I've sat this discussion out several times, but here goes:
How do you know it will not cause warranty problems? You are adding a non-factory part that modifies the PCV system on an extremely complicated and expensive engine. If you have an engine related problem during the warranty period, my guess is you will be going round and round with them about wether or not this modification contributed to the failure in any way.
How could it cause a problem? Well, if for any reason the PCV system was to get plugged up, it would create a dramatic increase in crankcase pressure that would cause all kinds of problems.
Is it likely, probably not, but it can and has happened to other manufacturers oil separator designs.
BMW had a huge, well known oil separator problem:
What years of X5's are most susceptible to the dreaded oil separator failure? - Bimmerfest - BMW Forums
Porsche warranty claim problem with oil separator:
Can oil separator cause catastrophic engine failure? - Rennlist Discussion Forums
I completely understand the oil vapor issue in play here as I have had several factory blown fords over the past 10 years, but if hassle free warranty service is important to you, I would wait and put the separator on after 3/36,000.
And please don't quote Magnuson Moss, I get it, but IMO this is not a fight you want to have if you plan to keep the car otherwise stock.
Take care,
Kevin
I agree anything can happen, but the chances of an oil separator causing failures/warranty problems on this particular engine is remote at best. How do I know this? Hundreds of GT500 owners of all years have used separators and I don't know of one failure. Even if there was some kind of blockage it would immediately cause a CEL from the sensor on the PVC before it could do any damage. With that logic ANY mod could void the warranty, i.e. hood struts bending the hood, etc.
To each his own but I'd rather not wait 3 years (or longer with and extended warranty) and have a gummed up intercooler for an occurrence that has almost no chance of happening. I've seen the shape of my last intercooler after only 15k with no separator and I was shocked.
In the past I have installed mods that could have very well caused engine damage (tunes and other power adders) but I'd say it's a pretty good be we'll be OK with this one. Like I said, to each his own.
Enjoy