Tundra Solutions Logo

Go Back   Tundra Solutions Forum > SUV Forums > 1Gen-Sequoia

Readylift.com

Free Shipping at Buy.com!
FREE Personal Trainer Program

Notices

1Gen-Sequoia General discussion forum for the first generation 2001 to 2007 Toyota Sequoia.

This is a discussion thread titled "Help diag A/C problem", within the 1Gen-Sequoia forum, part of the SUV Forums category.


Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 07-02-2008, 01:48 PM
hill8570's Avatar
Registered Member
 
My Garage
Dealer : Peterson Toyota
2002 Toyota Sequoia
hill8570's Photo Albums
Last Online: 08-12-2008 09:02 PM
Join Date: Apr 2006
Location: Boise, ID
Posts: 103
Rep Power: 3
hill8570 is on a distinguished road.
Default Help diag A/C problem

I've got a 2002 Sequoia with the dual A/C. The A/C has never cooled all that well since I bought it (back in 2005), but since it was my first R134a A/C, I figured it was just the refrigerant. I did a bit of adjustment on the water control value based on some TSB for that model, but it didn't seem to make any difference. I also checked to see if the TSB for the compressor had been applied, and it looks like it had. However, while fixing the A/C in my wife's 1995 Camry (which I thought was R12, but turned out to be R134a when I checked the specs), I realized that it's possible for an R134a system to be colder than a witche's t*t when adjusted correctly.

So, I'm now trying to troubleshoot my rig. Symptoms are: somewhat cold air when it's not too hot out, colder at highway speeds. Occasionally gives up the ghost entirely and just blows hot air (usually on the days I need it the most).

I've checked the auxillary pusher fan in front of the condenser, and it seems to be working OK. The condenser itself seems clean. When the system is running, the sight glass is milky white (not just bubbly), but is clear when the system isn't running. Operational low side pressure is 53psi, operational high side pressure is 245psi. Ambient around 85-90F. According to the FSM, specs for the dual A/C are 36-51 psi low, 275-305 psi high, so my high side pressure is pretty low, and the low side pressure is pretty high.

To me, the pressure readings sorta-kinda indicate a duff compressor, but I don't understand why the sight glass is milky white. Any suggestions?
Reply With Quote

  #2 (permalink)  
Old 07-02-2008, 05:32 PM
mcmatt's Avatar
Registered Member
 
My Garage
Dealer : Classic Toyota Scion of Round Rock
2001 Toyota Sequoia
mcmatt's Photo Albums
Last Online: 07-21-2008 08:56 PM
Join Date: Feb 2002
Location: Cedar Park, TX
Age: 42
Posts: 91
Rep Power: 7
mcmatt is on a distinguished road.
Default Re: Help diag A/C problem

not an expert here, but I have fixed a dozen or so A/C and have replaced most individual parts.

Anyway, my 0.02. You sight glass should bubble or foam for a couple of seconds when the compressor kicks on, then it should run clear. Clear when off is normal and not indicative of anything other than there is some freon.

It sounds like a simple undercharge. Your high side is pretty high. I would watch that and charge a little with 134a until you get a clear sight glass, then evaluate the system and pressures, etc. If the bubbles don't get better with 1/2 to 1 can STOP don't add any more.

You may need to evacuate it, leak check it and recharge it. You must use a recovery compressor for this or maybe you have a contact that has one.

Good Luck.

PS - Normal waivers apply. The pressures are high enough to be deadly from explsion or fire, etc. Attempt any and everything at your own risk.
Reply With Quote
  #3 (permalink)  
Old 07-03-2008, 08:08 AM
Registered Member
 
My Garage
Dealer : Toyota of Glen Burnie
2004 Toyota Sequoia
niknine's Photo Albums
Last Online: 07-03-2008 08:17 AM
Join Date: May 2006
Location: Annapolis, MD
Posts: 4
Rep Power: 0
niknine is on a distinguished road.
Default Re: Help diag A/C problem

I'm thinking my A/C is under-achieving also. I haven't done the sight glass test yet; but I did stuff a thermometer into the dash vent. The best I've seen is a 20F drop from ambient.

Does that suggest an undercharged system?

