|
|
|
Hello Fellow Brick Owners!
I have ran into a issue that I know you all will probably have diagnosed in minutes. I have a 1986 Volvo 240 Sedan. The A/C will blow what I consider cool air, but definitely not cold. Upon popping the hood, I realized the A/C clutch was not engaging. Since the car has been converting to R-134a about 10 years ago, I dumped about 6 ounces of refrigerant into the compressor to see if it would start the clutch. I didn't want to put anymore than that because I was unsure of how much was actually in there. No luck. However, upon crawling under the car I noticed a green wire with an exposed area sitting next to the compressor. It was still intact, but severely exposed. My question is this, will this exposure cause the clutch to not engage? I am repairing that portion of wire regardless, but was wondering how much impact it would have on the A/C systems function. Where is the compressor grounded to? What other items can I test with a test light or a voltmeter before I assume the clutch is unserviceable and buy a new one? The fuse is good and intact, but beyond that I do not know enough about the A/C systems on these cars to get a good start. A/C work has always been one of the very few mechanic jobs I actually pay for, but finding a competent Volvo mechanic in my area is almost impossible. Any help would be greatly appreciated!
|
|
-
|
|
|
Ground wire from clutch to engine is notorious for falling apart if the 86 has one?.If the clutch wasnt engaging the "cool air" you are feeling is your imagination. Check the eye on the collector for bubbles aka air in the system.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Fri Jul 10 19:52 CST 2015 [ RELATED]
|
|
Haha! I am sure it was my imagination. It could also be the fan blowing on my face in 100 degree temperatures. Haha! I guess anything at that temperature would appear to be cool. There are no bubbles in the sight glass. I ran the A/C on 4 and saw nothing. Any other things to check?
|
|
-
|
|
|
Hi,
When you added more refrigerant to the system were the gauges ok? Was the system empty? If it was then you have to look for leaks first and repair them.
If the system was ok use a voltmeter to determine the compressor is properly grounded. Then find the power wire to the compressor's clutch and test it with another wire direct from the positive batt terminal. You should hear it the clicks. If not then the magnetic coil is toast.
If the coil is ok then you'll need to check power from the dashboard when AC switched on.
No bubbles will be there if the clutch not engaged. With the compressor running in R12 system no bubbles means the system is fully charged. In R134a system there would still be bubbles if fully charged. No bubbles means overcharged. For this reason the sight-glass is not provided in a proper R134a system.
Regards,
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sat Jul 11 11:26 CST 2015 [ RELATED]
|
|
The ground is good and I am unsure if the system is fully charged, partially charged,or empty because I thought I needed the clutch to engage to get a proper reading using the current ambient temperature. Like I said, I can change clutches, do 16v head conversions, and the like, but ask me anything about the A/C and I am clueless. I will try jumping the power wire to the battery. If the clutch comes on, what wire am I looking for behind the switch. What color is it and should it read 12V?
|
|
-
|
|
|
Even if the compressor is NOT running you can ESTIMATE the system's state of charge by reading the system's OFF pressure. Engine must be stone cold. Just hook your AC gauges and read from your low gauge. For ambient temp 80F the pressure should read around 86PSI. For ambient 90F the pressure should read around 104PSI. However these are approximates. Any pressures lower than these the system may be empty or partially empty.
Here's R134a to ambient temp chart for other ambient temp values:
http://mrmech.com/technical-references/refrigerant-info-and-properties/pressure-temperature-charts-refrigerant/r12-r134a-r401a-r401b
If the pressures are low then you may refill the system just by directly connecting the compressor clutch's wire to the positive battery terminal (just to override the pressure switches). Its best to weigh in the refrigerant charge. It should be 85% of R12 charge weight. The R12 charge weight should be there on the placard around the engine bay.
Otherwise you may refill by reading the system's WORKING pressure. But this is not the best method as lots of inaccuracies may occur while you adjusting the system to ambient temp (factor in the raising engine bay's temp while refilling). With this method only estimated values are used such as the low pressure gauge should read between 35 to 45 PSI and high gauge 155 to 220 PSI. The readings also depends on system type i.e. CCOT or TXV. But I guess yours must be a TXV with sight-glass included.
There shouldn't be any power to the compressor's wire IF the system is not properly refilled. This is due to the pressure switch cutting off power to prevent compressor damage in case of low refrigerant. With the system properly refilled the compressor should be working WHEN you reconnect back the compressor to its original wiring. Yes there should be 12V to the green compressor wire when AC is switched ON.
