No Heat and NY is cold!

[Haibach boys]

85 sc mostly stock, and has been rruning GREAT! love the little car, (this is for the people that have fallowed my prior nightmares.) any way the car is not prodducing any heat out of the heater, and not exeactly sure why. it has a 185deg thermostat in it, the heater core is not plugged, the cars runs at temp fine, and its full of anti-freeze. and the blower and control swith seems to be working. the only thing im not sure on is there apears to be a vacuum switch at main coolant line that branches to the 2 heater core lines, im wonder if the is stuck closed? also can i bypass the vacuum thing completely? its just nice to at least have a defroster on the NY mornings and evening.

also i have thought about putting my snows on it for the winter and driving all year, if i do that how bad will i be hated?

[Murphy]

yes you can bypass that switch. one goes to the t stat housing, one to the water pump and 2 to the heater core. hook one side of the heater core to the t stat and the toehr side to the water pump

---------- Post added at 07:09 PM ---------- Previous post was at 07:09 PM ----------

In my truck, I have a valve to replace that hose, in the summer i just close the valve so nothing is flowing through the heater core

[turbovanman²]

Do you get any heat or is it just cold air? Check the heater hoses, are they both warm/hot? If one is cold, then that valve could be stuck. Its for the a/c, so when you want MAX A/C, it blocks the coolant flow. There should be no vacuum to it and the actuator should move freely. IF one line is cold, it could be blocked so remove it, you don't need it if you dont' have a/c. If both lines are hot, then you have a plugged heater core or the heat door inside is jammed/broken. One more thing, if your getting lukewarm air, block the rad with some cardboard, I have to block mine or I don't get any heat as it runs too cold in winter, :(

[trannybuster]

JUst because fluid flows through it doesnt mean it isnt plugged somewhat....

[turbovanman²]

JUst because fluid flows through it doesnt mean it isnt plugged somewhat....

I have to CLR mine every year, too lazy to replace it, :lol:

[Haibach boys]

looked at it today briefly. top line is hot and lower is cold, gunna do some further investgateing this week end.

[turbovanman²]

looked at it today briefly. top line is hot and lower is cold, gunna do some further investgateing this week end.

So bad valve or plugged core.

[cordes]

So bad valve or plugged core.

Agreed. My money is on the valve.

You can totally eliminate that valve if you want. It's only there to aid in AC efficiency.

[Aries_Turbo]

also i have thought about putting my snows on it for the winter and driving all year, if i do that how bad will i be hated?

ill show up at your house with a TD preservation posse. :)

brian

[cordes]

ill show up at your house with a TD preservation posse. :)

brian

I'll offer moral support via the internet. I do say that it's beating worthy though.

[Aries_Turbo]

its a super clean car too. :)

[turbovanman²]

Let the beatings commence. :eyebrows:

[cordes]

its a super clean car too. :)

Driving it in the winter is off the table then.

[Haibach boys]

yeah i ended up going to the shop lat night and took the valve off and we now have heat! and im thinking plates are getting tranfered to my diplomat on friday, so the SC will be in storage...or in my shop getting painted???

[trannybuster]

I have to CLR mine every year, too lazy to replace it, :lol:


I had a Shadow that had nearly zero heat, ran some CLR through it and afterwards it was my best vehicle for heat...it works!

[AngelesRunner]

Just repaired a similar problem on my 89 daily driver Horizon. Plenty of blowing, all cold. But a clue was that the blowing all came partially out of the vents and partially from the heater outlets with none from the defroster outlets. When I looked at the under hood heater valve on the two lines to the heater core the vacuum operated plunger was retracted as if vacuum was applied like the system was Heat = OFF. The plunger stayed in the same position when the heat button was pushed in on the dash. No water could flow through the core.

The buttons were balky on the heater control and it was as if the off button did not want to go fully in. Pulled the heater control and it had broken. Pushing the balky buttons had broken off 3 of the melted tabs and the back, vacuum control part had separated from the front mechanical part. Replaced it with the same, good heater control from the 88 Horizon "Hangar Queen" which has donated critical parts one by one to the 89 daily driver.

I would say set your heater control to both positions, On and Off and see if it changes the position of the under hood valve. On mine, I could have pulled off the vacuum line and plugged it and it would have flowed hot water to the heater all winter but as the heater control was broken I would not have had control of the air flow, and would not have had use of the defroster, intolerable condition here.

Engineer by trade, cars by hobby since 1970.
94 Shadow
88 Horizon
89 Horizon
91 Caravan
89 Turbo Voyager
91 Acclaim
92 Acclaim

---------- Post added at 02:25 PM ---------- Previous post was at 02:20 PM ----------

Also, the 91 Caravan's heater core seems to trap sediment but clears up with backflushing. I flush from both sides with Prestone's flushing rig sold at Wal-Mart.

You should not have much problem with one good flushing then good quality antifreeze replaced every 2 to 3 years. If you do I would try just flushing rather than acid. The heater cores are fragile. Look at one at Autozone and see if you want to put acid through it more than once. If you do use an acid don't leave it in there very long. Dissimilar metals are undergoing a chemical reaction and one of them is disappearing until the acid is removed. Trouble is that it is hard to get it all out unless you isolate the heater core by removing both hoses and make really sure you have it ALL flushed out.

[Mudman]

Not meaning to hi-jack this thread, so I'll keep it short.
What is the "procedure" for using CLR? My heat is luke warm and I've checked over everything else in the past, figured I'd try cleaning out the core.

[turbovanman²]

Not meaning to hi-jack this thread, so I'll keep it short.
What is the "procedure" for using CLR? My heat is luke warm and I've checked over everything else in the past, figured I'd try cleaning out the core.

Unplug both heater core hoses, blow it out, then put new hoses on, aprox 2-3 feet worth, then fill up the core with CLR and let it soak for 30-60 mins, depends on how daring you are, lol, then back flush using your water hose. The inlet is the heater hose from the water box up front, the outlet is the hose that goes to the waterpump housing.

NOTE/WARNING, this could induce a leak so proceed at your own risk.

[trannybuster]

Think I went 15mins, then flush.....no leaks :)

[supercrackerbox]

Yet . . .

[turbovanman²]

Yet . . .

On my 7th year doing it, knock on wood, :eyebrows: