I too have a 12 Jetta GLI, and bought a Nissens Heater Core from rock auto and was unable to close metal clips onto the new heater core. I had no trouble closing it with the original heater core.
I then removed the existing heater core and replaced it with the new one (Nissens) and checked for leaks in the coolant system using my coolant vacuum. I had no pressure leak offs after 1hr., 15min. so I assumed since it was holding pressure there was no leaks.
After polling the audience, seems like Nissens is a reputable brand to go with. I wanted to try something different than OE since the OE doesn't have a good track record to begin with.
I went with the nissens heater core as opposed to OEM. The veins on the heater core are definitely bigger which may help prevent future clogs as well. Of course it's a snug fit for it as opposed to the OEM that slides in like butter. I tried blowing air through the clogged heater core and it was like breathing through a straw. The new one is wide open.
Nissen is a quality brand. They’re designed that way to produce optimum heat. I think it’ll be a long time before you have to deal with clogging again.
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The brand is registered in Denmark.
In March 2026, PartReview does not yet have a formed opinion of Nissens heater core. You can help by adding a review for Nissens heater core.
Currently there are 5 reviews and 16 votes. Average rating — 4.2 out of 5. Vote balance: 14 up, 2 down.
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