If still no power you may refer to 240 AC wiring diagram at page 19:
http://www.volvowiringdiagrams.com/volvo/240%20Wiring%20Diagrams/Volvo%20240%201986.pdf
Regards,
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sat Jul 11 13:31 CST 2015 [ RELATED]
|
|
Thanks. I just went outside and tested the clutch by running the jumper wire directly to the battery. It clicked! So I am guessing I am good there. As I previously stated, the clutch power wire and the green wire that connect to each other in the engine bay were missing insulation, but the wires were intact. I spliced a new piece of wire in and reconnected those wires, but still nothing. I do not have a professional set of A/C Manifold gauges, but I do have the gauge that came with my refrigerant. Will that work? It appeared to be at about 99 psi at 90 degrees ambient so that would lead one to assume that it is partially charged or empty, correct? I will try and check power at the switch before I charge the system anymore. If the switch checks out and the fuse is good, is it then safe to put more refrigerant into the system? Thanks for all the help!
|
|
-
|
|
|
Good thing your AC clutch works via direct connection!
With your non-professional AC gauge your current reading (about 99PSI at 90F) should be OK after factoring in any slight inaccuracy of the gauge. A professional gauge would read about 104PSI. I don't think you need to add more refrigerant at this time. For R134a there must be optimal charge (not more or less) for it to work its best.
Next to check is the pressure switch at the drier (near where the sight-glass is). This is a low pressure switch meaning the switch is OFF at low refrigerant pressure (in case of leak) and should ON when system is charged (like now).
Disconnect the switch's electrical connector and test any of its electrical terminals for power while engine running and AC switched on. If there is power (12 volts) then short both terminals using a paper clip or wire. Hopefully the clutch SHOULD engage now. If it engages then your pressure switch could be at fault. It needs to be replaced for long run compressor protection in future cases of low refrigerant. As your system is full now you may leave the connector terminals shorted just for the AC to work while finding replacement pressure switch.
IF there is NO power at the pressure switch connector then the fault may be at the grey-coloured AC delay relay (located inside centre dash), thermostat or AC switch found at the dashboard. Also clean the fuse's (yes its not blown) electrical contacts.
If you're good with soldering iron you may dismantle the relay and try re-solder all connections in case of any cracked solder joint.
May the provided wiring diagram be of help.
Regards,
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sat Jul 11 16:43 CST 2015 [ RELATED]
|
|
I will check the switch and relay this evening and afterwards I will post my results. Thanks for all the help!
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sat Jul 11 19:35 CST 2015 [ RELATED]
|
|
So with the power to the clutch and the low pressure sensor bypassed...the clutch did not spin. I went ahead and ordered a new sensor just to be safe because it was cheap. Now here's the deal. With the bypass in place and the clutch connected directly to the battery and the clutch running....no cold air in the cab. Am I correct in suspecting the relay or switch in the cab is faulty? Or is it still low on refrigerant? Should I take another psi reading with the clutch running to see what I get?
|
|
-
|
|
|
Q1 - "Am I correct in suspecting the relay or switch in the cab is faulty?"
You should suspect those above are faulty IF there is NO power to any of the low pressure sensor terminals inside the connector. Use your voltmeter or a test light. With the clutch directly connected to battery and engine running actually you've BYPASSED all of the above.
Q2 - "Or is it still low on refrigerant?"
Q3 - "Should I take another psi reading with the clutch running to see what I get?"
Check that your heater (if equipped) stays OFF.
With clutch directly connected to battery, engine running, did you notice ANY bubbles at the sight-glass? There SHOULD be if the refrigerant is running and circulating. If there ARE bubbles then connect your non-professional gauge to the low side and get a reading from there. The reading should be around 35 to 45 PSI for a fully charged system. If its any lower then you may SLOWLY add more refrigerant let the system stabilise for few minutes and add some more until the reading is around the above.
IF there is NO bubbles with clutch directly connected to battery, you SHOULD connect professional AC gauges to the system in order to read the high side. Possible problems could be:
1) Damaged compressor - no refrigerant compression due to wear and tear - need to replace.
2) Stuck thermal expansion valve (TXV) - stuck closed causing refrigerant BLOCK - need to replace.
3) Clogged filter drier - need to replace.
These could be diagnosed using professional gauges. If it comes to this stage I think better to let an AC shop repair the system (because special parts, tools and skills are needed here).
