Car AC gets warm after 30 minutes of driving.

B

Brybo86

Joined
Oct 8, 2011
Messages
3,493
Location
Madiganistan/Chiraq
2008 accord 145k miles
AC system is stock and untouched in 10 years other than cabin air filters.

AC is cold when car is started but declines to the point where I don't think the Compressor is coming on and air is same as outside.

Turning AC off for 10 mins and it will blow cold again for awhile.

What should I be looking for?
 
Last edited:
My first guess is an open in your magnetic coil on your compressor. It works till it gets a certain temp then opens up. Or maybe the relay.But I'm just guessing. Its due for a proper recharge due to age. I'm sure it has lost some refrigerant and oil in the last 10 years. Don't try to add using a can. Find a shop with a proper ac machine.
 
Originally Posted By: sprite1741
Evaporator is icing up. When you turn it off the ice melts and it works again. Did you add Freon recently? Check for a dirty cabin air filter.


+1 on this as the likely culprit.
 
Originally Posted By: ABerns
Originally Posted By: sprite1741
Evaporator is icing up. When you turn it off the ice melts and it works again. Did you add Freon recently? Check for a dirty cabin air filter.


+1 on this as the likely culprit.


I'm thinking that is the case as well. I'd put gauges on it and see what's going on.
 
Do you have the fan on high setting? In humid times without outside air the coil will ice up that is your evaporator coil inside the car. Maybe using recirculate air setting and high speed on the fan will help you out on this issue. Could also need the evaporator coil cleaned.
 
Originally Posted By: demarpaint
Originally Posted By: ABerns
Originally Posted By: sprite1741
Evaporator is icing up. When you turn it off the ice melts and it works again. Did you add Freon recently? Check for a dirty cabin air filter.


+1 on this as the likely culprit.


I'm thinking that is the case as well. I'd put gauges on it and see what's going on.

+3
Maybe a little low on freon. Low freon will cause the evaporator to freeze up. Gauges will tell you what is going on.
Also, the compressor clutches are prone to failure. When they get hot they stop working. Honda had a 10 year warranty extension on them for several models. If the compressor isn't coming on, this is likely your problem.
 
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Could be the same symptoms but for the opposite reason. Tops off with can of AC Pro without adjustment for ambient temperature. Now there's too much freon and the hotter it gets the less the AC compressor runs because there's too much pressure so the compressor keeps shutting down.
 
Originally Posted By: LeakySeals
Could be the same symptoms but for the opposite reason. Tops off with can of AC Pro without adjustment for ambient temperature. Now there's too much freon and the hotter it gets the less the AC compressor runs because there's too much pressure so the compressor keeps shutting down.

The OP said... "AC system is stock and untouched in 10 years other than cabin air filters".
 
I typically drive using the auto setting.
I did change the cabin air filter when I noticed this and it was dirty but nothing crazy.

If I turn fan to high there is great air flow. When I turn off the car after a long drive it doesn't drip at all which makes me think there is no ice on the evaporator, and I don't hear the compressor run after a low drive.
It does seem like when first started and driven the compressor cycles frequently.
Can I borrow/rent AC gauges from an autozone or advance? Or harbor freight has a set a gauges for $45. ?
Does Freon naturally escape over 10 years?
I typically like to do my own fixing if possible.
 
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Originally Posted By: Brybo86
I typically drive using the auto setting.
I did change the cabin air filter when I noticed this and it was dirty but nothing crazy.

If I turn fan to high there is great air flow. When I turn off the car after a long drive it doesn't drip at all which makes me think there is no ice on the evaporator, and I don't hear the compressor run after a low drive.
It does seem like when first started and driven the compressor cycles frequently.
Can I borrow/rent AC gauges from an autozone or advance?
Does Freon naturally escape over 10 years?
I typically like to do my own fixing if possible.

"Can I borrow/rent AC gauges from an autozone or advance?"
I think that you can. Give them a call.
"Does Freon naturally escape over 10 years?"
Yes. It is common for an A/C system on a vehicle to have lost 2 or 3 ounces of freon in 10 years. A couple of ounces low is all it takes to cause evaporator freeze-ups. Compressor short-cycling is also a sign that the freon is low. Whatever you do, do not overfill the system. A little freon is all it will need. Use the BIG gauges to add freon. Do not use one of the refill kits that only have a low pressure gauge, you also need the high pressure gauge to fill it properly.
Don't discount the possibility that the compressor clutch has gone bad. Honda had a lot of problems with them during that time frame which is why they issued warranty extensions.
You could have either problem, but you could also have both problems. The gauges will tell you if the system is low on freon and you can top it up if needed. Short-cycling of the compressor can cause the clutch to get very hot very quickly because the system's pressure doesn't have a chance to equalize between cycles. If the compressor does not engage after it gets hot, then you have a bad clutch. My guess it that it is low on freon AND the clutch is on it's way out.
 
