Gearbox oil pipe running through the radiator

[db2boy]

Folks,
Have been tinkering on the Cosmo - pics and details to follow - and came across an interesting aspect yesterday when fitting the new alloy radiator. It was 2 fittings along the bottom that
came from the auto box, passed through the bottom of the stock rad and through the heat exchanged under the RHD side wing/lamps. Once the stock rad was removed this appears to be a copper
pipe running through the rad between the box and heat exchanger.

All my friend and I could conclude was it acts as some sort of pre-heat for the gearbox when the weather is colder to bring the gearbox oil to temp quicker. Anyone have specific details on this please?

Thanks

Ant

 

[db2boy]

Had a few mins to poke around. Seems this is actually transmission oil cooler when its run through the bottom of a radiator like this. So why have this configuration and then flowing into the heat exchanger under the wing also? If the new radiator does not have this "cooler" running through the bottom of it do I now need to add another transmission cooler/radiator in place of this?

 

[philrab]

Probably wouldn't be a bad idea to upgrade to a separate oil cooler in any case. I'd imagine a small air/oil cooler kinda like a small radiator would be right up your alley.

 

[frank20bcosmo]

Had a few mins to poke around. Seems this is actually transmission oil cooler when its run through the bottom of a radiator like this. So why have this configuration and then flowing into the heat exchanger under the wing also? If the new radiator does not have this "cooler" running through the bottom of it do I now need to add another transmission cooler/radiator in place of this?

Yes Ant,, you will have to run a separate transmission cooler otherwise you may end boiling the transmission fluid which will cause slippage, you can get an aftermarket one cheap enough and locate it somewhere where it has a good flow of air,, I gather you are back in the UK if you are tinkering?

 

[rodneooo]

Your right, its to get the box up to temp quicker, and keep it at a reasonable temp in super cold weather. You can just bypass it with no dramas and hook back up to the factory trans cooler, you will need longer oil lines. It will just take slightly longer to get up to temp.
U wont need to add another trans cooler (unless u have modified the box or running musch more power). If that was the case your better off replaceing the small factory one with something larger, not musch point running 2 trans coolers.

 

[cosmojc]

As of this afternoon, I think I can add something here. On two of the Cosmo boys last cruises out of Sydney, I had clearly an overheating of the gearbox fluid characterised by a sudden and dramatic spewing of gearbox fluid onto the exhaust dump pipe causing a large white cloud and a sprayed fluid mist out of the back. This was partially due to a slight overfill, hot day and enthusiasm on a nice bendy bit of road!

I had the gearbox serviced today by a knowledgeable shop with Penrite ATF FS. He found that the pipe from the gearbox to the radiator and transmission cooler was running at 90PSI! There is clearly a restriction in the line. He surmised that the heat exchanger in the bottom of the radiator (a cylinder with an inner and outer skin with brass spiral radiator type fine fins inside) had lost some of its fins and was partially blocked. Apparently not uncommon This was causing the fluid to not get adequate flow and the transmission cooler was unable to do its job. Transmission guy was adamant to slightly under fill rather than overfill, thus potentially causing foaming and overflow!

This was on a replacement OEM radiator that I had installed after the two dramatic white clouds. Coincidentally, that original radiator was in for a small repair at a good radiator shop. I got the guy there to run some high pressure air through the heat exchanger in the bottom of that radiator. He was reluctant as he had only seen it in Ford radiators as a problem previously. There was a clearly observable loss in air pressure and an obvious blockage. Clearly both radiators have a similar problem. Even if the problem isn't a blockage, the flow rate causing it to run at 90 psi instead of 60-70 was causing a problem in the cooling system for the transmission.

The solution from both guys - by-pass the radiator and rely on the transmission cooler! If that isn't adequate - bigger transmission cooler.

Kramer
PS 2nd annual Thunderbolts way run in 4 weeks! All Cosmo guys welcome!! Bring your daily if the Cosmo isn't working!

 

[db2boy]

Frank - Yes I'm in the UK, quick work trip, fly out Sunday be back in a couple of weeks.

As well as her few other additions she now has a 10 row transmission cooler to replace the cooper tube in the bottom of the rad. From Kramer's comments this was the safest and most sensible thing to do in the short term. I would like to get a thermocouple on their and watch how she reacts but this trip will not allow. Actually, I'd like to have a thermo controlled fan and on the cooler that I can adjust in the future.

On a side note, the sensor in the top of the radiator, is that just a level sensor? Stock sensor wont fit the after market rad as the bung in there is larger - need to get an adaptor.

Cheers, Ant

 

[rodneooo]

as stated an extra trans cooler isnt required, a simple bypass would have sufficed for the short term.
For a long term solution, Id suggest removing the factory transcooler and fitting a reputable after market one which is thicher and larger in a good airflow path. (some shrouding will help alot if the using the same position under the headlight area. A fan on this cooler is not needed if good airflow is available.

The sensor on the rad is the level warning sensor.

 

[cosmojc]

Has yours ever given a hint of any overheating Rod? Have you got an OEM radiator? Do you have a bigger tranny cooler??

Kramer

 

[rodneooo]

the only time my car has overheated was on a heatwave scorcher of a day stuck on parramatta rd traffic, barely moving.. water was sitting fairly steady at 95 slowly rising, fans going crazy, but once the oil and water temp got up to 100 i pulled into a servo too cool down. the twin oil coolers make the world of difference for cooling. but with no airflow on a super hot day, oil temps rise quickly. maybe a fan on one of the oil coolers would be handy for those traffic jams.
As long as im moving, i wont overheat, no matter how hot the day gets.
Iv got thicker alloy rad (16in + 10in thermos, with factory clutch fan and shroud), twin oil coolers (1 under each headlight) and decent sized pwr trannny cooler mounted on the ac condensor.
never had any trans dramas, ever.

 

[db2boy]

I went with a small trans cooler for now and also mounted on the ac condensor. Will keep an eye on things as I continue to progress with the car. Thanks for all the input.