7m cressy AUTO tranny cooler's....how efficient are they?

[IN 05 NT]

hey guys,

well the cressy is finally getting a tow bar asap, to start towing the celica n the commy thrasher around to race meets n the like,

i know with commys n falcons there tranny coolers are recomemded to upgrade if you are towing.......

so how efficent are the 7M coolers...and is it worth upgrading to a bigger one, ....

or doubling them up and having them both running together?...

just wondering if i should bother....

cheers, blake

[BabyZ]

I don't remember my 7M having a separate cooler, just the loop through the bottom of the radiator. When I went 1JZ, I found a $10 oil cooler at the wreckers (Mitsubishi Magna of late 80's vintage, I think) which was about 150x200 mm.

I mounted it to one side behind the bumper on some fabricated brackets - seems to get reasonable air flow. I could dig up some photos if it would help.

And yes, I ran it in series with the in-radiator cooler so I knew that, at worst, I'd have the same cooling as before and probably much better.

So the hoses went Trans --> radiator --> cooler --> trans.

I'd definitely be going to the trouble, even for the 7M; when towing, things definitely get hot in auto-trans land

[kingmick]

factory will be good for general stuff but towing on a summers day a good aftermarket one like B&M etc will go a long way. I fitted a big drag racing B&M to my patrol and a remote filter setup, just using a K&N oil filter.All up it added around 2 litres of tranny fluid to the system, so that helps aswell.
The reason i did the above was for towing and on the beach.

P.S when you do put a coller on, change the fluid and filter in the box if you havnt done it already

[Vios-GT_07]

So the hoses went Trans --> radiator --> cooler --> trans.

is that right though?? i'd have gone Trans -> cooler -> radiator -> trans

just because the oil has to be at a right temperature i.e. not too cold and not too hot, to be in the transmission... and if it goes to the radiator first, it'll be of the right themperature, then when it goes into the cooler, it might be below,.. hence the transmission receiving cooler oil...?

then again i guess it wouldn't make much difference anyway because the transmission heats up pretty hot... but i've alway thought that it should go into the cooler first, so the radiator doesn't receive overly hot oil, or is unable to cool down the oil efficiently to the right temps before going into the transmission?

or does it really make no difference at all?

[BabyZ]

is that right though?? i'd have gone Trans -> cooler -> radiator -> trans

You could be right, but I do recall figuring out which direction the oil was pumping before doing the plumbing, so I must have been trying to do it one particular way or the other.

There could be arguments either way - for example why cool the oil only to have it heated again by the radiator?

However I suspect that it may be one of those things that, in theory, should maybe be done one way only but, in practice, it really doesn't matter.

I would be happy to hear reasoned arguments to the contrary though

[ProjectSleeper]

Trans -> Radiator -> Cooler -> Trans is the correct way..

Remember, bigger isn't always better with some coolers. The quality is FAR more important than the overall size..

[IN 05 NT]

sweet...well i picked myself up a DAVIES CRAIG cooler....$30 its a basic flow thru bent pipe setup with fins between,

as mentioned, somethings better than nothing,

thanks guys, rep given to who i can still give it too, lol

cheers, blake

[Vios-GT_07]

There could be arguments either way - for example why cool the oil only to have it heated again by the radiator?

However I suspect that it may be one of those things that, in theory, should maybe be done one way only but, in practice, it really doesn't matter.

erm.. cool the oil first so the radiator won't get extra heat, and can actually heat up the oil to get it into correct operating temperature for the transmission... which should be below 90 degrees, but above 70 degrees or something...

yeh could be in practice it doesn't make a difference.. piping is really short and the cooler won't drop temperatures below the normal operating range.. and also the radiator would never have heat that is higher than the transmission oil...

[kingmick]

or take the cooler in the bottom of the radiator out of the loop so you have one less thing to go wrong coolers in the bottom of radiators are known for there problems

[ProjectSleeper]

or take the cooler in the bottom of the radiator out of the loop so you have one less thing to go wrong coolers in the bottom of radiators are known for there problems

They are ???
What goes wrong with them ??

[M.J.H]

They are ???
What goes wrong with them ??

They can get a hole in them and mix the oil and water. Not a good outcome at all.


As far as cheap coolers go a secondhand Magna one would be the go in my opinion.
has the row of tubes with the fins in between not just bent pipe.
They seem to be a decent size and could even run two of them if needed. Should be plenty to be had at the wreckers.

[ProjectSleeper]

Ahh yes, but impact damage could happen to anything - right ??
or are these just "prone" to forming holes..

I mean - one could say that fitting an additional cooler is just as risky as there are more fittings that "may" come off, thus losing fluid...

What I am trying to discover is...
Is there an inherrent problem with these factory set ups, and what sort of failure rate do they have, or is it just " a mate of a mate heard that someone had one break etc"

I am not trying to be smart, but if someone says there are "known problems" - then what are they ??? and are they "REAL PROBLEMS" or a rare occurance...

I mean, just about ALL manufacturers use them, so surely they can not be that bad...

[BabyZ]

Is there an inherrent problem with these factory set ups, and what sort of failure rate do they have

Well ... I've never personally had any troubles with the factory radiator-based coolers, and I've had/worked on a fair few autos over the years.

I just spoke to my radiator specialist (radiator repair and fitting is absolutely all he ever does, and he is also a member of a very small and elite group - "mechanics I actually trust") and he said that they were not, in his experience, particularly prone to failure.

As a side note, when I used the Magna cooler, I had to silver solder bigger fittings onto it. The originals were smaller than the 1/4 inch rubber piping in the Cressida, and screwed in with a wierd thread, so a screw-in replacement wasn't an option. Even the bigger fittings were still way smaller than the internal tubing of the cooler, so I doubt I am 'overloading' it. Another possible point of failure I guess (I'm not the worlds greatest solderer), but no leaks after 12 months or so. And yes, it is a 'proper' tube/fin radiator not a coiled pipe type.

[kingmick]

sorry missed this!
The main problem is them getting cloged up inside because they are small ! This is why even with an bigger after market core i use a filter before it.
The other is that they can only ever get down to radiator temp, under heavy towing loads they dont cope aswell as a air/air unit.

[Officer Doofy]

I have had a standard jzx80 cooler fail on me awhile ago. I bought a 80 series radiator from sss and didnt think to check the cooler function before i installed it. Before long i noticed my tranny fluid going to the colour of strawberry milk!!!! Not good at all.
Pulled the radiator out and had it pulled apart and found that there was a small leak where the entry exit spouts had been overtightend, It twisted the cooler and caused the copper welds to crack.
So yes they can fail but only through human efforts...