a/c tune ups?
Osmosis? Yep.
All rubber leaks... tiny bits that over time add up. The original hoses were before they produced a new barrier version used now. Multiple layers of rubber, reinforcement, and pvc sheets are the most recent development.
On to Sanden, it's subjective in my opinion. If your system's working up to spec; leave it alone as Bwana suggests. Adding a little freon after two or three years is pretty good.
But, if your York compressor is shot , you're adding a new system, or you can't get past your rpms dropping everytime the yorky kicks in... go for the best the budget will allow. ( discounting originality, of course if you're shooting for that.)
Sanden- 508, double groove. Really cheap now that they make them in China. $125 new. But guess what- they just came out with new lines- full rotary vs. wobble plate. Too new to say if there's a direct fit. Back to the 508- check the type of oil for the type of freon you're intending to use. The new oils are compatible with both. 12 uses mineral and 134 uses a product call PAG oil. (synthetic) .
Weight- a York weighs 3 lbs more than a Sanden.
Brackets- if you have a system- an adapter plate for a York mount- order with the compressor. If not, custom offset ( remember the 30 degree M30 tilt and the water jacket bumps?) or later model bracket- 635, evilbay etc. The 02 guys website has a recent great thread and one of the members sells nice custom brackets. I'll find the link if you guys want it.
Sandens don't come with charging fittings/ 90s. And the hoses- at least the first ones coming off the compressor.
If you're running headers or big 3.5 manifolds- it's going to be close on the clearance/ fittings. But racer suppliers have come up with heat shield wrap.
Universal hose kits- great idea for the DIY's. You'll know the hoses fit, but you'll have to have them crimped at the local auto parts store... $600 for the hydraulic crimper which doesn't make sense to buy unless you're going to do up a bunch for your buddies. One tip- put an extra charge fitting in away from the exhaust!
Of course, if you're converting to 134a, there is more to consider..... slightly less efficient ( use 75% of an r12 charge). So to make up for that if you live in Arizona or feel like you do, change your condenser coil to the new type ( crossflow) which cools your refrigerant better. ( Think intercooler packed with ice)
Gauges- absolutely a must for trouble shooting. No guessing on this one.
There are a lot of variables to consider. If you're going to a shop- make sure they've done something similar to yours the right way.
Porsches have been converting forever. And there's over 30'-40' of a/c hose to replace!