-Nik
Reply With Quote
  #4 (permalink)  
Old 07-03-2008, 10:04 AM
mcmatt's Avatar
Registered Member
 
My Garage
Dealer : Classic Toyota Scion of Round Rock
2001 Toyota Sequoia
mcmatt's Photo Albums
Last Online: 07-21-2008 08:56 PM
Join Date: Feb 2002
Location: Cedar Park, TX
Age: 42
Posts: 91
Rep Power: 7
mcmatt is on a distinguished road.
Default Re: Help diag A/C problem

yes it is under performing. My seq delta from outside temp is about -40 deg F

This will vary. The smallest ambient is idling sitting still with high fan. the best ambient delta will be on the highway with a lower fan. the lower fan allows longer dwell time which gives a lower vent temp.

You have a very high pressure delta from low to high guage pressure. That looks like your compressor is doing a good job.

Remember that the Low side pressure is also an indication of temperature. If if it just warmer because of low freon the pressure will go up.

I still think you are low.

Have you ever added freon? It is a fairly straightforward operation.

also the most common place for a slow leak is the schrader valves in the high and low side ports. With a special tool, these can be changed without losing any freon from the system. The tool is a JRA valve core remover/installer. You can get one for under $30 or a kits with 6 different sizes for $125.

The valve cores for this system are the same for hi and low. They are JRA M6 or 6mm high flow cores. They can be found here
http://www.acsource.com/index.asp?Pa...ROD&ProdID=528
Hope this helps,
Matt

Last edited by mcmatt; 07-03-2008 at 10:06 AM.
Reply With Quote
  #5 (permalink)  
Old 07-04-2008, 01:16 AM
hill8570's Avatar
Registered Member
 
My Garage
Dealer : Peterson Toyota
2002 Toyota Sequoia
hill8570's Photo Albums
Last Online: 08-12-2008 09:02 PM
Join Date: Apr 2006
Location: Boise, ID
Posts: 103
Rep Power: 3
hill8570 is on a distinguished road.
Default Re: Help diag A/C problem

Quote:
Originally Posted by mcmatt View Post
not an expert here, but I have fixed a dozen or so A/C and have replaced most individual parts.

Anyway, my 0.02. You sight glass should bubble or foam for a couple of seconds when the compressor kicks on, then it should run clear. Clear when off is normal and not indicative of anything other than there is some freon.

It sounds like a simple undercharge. Your high side is pretty high. I would watch that and charge a little with 134a until you get a clear sight glass, then evaluate the system and pressures, etc. If the bubbles don't get better with 1/2 to 1 can STOP don't add any more.

You may need to evacuate it, leak check it and recharge it. You must use a recovery compressor for this or maybe you have a contact that has one.

Good Luck.

PS - Normal waivers apply. The pressures are high enough to be deadly from explsion or fire, etc. Attempt any and everything at your own risk.
Yeah, the milky-white look of the sight glass would normally make me think the system is undercharged (or the refrigerant is contaminated, but I'd think it'd stay white with the system off in that case). The low-side pressure just seems awful high for an undercharged system, 'tho. The high-side pressure seems high for a "normal" system, but the specs given in the FSM are quite a bit higher for the dual-evaporator A/C system (which I have) than for the single-evaporator system. I hate to guess and hope, but I suppose tossing a half can of refrigerant into the system couldn't hurt things too badly.
Reply With Quote
  #6 (permalink)  
Old 07-05-2008, 06:58 AM
DH's Avatar
DH DH is offline
 
My Garage
Dealer : Thompson Toyota
2006 Toyota Tundra,
2007 Toyota Sequoia
DH's Photo Albums
Last Online: Today 04:14 AM
Join Date: Mar 2007
Location: Bel Air
Posts: 363
Rep Power: 2
DH is on a distinguished road.
Default Re: Help diag A/C problem

I think you may need to do a better search on here. This is a common problem for the Sequoia. Mine does it but only on the hottest days and after sitting idle for a very long time.