Regards,
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sun Jul 12 10:38 CST 2015 [ RELATED]
|
|
No power at the low pressure switch on the drier following your directions above. When I hooked up the gauge to the low pressure port with the clutch connected directly to the battery, fan off...the pressure is around 25 psi. The air was briefly charged and it feels cooler. It is now stabilized just a hair above 25. Is it safe to slowly add refrigerant? It is apparent that a leak exists so I will be addressing that this fall. Just trying to make it through this hot, humid summer. Was I supposed to take the pressure reading with the a/c fan on or off? And yes the bubbles are visible with the clutch directly connected to the battery and the A/C running.
|
|
-
|
|
|
Good there are bubbles!
Ok by now there are two parts of this troubleshoot. Part 1 - refilling, and Part 2 - trying to find why there is no power to the compressor via the dashboard control.
Part 1:
Q1 - "Is it safe to slowly add refrigerant?"
Yes it is safe. Do this SLOWLY bit by bit. I think you're about 80% to 85% full. So add a little bit more.
Q2 - "Was I supposed to take the pressure reading with the a/c fan on or off?"
Take reading with AC fan ON at highest setting (number 4).
With your gauge reading 25 psi that is very low. You might add up more refrigerant SLOWLY, wait for a few minutes then add some more. Your aim is to get that air coming from the vents as cold as possible. All these refiling and waiting for the system to stabilise then adding again might take up to 30 minutes of your time.
Two methods here - window/door open OR closed.
Window/door open - Your gauge might read higher up to 45 PSI when the system is full. This is because the AC takes hot air from outside and tries to cool it down in one go. This results in HIGHER gauge reading. Aim between 40 to 45 PSI. When the vent air is cold STOP there. Don't add more refrigerant.
Window/door close - Your gauge might read lower between 30 to 35 PSI. This is because as the cabin air is slowly cooled down, the cold air is sucked right back into the AC and this LOWERS the gauge pressure. If you choose this method instead, aim your gauge to read between 30 to 34 PSI. Then STOP there. Do not add more refrigerant.
Part 2:
If there is no power to the pressure switch, have a look at your AC delay relay INSIDE the centre cluster in cabin. Its a grey coloured tall relay if its still original part or a black tall aftermarket relay if it had been replaced before. With your voltmeter test if power is going to the relay from the AC dashboard switch. The wire from AC dashboard switch to relay is coloured red-white (red wire with white strip). If there is power in this wire when AC switch is ON but no power came out of relay, then your relay may be faulty. You can try to open the relay case and re-solder the circuit board. Sometimes its just cracked solder joints causing faulty relay.
You may directly connect the clutch to batt for the AC to work all this summer BUT leaving the compressor continuously running may freeze the evaporator (ice forms at evaporator inside cabin). When ice forms it will block the airflow and you might feel the vent air become lesser (despite blower turned to 4 setting). Then you'll have to disconnect the compressor for the ice to melt down and switch on again for cooling. The thermostat control on your dashboard DOES this (switching off and on again to prevent ice) automatically. So have your part 2 troubleshooting done to get back your normal AC function.
Regards,
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sun Jul 12 11:36 CST 2015 [ RELATED]
|
|
Done. Although, with the AC charged about 43 psi, fan on 4, and clutch jumped the air is still only cool, not cold. It is better than it was though. I am checking the relay now.
|
|
-
|
|
|
"air is still only cool, not cold"
Give it some time for the AC to cool down the car. With windows and doors closed it should take about 10 to 15 minutes to cool down. I think now the car is in the driveway at idle. When you drive it later at higher engine RPM plus better air flow on the road these will cool the cabin better.
Have a look at your sight-glass with AC running. There should still be bubbles although FINER in sizes. If there is NO bubbles or OCCASIONAL bubbles then you've overcharged. Dump a bit of refrigerant out until FINE bubbles are there. To me they may look a bit like "whipped egg-white" running under the sight-glass. This is subjective but you knew how the bubbles looked like when the system was undercharged so it shouldn't look like then. Your gauge should read 1 to 2 PSI lower than before. So do this bit by bit.
First cooling tip - clean your condenser at front of car. Laundry detergent is good enough. Make a pail of soapy water and splash on the condenser with engine OFF. After about 10 minutes spray it off with garden hose. Leave chemical cleaning to specialised AC shop.
Second cooling tip - ensure your radiator is clean. Dirty radiator may hinder air suction thru the condenser resulting in poor AC performance. Replace your coolant if it is long due. Poor radiator performance with old coolant could result in slow heat removal from engine. This heat could RADIATE BACK to the condenser (because they're close together) and hinder condenser cooling.
