Aluminium Radiators

[GeeDog]

I have a few questions about fitting an aluminium radiator to my 03 coupe. My temp has drifted upwards several times over the summer, mostly when pushing hard on very hot days. Because I do some events in the car I want to try & stop this, and I'm thinking of replacing the radiator with a larger, more efficient one.

Does a 350Z alloy radiator fit into the V35, and are any mods needed. I'm looking at a 50 / 52mm thick core. There are a lot of 350Z radiators available.

Has anyone fitted an alloy radiator to a V35, and what effect did it have on temps?

My car is auto, and I've fitted a large auto trans cooler, in addition to the one in the radiator. Any thoughts on whether I need an auto radiator, or just a manual one with the external cooler?

Cheers

[scotty nm35]

You will most definitely need an auto radiator, but a 350z alloy unit will not fit. The neck is on the opposite side for a start. You could perhaps run a G35 radiator from the US like a few of the stagea guys run, but this won't fix your overheating issues. Do some research in the Stagea section, I and many others have had this issue for a while, and I have eventually had to design a mod to cool the block separately. I call it the VQ coolant mod, to help you search.

[Nightcrawler]

350Z alloy radiators DO fit, but it takes some massaging to get it in. The biggest problem is that due to it being so significantly thicker than the stock V35 radiator the top and bottom mounts don't properly line up, so you have to modify them. Also it fouls slightly on the air conditioner hard lines, and the radiator pipes touched the fan shroud on the passenger side. In the end my Ebay alloy rad ended up developing a weeping leak in the core (presumably due to being wedged in my car for 2 years) and I have now put the oem one back in. All in all not recommended.

I did however also fit a Davies Craig trans cooler in front of the oem radiator, and disconnected/rerouted the trans fluid pipework. This takes a heap of heat OUT of the oem radiator, and makes it work better. I also fitted an oil cooler and again, this helps keep the whole lot cool.

My recommendation: keep the oem rad, disconnect the oem trans cooler pipes running through the radiator, fit a decent trans cooler, fit a decent oil cooler.

[scotty nm35]

^^ and be stuck with 4 gears most of the winter. It won't work well like that at all without a thermostatically controlled fluid supply or hiding the cooler away with a thermo fan. (not a good option) Keep the radiator fluid 'warmer', as the trans would never get near the engine temps without it anyway.

An oil cooler will not cool the water temps down too much, and the hassle with loading up the cold air space in front of the radiator is it then gets a gutload of hot air as it has already passed through multiple coolers before the radiator, making the problem worse. I agree an oil cooler is a good idea if you plan to track the car, otherwise it is a liability.

If you do a few searches, you will see a common trend, VQ's are a bitch to bleed and missing only a cup full of coolant can be enough to airlock the system, pushing water temps through the roof. Many an engine has been lost this way, mainly due to the poor design of the cooling system.

[GeeDog]

My trans fluid goes through the new cooler first, then the radiator, so it wouldn't be adding a lot of heat to the coolant. Its only got hot a couple of times, both on extreme heat days (one was 45 degrees, the other 42 or so) when under load. Daily driving isn't an issue - the gauge sits a fraction under half. I'm just concerned that a track day will be a major problem, and want a bit more cooling ability. I really don't think it's a bleed problem, I just think the cooling system isn't quite good enough for extreme conditions. I will put an oil cooler in before I do a track day, but I will probably also get a larger radiator. I've found some 40mm V35 ones, so I might try one.

Thanks for the input - it was helpful. NC - where did you mount the oil cooler? I'm running out of space as I've already fitted a large trans cooler on the LHS, and a larger than stock Power Steering cooler on the RHS.