The heater valve is one of those things that, for a number of reasons, the original parts last a long long time and the replacements don't. Ignition switches, window rubber, cv boots and clutch slave cylinders come mind. 

I checked and and the ones I buy locally (but not from the dealer) are Meyle. They do not last fifteen years like the originals did, but they last a lot longer than what you are experiencing. 

Bad batch? I've seen that happen with coolant reservoir caps, another item to add to the above list of crappier product. 

Except for the ignition switch mentioned above--all the other mentioned items share their weakness at one point, it seems: the rubber. 

Jim

On Feb 1, 2012, at 10:22 PM, Roger Barkley <rvbarkley4347@GMAIL.COM> wrote:

> Try this again, hope it's readable
> 
> 84 Westy stock 1.9 A/C A/T. My front heater valve is leaking again. (dripping antifreeze on to the spare tire/ground). Replaced it last year shortly after I bought the van. It, (new #1), started leaking after about 5K miles. Replaced it, (new #2), has started leaking after less than 1k miles. Don't remember which vendor they were purchased from, either B. Depot or V. Cafe....or both. Is there any alternative to the typical plastic POS? ?.....Thoughts? Haven't tested pressure on radiator cap, PO said it was new. 
> Thanks, Roger B.