At this stage, the cooler is in the cooler until the ol' Calaber gets the trans checked out. If I go ahead with this one, it will be one to report on after a bit of use.

 

[Pollushon]

Yep, after the factory cooler, Fairly damn sure that is how external cooler is in the VS.

No, it's the other way, I discovered this the first time I changed and flushed the fluid. That's a factory fitted cooling system. Trans> External Cooler> Rad> Trans.

That chart is the reason I bypassed. If the fluid hits a 135kpa system on a 30-35c summers day it's potentially going to be anywhere up to 115c or 240f in that rad. Right now I'm hovering on the 80c (175f) sweet spot.