Third tip - Ensure the radiator fan sucked air THRU condenser and NOT around it. Use foam or similar material to close air gaps between radiator and condenser so that the radiator ONLY gets air thru condenser.
Fourth tip - you could add an electric fan in front of the condenser which should be ON whenever the AC clutch is ON.
Fifth tip - Especially for R134a the condenser airflow must be maintained very good. REMOVE any front grille badges, horns or spotlights that stays in the way of airflow. Yes this does a BIG difference.
Sixth tip - park the car under shade whenever possible. The AC has to work very hard to dump off the cabin heat after parked in hot sun.
Regards,
Amarin.
|
|
-
|
|
|
Amarin has got you going on he right path.
I might add he is doing a great job and that he does not need a nod from anyway.
Jeez, he even knows the wiring colors on these cars!
He did mention the heater valve on the left side of the console.
I will add a thought to Check the valve lever as it may not be closing all the way off.
The cable gets out of adjustment or even the valve might be leaking. Feel the outlet hose from it to the core.
The 45 pound readings could be too high but as he said, that depends on tha ambient temperature of the air coming in over the cooling coils. Read over his other post again and think about what stabilized means and the parts about the car going down the road!
You should fill the '86 system by using the sight glass. Have bubbles when you cycle the compressor on and off. Only a short stream and flash clear. It should stay clear while running.
Cycle the compressor off for a bit of time for the high side to issue some liquid through the TXV.
That way you get a build up gas coming back to the compressor.
This will help surge the high side so the flash will be of a very short duration to fill that usage from the bottom of the condenser. At that point you are filled up.
If you never see any at all, then you are most likely overfilled or very flat on charge.
You do not want to over fill the system. If the low side is too high it might be because the compressor cannot pull the low side down. It has to put gas into the high side.
If there is no room, it's like a busy elevator, the other molecules have to wait outside!
You don't want that because they are standing there holding the heat, you want moved to another place!
Do not wait till fall season to look for your leak as you will be back there sooner than you think!
Besides you won't do it like last year! When it gets cool
You are wasting refrigerant. That's the reason why they want to take away, from (Joe) consumers, those over-the-counter recharge packs any several states.
Just how are you going to put in a new sensor (switch) your buying with it filled up?
You can jumper around that delay relay by finding the two terminals that the contacts operate or connect to.
Mine failed years ago and I tossed the relay out and left the jumper in. It only delays the pull in of the clutch after cranking. It's an over engineering thought to help with idle response if one was that particular. I am not, especially if I am hot and it decides to quit!
The IAC usually over revs the engine anyway.
The clutch does not operate with the start switch in the position three. So it's on and off during the turning and back.
You will notice the fan goes shuts off and the "wizard" did not worry about it coming back on during the roll back.
Keep Amarin busy! (:-)
Phil
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sun Jul 12 13:50 CST 2015 [ RELATED]
|
|
This was in fact in my garage with only a two foot gap under the door. Needless to say it wasn't rolling down the road or in the complete open air either. I will take it to the grocery store for my while in a bit. How would I get some of the refrigerant? Connect it to the gauge with a cannister of refrigerant and pull the trigger in short bursts?
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sun Jul 12 13:51 CST 2015 [ RELATED]
|
|
I meant to say without the can of refrigerant.
|
|
-
|
|
|
Sorry I forgot that you're using the quick-refill refrigerant pack. Ok you could press down the Schrader valve tip inside the low-side valve (just like tyre valve) with a small screwdriver while wrapping it whole with a small towel (to prevent splashing). If usual tyre pressure is around 190 to 210 PSI then this AC valve has about 100 PSI. Just a quick burst off one or two seconds. Check the sight-glass again with system running. Do a little bit more till fine bubbles are there. Once or twice should do it. Just to reduce 1 to 2 PSI.
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Sun Jul 12 18:07 CST 2015 [ RELATED]
|
|
The AC Relay is in fact bad and I am now questioning the validity of my non professional ac gauge. After releasing the pressure for 2 seconds, the pressure it showed increased. I do see fine bubbles moving through the system though. The AC relay had cracked contacts, but two of the capacitors were also leaking. I figured it just wasn't worth me messing with it and ordered one from IPD for about 24 bucks. Time for a new one. It was an original Volvo. After cruising around for a bit, the air temperature never improved. I did also feel air hitting my legs as I was driving, yet the under the dash vents were not activated? It might just be a poor functioning compressor. Belt is tightened within spec so I know I am good there.
|
|
-
|
|
|
First, I highly recommend checking the heater valve and its pipings as Machine Man suggested. Do this first then below. Actually if you noticed the AC was colder on first starting up the car for the day (engine stone cold) but later it becomes less cold as engine heating up then this may be a sign of still working heater (despite turning it off).
