Coolant reservoir on Mazda 626 models has a design flaw. Our vehicle has required 4 of these since we've owned it. Each time, the part is no longer under warranty as it is over 12 months old. Failures occurred on 5/30/06 at 118K and again on 6/1/07 at 138K, and now on 7/11/08 at 162K. The problem is that they are manufactured with a seam on the bottom. The seam leaks and so coolant gradually leaks from the reservoir until you notice your vehicle slowly running hot. Since I watch may gauges closely, I always see when this is happening. Replacing coolant will prevent the engine from overheating but replacing the reservoir is always required. Locally this part costs $100. This does not include labor to remove/discard the old reservoir and to attach the new one. Our local Mazda dealership has 50 of these in stock at any given time. Seems like a large inventory for a part. This item needs to be redesigned so that the seam is more durable or so that there is no seam at the bottom where the leaks keep occurring. Others not aware of this problem may have allowed their engines to overheat causing much more costly problems in their engines. We have been fortunate in that we have always caught it early and that we have a good mechanic not associated with a dealership but who is Mazda certified.

- Elgin, SC, USA

: the contact stated that the engine overheated due to a coolant tank leak. The vehicle was inspected by a service dealer, where the coolant tank was replaced. After a year a half the new coolant tank started to leak causing the same overheating issue.

- Fort Washington, MD, USA

Vehicle overheated and spilled coolant. It had been to the repair shop 5 times for overheating.

- Loma Linda, CA, USA