AC guys please help

thats duct surface temperature. Not really accurate. You need a probe thermometer, the kind you would use to poke meat with to check internal temperature. I think it will be between 45-50. If you have one, take temp and get back with us, I would really like to know.

 

That’s what I was thinking, but the cold has to come from somewhere.

 

I also replaced the high pressure hose 2 weeks ago because the connector was leaking. However I planned to replace the small screen filter but I never did because I was in rush and I didn’t want to risk causing another leak.

Now I think there might be a blockage because my system is still not running as good as before. I’m thinking of changing the filter now. Would you mind telling me the steps? Do I have to remove the expansion valve to get to the filter or is it inside one of the hard lines?

 

Disconnect the coupler at the firewall on the smaller line, pull out the screen filter.

 

Others will correct me if I’m wrong, but I thought the filter was in one of the lines right where it goes into the firewall. Where those clamps are that require a special tool or screw driver to open.

But I hope someone chimes in with which line has the filter.

 

Bingo, thanks Curt!

 

There’s a special tool that you can buy that makes this easier.

after a little more searching, a paper clip bent in a u shape will also work.


https://www.youtube.com/watch?v=ViVXwETteyU

 

The temp would be exactly the same. Laws of thermodynamics says the duct would eventually reach equilibrium with the temperature of the air traveling through it. I let the ac run until the temperature on my laser stopped dropping and remained steady for a good 15 mins. A probe just makes taking the temperature faster since there's less surface area on the metal probe and the reading is instant. The temp would be the same with either method.

 

Yes, I highly, highly recommend changing that filter. Mine had very small fine metal shavings coated near the tip of the filter, wasn't much but I'm sure it doesn't take much to restrict the flow in such a tiny cavity.

You need to remove BOTH the big and small hose going into the firewall to remove that filter. The filter is inside the manifold that the small hose plugs into (not the small hose itself). You need to completely remove both hoses, AND the manifold from the firewall. The manifold must be removed because the filter can only come out towards the rear of the truck (hope that made sense).

Filter is located inside manifold (RED arrows).
Filter only comes out one way (BLUE arrow). (Use an E10 socket to remove the bolt (GREEN arrow))(You may not have this socket as it's not common, I had to go buy it).

It's really not that difficult once you get those round plastic clamps removed. I taped 2 flathead screwdriver bits together to help me remove those clamps.

Once you remove the hoses you will need to remove the rubber grommet on the firewall to see the manifold.

I highly suggest replacing those O-rings on both metal hoses as they are known to leak. There's 2 on each hose.

Larger hose O-rings part #: 90301-A0006
Smaller hose O-rings part #: 90301-A0012

Good luck. See pic below for arrows and location of parts.

 

That's not where I thought it was. I thought it was in the tube just before the manifold. This is not the first time I've been wrong, nor the last. Sorry for the bad info.

 

Thanks I appreciate your very detailed information. I’ll try to attempt it next weekend when I also change the condenser.

 

@CurtB no problem. I also made the assumption that it was in the small hose too and was perplexed that it wasn't in there and thought maybe toyota forgot to install one. Had I not planned to replace the expansion valve, I would've never taken apart the manifold to find it inside there. Funny thing is I was trying to figure out how I was going to shove the new filter in that small hose. So glad I didn't try it lol.

 

Real pictures may help a little.

Tube manifold bolted to the expansion valve with E10 Torx.



Filter located on the expansion valve side of the manifold.



Old verses new filter assembly.

 

Do you even know why evaps freeze? It has nothing to do with how cold your air blows out of your ducts. It's all about having adequate air flow around the eval coils. Google dirty air filter problems.

 

Good stuff Jimmy .

 

The temperature should be regulated by the Thermistor that reads the evaporator temperature and cycles the compressor off before freezing the evaporator.

 

Would a clog this bad be visible while doing pressure checks with a quality manifold set? I have good pressures, but ac is still meh... Your post got me thinking, but I really don't want to start tearing shit apart if I can rule out possible problems with a manifold set.

 

@Jimmyh is correct. The themistor on the face of the evap will shut off the compressor around 36* to prevent icing.

Either your thermistor is bad (or disconnected) or your thermometer is wrong

Freeze up isnt instant. Humidity levels, fan speed, choice of recirc vs fresh all factor into how long it takes.

On your next road trip you'll see some 'smoke' coming out the vents, airflow will almost stop while becoming tepid.

You'll never have a center nozzle temp under the low to mid 40s range if the thermistor is doing its job.

 

I did mention that duct surface temp is not the same as air vent temp, and I got thrown the laws of thermodynamics at my face. My Fluke process meter with a thermocouple attachment is giving me 45*, but my Flir temperature camera is giving me 25-30*, if the AC vent temperature was really that cold, it would be at least 5 degrees colder at the coil, so for sure it would be all frozen up. There is plenty of other people here in this forum that will agree with me, the only way to accurately check the outcoming AC temperature is with a temperature probe, not a temperature gun.