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Expansion Valve Bad? Pages: 12

smithly on Sat April 25, 2015 6:45 PM User is offline

Year: 2006
Make: Honda
Model: Accord LX-SE 4 Dr
Engine Size: 2.4L
Refrigerant Type: 134a
Ambient Temp: 75F
Pressure Low: 25psi
Pressure High: 150psi
Country of Origin: United States

Brand New to the forum. Needing some help diagnosing an air conditioner problem. I have a 2006 Honda Accord LX-SE 4 Dr w/ 2.4L and no dual climate control. I have never serviced the A/C until now.
A shop said they topped off the system a few days ago w/ 134a, and it worked for a day or so, but now having the same problem.
It blows cold most of the time, then every now and then, it blows warm for a while, then back cold again. I borrowed some 134a A/C gauges (since the last time I attempted A/C work was in the R-12 days and my old hoses need new seals). This is what I found....
I still had my Halogen detector from my R12 days (long time ago). I got it to detect some 134a where it leaked out when I connected the gauges, so I figured it still worked and works on 134a as well. I sniffed every connection and no leaks detected at all and no signs of moist connections or dust collection / oil stains, so I don't think I have any leaks.
Outside Temp was 75F and very humid (94%) in Louisiana.
Put A/C on Max A/C w/ High Fan and A/C blew very cold at 38-42F.
System pressures were 25 psi on low side and 150 psi on high side at idle (~750 rpm). Worked for a long time at idle.
Rev engine to about 2500 rpm and low side starts to drop to around 18 psi and high side went up to about 175 psi and still blowing very cold at 42F in cab.
Continue 2200 rpm and low side continues dropping very slowly. When low side gets to about 15 psi, high side around 180-190 psi, compressor kicks off and cab air gets very warm (b/c compressor is not activated... No A/C).
Let car idle again and low side pressure starts to climb. At about 55 psi on low side and 100 psi on high side, compressor kicks back on and then low side goes back down to 25 psi and high side at 150 psi and cab back to 40F.
Both radiator / condenser fans run continuously whether the compressor is running or not when on Max high.
Seems to stay blowing cold (compressor stays on) when idling. Once engine revs up and low side gets too low, it cuts off the compressor and air starts getting hot.

I found a Honda Accord temp / pressure chart and it said high side should be around 140 psi for 75F (doesn't account for high humidity) and for 40F cab (vent) temp, low side should be between 20-25 psi, therefore that makes me think that the Freon level is correct. The compressor sounds fine. I listened with a mechanic stethoscope and it sounded smooth. Compressor clutch seems to be working. I'm assuming some kind of low pressure switch is cutting power off to compressor.

Does this sound like a sticking (closed or open) Expansion Valve or is the Compressor getting weak / worn or is it a bad Pressure Switch? I'm thinking Expansion Valve, but I want to get input from someone that knows what they are talking about before I go through all the trouble and time to remove the evaporator to replace the Expansion Valve. Please give me some guidance.....

Dougflas on Sat April 25, 2015 11:29 PM User is offline

Does this vehicle have a sight glass? If so, it should be clear. I think you're low on refrigerant. R134 is harder to detect. I would place a shower cap or plastic bag around the front of the compressor. Let it sit for a few hours or overnight. Poke a hole in the bag or move the shower cap so the sniffer probe can enter the bag/cap. If the seal is leaking, the sniffer will indicate.

mk378 on Sun April 26, 2015 12:00 PM User is offline

I'd be thinking clutch gap. It seems to work fine until the compressor turns off for the first time, then it is balky to re-engage and the air goes warm. The compressor is controlled by evaporator temperature in this system, it should cycle back on before the air gets warm.

If the air is not getting cold while the compressor is turning, then you diagnose the refrigerant charge, TXV, etc parts of the refrigeration loop.

Edited: Sun April 26, 2015 at 12:02 PM by mk378

smithly on Sun April 26, 2015 5:00 PM User is offline

No. It doesn't have a sight glass. I will try the bag trick on the compressor seal. I like that one. I will check the clutch gap if the evacuate, vacuum and recharge doesn't work. Heck, I might just check it anyway. I've read that it is a common problem on these Honda Accords. Problem is that if the gap is unacceptable, the compressor will have to be removed from the engine to change the shim. Not that big of a deal I suppose. It is in the front.... just on the bottom!!
Thanks for all the help and advice!!! I'm learning quickly.

mk378 on Sun April 26, 2015 5:57 PM User is offline

You may be able to unbolt compressor and lower it down to work on the clutch, keeping the refrigerant hoses attached and system charged.

