Twodose

You stated that “If you ever used 134a with a sealant in it you are screwed long term”. I don’t know why anyone would make a product that was detrimental to a system in any term short or long. I know the product I used stated it has sealants in it, but my understanding was that it was more of a conditioner for the seals, than a sealant that could damage the system. Why did you say that? Just curious.

I have guages and a vac pump ordered.

So you never have to worry about adding oil to the system, for the life of the system unless you do a recovery? Also 1.8 lbs would be 28.8 ozs of freon.

When you pull a vacuum on the system, does it suck the oil out also?, I wouldn't think so but I don't know, and do you have to add any oil back to the system after running a vacuum pump? Any oil need to be added after evacuation? Looks like it needs 1.8 lb, truck only has a/c in front.

How can it be overcharged if the pressure is only 30 psi?

What do you think I should have done, to do it correctly?

Yes, I unplugged the connector to the pressure switch and jumped it, it only had 6psi, I charged it to 30 psi, put the plug back on and it works fine, used ac, pro, it took a 20 oz and a 12 oz, the get it to 30 psi, is 30 psi enough? I thought the pressure switch was bad, but it must me OK. The compressor is running for a long time now and shuts off when I either turn the ac off, or turn the fan off, so it seems it is running fine, old gmc’s never die, they just go faster…lol. It’s funny because the temperature on the 1999 sierra is 48.4 @ 30psi, and the temperature on the 2011 sierra is 55.6 @ 36 psi. I don’t know what the pressure should be, according to the can below 50 psi is good.

AC compressor kicks on and off every couple seconds, when compressor kicks on, pressure goes down to about 16 psi, when it kicks off, it goes to 70 psi, the pressure goes up and down form 16 to 70 as the compressor kicks on and off. 1999 GMC Sierra 1500 5.3 slt.

What type of brake pads came stock with a 2011 sierra 1500 5.3L? I would like to replace with something similar. I have 87,500 miles and the pads are still decent. At last inspection, in Jan 2022, at 84,769 miles the front were 8/32 and the rear 6/32. Need new rotor's, so I'm going to replace both at the same time.

I appreciate the input, but I would rather buy a new truck, If I could find one...just to probably have the same problems again.... lol.

Do the Range afm/dfm disabler's work? I never thought the 8-6-4 was a good idea, my father 40 years ago bought a new cadillac that had that when it first came out, they had nothing but problems with it.

83,600.

I bought Amsoil Engine and Transmission Flush but haven't used it yet, I will try on this oil change.

The first thing I did when I noticed it was low was check the oil pressure and it was fine, I never had a light or any warning for low oil pressure. About a year ago I made this post I made on a different forum: https://www.truckforums.com/forum/chevy-silverado-gmc-sierra-forum-11/change-full-synthetic-now-burning-oil-22886/ 4419 miles used 2.5 quarts of oil. < this was a year ago. 4872 miles used 3 quarts of oil < this was from last oil change to now and there is 29% life left on the oil monitor. I only put about 5k miles a year on the truck. Before switching to full synthetic, this truck never used a drop of oil.

I have a 2011 GMC Sierra 1500 SLT, I started using synthetic amsoil about 2 years ago, I just checked the oil and had to add 3 quarts of oil, it takes 6 quarts for an oil change with the filter, the check engine light did not come on, could this have possibly done some damage to the engine?