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Test condensor fan motor

needlenose on Tue July 01, 2014 7:38 PM User is offline

Year: 99
Make: Honda
Model: Civic
Engine Size: 1.6L I4
Refrigerant Type: 134a
Ambient Temp: 88
Pressure Low: 30
Pressure High: 380-400
Country of Origin: United States

My high side pressure appears to be spiking when I turn on the ac and the belt is squealing. I've been fighting this for several years now and may have determined that it is a cooling problem. The reason that I didn't suspect it before was because the condenser fan comes on immediately and seems to move plenty of air. Maybe not quite as much as the radiator fan, but then again, it's not as big.

How do I determine that I actually need a fan motor? I turned on the ac and waited for the pressure to reach 400psi, then sprayed water on the condenser. It immediately dropped to 280. It would be great if it was as simple as a condenser fan, but I would like to be sure. I've put a *lot* of time and money into this ac system over the last few years. Is there any way to determine that the fan motor is indeed the problem? The internet is swamped with how-tos for determining if it's coming on or not. I want to know if it's moving adequate air.

Everything I've done to the system is in this thread. Sorry, I posted it to the wrong forum. :-)

http://autoacforum.com/messageview.cfm?catid=20&threadid=30512

bohica2xo on Wed July 02, 2014 12:08 AM User is offline

If the fan runs, and it blows air, it can be hard to quantify it. An optical tachometer will give you a speed, but the FSM does not list a test speed - a common issue.

If you sprayed water at 88f ambient, and it only dropped to 280, I would clean the condensor. Straighten any bent fins too. Dirt, bugs, oils, etc. can pack the fine fins in newer condensors. A deep cleaning


To properly clean the air side of a modern condensor, you may need to remove the grille, and any fan(s) in front of the condensor. Start with a cold condensor.

Use a strong surfactant type cleaner. I recommend things like Simple Green, or Zep Orange. Commercial floor stripper is great for this job, but it can de-gloss paint, so be careful with it.

Use whatever cleaner you have full strength. Spray it from a spray bottle deep in to the fins. Soak the condensor from top to bottom. Let it stand for a few minutes, but do not let the cleaner dry. Spray it again if it is drying. Us the stream setting on a pump sprayer & get the cleaner deep in to the fins.

To rinse, use a garden hose with a spray nozzle - do NOT use a high pressure washer, as this can bend or flatten the fins on the condensor. Plenty of flow @ 30psi is better than 2500psi.

Driving a car here in the dry Nevada desert I still find I need to clean the condensor every few years. Small insects, dust, pollen, etc stacks up in the fins below the front surface and the build-up reduces both airflow and heat transfer. You will be surprised at how much dirt rinses out of the average condensor after 5 years on the road.


.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Jag987 on Wed July 02, 2014 12:22 AM User is offline

Quote
Originally posted by: bohica2xo






To properly clean the air side of a modern condensor, you may need to remove the grille, and any fan(s) in front of the condensor. Start with a cold condensor.



Use a strong surfactant type cleaner. I recommend things like Simple Green, or Zep Orange. Commercial floor stripper is great for this job, but it can de-gloss paint, so be careful with it.



Use whatever cleaner you have full strength. Spray it from a spray bottle deep in to the fins. Soak the condensor from top to bottom. Let it stand for a few minutes, but do not let the cleaner dry. Spray it again if it is drying. Us the stream setting on a pump sprayer & get the cleaner deep in to the fins.



To rinse, use a garden hose with a spray nozzle - do NOT use a high pressure washer, as this can bend or flatten the fins on the condensor. Plenty of flow @ 30psi is better than 2500psi.



Driving a car here in the dry Nevada desert I still find I need to clean the condensor every few years. Small insects, dust, pollen, etc stacks up in the fins below the front surface and the build-up reduces both airflow and heat transfer. You will be surprised at how much dirt rinses out of the average condensor after 5 years on the road.





.
Was that a copy/paste? I seem to have read that a few days ago in another thread. Still great advice. On this one, air flow issues is where I would start as well. A good cleaning never hurts. I always check for air flow restrictions even when pressures are normal. Just today, I pulled a good sized piece of a grill out from in front of a condenser. The guy was almost more excited about finding that and being able to "glue it back in" than he was about getting his ac fixed (leak, due to missing high side service cap).


-------------------------
I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

mk378 on Wed July 02, 2014 10:11 AM User is offline

The amount of oil is really critical in these small systems with scroll compressors. Excess oil will end up coated on the inside of the condenser and impairing heat transfer.

The easiset way to check if fan performace is adequate is to get some pressure readings with the car moving. At highway speed, the fan is irrelevant. Note that the Civic has very simple controls-- it is wired so the condenser fan will just run all the time the compressor is engaged.

Edited: Wed July 02, 2014 at 10:11 AM by mk378

needlenose on Wed July 02, 2014 10:52 AM User is offline

Sorry, I probably should have just copied in the content from the other thread. The condenser is brand new, as is the compressor, dryer, and expansion valve. I used 2 quarts of flush on the system, charged it with 4.6oz of PAG46 measured with a horse syringe(2.5oz compressor, 1.1oz dryer, 1oz suction line near evap), vacuumed it for 8 hours, and weighed in 21.2oz of DuPont Suva 134a.

Since it's brand new, I'm positive that the condenser is flowing air at whatever maximum capacity it is able. I will just replace the fan motor and see what happens. I'm completely lost at this point.

I saw a post on this forum about rubber hoses collapsing internally? I haven't replaced those yet. What the heck, it's just money... :-|

Thanks for the responses!

needlenose on Wed July 02, 2014 10:58 AM User is offline

Quote
Originally posted by: mk378
The easiset way to check if fan performace is adequate is to get some pressure readings with the car moving. At highway speed, the fan is irrelevant. Note that the Civic has very simple controls-- it is wired so the condenser fan will just run all the time the compressor is engaged.

I have found that once the car is moving, it cools fine. It seems to be mostly when the car is still (which is usually just when I start it and turn on the ac). I will have to pull the hood and get readings while it's at 60mph.

What I don't understand about the water cooling method of troubleshooting is that, since water will always cool better than air, I would think the pv/t formula would dictate that there would always be a significant drop in pressure when using water over air to cool the condenser. Since the fan seems to be moving plenty of air, I'm just a little confused why this would indicate a cooling problem.

wptski on Wed July 02, 2014 12:13 PM User is offline

Quote
Originally posted by: needlenose
Quote
I will have to pull the hood and get readings while it's at 60mph.
This is only the second time that I've seen it mentioned here about taking reading while driving. For vehicles that the hood opens up to the windshield, it's possible by carefully routing/tying and using long hoses but if it has a cowl in front of the windshield, forget it.

needlenose on Wed July 02, 2014 1:56 PM User is offline

LOL, I will duct tape hotpads to my butt and ride on the engine while my wife drives if it will help solve this problem. This has got to end.

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