smithly on Sun April 26, 2015 11:52 PM User is offline

Well I just finished changing all the O-Rings except the Expansion Valve O-rings. I decided to change the drier before I vacuum and recharged it, in case it was moisture causing the problems. I had to pull the condenser out from behind the radiator to change the drier (it was attached to the side of the condenser). I knew I would change all the condenser O-rings, so I took the advice to change all the compressor O-rings since the compressor gets hot enough to deteriorate O-rings over time. There was only one O-ring left after that (coupler connection on the low pressure line), so I just changed it too. So now they are all new except the expansion valve O-rings. BUT, I did run into one problem. When I removed the compressor relief valve, the O-ring kit didn't have an O-ring to match that one. It appears to be holding a vacuum, but I wont trust that one, so I'll have to get that one and replace it before I recharge it (too late tonight). Also, O'Rielly and Autozone were the only thing open today and O'Rielly didn't have Schrader Valves so I reluctantly tried AutoZone.... BAMP!!!!! Wrong Schrader Valves, so I have to get those also. I also replaced the cabin air filter (it was dirty) and blew out the drain line from under the car. Hopefully after I replace the Schrader valves and Relief Valve O-RIng and vacuum and charge it, it will work w/o having to replace the Expansion valve. I was dreading that job!!! I still will measure the clutch gap to have an idea what that is like. I have to get a dial indicator. I oiled all the O-ring with Ether 100 and clean hands. Been pulling a vacuum on it for about an hour and a half now and it seems to hold when I cut off the vacuum pump. I will bring it to a shop to pull another vacuum and charge with proper amount of 134a with their automated machine when I'm done. Do I need to tell them to add oil or does the automated machines do it automatically? Do I even need to worry about it? Drier only holds 1/3 Oz. I let all the Freon out in a sealed clear cup. Not much oil came out in the cup.

smithly on Mon April 27, 2015 7:53 AM User is offline

One other thing I forgot to mention... When I removed the compressor relief valve to change the O-ring, NO oil came out. I thought that was odd, but maybe not.... Is that normal or is that an indication that I need to add some PAG46 oil?
The whole system is supposed to have 5-1/3 Fl Oz. As I said previously, there were no apparent leaks on this system previously. How much oil should I add, IF any?

smithly on Mon April 27, 2015 1:36 PM User is offline

By the way.... Maybe everyone already knows this but me, but the compressor relief valve was at the very bottom and very rear of the compressor. That's why I expected oil to come out, but none did. Is the relief valve such that oil should not get there or should oil have come out?
Thanks again for helping the newbie!

smithly on Mon April 27, 2015 6:16 PM User is offline

mk378....It looks like you might have hit the nail on the head. After doing all that work and vacuuming and recharging, it is still doing the same thing. The shop said they tapped on the clutch when it wouldn't engage and it kicked in. Looks like I need to purchase a dial indicator and check the gap and reshim while still connected to my AC lines so I don't have to recharge. I think I can find the clutch gap in a Honda Accord manual I found online. Now I just have to figure out how to remove and reshim the clutch. I think I have to purchase a special tool to hold the pulley (or clutch?) while I unbolt the center bolt???? And then where is a good place to buy shims? Are those shims common to any auto parts store like NAPA or is that unique to an AC shop or only online? Thanks for all the help!!

One other question... Is 1 Lb or 134a = 16 Oz? The label under the hood said 17.6 min to 19.4 max Oz. If it is 16 Oz to 1 Lb, then that would be 1.1 min to 1.2 max Lbs of 134a. Is that correct? I hope so!! Because that's what I told them to put. Their machine only took input in Lbs.

I also put 3/4 Fl Oz of PAG 46 to account for 1/3 Fl Oz for replacing drier and some minimal losses to evacuate in cup although it had no real level in sealed cup after I let the Freon out to replace Drier.

I sure am learning a lot quickly!! Thanks for all the help!!

mk378 on Mon April 27, 2015 7:23 PM User is offline

Yes 16 oz is 1 lb. You shouldn't need to buy any new shims just take some or all of them out. The gap doesn't have to be exact-- you want it small but not so small that it drags when off. Gap constantly increases due to wear anyway, which is how you got to this point. There is a special tool for holding the clutch plate so compressor doesn't turn while you unscrew the nut, but if it has big rivets on the front you can probably just lay a screwdriver across two of the rivets and hold it that way.

