Clicking and RPM jump when AC is on

[atalarico]

Hey all,

New noise today. I was slowly recharging the AC today after noticing it wasn't blowing quite as cool. It had been a couple years since I recharged it last so figured it was due.

Now I'm noticing that there's a clicking noise and the RPMs jump at idle from 600ish to 1100ish when the AC compressor (?) on. It does blow colder air now though.

Whaaaaattt did I do?! I was very careful about not over charging it. Here's a video and you can see the pressure gauge is still in the green and then the click happens and it goes to red.

I let out some of the r134 from the L connection too to see if that would help. Should I keep doing that (and then ducking to avoid inhaling the cloud)?

https://vimeo.com/181248670

 

[atalarico]

Unless I did nothing wrong and that's just the sound of a 238k mile AC compressor. But do let me know if I should drain the system a bit so when it kicks on the needle isn't in the red like that.

 

[Collkid]

So, I don't know Toyota as well, but...

In Cherokees that is very normal. The compressor is clicking on and off and the engine has to compensate for the added draw.

 

[LittleCaesar]

I'd tell ya to get a pair of working AC gauges to read both the low and high side to get the correct readings.

If the cheapo gauge is all you have to work with my guess is that you are still low on refrigerant.

 

[atalarico]

Low still then? Eeep. Ok. Driving it around right now (parked) and with the AC that clicking noise sounds way worse in the cabin. Like a low grind or almost a rubbing noise. Damn. Leaving the AC off for the rest of today's adventure

 

[nissanh]

Freon

Locate the AC filter (in front of the AC condenser next to the horn). On top of the filter there is a glass window to watch the freon (1st picture: bubbling low on freon). I recharge the system today after owning the runner for 7 years. I recharge it until there is no more bubbles inside that glass window. You may see a bubble or two while the AC is running but not lots of bubbles (2nd picture). Then that's it.

What is that grinding sound? It can be the bearing inside the AC idler pulley or the AC compressor. Both are super easy to replace and DOES not need to recharge the system.

You can remove the AC belt and spin the idler pulley and listen. It if makes a noise it needs a new bearing. Bearing is like $6 and you can press it in to the pulley or buy new pulley for like $30. You can also spin the AC compressor pulley and listn to any sound. If it is, then the bearing is about $22 (not OEM) and you can still insert it. I can make thread on it if you want me to.

 

[StreetCreeper]

Locate the AC filter (in front of the AC condenser next to the horn). On top of the filter there is a glass window to watch the freon (1st picture: bubbling low on freon). I recharge the system today after owning the runner for 7 years. I recharge it until there is no more bubbles inside that glass window. You may see a bubble or two while the AC is running but not lots of bubbles (2nd picture). Then that's it.

What is that grinding sound? It can be the bearing inside the AC idler pulley or the AC compressor. Both are super easy to replace and DOES not need to recharge the system.

You can remove the AC belt and spin the idler pulley and listen. It if makes a noise it needs a new bearing. Bearing is like $6 and you can press it in to the pulley or buy new pulley for like $30. You can also spin the AC compressor pulley and listn to any sound. If it is, then the bearing is about $22 (not OEM) and you can still insert it. I can make thread on it if you want me to.

I don't know if OP wants you to make a thread on it — but I do. This is just the kind of write up that I'd want if I had the same problem. All write-up/threads are are good in my book

 

[atalarico]

Thanks for the info! I'll have to check it out in the morning. The AC stopped blowing cold on the short drive earlier today too.

I recall that window was clear on mine but I'll check again tomorrow.

Definitely interested in a write up on the rest!

 

[TheDurk]

You might actually be overcharged. I found that the FSM spec for pressure is actually at the very low end of the green on those cheapo self-charge cans. I use real gauges and go for the FSM spec of 22-36 psi on the low side and 198-228 on the high side, with engine at 1500 RPM and A/C fan on HIGH, and with temps in the range of 86°F-95°F. 22psi was well below the green zone on the cheapo can.

