Question: No real "wind" behind the AC

[woodpuppy]

I have a 1986 coupe with AT. The AC is fully charged and it gets cold as cold can be. The problem is the fan/blower doesn't really "push" it out of the dash vents. It comes out, but with very low pressure unlike any other car I own or have own. I've only had it a few weeks and it's been like this from day one.

Using the digital/electronic climate system when I choose defrost air comes from the defroster. Heat; air comes from the dash vents and/or the floor vents. AC; air comes from the dash vents. So I think the plumbing is all in place.

All of the AC system components appear to be original to the car and I'm still using R12.

Question; Is low "push" normal on C4's or do I have a problem I need to address somewhere in the AC or fan/blower system?

If you're reading this and going "Well my friend you have the classic C4 X problem" I would appreciate any help in how to correct it or what corrective steps to take.;help

Thanks in advance for your assistance.

Jeff

 

[bill5674]

well jeff welcome.had a similar problem with my 90.cleaned out abunch of crap from the evaporater.you have to get a little creative with cleaning it. try a search ,i posted about this awhile ago.good luck.....bill

 

[CorvetteArchives]

There are blower motor resistors that increase motor speed with the fan switch. Does the wind increase with each change in the fan switch setting? If one or all becomes corroded than that does effect "wind" speed. There is also a high speed blower motor relay (see here-its for 84 but you'll get idea of how it works http://misterbill.homeip.net/vette/wiring/air%20conditioning.jpg)

btw something you should have is Factory Service Manual..it comes with an Electrical Troubleshooting guide..step by step!! http://www.helminc.com/helm/Result....edia=&mscsid=X883JJ57KM369MEX238XVXVN5S83F9WD

 

[woodpuppy]

Thanks

 

[woodpuppy]

thanks

 

[JimBobC4]

Also, the vents have foam seals behind them. They tend to melt and turn into some kind of nasty black goo. I have removed the old seals from mine and havent really found a good replacement yet.

Ive tried to make new ones out of foam.The attempt was far less than pefect though.

 

[minifridge1138]

I have a similar problem with my 1982. Speeds 1, 2, 3 are almost the same. Speed 4 is definitely faster, but still not a whole lot.

Some people have put in blower motors from newer cars (you probably wouldn't need the fabricating that I would). Others have re-wired their blower to get more juice (I don't know the details).

Good Luck, and let us know if you come up with any ideas.

 

[85dougnash]

woodpuppy. . .

To answer your question, your A/C should blow about as strong as you would expect from a GM vehicle. My '85 (still R12) blows pretty good even considering where I live. (the high is still over 100 here in Sept.) The compressor is starting to make an odd noise at low idle however, but . . . it's late and I am rambling off topic so this post is really a waste of eveybodies time, okay bye.

Foy
Las Vegas

 

[CorvetteArchives]

I agree. Its same force as any GM car. Mine blows as strong as our pontiac.

Is it possibly a vacuum leak not controlling/mixing air to proper ducting?
Maybe its blowing out all the ducts and not just the ones selected or the door is stuck in semi-closed position?
Does the top only blow when its on desfrost or is there air at feet like in bi level too?

 

[woodpuppy]

CA,

Thanks for the reply. I think the vaccum is fine (but I'll double check) and the ducting and plumbing is fine as it blows out of the vents it is supposed to based on the selection (heat, air, defrost, etc...).

It's been a busy weekend and I haven't had time to check the resistors and relay info that you sent me previously, but it is at the top of the list for tomorrow.

Thanks,

Jeff

 

[jmccloud]

A/C wind

If you have the C68 electronic A/C control, the fan speed is controlled by an electronic controller.
More often than not, there's crud on the inlet side of the evaporator. Real PITA to get at and clean. The inlet side is next to the passenger side of the car (not the side toward the center).
Do a search. There are some good pictures of how to access the evaporator and the kinds of crud you'll likely find as well as how to view and diagnose the operation of the temperature doors. The temp doors can screw up the temp but if you've got low flow, it's almost certainly a restricted evaporator or dead fan motor (with C68).

 

[bill5674]

If you have the C68 electronic A/C control, the fan speed is controlled by an electronic controller.
More often than not, there's crud on the inlet side of the evaporator. Real PITA to get at and clean. The inlet side is next to the passenger side of the car (not the side toward the center).
Do a search. There are some good pictures of how to access the evaporator and the kinds of crud you'll likely find as well as how to view and diagnose the operation of the temperature doors. The temp doors can screw up the temp but if you've got low flow, it's almost certainly a restricted evaporator or dead fan motor (with C68).

I think I said the same thing couple of days ago?? keep us posted

 

[woodpuppy]

Status

Thanks to all who have offerd help and advice.

After reading all of your replies and doing research on the CAC web site I have developed a few actionable items I need to do and then evaluate whether or not my problem is solved or regroup and try somethng different.

1. I am going to clean the evaporator.

2. I am going to clean the C68 electronic climate control unit. Found a lot of good info on how to do this on CAC.

I'll post an update once I have completed the above steps.

Thanks again!

 

[John '85]

I agree. Its same force as any GM car. Mine blows as strong as our pontiac.

Is it possibly a vacuum leak not controlling/mixing air to proper ducting?
Maybe its blowing out all the ducts and not just the ones selected or the door is stuck in semi-closed position?
Does the top only blow when its on desfrost or is there air at feet like in bi level too?

Mine blows out of all the vents, is this a vacuum problem? Where should I start looking?

John

 

[woodpuppy]

John,

I'm learning my way through this problem, so I am no expert. I have discovered that it depends whether or not you have the manual climate system or the electronic climate control system, generally refered to by it's RPO - C68 and the model year of the Vette as well.

There is more than just the difference of manual or electronic controls and faceplate than you think. The C68 system has a lot more pieces to the system than the manual system does.

I found a wealth of information on the CAC web site under the C4 Technical and Performance Forums. Do a search for A/C or C68 (if applicable), or climate control.

Here are links to the pages I found to be most helpful to me and my situation, yours may be different;

http://www.corvetteactioncenter.com/forums/showthread.php?t=104916&highlight=evaporator

http://www.batee.com/corvette/acrepair/c68pgmrboard/c68.shtml

http://misterbill.homeip.net/vette/w...nditioning.jpg)

I'll keep posting updates on my progress and whatever the final resolution is and the steps taken to correct the problem when I get to that point.

You may want to create your own new post and ask for help with your problem. Be as descriptive as possible and provide as much info as possible about the AC system in your Vette.

Good luck.

 

[John '85]

woodpuppy,

Thanks for the info. My RPO code for A/C is C60 Manual air conditioning. I took the car to have the system charged, and he also thinks theres a vacuum problem somewhere. I removed the control panel and took a look at all the connections, and they looked fine, I will look in the engine compartment next to see if there are any obvious vacuum line defects.

 

[woodpuppy]

It appears doing some basic maintenance has corrected by AC problem. Yeah, check issue # 2 off of the punch list. Thanks to all who offered support/advice/guidance, it was appreciated. Look soon for my new post on the next problem on my punch list; heater core. Hello weekend!