Carpokes Porsche Forum

Also my new reciever dryer doesn’t have inlet or outlet ports marked so I don’t know which way to install it.

Where did you get that receiver drier? Did it come in a Porsche box or a Mahle box? Look for faint arrows. If it's like mine, the port further from the sight-glass is the IN side, but look for a faint arrow or faint markings.

It came in a Mahle box, and I don’t see any markings. Does the “in” side point to the front bumper or firewall?

Okay I’ve installed the new receiver dryer and put new o rings in for the dryer and the compressor. Ran vacuum for 10 minutes out of curiosity and after shutting the pump off and waiting for 10 minutes there is zero vacuum. Going forward now with the condenser o rings but I don’t know how to remove the front bumper on an early model NA to access the fittings. Any help would be greatly appreciated

Do I need to pull vacuum for longer to account for any moisture boiling off in the system?

Poorsche44 wrote: Sat Jun 21, 2025 7:34 pm Okay I’ve installed the new receiver dryer and put new o rings in for the dryer and the compressor. Ran vacuum for 10 minutes out of curiosity and after shutting the pump off and waiting for 10 minutes there is zero vacuum. Going forward now with the condenser o rings but I don’t know how to remove the front bumper on an early model NA to access the fittings. Any help would be greatly appreciated

Zero vacuum? Meaning it did not hold any vacuum at all after 10 minutes? That would mean a pretty big leak somewhere. Your goal is to get it to hold 29+Hg of vacuum for an hour after the vacuum pump is turned off, without any sign of it going down -- better if it holds over night. Once you get to that point, you want to put the vacuum pump on it and let it run for 45-60 minutes to help get all the moisture out.

p.s., for future reference, you normally want to install the receiver drier as the last thing before pulling a vacuum, so it doesn't have a chance to absorb much moisture.

My pump is only producing 22 hg of vacuum. Although the pump did make a weird gurgly noise after I turned it off and vacuum dropped significantly when that happened.

Poorsche44 wrote: Sat Jun 21, 2025 8:04 pm My pump is only producing 22 hg of vacuum. Although the pump did make a weird gurgly noise after I turned it off and vacuum dropped significantly when that happened.

Hmmm, that's not going to cut it. Does the pump get to 29+ if you close off or cap off the fitting? If you have a big enough leak, the pump won't be able to pull a strong vacuum. But if the pump itself is bad, that's a whole different thing...

I believe the pump is bad. I ran vacuum without being connected to the system and still only pulled 22 hg. Also when I turned the pump off it immediately started losing vacuum. One of the ports is sealed only with a plastic cap and I could hear it lose pressure from the cap.

Make sure all the fittings are sealed. More often than not, an inability to pull a full vacuum is due to leaking fittings.