Regarding the recurring issue of low coolant levels I encountered: the root cause lay primarily in the auxiliary radiator, which harbored multiple pinhole-sized leaks. While the vehicle was still under warranty, the dealership merely replaced the expansion tank—a repair that, in reality, failed to resolve the problem completely. It was not until recently—while replacing the gloss-black trim on the front bumper—that I finally discovered the true source of the issue. If any fellow enthusiasts are experiencing a similar problem, I strongly urge you to insist that your dealership conduct a thorough inspection of the auxiliary radiator. As my vehicle was already out of warranty at the time, I ultimately had to purchase a replacement part myself for $110 on eBay and perform the installation personally.

 

Yep, this happened to me. Luckily I was still under warranty. Had several pinhole leaks caused by rocks hitting the aux radiator. Haven't had any issues since.

 

My aux radiator leaked since new. It’s was a very small leak but got annoyed with it enough to track it down and take pictures of it for when I brought it in for warranty work. If they do a leak check they won’t find it. I brought my defender in and told them it was leaking then got a call saying they didn’t see anything then I sent them pictures of it leaking. It got fixed. It’s annoying but dealers don’t give their techs enough time to diagnose. If you smell coolant and don’t have a big leak it is usually the aux radiator or a turbo coolant line.