Second, to simulate almost ideal condenser cooling, you could splash a pail of cold tap water onto the condenser while system is running. Maybe do this outside the garage. If the cooling doesn't improve a bit (it should improve within minutes) then stop there. Take this to ac shop.
"The AC relay had cracked contacts, but two of the capacitors were also leaking. I figured it just wasn't worth me messing with it and ordered one "
Yes the relay doesn't owe you a thing. I think this is the cause of your no power. You could jump the relay as Machine Man suggested.
"It might just be a poor functioning compressor. "
Its possible. But to know this you'll have to use pro-gauges as they have that high-side gauge too. Lots of diagnostic info can be obtained from the high-side reading because thats the part that supposed to deal with the heart of AC system - the compressor. And for TXV system the high-side reading may help to diagnose its problems too.
"I am now questioning the validity of my non professional ac gauge"
Fairly speaking the non-pro gauge that came with the kit was supposed to be a "guide" for refilling. Its not for reference as pro-gauges could be. Your gauge may show increased reading as the ambient temp may have increased a bit from last time. THIS is the reason why refilling by WEIGHT is preferred. You weigh the refrigerant tank, dump the refrigerant into the system, stop a while and weigh the tank again to know how much have been dispensed. With a digital weighing machine you could leave the tank on the machine and watch its weight reduce as you refill. Then stop when there is enough.
If refilling by weight is done AND the AC still not performing well then you know its not about refrigerant charge anymore, the fault must be in OTHER AC components. This makes troubleshooting simpler.
I think if cooling doesn't improve by this time take it to ac shop for quick cool-down this summer.
Regards,
Amarin.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Mon Jul 13 19:23 CST 2015 [ RELATED]
|
|
How exactly do I adjust the cable on the heater valve? The small screw on top is too close to other components of the car to get a small screwdriver in there. Does the silver barrel on the cable help at all? Is there a good site that shows how to undergo the adjustment? My Bentley manual has nothing about the adjustment procedure. By the way, I got a relay today and it fixed the power to the compressor problem. However, the compressor seems to cycle on without the switch being activated? I know it is probably best to take it in to get it diagnosed, but I am trying to do everything I can before going that route. Plus, good Volvo mechanics are hard to come by in my area. Thanks Machine Man and Amarin!
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Mon Jul 13 20:24 CST 2015 [ RELATED]
|
|
I probably should've mentioned I believe the cable needs adjusting because the temperature slide control only moves halfway into the blue and stops.
|
|
-
|
|
|
Heater valve replacement:
How it works (for earlier type with temp sensing capillary bulb):
Regards,
Amarin.
|
|
-
|
|
|
"I probably should've mentioned I believe the cable needs adjusting because the temperature slide control only moves halfway into the blue and stops."
Ha! That could be why there's not much cold air. The cable is a simple one and you can "move" the end metal sleeve (silver barrel) forward or backward to adjust the degree of control, then retighten the sleeve holder screw (...for lack of proper term). If yours is the "earlier" type heater valve you can adjust the end length of its inner cable at the valve lever (adjustment screw is there at lever).
"The small screw on top is too close to other components of the car to get a small screwdriver in there."
Maybe you could undo the screw via sideways. Use a pair of pliers to grip the screw's sides and twist it anti-clockwise (if viewed from the screw's top).
But first, undo the cable at its heater valve end. With the cable undone, play with the valve lever to ensure its able to close properly. The heater valve could be stuck open too (rusts inside?) and that could be why you couldn't fully push the temp lever to extreme left (blue). If the valve is stuck then you'll have to replace it (and this includes first draining your radiator coolant to prevent flood in your cabin..installing new valve...refilling it later..and so forth).
For more convincing troubleshooting (if left up to me), drain your coolant, dismantle the heater valve out and play with the valve lever. You could blow into the valve with lever at extreme positions to see if its really able to stay close or open.
Here's a website for guide:
http://europartshouse.com/index.php?main_page=page&id=7
Regards,
Amarin.
|
|
-
|
|
|
Go ahead and see if it will take more 134a in? Does can get cold? If its low pressure it will fire up when gets enough freon. Most likely have a leak somewhere thats needs to be addressed.
|
|
-
posted by
someone claiming to be SwedeSpeedBrick
on
Fri Jul 10 20:27 CST 2015 [ RELATED]
|
|
Ground wire is intact.
|
|
|
|
|