Edited: Mon April 27, 2015 at 7:25 PM by mk378

smithly on Mon April 27, 2015 7:42 PM User is offline

Looks like what I need here...... Got this from my Honda Accord Service Manual.... Maybe it will help someone one day...

Measure the clearance between the pulley (A) and the pressure plate (B) with a
dial indicator. Zero out the indicator, then apply battery voltage to the A/C
compressor clutch. Measure the movement of the pressure plate when the
voltage is applied. If the clearance is not within the specified limits, the
pressure plate must be reshimmed (see A/C COMPRESSOR CLUTCH
Clearance: 0.35-0.6 mm (0.014-0.024 in.)
Fig. 117: Measuring Clearance Between Pulley And Pressure Plate With
NOTE: The shims are available in three thicknesses: 0.1 mm,
0.3 mm and 0.5 mm.

Remove the pressure plate (A) and shim(s) (B), taking care not to lose the shim
(s). If the clutch needs adjustment, increase or decrease the number and
thickness of shims as necessary, then reinstall the pressure plate, and recheck
2007 Honda Accord
2003-07 HVAC Heating/Air Conditioning - Accord
its clearance (see A/C COMPRESSOR CLUTCH CHECK ).

Check resistance of the field coil. If resistance is not within specifications,
replace the field coil (see A/C COMPRESSOR CLUTCH OVERHAUL ).
Field Coil Resistance: 3.9-4.3 ohms at 68°F (20°C)

If you are replacing the field coil, remove the snap ring (A) with snap ring
pliers, then remove the pulley (B). Be careful not to damage the pulley or the
A/C compressor.
Remove the screw, the wire harness clip (A), and the holder (B). Remove the
snap ring (C) with snap ring pliers, then remove the field coil (D). Be careful
not to damage the field coil or the A/C compressor.
Reassemble the clutch in the reverse order of disassembly, and note these
Install the field coil with the wire side facing down, and align the boss on
the field coil with the hole in the A/C compressor.
Clean the pulley and A/C compressor sliding surfaces with contact cleaner
or other non-petroleum solvent.
Install new snap rings, note the installation direction, and make sure they
are fully seated in the groove.
Make sure that the pulley turns smoothly after it's reassembled.
Route and clamp the wires properly or they can be damaged by the pulley.

Dougflas on Tue April 28, 2015 4:26 PM User is offline

save yourself some work and expense. If you have a standard business card from anyone, use that as a guage to check the glutch gap. I have done that many times and it works.

smithly on Sun May 03, 2015 11:26 AM User is offline

Well, I finally got to work on it yesterday. The compressor quit coming on all together during the week. When I checked it yesterday, it was getting 12 V to the compressor, but not engaging at all. I even brought a 12V wire straight from the battery and nothing. Checked the resistance on the coil and it was an open circuit. Therefore, it appears that it was the coil going bad all along and it finally went out completely during the week.

Honda wants $183 for a new coil. Regular Parts stores like O-Rielly & NAPA don't carry the coil or clutch, only a complete compressor that requires purchase of a drier and expansion valve and a can of oil to have a warranty. Best price for a decent brand of compressor is about $315. I found a Denso compressor for $340. Compressor turned smooth and easy by hand, but it is almost 10 yrs old. Clutch gap was a little over the max limit of 0.024", but not by much. I will re-shim it if I replace the coil. Debating on a whole new compressor, unless I can get the coil cheaper than $120 or so."

Anyone know a good source for a good, but cheap coil? Is re-using a 10 yr old compressor a bad idea?

Thanks again for all the help!

smithly on Sun May 03, 2015 5:51 PM User is offline

Wow!!! Only $18.80! Am I missing something here? How can they offer it for $19 and the Honda dealer wants $183?

smithly on Sun May 03, 2015 7:58 PM User is offline

There is no info on warranty on their website.

Has anyone used these coils? Any feedback on reliability?

TRB on Mon May 04, 2015 4:33 PM User is offlineView users profile

We would be happy to raise the price if it would make you feel better.

I deleted Jag987's post by accident when editing it to make the link work.


Electric items do not really have a warranty do to the fact they can be shorted out. Manufacture will cover a item if it is truly defective.


