I am the original owner of a 2008 G35X Sport, just going past 130K miles yesterday and am thinking about changing the radiator out as I intend to keep the car for another 8 years.

Seeing some threads recently about issues with the radiator failing, resulting in coolant contaminating the ATF.. Don't know how prevalent the failures are...

So, I'd like to hear from G owners who have changed the radiator on their V36 sedans. If you can post why you changed the radiator, mileage of the car, age, and cost of the change, that would be great.

 

Just remember that the radiator also includes the AC condenser in the V36+ cars so you will have to evacuate the AC system and recharge if you replace it. Honestly I wouldn't replace it unless it has failed.

 

Same, all that's been done with mine was a previous owner bypassed the transmission cooler, now it goes straight to an external cooler and avoid the radiator tank completely.

 

That works great in the summer but just be careful in the winter with it bypassed like that. It's hard on a tranny when the ATF isn't up to temp and that's why it passes through the radiator. The radiator warms up the fluid in the winter and also keeps it regulated in the summer. It takes a transmission quite awhile to warm up in cold weather by itself.

 

I'm figuring out something to allow me to cover up the cooler in the winter. Also, during the winter I typically run a partially blocked grille to reduce airflow coming in. I might just create a section of ducting between the outlet side of the cooler and the condenser and reverse the fan direction until warmed up. I'm pretty soft on the pedal in the winter anyway. I'm working on getting a trans temp monitor at the moment, once I have that up and running it'll make things easier. I've seen several instances where the trans fluid line in the tank has sprung a leak and completely screwed the trans, I'd rather avoid that.

 

Might get something like this and piggyback it on the coolant line that goes through the oil cooler. I'm planning on adding an external oil cooler as well. I could add a small solenoid valve to shut off the coolant flow once everything is up to temp.

 

I have personally only seen one radiator / trans loop open up and share fluids and that was over 20 years ago. I have heard of it happening quite a bit but not sure if it's manufacturer defect or other things that cause the problem IE: shock, physical damage, lines bent.... I do know when it happens it will share fluids both ways and you will be able to open you radiator cap and tell right away. I'm not too worried about it on my 08' since I check all the fluids weekly and would probably catch it before it ate the TCU up. You could split the risk and only use the radiator loop during winter months Your idea of a heat exchanger could work well as long as it's built better than what is in the car.

 

I'd be good with that, could probably use some 3 way diverter valves to choose where to send the fluid.

I don't doubt it's at least equal to the car, my only concern is dissimilar metals and coolant all mixing together.