Here is a quick synopsis of the problem, its a 87 Bird with a 3.8 and 160k miles. Got up this am to a horrid -20 started the car to let it warm up before heading off to find some people. While driving back from about a 30 mile trip I said to my self, self its still pretty dam cold in here. Got home and checked figuring heater core or head gasket or something else equally fatal. Here is where it gets weird, everything seems fine at this point but the only thing I noticed is that the a/c compressor clutch doesnt engage. It used to engage as I would hear it and honestly it engaged more often than I thought it should. So does anyone think there might be a connection between that and my sudden lack of heat? or any other suggestions. Thanks in advance for any and all ideas. :bowdown:
Blend door frozen/stuck open?
Assuming you have sufficient coolant, I'd go with Chuck's guess.
The A/C's low pressure cutoff switch opens ~18-22 psi. This occurs around 20-25 degrees for R-134a. Thus your A/C clutch will never engage blow that temperature range.
Stuck thermostat?, low fluid in rad. not getting hot enough,
same as first answer. not sure why the ac isn't cycling. -20 is cold.
Coolant is full, and level in overflow bottle is adequate as well. It did warm up to a whole 10 by days end. Man I hate it here. Hopefully its a stuck blend door as everything was fine the day before.
What did your temp gauge read? If it was on C then its probably a thermostat.
Could be frozen, or even slushy (slush would still flow through the engine but would clog the heater core), too, if the coolant isn't up to snuff.
mine has a bad thermostat, and I only get to the second bar on the digital dash. Its up to 40 today. It still gets warm, compared to the outside air, but nothing like it should do.
Ok, quick update. Its nearly +20 today coolant level is fine, overflow bottle is fine. I ran the car with the rad cap off for a bit and I dont see a lot of flow which leads me to believe something is plugged but I am now getting heat and defrost. Temp guage reads normal as it always does but of course it is just a factory guage
You won't see any flow in the rad until the T-stat opens. If something was plugging colant flow to the rad you'd have the opposite problem from what you've got - you'd have too much heat.
If it's working now that it's warmer I'm leaning toward my first suggestion: Slush in the coolant. I'd strongly recommend checking the coolant with a tester, because if it got cold enough to slush at -20 it'll freeze solid at -30, which will destroy your engine (and heater core, and rad).