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If no water is dripping maybe the evaporator area is full of water. Run the ac parked with the windows open for a while if there is no water you have a clogged drain.
 
Originally Posted By: sleddriver
Spray the A/C compressor clutch with water when hot. If the clutch engages once cooled off, then you know the gap is excessive and/or clutch needs replacing. Sometimes you can shim them.

How much water? a couple squirts? Or garden hose?
Since it works fine when started I'm leaning towards the clutch being shot.

Currently on vacation and debating if I want to try and tackle the AC at the in laws without all my home tools
 
Originally Posted By: Brybo86
Originally Posted By: sleddriver
Spray the A/C compressor clutch with water when hot. If the clutch engages once cooled off, then you know the gap is excessive and/or clutch needs replacing. Sometimes you can shim them.

How much water? a couple squirts? Or garden hose?
Since it works fine when started I'm leaning towards the clutch being shot.

Currently on vacation and debating if I want to try and tackle the AC at the in laws without all my home tools

Put gauges on it and check the state of charge first. You don't want the compressor short cycling or any repair that you do won't work for very long.
You don't need to spray any water on the compressor clutch to know that there is a problem, you can see that the clutch is not engaging when it is supposed to. You can also check the clutch gap clearance with a feeler gauge. If there is too much clearance you can remove a shim to reduce the clearance and this should buy you some time (and maybe get you home) before you have to replace the clutch.
https://www.youtube.com/watch?v=yXNXls-sRQ8
https://www.youtube.com/watch?v=ChtMXWjkx0Y
https://www.youtube.com/watch?v=x6084NqhbeE
 
Originally Posted By: Brybo86
How much water? a couple squirts? Or garden hose?
Since it works fine when started I'm leaning towards the clutch being shot.

Currently on vacation and debating if I want to try and tackle the AC at the in laws without all my home tools
You can mist it with a garden pump up sprayer or dribble water on it if accessible.

I wouldn't tackle the AC at the inlaws without sufficient tools...bad idea.

To remove shims, you're going to have to pull the clutch which can be quite an ordeal even with tools. You can measure the gap with a feeler gauge and shim with aluminum from a beer/coke can. I'd suggest the later rather than the former if away from home.
 
Originally Posted By: Chris142
My first guess is an open in your magnetic coil on your compressor. It works till it gets a certain temp then opens up. Or maybe the relay.But I'm just guessing. Its due for a proper recharge due to age. I'm sure it has lost some refrigerant and oil in the last 10 years. Don't try to add using a can. Find a shop with a proper ac machine.
I am pretty sure the clutch is gone on my 2003 Avalanche. It started acting up infrequently a year or two ago. Now it is much more frequent, it always does it when I am away from home and don't have the tools to check it. Tonight I got home and hooked up my scan tool and all the data shows that the a/c should be working.
 
Update
So I got the gauges from harbor freight,
a can tap from advance (that must not be made for self sealing cans because it had to be at a specific point halfway between open and close for the refrigerant to leave the can, and it took kind of a long time),


A self sealing can 12oz can of r134a from Walmart

I did not buy a vacuum pump,if we drive home and it seems to leak out Mb I will get one and some UV dye. To start checking around.

Turned on the AC and let it run for 10 mins
This was the initial pressure check, ambient temp 77 F

Added a can of r134a and it brought the pressures up to this

Chart I read online said to aim for about 40 PSI low and 170 high at 77 F

I think I could use a little more refrigerant
Took a drive, air is much colder....??? Evaporator dripping lots

Label under hood says 16oz Max and 14oz min
So it was basically empty? Mb I do have a leak.

It the pressure check supposed to be done with compressor running or when it temporarily cycles off, or both?
 
Last edited:
Originally Posted By: Brybo86
It the pressure check supposed to be done with compressor running or when it temporarily cycles off, or both?

The pressure check is done when the compressor is running.
Those numbers look good to me. It doesn't need any more freon.
Your compressor should not be short-cycling anymore.
 
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