Another AC thread...but this is different?

Alrighty so first things first, I’ve searched and searched and haven’t found anything that answers my questions. Many threads pertaining to the general symptom of not blowing cold when stopped, but nothing with that encompasses the entire spectrum of weirdness.

If you read this and know of thread, please post it in the replies.

The problems:
1. Resonating/humming sound at 1500rpm with AC on, only when in gear/driving. Can be heard in cab.
- not a normal hum, I’ve had people try to tell me it’s normal w/o hearing it themselves. It just started a month ago. Very noticeable.

2. Clicking/slapping sound when AC is on. Cannot be heard in cab, only with hood open, sound like it’s coming from the timing belt...?

3. AC does not blow cold when stopped.

What I’ve done so far:
1. No AC when I got the truck, finally had it charged/tested in April. Passed all leak/vacuum tests, but was missing high/low pressure line caps. All belts/idler pulleys were replaced in January.

2. May: AC doesn’t blow cold when stopped, humming/resonating sound starts. Local shop says it’s the blend door actuator.

3. Replaced blend door actuator, no change. AC system tested again at different shop. Passes all tests...allegedly.

4. Replaced expansion valve per some other shops advice. They said expansion valve because there was only 8 degree temp difference between inlet/outlet. Passes all leak/vacuum tests again.

-everything works great for a day-

5. Humming/resonating sound and clapping sound gone for about 2 days and then back again. AC not as strong when stopped.

Additional note: I am stationed in 29 Palms, CA. It’s over 100 degrees every day. I desperately need that ice cold AC...it’s good for morale.

 

I have a video of the clapping/slapping sound and the humming resonating sound. Trying to upload them.

 

Thank you for your service.

I know very little about air conditioning, as a system. However, I do know it's belt-driven and that the belt tension should be 100 lbs. How's yours?

 

There is lots of info on a slapping noise on this, but not many answers so far. I have read 3 threads so far.... try this one
https://www.tacomaworld.com/threads/ac-blower-motor-repair-fix-not-working-or-noisy.89219/

 

Need to upload to YouTube then post link here

 

Thank you for the support.

Not sure if it’s at exactly 100lbs, when I replaced them, I used the old 1/2” deflection rule.

If pulley centers are > 6 inches apart: 1/4" to 1/2" deflection between the pulleys
If pulley centers are < 6 inches apart 1/4" deflection between the pulleys

 

Thanks, I had read that one, can’t find anything that relates it to the AC being on/off and causing the sound. Plus it can only be heard from under the hood, definitely not coming from the blower motor inside the cab.

 

not blowing cold when at a stop is an indication of poor air flow across the condensor, either the fan clutch is defective, the shroud isnt there or there is blockage on the condensor itself or there is internal blockage inside the condensor.

 

Makes sense, thanks for that.

Any idea how that would play into the slapping sound (see video below)? Or the humming sound at 1500rpm?

 

https://youtu.be/rl9ugLSNjsE

 

i have a weird gremlin rattle sound too (just started in the past several months) but it occurs at about 2.1k rpm and only in gear on the road shifting 2nd 3rd 4th 5th
mine sounds like its rattling behind the dash on passenger side, but only after A/C has been turned OFF after being on extended period (still troubleshooting)
it drives me batkrapkrazy

 

Sounds like its directly behind that pulley once its engaged.

 

quick ? for you OP
have you had any fuzzy foamy grey cushion stuff start spewing out of your vents yet?
this has happened to me this year for the first time, which may be part of my rattle problem that is still under investigation


so far my A/C stills blows cold (very very cold if conditions are good!) ... had the system recharged about 6 or 7 years ago when it stopped blowing cold

i can understand the morale part, my first pickup had no A/C just a rear sliding window in 100+ midwest summer heat for 2 years

 

Thankfully not, sounds gross.

Ordered a new condenser and fan clutch, we'll see what happens. I figure I'll just replace things starting with the cheaper parts and hope I replace whatever is broken along the way.

Bad condenser or fan clutch would explain it not blowing cold when stopped, but haven't found anything that would explain the weird clunking/slapping noise when the AC is on.

 

The grey stuff is most likely foam that is breaking down. The foam connects some of the ductwork, and that will break down over time.

 

Shot in the dark here. Look for red or brown dust around the AC compressor pulley. If dust is coming off that pulley it will throw it around. I saw this dust on the body around the ac and turned out to be the bearing. It was making sort of that clicking sound.

Very cheap fix. I paid 25 for the part and took me half a day to get it done. take the compressor bolts out to be able to make the clutch holding bolt face up and used an impact driver to get it loose. I greased the new bearing and screwed it back in.

 

so i am now learning! and it has possibly introduced a rattle with the fresh air inflow at highway speeds mentioned in another thread
now the issue is to find out what to do about it and fixIt! so that it functions as it always has
new foam around the area of issue, a needed mod on the box/lid whatever it is or a whole new fan motor assembly!
I think that this motor box is removable without having to take the dash out, just the glove box (which is already out under diagnosis/troubleshooting)

what has anybody else done to resolve this?


https://parts.camelbacktoyota.com/p...siteid=214329&vehicleid=84921&diagram=8510105

 

Interesting, my compressor clutch does have that reddish brown dust on it.

I’m going to do a whole clutch rebuild kit, might just replace the whole compressor depending on how much a rebuild kit costs.

I figure the noise has to be something with the compressor/clutch since it only happens when the AC is on, unless when the AC is on it’s putting extra load on the fan clutch or something like that.

 

if there is blockage the high side will be too high putting a strain on the internals of the compressor and this translates into noise.

There is a clearance specification on the clutch assembly... if there is too much clearance the clutch will have problems engaging, the magnetic field is only so strong, if it is too close it will drag on release.

 

How many miles are on your truck and how long have you owned it? Do you have access to compressed air while you work on it?