Basic A/C Questions..1999 Blazer..thanks

a99blazer · 07-30-2007, 06:12 PM

Ok here are my basic AC questions.
I have a 1999 Blazer S-10 2dr.

1. Which port is the low pressure port. I think it is the one on the side of the silver cylinder near up near the passenger/windshield side of the engine. There is another port heading towards the front of the car on a 1/2 steel pipe.

2. The compressor clutch seems to cycle on for 3 seconds and off for 3 seconds. With this cycling there is a drop and increase in the pressure guage from about 20-40psi and back to 20 again. It really jumps around.

I'm worried about overcharging the system or doing further damage if there is damage....

Thanks
Robert

badSol · 07-31-2007, 01:51 AM

Yes, the low pressure port is on the receiver/dryer (i.e. the silver cylinder). The one on the line next to it is the high side port.

Do you have your AC on max with the fan on high? If it is, your compressor is probably short cycling, which usually means low charge. The pressures will jump around some when the compressor goes on and off, as when it's off the compressor is no longer creating pressure on the high side and the high and low pressures roughly equalize. When you're checking pressure everything needs to be on full blast, if it is and is still cycling like that, add some R134a and it should stop short cycling so you can actually check the pressure correctly.

cpolaris502 · 07-31-2007, 11:43 AM

x2 on everything he said. my compressor was short cycling like that and i could really feel it bogging down the engine even on the freeway. it was very noticable, big loss of power. so i added more and now it stays on for longer and it is colder.

opeth13 · 04-02-2008, 09:21 AM

hey guys, bringing this one back from the dead. I just want to be absolutely 1000% sure I got the right ports here, so I've included pics. It's not my truck so I don't want to screw this up. Did I get it right?

and

Is that right?

Yogi · 04-02-2008, 12:12 PM

Yes, That's right.

Onimun · 04-02-2008, 05:07 PM

This picture cracked me up

Curtis2k · 04-02-2008, 05:20 PM

It should say High side on that black cap too

cpolaris502 · 04-02-2008, 05:36 PM

why would that crack you up?

opeth13 · 04-02-2008, 06:48 PM

Quote: Originally Posted by cpolaris502

why would that crack you up?

maybe it was the mad Adobo Paintshop skills

. Thanks for the replies.

Onimun · 04-03-2008, 06:07 AM

Quote: Originally Posted by opeth13

maybe it was the mad Adobo Paintshop skills . Thanks for the replies.

I like the upside down ? and the MS paint. I like you.

Onimun · 04-03-2008, 06:08 AM

Quote: Originally Posted by cpolaris502

why would that crack you up?

Dont hate the player, hate the game.

cpolaris502 · 04-03-2008, 08:33 AM

oh i wasn't hatin yo.

07-30-2007, 06:12 PM	#1
a99blazer Registered User Age: 35 Join Date: Sep 2003 Posts: 31 Location: User is: OffLine	Basic A/C Questions..1999 Blazer..thanks Ok here are my basic AC questions. I have a 1999 Blazer S-10 2dr. 1. Which port is the low pressure port. I think it is the one on the side of the silver cylinder near up near the passenger/windshield side of the engine. There is another port heading towards the front of the car on a 1/2 steel pipe. 2. The compressor clutch seems to cycle on for 3 seconds and off for 3 seconds. With this cycling there is a drop and increase in the pressure guage from about 20-40psi and back to 20 again. It really jumps around. I'm worried about overcharging the system or doing further damage if there is damage.... Thanks Robert
	[Reply w/Quote]

07-31-2007, 01:51 AM	#2
badSol Registered User Age: 23 Join Date: Feb 2007 Posts: 69 Location: DFW, TX User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks Yes, the low pressure port is on the receiver/dryer (i.e. the silver cylinder). The one on the line next to it is the high side port. Do you have your AC on max with the fan on high? If it is, your compressor is probably short cycling, which usually means low charge. The pressures will jump around some when the compressor goes on and off, as when it's off the compressor is no longer creating pressure on the high side and the high and low pressures roughly equalize. When you're checking pressure everything needs to be on full blast, if it is and is still cycling like that, add some R134a and it should stop short cycling so you can actually check the pressure correctly.
	[Reply w/Quote]

07-31-2007, 11:43 AM	#3
cpolaris502 The Dreamsicle Age: 20 Join Date: Jul 2005 Posts: 16,052 Location: Rogers, MN User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks x2 on everything he said. my compressor was short cycling like that and i could really feel it bogging down the engine even on the freeway. it was very noticable, big loss of power. so i added more and now it stays on for longer and it is colder.
	[Reply w/Quote]

04-02-2008, 09:21 AM	#4
opeth13 Registered User Join Date: Apr 2008 Posts: 2 Location: User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks hey guys, bringing this one back from the dead. I just want to be absolutely 1000% sure I got the right ports here, so I've included pics. It's not my truck so I don't want to screw this up. Did I get it right? and Is that right?
	[Reply w/Quote]

04-02-2008, 12:12 PM	#5
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks Yes, That's right.
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04-02-2008, 05:07 PM	#6
Onimun Mr. Sparkle Age: 20 Join Date: Sep 2006 Posts: 8,285 Location: Kow-a-fo-knee-uh User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks This picture cracked me up
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04-02-2008, 05:20 PM	#7
Curtis2k 4 Bangin' Age: 21 Join Date: May 2006 Posts: 252 Location: Oklahoma City User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks It should say High side on that black cap too
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04-02-2008, 05:36 PM	#8
cpolaris502 The Dreamsicle Age: 20 Join Date: Jul 2005 Posts: 16,052 Location: Rogers, MN User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks why would that crack you up?
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04-02-2008, 06:48 PM	#9
opeth13 Registered User Join Date: Apr 2008 Posts: 2 Location: User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks Quote: Originally Posted by cpolaris502 why would that crack you up? maybe it was the mad Adobo Paintshop skills . Thanks for the replies.
	[Reply w/Quote]

04-03-2008, 06:07 AM	#10
Onimun Mr. Sparkle Age: 20 Join Date: Sep 2006 Posts: 8,285 Location: Kow-a-fo-knee-uh User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks Quote: Originally Posted by opeth13 maybe it was the mad Adobo Paintshop skills . Thanks for the replies. I like the upside down ? and the MS paint. I like you.
	[Reply w/Quote]

04-03-2008, 06:08 AM	#11
Onimun Mr. Sparkle Age: 20 Join Date: Sep 2006 Posts: 8,285 Location: Kow-a-fo-knee-uh User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks Quote: Originally Posted by cpolaris502 why would that crack you up? Dont hate the player, hate the game.
	[Reply w/Quote]

04-03-2008, 08:33 AM	#12
cpolaris502 The Dreamsicle Age: 20 Join Date: Jul 2005 Posts: 16,052 Location: Rogers, MN User is: OffLine	Re: Basic A/C Questions..1999 Blazer..thanks oh i wasn't hatin yo.
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