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My AC quit cooling recently. All the controls on the dash are being seen AND the "compressor clutch demand" signal is engaging according to my diagnostic tool, but the clutch does NOT engage. I have checked the associated fuses and swapped relays to no avail. I was underneath my car today and saw an oily substance all over the bottom of the lower control arm and underbody panels on the compressor side and on the right/front shock.
Looking for opinions - do you think this could be freon/oil blown from a bad seal or a leaking MSRC shock? This is the best pic I could get. The dark area is the oil. I wiped the shock down up close to the boot so I can see if it's coming from there.
Thanks in advance.
Last edited by stevettec7; Dec 15, 2022 at 04:37 PM.
Reason: Title typo
I can't tell much from the picture. It would be reasonable to think that the ac system has a low pressure switch. If your car did leak the refrigerant, the compressor will not run.
If oil isn't running down the lower control arm from the area where is mounted to the cradle I doubt any oil seen on the LCA is from the compressor. Diagnostics can be easier if you can get access to a scanner capable of reading GM body codes. The GM MDI2 or equivalent will work plus a Windows PC to run GM software. Having the codes read helps tell you where to start diagnosing the problem. Otherwise, all you are doing is shooting in the dark.
If oil isn't running down the lower control arm from the area where is mounted to the cradle I doubt any oil seen on the LCA is from the compressor. Diagnostics can be easier if you can get access to a scanner capable of reading GM body codes. The GM MDI2 or equivalent will work plus a Windows PC to run GM software. Having the codes read helps tell you where to start diagnosing the problem. Otherwise, all you are doing is shooting in the dark.
Bill
The only DTC set right now is related to my vents stuck at mid-point. There are no other BCM DTC's. I am using Autel's MaxiPro MP808 TS scan tool.
Why exactly are we making this difficult? Just go check your A/C charge.
Well sir, we're just having a conversation. I was curious if the Magride shock has a large enough oil capacity to make the huge mess I'm seeing, or would it be mostly seepage? I have an appointment at the service department Monday. I was just trying to get educated by some of the Vette Guru's in the forum.
Shocks usually leak from the shaft seal -- which is to say the top of the body, not the bottom. Not immediately familiar with the mag shock failure modes, but I've seen crazier things than what's pictured. I also don't think it's related to your a/c, it's too far outboard and too localized for a freon leak.
Occam's razor dictates it is low on freon. I'd bet the mess you see on the LCA is unrelated.
It certainly is possible to have two failures, the AC not working and a leaky shock. However, they are not related. Given you said that your 'AC quit cooling'; I would look at AC components first. An small amount of lubricant will be lost with the refrigerant. Later, inspect more closely the shocks.
You are certainly correct, it's always wise to be informed on the condition of your vehicle before leaving it for service.
Good luck with your service appointment.
I know they sell the kits at autoparts stores to top off freon but you really need to check high side and low side pressure to make sure you do not overcharge and cause other issues. Just my .02. You can buy a set of gages from Harbor Freight if you want to do it yourself.
My AC quit cooling recently. All the controls on the dash are being seen AND the "compressor clutch demand" signal is engaging according to my diagnostic tool, but the clutch does NOT engage. I have checked the associated fuses and swapped relays to no avail. I was underneath my car today and saw an oily substance all over the bottom of the lower control arm and underbody panels on the compressor side and on the right/front shock.
Looking for opinions - do you think this could be freon/oil blown from a bad seal or a leaking MSRC shock? This is the best pic I could get. The dark area is the oil. I wiped the shock down up close to the boot so I can see if it's coming from there.
Thanks in advance.
I’m assuming you’re talking about the “AC Request” input data PID ??…you should have an “Output Control” on your scan tool…see if you see one for AC Clutch…turn it on and off and see if you can hear or see your AC clutch engage. I moved this post to “Tech”.
I’m assuming you’re talking about the “AC Request” input data PID ??…you should have an “Output Control” on your scan tool…see if you see one for AC Clutch…turn it on and off and see if you can hear or see your AC clutch engage. I moved this post to “Tech”.
My AC quit cooling recently. All the controls on the dash are being seen AND the "compressor clutch demand" signal is engaging according to my diagnostic tool, but the clutch does NOT engage. I have checked the associated fuses and swapped relays to no avail. I was underneath my car today and saw an oily substance all over the bottom of the lower control arm and underbody panels on the compressor side and on the right/front shock.
Looking for opinions - do you think this could be freon/oil blown from a bad seal or a leaking MSRC shock? This is the best pic I could get. The dark area is the oil. I wiped the shock down up close to the boot so I can see if it's coming from there.
Thanks in advance.
This is certainly not what we like to hear, stevettec7. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your vehicle. To do so, please send an email to socialmedia@gm.com with ATTN: stevettec7/Corvette Forums in the subject line.
Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.
Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information. www.gm.com
This is certainly not what we like to hear, stevettec7. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your vehicle. To do so, please send an email to socialmedia@gm.com with ATTN: stevettec7/Corvette Forums in the subject line.
Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.
Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information. www.gm.com
I really appreciate the response. I already have a case number for other problems with my car. Can you amend the current one instead of creating a new one? By the way, this next trip in for service is going to be VERY expensive! I know my ‘15 with 70k miles is not new, but you’d really expect a car of this cost to last longer than it has without breaking down.
Very disheartening!
Here’s the current case I have open.
Last edited by stevettec7; Dec 27, 2022 at 11:47 AM.
Shocks usually leak from the shaft seal -- which is to say the top of the body, not the bottom. Not immediately familiar with the mag shock failure modes, but I've seen crazier things than what's pictured. I also don't think it's related to your a/c, it's too far outboard and too localized for a freon leak.
Occam's razor dictates it is low on freon. I'd bet the mess you see on the LCA is unrelated.
AC Quit - Could this the reason?
