Hi everyone, still trying to find an answer to this I think common problem on my 89 TC. Under acceleration, I lose the ac and panel settings on the climate control. I end up with heat and defrost until the engine comes back down in rpms. I think im losing vacuum on the accuators or what have you. I can't seem to find a leak though. Is anyone familiar with this or where the leak may be? my 88 TC also did this but wasn't nearly as bad. thanks
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89 town car heat/ac vacuum issue
- Thread starter gilly2008
- Start date
abe_lincoln78
Active LVC Member
you probably have multiple leaks. The car is now about 20 years old, meaning there's likely serious dry rot compromising your vacuum lines.
Now, before you go ape looking for your leaks keep in mind you're driving a 4000 pound car with a 150 hp engine. When you're accelerating from a light or maintaining speed up a hill you are actually asking for a high percentage of its available power, robing your AC of vacuum.
That said, the first thing you should do is check the item that looks like a giant can of soup on the drivers side fender well and the vacuum line that goes to it. If its rusted out or the line that goes to it is broken, it should be high on your list of things to fix.
After checking the vacuum reservoir, get a butane torch (don't light it) and with the gas on run it along the vacuum lines. If your engine revvs up you've found a leak.
The sooner you fix your leak the better because it will kill your engine. Good luck.
Now, before you go ape looking for your leaks keep in mind you're driving a 4000 pound car with a 150 hp engine. When you're accelerating from a light or maintaining speed up a hill you are actually asking for a high percentage of its available power, robing your AC of vacuum.
That said, the first thing you should do is check the item that looks like a giant can of soup on the drivers side fender well and the vacuum line that goes to it. If its rusted out or the line that goes to it is broken, it should be high on your list of things to fix.
After checking the vacuum reservoir, get a butane torch (don't light it) and with the gas on run it along the vacuum lines. If your engine revvs up you've found a leak.
The sooner you fix your leak the better because it will kill your engine. Good luck.
ok thanks.
I have a spare vacuum reservoir, but the one on the car actually looks better. Could it be bad internally? when I disconnect the line I can hear it let go of the air. will that butane trick work on the lines in the car near the glovebox?
I have a spare vacuum reservoir, but the one on the car actually looks better. Could it be bad internally? when I disconnect the line I can hear it let go of the air. will that butane trick work on the lines in the car near the glovebox?
Mr Wiggl3s
Dedicated LVC Member
It's no leaks... I remember hearing about this but i dont remember what it's from... Someday though try to check the heater core
abe_lincoln78
Active LVC Member
gilly, i think it would, though I'd be concerned about all that butane being inside the car. . . .
The issue you're probably thinking about Mr Wiggl3s is that of the thermostatic valve that moves vacuum to or from the heater door in response to a combination of the cabin air temperature and dash settings. This is the most common climate control problem for '80's TC's, but is not the problem spoken of above. I believe its called the heater control valve, but I can guarantee the guy behind the parts counter at Autozone will have no idea what you're talking about.
If the heater control valve were the problem gilly would simply not have heat when he wants it no matter what the engine condition. That may be the same for AC too, but the most noticeable issue would be no heat. Also, vacuum to the defrost door is sent via a non-variable valve attached to the function selector as opposed to the heater control valve, meaning it doesn't matter whether its bad you will always get air out of the holes you selected on the dash, just not at the right temperature. I've replaced that part on both '80's model towncars I've owned. It was worth it on mine, but will not make a difference for Mr Gilly.
What gilly is describing sounds exactly like the system is being starved of vacuum when the engine is under load.
Gilly, you may want to check the vacuum level at idle with a gauge. I don't remember what the spec is for vacuum but if you find it falling short at idle you'll have confirmed you have a problem.
The issue you're probably thinking about Mr Wiggl3s is that of the thermostatic valve that moves vacuum to or from the heater door in response to a combination of the cabin air temperature and dash settings. This is the most common climate control problem for '80's TC's, but is not the problem spoken of above. I believe its called the heater control valve, but I can guarantee the guy behind the parts counter at Autozone will have no idea what you're talking about.
If the heater control valve were the problem gilly would simply not have heat when he wants it no matter what the engine condition. That may be the same for AC too, but the most noticeable issue would be no heat. Also, vacuum to the defrost door is sent via a non-variable valve attached to the function selector as opposed to the heater control valve, meaning it doesn't matter whether its bad you will always get air out of the holes you selected on the dash, just not at the right temperature. I've replaced that part on both '80's model towncars I've owned. It was worth it on mine, but will not make a difference for Mr Gilly.
What gilly is describing sounds exactly like the system is being starved of vacuum when the engine is under load.
Gilly, you may want to check the vacuum level at idle with a gauge. I don't remember what the spec is for vacuum but if you find it falling short at idle you'll have confirmed you have a problem.