Repeated Heater Core Replacement

I have a 2008 Hyundai Santa Fe . Since January 2013 I have had the heater core replaced 3 times. The repair shop has done the last 2 at no charge to me. The dealership ran a diagnostic and could find no reason for the repeated heater core failures. There suggestion was for me to let them replace it at full cost to me and see what happens. Has anyone else had a problem like this? I feel there has to be something going on with the car that is causing the heater cores to keep failing. When the original one started leaking I had around 70,000 miles on my car. I bought it new.

Well it is possible that the shop is using second-rate parts or that they just don’t know what they’re doing with the installation.

You could request that they use only a genuine Hyundai replacement but that won’t help if it’s installer error.

I would find a good independent mechanic to repair your heater core problem. There are too many novice mechanics at some dealerships. There is no way that 3 heater cores can fail in just a few months. A new heater core can be easily pressure tested before it’s ever installed. Someone is not crossing all their T’s and dotting all their I’s with this repair just as @Bisbonian alluded to.

I know the possibility is remote, but could water in your area be very corrosive and is used to make the 50-50 mixture of coolant and antifreeze?

Some vehicles have a ground strap attatched to the heater core to prevent electrolysis. This is a picture of a Grand Cherokee heater core. The ground strap is on the left side of the picture, the other end of the ground is attached to the HVAC unit mounting stud. The Hyundai service manual should show if a ground strap is used on your vehicle.

I’ve also seen a heater core fail because the hose had insufficient relief loops and was stressing the inlet at an angle. The failure was at the seam between the inlet and the inlet tank (manifold or whatever term is correct).

Yes, lack of slack in the hoses or a leaking head gasket are likely causes for the failures. What were the points of failure on the 3 failed heater cores? Were the leaks at the joint between the pipe and core or was the core burst open at a flue or on a seam? Does that vehicle use a presurized coolant reservoir? If so is that reservoir filled to over flowing?