It hit 72 degrees and sunny today for the first time in Michigan and after tooling around town I parked with engine idling. I reduced cabin temp to 65 to cool it off a bit for a phone call. Shortly after, I heard a 2-3 second jet-like woosh from the right side of the engine bay. It sounded like someone poked the side of my tire with a knife! After another 15 seconds or so I heard it again for 2-3 seconds and saw a greyish-white vapor come up from the right front and from between the hood and fender gap. It dissipated like a vapor, not smoke (freon?). It smelled a bit rubbery but not strong when I opened the hood. No cabin smell at all. There was a watery condensate-like coating on the subframe down in front and to the right driver side of the AC compressor. I turned the temp up and it didn't happen again. A/C is one of the few systems I do not understand well. I'm not sure what freon/refrigerant smells like. The jet-like wooshes sounded as though a high pressure valve purged to relieve pressure.

It does appear that I do not have heat since I increased temp to 80 and felt cool air. I hear a low buzzing noise coming from the center of the interior dash. A similar sound is coming from the engine bay down near the AC compressor. The interior buzzing is much less when I turn the climate control OFF.

What has likely happened? And why no heat now? What should I be looking at to confirm? Thank you!

 

This morning I found that the battery is completely dead.. this makes me wonder if the alternator is also involved...

 

compress/clutch issue. maybe the relay got stuck or fried or something.

 

Thanks Thoiboi.

I charged the battery, started it and alternator checks good at 14.36 Volts. I'm not sure why the battery was fully discharged this morning. If the relay is fried, it may be shorting out so I will check battery voltage later. Will do a search but would love to know where this relay actually is. Should I unhook it for any good reason?

After warming up it did that crazy loud purge of grey-white gas again so I shut her off. Climate control was OFF. I will have to warm it again and watch where that is coming from. I'm thinking of taking it to AutoZone for a diagnostic check. Not sure it will reveal anything. Does anyone have any recommended, logical next steps? Thanks.

 

The call to AutoZone was helpful. The guy explained that Freon is not so heavily pressurized as to make the jet-like woosh I'm hearing. I replaced my radiator about a month ago and things have been just fine since then. I'm gonna heat her up and see where the purge is coming from and report back. Probly gonna remove the belt and check pulley play for alternator and AC compressor because I do have that odd new buzzing sound too. This is frustrating.

 

I started my 2008 TL to hear the gas purge again and watch where it was coming from. It started cycling from idle to lower rpms and there was a hissing sound from near passenger side of valve cover. Then a rough clanking directly behind the engine. I can't figure how to get the mp4 phone video attached. I went to hit the gas pedal to rev it and smooth it out but it did the jet-like purge (a sound like a car lift being let down with the massive rush of compressed air), then it stalled! The Purge appeared to come out down below the steering fluid reservoir. Some oil drops are now seen on the bottom of the frame below the oil filter (it's NOT from a leaky oil filter). Will post picture in Reply to follow. Any ideas? Thanks.

 

 

You can eliminate the AC system by turning your climate control off and then start the car. With the car running check under the hood to confirm that the AC compressor clutch is not engage (center of the AC clutch is not turning, only the perimeter is turning where the pulley is in contact with the belt).

If the car doesn't purge then there is a freon leak. You can confirm by turning the AC back on. If it's the freon leaking then most likely a defective O-ring connection.

 

Check out this TSB for the 2007-2011 MDX. Your issue is likely the same. Make sure you replace the A/C compressor clutch relay with the -A05 one.

Battery Is Dead, or A/C Cools Poorly
http://techinfo.honda.com/Rjanisis/pubs/SB/B11-031.PDF

 

I tried to accelerate after this and I heard the loud Purge from low on the passenger side of engine that lasts about 2 seconds (every time) with a puff of greyish smokey vapor.. then it stalled. What in the Wide World of Sports is going on???

 

EE4Life, wow.. I've been stressing on this all day! That Bulletin sounds like Xanax I need. You get the Star today. Thanks a billion. Really.

 

The Bulletin from EE4Life addresses my issues mostly. I did find that the battery was down to 6 Volts shortly ago and the AC Relay had been pulled last night.
> Can I drive the TL with the AC Compressor Clutch Relay removed and possibly the 7.5 A #12 MG Clutch Relay fuse?
> The Bulletin says to replace the Compressor Relief Valve if it shows signs of being opened. Mine has opened or 'relieved' itself 5 times. Must I replace the valve and have to deal with the change of refrigerant, etc? I suppose it will be slightly low on refrigerant since some spewed.

Thanks.

 

Yes you can drive the TL with the AC relay and the fuse removed. Assuming the circuit doesn't turn off any other components. However, i would suggest that you leave the fuse in to see if there is still a short in the remaining circuit without the relay.

If your battery doesn't drain dead over night or however long it took for your battery to go dead then you may have found your problem.

In regards to the relief valve, you're replacing the O-ring on the valve not the valve it self. It appears the O-ring may have been compromised with the higher than expected pressure caused by the stuck relay, causing the AC compressor to run without the AC fan being on at the same time.

Likewise, the purging of the AC freon may have cause a low freon and/or low compressor oil situation so an evacuation of the AC system is required to replenish both freon and oil in the AC system. The best time to replace the O-ring is when there is no pressure in the AC system.

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Bmcarp, I found the new Relay #39794-SDA-A05 OEM Intermotor at CarQuest/Advance Auto locally for just $6.29! Rock Auto was just under $5 bucks. AutoZone was $16.99.. yikes. I'll check parasitic draw with the new relay installed. I did have a slight draw with the relay removed so I hope it resolves with no more troubleshooting. I drove with the relay removed and had heat.

I also have noticed that an intermittent metallic rattle has gone while the AC Compressor has been disarmed. That rattle has been going on now for over a year and will likely return when I put in the new relay tomorrow morning. So I need to look into the mechanics of that and see what may need to be done.

 

 

New relay is in but still had draw on battery. Rather than troubleshoot I unhooked the HFL between visors and that stopped the battery draw. Love the feeling of accomplishment. Thanks for help All.

 

 

I was lost but now I am found. In reality, I had been saying for the past 6 months that this is the most reliable car I have ever had, which it is. I had been saying that I have never had a major malfunction with it ever, well except for the frickin pothole I hit a month after purchase that blew out the tire and bent the rim. A month ago the trans fluid elbow gave out on the radiator (engineering brain-fart), thankfully in the garage. Easy replacement and just $150 bucks. This AC Relay at just $6.29 was another fortune. Acurazine was the ultimate benefit however.

 

old thread but check both fans are coming on, what is happening is the refrigerant leaks escapes because of high head pressure, its a safety valve. usually happens when there is not enough air flow across the ac condenser.

 

Had this same issue and after quite a few things and the precursor of this happening was a dead battery, I figured it's the RELAY. And since I got 5 relays, I replaced ALL three and it's been smooth since then.