Temp Change of HVAC system is too low... doesn't get hot enough or cold enough
05-21-2013, 04:32 PM
#1
Racer
Thread Starter
Temp Change of HVAC system is too low... doesn't get hot enough or cold enough
I'm re-doing the carpet in my 87, and want to take care of as many "while you're at its" as possible. Since owning the car, it has been a disappointing performer in the cabin heating and cooling department.
In the winter, the engine temp on the gauge barely creeps up past 1/3. This also causes the heat to not be as hot as I'd like it to be.
In the summer, my back sticks to the seat from sweat if the outside temps go above 70. I'm used to seeing consistent A/C temps of 35 F in my other cars. In the morning, the A/C is sufficiently cold... about 40 F. However, after sitting in the parking lot all day the A/C has a 'Delta T' of about 20 degrees below ambient. The fact that it's ice cold after sitting in the garage leads me to believe that I DON'T have a leak, though I have not yet had it pressure tested.
I should also note that the vacuum lines will need replacing, as the system cannot be switched to top only, bottom only, or a combo of the two. It only works out the window vents and top vents, or the 'square' setting on the switch (or what I think it should be).
Finally, due to sagging motor mounts (my research has shown), heat from the exhaust and transmission enters the cabin near the ashtray area when the windows are open. But that's another issue entirely.
In the winter, the engine temp on the gauge barely creeps up past 1/3. This also causes the heat to not be as hot as I'd like it to be.
In the summer, my back sticks to the seat from sweat if the outside temps go above 70. I'm used to seeing consistent A/C temps of 35 F in my other cars. In the morning, the A/C is sufficiently cold... about 40 F. However, after sitting in the parking lot all day the A/C has a 'Delta T' of about 20 degrees below ambient. The fact that it's ice cold after sitting in the garage leads me to believe that I DON'T have a leak, though I have not yet had it pressure tested.
I should also note that the vacuum lines will need replacing, as the system cannot be switched to top only, bottom only, or a combo of the two. It only works out the window vents and top vents, or the 'square' setting on the switch (or what I think it should be).
Finally, due to sagging motor mounts (my research has shown), heat from the exhaust and transmission enters the cabin near the ashtray area when the windows are open. But that's another issue entirely.
05-21-2013, 07:18 PM
#2
Rennlist Member
Rennlist Site Sponsor
There are at least twenty things that can reduce the cooling effect of the AC. Start by going to our web site, going to tips & links, then Wally's World, then HVAC. Download and print the paper on the HVAC system, and read it a couple of times.
Then start fixing things - that should keep you off the streets and out of trouble for most of the summer...
Then start fixing things - that should keep you off the streets and out of trouble for most of the summer...
05-21-2013, 11:07 PM
#3
Burning Brakes
Hi Traxstar,
I would strongly recommend that you read the following links several times- they helped me a lot.
http://www.dwaynesgarage.norcal928.o...0Procedure.htm
http://www.928gt.com/T-WallyHVAC.aspx
http://jenniskens.livedsl.nl/Technic...ACproblems.htm
http://members.rennlist.com/sharkski...er-HoodPad.htm
https://rennlist.com/forums/928/4650...vaporator.html
http://members.rennlist.com/v1uhoh/air.htm
http://members.rennlist.com/v1uhoh/combflap.htm
All of these write-ups were compiled by people with extensive knowledge of the 928, and each write-up was prepared with great care. They've helped me get one 928's HVAC system in order, and I am re-reading them every night in preparation to do a refurb of my other 928's HVAC system.
I would strongly recommend that you read the following links several times- they helped me a lot.
http://www.dwaynesgarage.norcal928.o...0Procedure.htm
http://www.928gt.com/T-WallyHVAC.aspx
http://jenniskens.livedsl.nl/Technic...ACproblems.htm
http://members.rennlist.com/sharkski...er-HoodPad.htm
https://rennlist.com/forums/928/4650...vaporator.html
http://members.rennlist.com/v1uhoh/air.htm
http://members.rennlist.com/v1uhoh/combflap.htm
All of these write-ups were compiled by people with extensive knowledge of the 928, and each write-up was prepared with great care. They've helped me get one 928's HVAC system in order, and I am re-reading them every night in preparation to do a refurb of my other 928's HVAC system.
