I've read on several other car forums that aluminum valve stem caps occasionally become almost impossible to remove. The problem is caused by dissimilar metals in contact (aluminum cap on brass stem).

Google it and you will see many examples of this simple part causing this headache. Sometimes WD40 and force could get them off but sometimes the entire valve stem needed to be replaced on multiple tires.

Anyone ever experience this?

 

Daily, at work. I usually get lucky and only destroy the cap, but sometimes the stem too. It usually takes a set of pliers to remove.

 

Would applying a tiny bit of grease to the valve stem threads alleviate this?

 

^^^^

Anti-seize works well, especially since you should already be applying it to your lug nuts prior tightening.

 

I've had valve caps seize, total pain in the ass to remove (pliers method worked without damaging anything). It was enough for me to only go with steel or plastic now. I also had a friend with aluminium lugs that seized on him. Shop cut them off after snapping two of his studs.

IMO not worth the risk.

 

I tried a set of these AL caps. Didn't have them on that long when I went to check pressure and was horrified to find them completely seized. Quick forehead plant as I instantly realized why. Managed to get them all off with no small effort.

Once I got them off I used anti-sieze, and so far that has worked. Still, a lot harder to remove than the cheapo plastic ones. For now I'm keeping the AL on there, but may eventually cave and switch back to plastic.

Its possible the seizing (and subsequent efforts to remove) buggered up the threads a bit. I wonder if I used anti-seize from the start if they would wind on/off smoother.