When considering your next auto A/C purchase, please consider the site that supports you:

Edited: Mon May 04, 2015 at 4:35 PM by TRB

smithly on Wed May 06, 2015 11:41 PM User is offline

Coil arrived today. Going to try to install it tomorrow (Thursday evening). I already rented a clutch holding tool from AutoZone and tried it and was able to remove the center bolt and remove the clutch w/o a pulley remover. There was only one shim. It was 1.22mm thick, therefore I wont have any clutch gap adjustment unless I purchase some shims. It didn't appear far out of spec, but it was difficult to measure with a feeler gauge since the pulley is in the way. The feeler gauge has to come in at an angle due to the pulley surrounding the clutch gap. I guess that's why a dial indicator is recommended in the Honda manual. I didn't attempt to remove the pulley snap ring and remove the pulley and coil. I will have to remove the (4) compressor mounting bolts to get to the snap ring w/ pliers. From the manual, it doesn't appear that I will need to rent a puller to remove the pulley. Please correct me if you know different. Seems pretty easy. Just a little tight on space. Any advice is appreciated

smithly on Fri May 08, 2015 1:26 PM User is offline

Got the coil installed last night. It cooled great!!! Thought my 17 yr old daughter would finally quit sweating it out. The new coil resistance was right at the upper spec limit (I think it was 4.6 Ohms.... if I remember correctly). I measured the clutch gap with a dial indicator and it was right at the spec upper limit of 0.024". Everything worked great last night, but I noticed that the coil area was a little hot to the touch. I wasn't sure if that was normal due to normal engine heat. Today the A/C quit working again. The compressor is getting 12V, but seems to be straining to engage the clutch (it wasn't doing that last night). The new coil also seem to draw too much amps. I say this because my brother tested it with some type of circuit tester he has and it would trip his tester repeatedly. The relays were switched and no difference. The radiator cooling fans are working properly.

Would a bad clutch cause the new coil to draw more amps or overheat? The compressor seems in good smooth quiet condition. Should I try to change the clutch and coil????

smithly on Fri May 08, 2015 9:14 PM User is offline

Just took off clutch and pulley. Coil is melted and made a huge mess. Plastic / copper is smeared in the pulley and clutch plate gaps. Bearing still seems smooth, but likely got hot. A little grease came out from heat, but that's it for bearing. I'm reluctant to try to clean this mess and re-use heated parts. Clutch plate is a little blue-ish, so it got real hot. I don't know what happened. Snap rings still in place. I rotated the pulley by hand after everything was assembled and it was very smooth. At this point, I'm probably better off scraping everything. Its probably not worth another coil, a new clutch and pulley with bearing. Thinking I just as soon replace this 9 yr old compressor (even though it still seems good) and get a new coil, clutch and pulley w/ bearing and chalk it up to lesson learned. Your thoughts???

smithly on Sat May 09, 2015 10:04 AM User is offline

Going to go ahead a replace the compressor w/ new clutch and coil. Too expensive for new clutch & coil not to replace 9 yr old compressor.
Is it possible that this all started due to excessive clutch gap and that caused the original coil to strain to engage clutch and eventually caused enough heat to cause an open circuit in original coil? Then once new coil was put in place, the same gap problem caused slippage of clutch which caused extreme heat to clutch parts and coil? That would mean the refrigerant side is ok. I say this because it worked sooo cold when the coil / clutch would work.
The other thing to note is that when the compressor was on the car and still hooked up to refrigerant lines, I turned the pulley to insure smooth operation. I turned it in both directions. Could that create a problem by pulling liquid Freon into compressor?
If neither of these sceanrios are too credible, then it sound like a flush is in order before I install the new compressor. If so, can I leave the existing expansion valve in place? Really dreading pulling evaporator! I already installed a new drier that is barely used and only open to atmosphere for a hour when I installed it and vacuumed it out until a shop could recharge it. I only added 3/4 Fl Oz of PAG 45 when I replace the drier. 1/3 Oz for Drier and the remainder to account for Freon I had to let out in a cup that showed no appreciable amount of oil.
Based on this, does it sound like it really needs to be flushed?

smithly on Mon May 18, 2015 9:46 AM User is offline

Well, I bit the bullet... Changed the Compressor (w/ new clutch & coil), expansion valve, condenser & drier. I flushed the evaporator and hoses. I then changed all the O-Rings & Schrader valves again and lubed them all with Ester 100 Oil. I added 5-1/3 Fl Oz of PAG 46 Oil to the low suction side of the compressor after it was installed on the engine and rotated the compressor about 10 times in the clockwise direction after the lines were re-connected to the compressor. I installed the drier last, then vacuumed it for at least 2 hours. I removed the vacuum pump and it held 29 in Hg for a few hours. Sending it to the shop today to get charged with 17.6 - 19.4 Oz 134a per spec.
I wasn't too sure on the way I added the oil. Am I ok with the way I added the oil?

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