Some say on here say you need to insulate your piping under the hood better. I’ve bought the insulation but never done this mod out of laziness.
__________________
MODS:

2.5" SAW Coilovers, 1" AAL, Added Heated Seats, Under Drive Pulley, K&N drop filter, Electric Fans, 295/70-17 Nitto's, 1.75" Wheel Adapters, Rhino Liner, Under Coating, VSE w/Dynamat coating.
Reply With Quote
  #7 (permalink)  
Old 07-05-2008, 02:15 PM
kathyricks's Avatar
Registered Member
 
My Garage
Dealer : Capitol Toyota
1993 Toyota Truck
kathyricks's Photo Albums
Last Online: 07-26-2008 11:33 PM
Join Date: May 2007
Location: Salem
Posts: 713
Rep Power: 2
kathyricks is on a distinguished road.
Default Re: Help diag A/C problem

Toyota spent extra bucks providing the sight glass (American car makers often don't) and the factory manual explains how to interpret the sight glass. Milky white sight glass when the compressor is running = foam = undercharged condition = marginal cooling.

The likely reason your compressor sometimes won't run is because undercharged condition = low system pressure = pressure sensing switch prevents the compressor from running.

The compressor oil circulates through the system with the refrigerant so undercharged condition = poor oil circulation = compromised compressor lubrication. The pressure sensing switch stops the compressor from running to protect it against the damaging effects of poor lubrication.

Normal center dash vent temperatures should be in the 38-44 degree range when the controls are set for maximum cooling regardless of outside temperatures. Temperatures from the side vents should be a few degrees warmer.
Reply With Quote
  #8 (permalink)  
Old 07-06-2008, 09:34 PM
hill8570's Avatar
Registered Member
 
My Garage
Dealer : Peterson Toyota
2002 Toyota Sequoia
hill8570's Photo Albums
Last Online: 08-12-2008 09:02 PM
Join Date: Apr 2006
Location: Boise, ID
Posts: 103
Rep Power: 3
hill8570 is on a distinguished road.
Default Re: Help diag A/C problem

Ended up having to add most of a 12oz can of refrigerant before the sight glass went clear. Pretty weird, too -- there was basically no "big bubbles" stage in the sight glass like I've seen in other systems -- it went straight from "foamy white" to "clear". Low side pressure never budged off of ~55psi (at 85 degrees ambient). That low side pressure still seems high, but it's hard to argue with the sight glass.

I'll put the system through it's paces to see if the problems are completely fixed by such a simple tweek, or if this is just the first layer of the onion...

Thanks for all the help!

Andy
Reply With Quote
  #9 (permalink)  
Old 07-07-2008, 03:38 PM
mcmatt's Avatar
Registered Member
 
My Garage
Dealer : Classic Toyota Scion of Round Rock
2001 Toyota Sequoia
mcmatt's Photo Albums
Last Online: 07-21-2008 08:56 PM
Join Date: Feb 2002
Location: Cedar Park, TX
Age: 42
Posts: 91
Rep Power: 7
mcmatt is on a distinguished road.
Default Re: Help diag A/C problem

Glad to hear you had time to work on it. The vent temps and performance will be very informative.

Also remember that the pressure of the hi and lo side are not an indication of a full or low charge. the pressure of the 134a gas will be the same based on it temperature not on the volume in the system. That is why you can judge whether a container is full just by the pressure. You have to take into account its weight, pressure and temperature. Let us know how it come out.
Reply With Quote
  #10 (permalink)  
Old 07-15-2008, 11:45 PM
mcmatt's Avatar
Registered Member
 
My Garage
Dealer : Classic Toyota Scion of Round Rock
2001 Toyota Sequoia
mcmatt's Photo Albums
Last Online: 07-21-2008 08:56 PM
Join Date: Feb 2002
Location: Cedar Park, TX
Age: 42
Posts: 91
Rep Power: 7
mcmatt is on a distinguished road.
Default Re: Help diag A/C problem

How is the cooling?
Reply With Quote
Reply



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On
Forum Jump




All times are GMT -5. The time now is 07:18 AM.


TundraSolutions.com is a registered trademark of Tundra Solutions, Inc.
Other trademarks and brands are the property of their respective owners. Use of this Web site constitutes acceptance of the TundraSolutions.com User Agreement and Privacy Policy.
Questions? Please use the Contact Us link.  Consumer Electronics Hunter  Dealer Hunter  JPV Photography  Tundra Solutions