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Discussion Starter · #1 ·
I have a 2012 Chevy Cruse LT.

It is my understanding from a mechanic and these forums that the coolant fan should be running when the AC is turned on. It currently is not and the mechanic can find no reason why. The dealership even indicated they were not aware of any issues.

Any thoughts on why it would not be running? This comes after recent fixes for a coolant leak and the coolant fan not working at all. The mechanic has replaced a hose for the leak and installed a new coolant fan. The fan does now work. It just doesn't come on when the AC is turned on.

By the way, the AC system was completely empty. Is it possible for a hot engine to eventually "burn off" the AC or is this most likely due to a leak? The mechanic cannot find any leak in the system so I wonder if it is related to the coolant fan not working and high engine temps.

We had previously replaced the water pump due to a leak. The coolant fan has always "acted funny" in my opinion. When it comes on you know it due to the high rpms. I am starting to think that maybe I ended up with just a bad one (car). I really like my Cruze and was going to give it to my daughter but now I don't know.

Thanks.
 

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AC being empty is a sign of a leak. These are supposed to be sealed units but they do leak over time. I'm not sure the main cooling fan is required for the AC compressor to run. I may be wrong about this though.
 

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Discussion Starter · #3 ·
Thought as much about the leak. It is probably a really slow one. I believe they can put a dye in there to help find the leak. I guess I just need to find out more about that coolant fan and when it is supposed to run.
 

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Normally, the fan would run, but it might depend on what's needed as determined by pressure. Certainly a high pressure will trigger a higher speed. Does the A/C work otherwise? How long have you let it run?

It seems a fairly common problem with the Cruze is the 3-speed fan looses the lower speeds - no nothing happens until things get bad enough that the ECM commands high speed.
 

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Discussion Starter · #5 ·
Interesting and good points. I pick the car up from the mechanic this afternoon. I will test the AC myself to see if I can determine what is going on exactly. I am just going off what they told me over the phone right now.
 

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From what I remember, if the cabin fan is on speeds one or two, the engine fan will not necessarily run constantly like on many cars. Reason is - Cruze has a variable output compressor. It's not creating very high pressures at slow speeds so it doesn't need the engine fan. Make sure to turn the blower to full which should command the engine fan always on at low speed.


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Tried switching on the AC in my 2012 2LT with a cold engine and cool outside, like in the lower 60's, fan did come on, but in low speed. Fuse/relay box has three cooling fan relays, possible low speed has dirty contacts.

Ha, started do my own AC work back in the 60's, AC shop that really didn't know what they were doing, charged me seven times the price I was earning as an engineer. In 1994, had to become 608/609 certified to purchase refrigerants. Only have the finest equipment, know what I am doing, not bragging, and can detect refrigerant leakage rates low than one ounce per year.

Have yet to meet any mechanic at a dealership that was properly trained in refrigeration.

This is what the problem is, yes, electronic leak detectors are capable of detecting less than one ounce per year of leakage. But you also have to know how to use them.

Also three different types of leaks, refrigeration only, lubricant only, or both. Other ways to find slow leaks is with liquid nitrogen using a high pressure leak down test.

If an R-134a system loses all refrigerant, has to be disassembled, flushed out, drawn a long 100 micron vacuum for at least an hour, charged with the proper weight of R-134a, then have the proper amount of PAG oil injected in. PAG oil is really susceptible to moisture and if not done this way, will form per a sludge and acid, your compressor WILL NOT last very long, and don't believe dey all do dat BS.

R-12 was never proven to deplete the ozone layer, but thanks to Al Gore, have to live with it, cost three times as much to service an R-134a system than R-12, but it your money not theirs.
 

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Discussion Starter · #8 ·
Well, i drove it home from the shop (about 5 miles with stop and go) and I don't think fan came on once. I didn't turn AC on until I got home (probably should have tried earlier) as I wanted to open the hood and watch the fan. None of the fan speeds caused the coolant fan to come on, so maybe there is an issue. I did notice too that the AC is not as cold as before. It is cooler than before the service but not cold. Could that be related to the coolant fan not coming on?
 

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I did notice too that the AC is not as cold as before. It is cooler than before the service but not cold. Could that be related to the coolant fan not coming on?
Quite possibly. I don't think it's an automatic given that the fan will come on. It's turned on based on conditions, but in normal operation, those conditions will cause it to come on. As such, I think it may be a symptom - either of a bad fan or a bad sensor.

However, if the fan is not running, the A/C could have a hard time cooling. More digging will be needed to know what is causing what.
 

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Cruze uses an electronically controlled variable displacement compressor, when its cool outside, vent temperatures are barely a few degrees below the ambient temperature so not even worth switching it on. Disturbed when switching to defrost mode, between 33*F and around 70*F, switches on the compressor with some strange hopes it will remove more moisture for what little is in there.

PAG oil, actually a form of women's facial cream is stiff as is the compressor seal, all you are doing is putting excess unneeded wear on the compressor. To get around this, in this temperature range, refuse to use defrost, crack open a door window instead.

But when it get hot outside, highest we hit was 105*F, that baby really kicks out the cold air. There are good things about this system as opposed to the older cycling switch compressors, the compressor runs all the time, and the engine load is a function of ambient temperature. Cycling systems were constantly switching the compressor on and off put super strains on the belt drive system plus wearing the hail out of the clutch. Either were working full blast or not at all in an attempt to maintain a constant interior temperature.

Yet another disadvantage of an R-134a system compared to R-12, R-12 used a tube and fin condenser that was easy to flush out. Next to impossible with a parallel flow condenser, so add this to yet another throwaway item. Debris left in the condenser will destroy a new replacement compressor, so if you do not replace the condenser, you will be replacing both the condenser and the compressor a second time.

What GM recommends that is in the idiot class is to add a filter in the outlet of the condenser, you already have a restricted condenser, than adding an additional restrictor with the filter. This drastically increases the high side pressures, reduced cooling, poorer fuel economy, and excessive wear on the new compressor.

Also not easy to replace the condenser on the Cruze, entire front end has to be removed first, a case of ease of production versus maintenance. But the major problem and a problem that is well over a hundred years old with a radiator or a condenser, they are bug collectors. If you think the front end of your Cruze and windshield is loaded with bugs, should look at your condenser.

Air conditioning system needs air flow, a bug loaded condenser restricts this air flow causing high pressures to drastically increase and cooling to decrease and engine overheating to increase. Cruze sets the record for the most difficult condenser to clean.
 

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Discussion Starter · #11 ·
So it sounds like what I really need to do then is just watch it and wait for the temp outside to get out of the 60s and low 70s. I can also look to see if I have a lot of bugs around the front end and clean them off if I can. I will update later if I notice anything different.
 
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