Automotive Air Conditioning Information Forum (Archives)

Mackab on Fri November 04, 2005 8:34 AM

Model: 5 CFM

I have the 5 CFM vacuum pump found on this site. It is brand new. According to the instructions, "after 2 minutes, close the gas ballast valve". When I do this, the pump gets VERY noisy (internal rattling). It goes away if I unscrew the ballast. Is this normal??

Chick on Fri November 04, 2005 9:22 AM

Is it the economy unit 0r the regular 5cfm unit...Also, is the oil level right? Sometimes upon starting it it will drop or raise..Check the oillevel glass and make sur it's properly filled...Then let us know..Hope this helps.

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Mackab on Fri November 04, 2005 1:51 PM

Its this one:

5 CFM Vacuum Pump
Ultimate Vacuum 25 Microns
1/3rd Horse Power Motor
Oil Capacity 18 Ounces

The noise only starts if I close the gas ballast or when I plug the vacuum line (finger over end). Releasing either makes the noise go away. I have changed the oil and made sure of proper level as per instructions. Also, how hot does that oil get?????

TRB on Fri November 04, 2005 3:11 PM

Closings the valve should make the pump sound as though in is pulling into a vacuum. No odd noises should be present. If it is a new unit I would call Mastercool and provide them with the invoice and ask for a RMT for the unit.

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webbch on Sun August 29, 2010 11:30 PM

Dredging up another old thread....

I also have the (economy) 5 CFM Mastercool pump from ackits (purchased about 3 years ago). I can easily pull down to 30-40 microns no problem, which is much more than I need, but this pump also exhibits the internal rattling noted by the OP, and has from day one. It's a little bit intermittent in that it doesn't always happen, but normally only happens when gas ballast valve is closed. I've also changed the vacuum pump oil whenever I've used the pump and checked the oil level per the instructions.

It's my first pump, and while the noise is very disturbing, I thought maybe the outgassing caused by the deep vacuum brought on the noise somehow. According to other posts, this is not normal. Not sure what I can do other than continue using it at this point, as I'm sure it's out of warranty by now.

Edited: Sun August 29, 2010 at 11:43 PM by webbch

webbch on Wed September 01, 2010 10:47 AM

So I contacted technical support on the noise issue:

ME: "I have a 90066 Vacuum Pump (5 CFM, two stage) that makes an internal rattling sound in the pump body housing whenever I close the gas ballast valve and start pulling a deep vacuum. It's been like that since the first day I owned it, and am wondering if this is normal, or if there's some way to fix it. I've always changed the oil with every use, and followed the instructions for adding the correct quantity of oil. Any information would be appreciated. Thanks."

MASTERCOOL: "Some noise is normal. If the pump pulls a deep vacuum, everything is OK. If pump under warranty, send to Mastercool and we will check if noise is to loud"

ME: "I expect some noise associated with the motor and suction sounds. The disturbing noise is one that sounds like a small metal object rattling around inside the pump. Also the oil level at the sight glass drops as I start pulling a deep vacuum. Is this normal? Thanks."

MASTERCOOL: "The conditions you describe are normal. Thank you, Customer Service."


Thus, according to Mastercool, this is normal behavior.......or they're blowing me off. I hope it's the former. The pump does pull a deep vacuum, so I guess I won't worry about it for now.

FYI - the oil capacity on the economy 5 cfm pump (90066) is only 8 oz. I believe the one line description on ackits.com is incorrect. The non-economy version (90065) has the 18 oz capacity. I always wondered why I could change the oil a couple times using a single 18 oz bottle of vacuum pump oil ;-)


Edited: Wed September 01, 2010 at 10:59 AM by webbch

TRB on Wed September 01, 2010 12:01 PM

It's very difficult for anyone to diagnose something over the phone. Maybe make a video of the pump in action and post it here. We "might" be able to determine if it's normal pump noise or if you should contact Mastercool again.

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