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air leak issues - a/c not working

zaprat

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I am a newbie

I have a Holden Commodore Calais S2 with Climate Control. I have no cool air. On acceleration, I note air vent directs warm air from face to feet and returns to face on deceleration. I also note the heater tap is letting hot water to the heater radiator and the cars effectively a cooker (no cool air). As I live in Qld my wife is NOT happy:bomb:

I have purchased another heater tap but have not fitted it yet because I want to find the cause of the problem before doing so.

I have read a few articles suggesting that this issue can either be air leak or a problem with the vacuum actuator located under the radio in center console. I have removed and checked the vacuum actuator and on inspection of solenoids, it seems ok. As the filter appeared clogged/deteriorated (big holes), I replaced the foam filter with home made filter using household vacuum bag replacement kit which included an additional air filter (as a short term workaround). The problem is still present. I am guessing therefore I may have a vacuum leak somewhere in my vacuum system.

I was wondering how I could go about finding a vacuum leak. I have seen several videos on YouTube of how to find engine vacuum leaks at the manifold using various techniques, the most common is to spray brake cleaner around the manifold and wait for change in idle speed, I have not done this as I am not sure if this has anything to do with a/c vacuum issues (and I don't want risk my engine to catching fire)

I have also read a post that there is air reservoir somewhere in the vacuum system which retains vacuum during sustained acceleration. It was suggested in the post that this sometimes this reservoir fails (but I am not sure how).

I am somewhat confused and therefore dangerous.

Q. How do I go about locating my vacuum leak in my instance?

Q. Could my issue be related to a so called engine Vacuum leak, are they related?

Q. Could it be a problem with vacuum reservoir and if so how to diagnose this? Where is it?

The air con currently blowing hot air which may something to do with heater being full of hot water and/or perhaps it needs a regas or both?

Regards
Zaprat
 

iChris

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first of all, does your air con compressor engage when the a/c is on? have a look under the bonnet at the compressor when the car is running and you'll see the center of the pulley spin with the rest of the belt if it's working. if it's not working it's faulty or it's out of gas. the compressor will not engage if it's low on gas as a failsafe.

climate control relies on the mixing of hot, ambient and cold air to reach the temperature you set. try setting it to maximum cold (keep hitting the colder arrow until "C" appears on the screen - below 18 on VS models and below 17 on VR) and see if this helps. this will close the stepper door that mixes the air off and only draw in air from the A/C box.

check the vacuum lines in the engine bay at the back of the engine. they are notorious for coming loose and the vacuum reservoir looks like a ball and I think it's located near or in the front passenger's side wheel well. as for finding vacuum leaks, try using the smoke from a stick on incense along the lines.

heater tap is a very common failure. they become seized over time but usually get stuck shut and not open unless it's so old there is nothing in there stopping coolant flow.

a huge indicator of vacuum problems with the doors that control the direction of airflow is the airflow dropping to feet when accelerating up hill. try giving the side of the console/radio surround the commodore love tap (a good slap) - this is sometimes enough to jolt the solenoid block and get the solenoids to move into position. this will indicate it's the block that's causing issues.
 

zaprat

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thanks for the excellent information. I will look at the compressor in the morning.

I did check the vacuum hoses behind the engine and found they were not entirely snug on the one way valve. When I tried to push them closer into position the entire one way valve came apart at the seam. Fortunately, nothing broken and all parts were in tact including the internal spring, the flange. I resealed the unit with a special type of super glue which requires a catalyst agent. I am hoping the seal will last at least until Monday when I can replace the unit. Given the ease in came apart, perhaps it was the valve causing me the issues. I am letting the glue cure overnight before I undertake another test. I checked all the other lines including the connection to the vacuum reservoir and they appear to be OK.

I did take a look at the air conditioner hoses and noted that one side was covered in oily substance. I am aware that a/c also includes oil so perhaps I have found a location of the coolant leak or perhaps I or previous mechanic was just sloppy. As the car was passed on to me, I not exactly sure when it was last gassed but the label under the hood indicates that the recommended next air con service should have been done in 2008 which means it about 5 years overdue.

Thanks for you help. I will post more info in the morning.
Regards
zaprat
 

iChris

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the a/c lines tend to leak around the crimps - where the rubber hoses join the aluminium ones or on the evaporator/condenser. keep in mind if they system does not hold gas, you've got a leak that needs to be found. most auto electricians will hook the system up to a vacuum pump and remove any remaining gas and whatever else may be in the pipes and add some refrigerant with a dye that shows up under uv light. after a month or so of general use the technician can look over the system with a lamp and find any leaks.

the general consensus is that the system should never loose gas unless there is a leak, but many workshop manuals do say that the system is indeed designed to slowly leak over time and this is to keep the seals lubricated and to prevent them from completely drying out and failing.

if your compressor is not engaging you don't have any other option other than to take it to be looked at.
 

Jxfwsf

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the a/c lines tend to leak around the crimps - where the rubber hoses join the aluminium ones or on the evaporator/condenser. keep in mind if they system does not hold gas, you've got a leak that needs to be found. most auto electricians will hook the system up to a vacuum pump and remove any remaining gas and whatever else may be in the pipes and add some refrigerant with a dye that shows up under uv light. after a month or so of general use the technician can look over the system with a lamp and find any leaks.

the general consensus is that the system should never loose gas unless there is a leak, but many workshop manuals do say that the system is indeed designed to slowly leak over time and this is to keep the seals lubricated and to prevent them from completely drying out and failing.

if your compressor is not engaging you don't have any other option other than to take it to be looked at.
Anywhere that is certified to work with refrigerant systems won't drain and refill (even slightly), if they vac the system out then it'll also likely remove some of the oil.
True that most ac systems leak, this is why it's recommended to use the ac for a few minutes every couple of months regardless of season, this moves some of the lubricant around and back into the seals.
We're talking a 20 year old system here... a more likely place for a leak is in the o-ring seals (not the crimped fittings on the hoses normally).

Apart from it's illegal to simply re-gas a system they do need to do some tests, generally it's add some dye with a slight charge that is enough to make the system work and tell you to come back in a couple of weeks after using (mostly it's only a minor leak and people think it's fixed and continue on their way for months..... by this stage the leak has slowed enough that no major point are visible and the dye is long gone.... taken care of by the elements)

This is the cheap option for most, are you likely to pay minimal for the quick test or spend heaps having them discharge and empty the system, replace all the seals, charge the system with an inert gas and inspect every joint for a leak, discharge again, recharge with the refrigerant finally after spending hours doing it perfectly to the book? General consumer wants it done now and cheap, this is why using a dye and telling you to come back in a couple of weeks is cheap, quick and generally reliable (unless they miss something)
 
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