See page AC-4, par 2.1. My psi numbers are the conversions of those numbers shown in MPa.

http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/ac/acsy/ovi.pdf

I can't read the numbers on your can, but on the one I had 36psi, the high end of the recommended low side pressure in the FSM, was right at the lower end of the green. At that level, my system works fine and the window stays clear as it should and foams when turned off, as it should. There are variations according to temp and humidity so YMMV.

To verify if you are overcharged, observe the sight glass when you turn of the A/C. If it just stays clear, you are overcharged. At correct charge, it should foam and then stay clear. See the chart on page AC-3 in my link.

After working with real gauges, I am no fan of those parts store cans.

 

[nissanh]

Here is the thread

http://www.toyota-4runner.org/3rd-g...ng-idler-bearing-replacement.html#post2461206

 

[tystaco]

This was the closest, and less than a year old thread that matched my issues. 2000 limited (auto climate control)...AC blows colder than uncooled air, but not near ice at all...went to recharge it today using AC pro can...initial low pressure reading was 20, I put a whole can in and got it to 25....still blows the same, but now I also realize my hunting idle problem is related to AC....I can hear the auto climate relay kicking on the compressor every 3 or 4 seconds...varies in duration but at idle, it jumps a few hundred RPM...

I put the same gauge (from the can) back on the low side and now after 2 hours the pressure reads over 60 psi. I am worried I over charged it, but I also watched the site glass and for the 10 seconds before the compressor gets kicked off, it is foamy the whole time. From reading this, people are saying foamy equals under charged. I really don't like how quickly the unit is being turned off and on.

Any help is always appreciated.

 

[fulltimervexplorer]

Mine has been doing this since i bought it almost 3 years ago and i always thought it was normal. Any update on this as it is sort of annoying the rpms jumping up every 30 seconds while in drive at a stop when the AC is on.

 

[19963.4lsr5]

Mine has been doing this since i bought it almost 3 years ago and i always thought it was normal. Any update on this as it is sort of annoying the rpms jumping up every 30 seconds while in drive at a stop when the AC is on.

I always thought it was normal to raise the rpm when the AC clutch engages to prevent engine stall at idle.


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[McClaxton]

Thanks for posting!

Here is the thread

Toyota Denso AC Compressor bearing and Idler bearing replacement - Toyota 4Runner Forum - Largest 4Runner Forum

Thank you, this was very useful!

 

[Bad Luck]

Mine has been doing this since i bought it almost 3 years ago and i always thought it was normal. Any update on this as it is sort of annoying the rpms jumping up every 30 seconds while in drive at a stop when the AC is on.

You are likely overcharged and your ac is cycling to prevent excess high pressure side. Have your ac recovered and then charged to the correct amount.

 

[fulltimervexplorer]

You are likely overcharged and your ac is cycling to prevent excess high pressure side. Have your ac recovered and then charged to the correct amount.

I will have it checked but i wa told its normal and just the compressor kicking on and off

 

[Bad Luck]

I will have it checked but i wa told its normal and just the compressor kicking on and off

It shouldn't be cycling on/off very quickly, but I don't know what's normal for your generation 4Runner. Your signature says you have a 4th gen 4Runner.

 

[jross20]

DO NOT MESS WITH THE AC SYSTEM UNLESS YOU HAVE TBE PROPER EQUIPMENT AND KNOWLEDGE.

No store bought cans, no no no. That's a major no no.

Take it to a shop and have it serviced.

 

[96RedRunner]

No store bought cans, no no no. That's a major no no.

.

Lol, It's all store bought cans.

 

[jross20]

Lol, It's all store bought cans.

No, it is not. You cannot legally buy a true tank of refrigerant without a license and for good reason. You also need compressor oil and most importantly an A/C service machine.

You need to pull a vacuum and evacuate the system, check for leaks, inject the correct amount of oil and charge the system to the correct factory spec. No more no less.
It's been a long time but I used to be certified on vehicle ac systems.

All this diy stuff on ac systems is absolute lunacy. You cannot properly recharge a system without the proper tools and machine. You will blow something up, ruin the compressor, or break other expensive shit So many things can go wrong.

Do NOT work on your AC system unless you are trained and have an AC recharge machine. The system should not leak, if it's low that is a sign of something being wrong and it needs to be properly diagnosed.