Should I be fitting an oil cooler to my 4×4?

A burst transmission oil cooler can cause coolant contamination

I own a ’96 Prado 3.0 A/T. The Cruiser’s got roughly 285 000 km on the clock and is still going strong. I’ve spent sometime browsing forum pages, where I’ve noticed a number of vehicle owners complaining about the fact that their transmission oil cooler is mounted inside the radiator. Why should this be a concern? I’ve heard some comments about the transmission cooler rupturing, but why should this happen?

I recently replaced my radiator as a precaution against overheating but I’m wondering if I should takes steps to separate the transmission cooler from the engine’s cooling system. Is it possible to add a separate transmission oil cooler and where can I get one from?

Answer: The failure of a radiator-mounted oil cooler is often the result of poor coolant quality – either the coolant isn’t of a high enough standard or the water / coolant ratio is incorrect. If this is the case the radiator coolant becomes corrosive and slowly eats away at the transmission cooler. After time, the transmission cooler eventually bursts, leaking transmission oil into the radiator and causing serious overheating issues – for both the engine and the transmission.

Fitting an external transmission cooler is not critical (provided you maintain your coolant / water ratios), but at the same time, it’s also never a bad idea. An external transmission cooler generally does a better job at keeping your gearbox cool, which is particularly important when you’re driving your 4×4 off-road and in high ambient temperatures. Try contacting Universal Coolers on (012) 666 8725 – they’ll supply you with the necessary kit, which is easy to install yourself.


Mitsi Tech Performance

Tel: 076 402 0046

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