Toyota pickup AC questions

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JohnHere
Posts: 117
Joined: Sun May 13, 2018 10:20 am
Location: South Carolina Upstate

Re: Toyota pickup AC questions

Postby JohnHere » Sat Sep 15, 2018 11:26 am

Sorry...accidentally hit submit before cleaning up my previous post. Buttons on my phone are just too small.
PromiseRing
Posts: 20
Joined: Thu May 24, 2018 2:28 pm

Re: Toyota pickup AC questions

Postby PromiseRing » Mon Sep 17, 2018 7:33 am

JohnHere wrote:Do you know for sure that it was low on refrigerant? I ask because it's not possible to tell how much is in it by pressures alone. Recovering the charge and weighing it is the only way to gauge the actual amount.

I guess I do not know for sure based off of pressures. I had just assumed that the lower-than-normal pressures equated to low refrigerant charge. Also, upon closer inspection, I saw some residue near the high side port (and I actually lost the cap last time I worked on it). I have the r12>r134a adapters and I think it is leaking from there. Unfortunately I do not have the proper equipment to evacuate and measure the weight of the remaining refrigerant.

JohnHere wrote:Vacuum and refrigerant amount look good, but what do you mean about adding dye to the fill line? A half-ounce or so of dye is all that's needed.
After vacuuming the system, I simply added a very small amount of this stuff (less than 1/4 of the bottle) to the yellow charge line on the gauges before charging. Afterwards, I was able to see the UV dye circulating through the system via the sight glass on the R/D. This will help me better track the suspected leak next time it leaks (assuming that it is..)
https://shop.advanceautoparts.com/p/int ... wAodxzMOLA

JohnHere wrote:Elevated high-side pressures usually indicate a condensing problem caused by insufficient airflow. With the engine warm at fast idle, the A/C on, and an ambient in the 80's, I would expect the fan to be roaring most of the time. Even if it's new, the fan clutch could still be out of spec. Something to consider. After the fan re-engaged, the pressures dropped to 35/200, which are just about right for a conversion like this. At those pressures, I would expect to see center vent temps of 45-50 degrees. Does the vent temp drop into this range at speed or does it still hover around 60 degrees? If so, and air from the heater core isn't leaking in, the evaporator might not be sealed enough around its edges, allowing ambient air to infiltrate.

Yes after the engine got warm the fan stayed on. The fan functions as a mechanical fan should. Cold start whoosh, then disengage, then very engaged when needed. It's the nature of the beast to disengage after 30 seconds or so, and at idle and disengaged there is insufficient airflow over the condenser. I told my neighbor that on cold starts she should do her best not to idle but rather just keep moving. I have been through this before with volvos. They do the same thing but then started using a pusher fan to help keep ac pressures lower. It works very well. I may end up adding an auxiliary fan to the toyota for better idle ac quality.

As for the vent temps, I think I was able to get to around 58F when revving to 2k-2.5k. Perhaps you're right and there's a leak in the evaporator box, or coolant is bleeding into the system. My vote is for ambient air getting in though. As of now I don't think she wants me ripping the dash apart again as summer is coming to an end.

A concern I had was with my TXV bulb mounting. I am unsure if it is sufficient or not. I believe I added a picture a few posts back and someone, maybe you, told me it was okay. Is there any chance the TXV is causing the less-than-ideal vent temps, or would that be shown with the pressures?

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