AC Blows Cold, then Warm (Thoughts?)
10-11-2017, 07:27 PM
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1998 C43, 2017 Honda Accord Sport
AC Blows Cold, then Warm (Thoughts?)
Hey folks,
Recently, I've developed an odd problem where every time I start the car, it blows cold, however, as the engine warms up, the AC blows warmer (never hot, just ambient/warm).
On a side note, I've replaced the following within the last 6k miles before I got this problem; I've also not had this problem for a solid year after these parts were replaced (so a leak is not likely): AC compressor, receiver drier, and condenser (with a full freon evac and recharge of course).
I'm thinking either 1) duo control valve (my mechanic surmises this is the culprit after he took the car for a quick spin; he installed the aforementioned AC components) or 2) expansion valve.
Thoughts? Has anyone had one of these components fail?
Recently, I've developed an odd problem where every time I start the car, it blows cold, however, as the engine warms up, the AC blows warmer (never hot, just ambient/warm).
On a side note, I've replaced the following within the last 6k miles before I got this problem; I've also not had this problem for a solid year after these parts were replaced (so a leak is not likely): AC compressor, receiver drier, and condenser (with a full freon evac and recharge of course).
I'm thinking either 1) duo control valve (my mechanic surmises this is the culprit after he took the car for a quick spin; he installed the aforementioned AC components) or 2) expansion valve.
Thoughts? Has anyone had one of these components fail?
10-12-2017, 10:44 AM
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12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG sold)
Could indeed be a sticky duo-valve. Sometimes tapping (gently with a soft head hammer) the side of each cylinder may free the sludge and faulty piston. If not, you can remove and clean out the gunk inside. They a a bit expensive new, ar least in my part of the woods, so be careful 
10-12-2017, 06:27 PM
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Could indeed be a sticky duo-valve. Sometimes tapping (gently with a soft head hammer) the side of each cylinder may free the sludge and faulty piston. If not, you can remove and clean out the gunk inside. They a a bit expensive new, ar least in my part of the woods, so be careful
I can always take apart the old one and see, after I swap the new one in. They're ~$150 USD here; not too bad given the price of other components for Mercedes.
10-18-2017, 11:19 PM
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Update: Replaced the duo control valve - still ambient air :/
I checked fuses and the compressor to verify correct operation. I guess I probably need a recharge (and/or a leak fixed) which I find hard to believe. Off to the dealer I guess to get a full AC inspection.
I checked fuses and the compressor to verify correct operation. I guess I probably need a recharge (and/or a leak fixed) which I find hard to believe. Off to the dealer I guess to get a full AC inspection.
10-19-2017, 05:24 AM
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12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG sold)
If your baby is loosing HEVAC gaz, my quick suggestion would be to check the stuff which will have accumuladrd between coolant radiator and condenser. I had sufficient dirt, schmuck, leaf and twigs to start a veggs garden
10-20-2017, 10:20 PM
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1998 C43, 2017 Honda Accord Sport
Not that, as I got in an accident the other year and got the whole front end rebuilt. It's been garaged and super pampered ever since (and only 3-4k miles since). Everything is clean.
