1999 Tahoe 2-Door CUCV - A/C Recharge

[Spectrese]

Hi...

The A/C in my Tahoe seems like it needs a partial recharge - at highway speeds when you would expect the best performance - it is just moderately 'cool' - not 'cold' like when you have a full freon charge on a new car. Gonna be 95 degrees today here in Chicago - was thinking some improvement might be in order this year.

How should I go about it? - - - Is there a real difference in recharging methods used by a professional mechanic say from an auto shop or dealership - or if I just got R134a freon cans at a local auto parts store and followed instructions and did it myself?

I am older - and can remember over 20 years ago needing a vacuum pump to evacuate the A/C system before then adding A/C oil and freon to get the most efficient charge.

Thanks...

 

[lesterl]

If it is low, just go to walmart or your favorite parts place, buy one of the big cans of freon with a hose/guage, Hook it up, and add a bit according to the guage to get it in the right area. If the guage shows good and it still doesnt cool good, you may have other issues.

 

[Big_Al]

I'm not a pro but I know one. Sorry he's not in your area. Many things can cause one to blow "not so cold". Yes you can ad it yourself but with 134a an overcharge will give the same effects as undercharged. Chances are it's just a little low but as you mentioned without pulling a vacuum (which helps determine if you have a leak) and adding the proper amount of Freon, you're guessing. Yes I've guessed and came out good. When I do guess with my Wal-Mart hose, I put a thermometer in the vent and ad a little at a time until the temp of the air drops. I bought a used S-10 once and paid a shop to fix it only to be told that they just had to let out excess Freon that the PO had put in thinking it was low when it had a bad "low Freon" pressure switch.
Nothing worse than a hot car. Gives me the feeling I'm being baked in the oven. Good luck.....Al

 

[Spectrese]

So...what air temperature might or should I expect to see if I put a thermometer in the vents to monitor it...?

 

[Big_Al]

Spectrese,

I'd put a thermometer in, turn it on max (recirculate) and see what it blows. If you have it around 50~55 F. @ idle you'll likely run around 40~45 while driving with outside temp around 85~90. This is what my 97 Hoe does with front air only. It cools it pretty good so far. You can expect the vent temp to go up some when the outside temp rises.YMMV HTH...Al

 

[lesterl]

I got 34* running 70mph the other day with it 85* out.... Center vent, max cool...... I wuz chillin'..... I typically see 40* when slower or if it is hotter out....

I sucked mine down for an hour and a half before I recharged it as it sat in a field for 6 years and was very nearly empty and devoid of freon.....