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very little heat. Dealer results...?

4K views 20 replies 8 participants last post by  catera00 
#1 ·
ok, so basically my heater doesnt blow hot air. Only luke warm. No matter how long I drive. It worked last winter. Since then I've had a new head installed, a valve cover gasket replaced, a new a/c compressor installed and replaced both auxilliary water pumps. I took it into the dealer this week and they say the heater core isnt getting warm. They think it could be blockage of some sort and wanted to flush the system for $250. I didnt have them do it though. Any thoughts? Could something actually plug up the heater core?

Heres my previous post about this: http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/115155-how-warm-should-heater-get.html?highlight=heat
 
#3 ·
It heats up quick to its proper operating temp ( almost half way up on the guage) even on rewal cold days, and never overheats.


I dont get it. I gotta be missing something. Every hose related to the cooling system is hot to the touch. How am I not getting warm air? Is there some hidden valve that isnt allowing water into the heater core? Its almost likr the heater bypass valve thing isnt working.
 
#5 ·
I actually just replaced that part. because it started leaking shortly after I replaced the aux. water pump on the radiator. I noticed the heater wasnt working and after poking around the engine bay, I saw the heater circ. pump leaking. I replaced it but the heater still didnt work.

Is there a way to test to see if the pump is working? Both hoses get hot. Infact, the only hose that doesnt get hot is the one coming from the heater bypass valve (Is that the right name) going into the heater core. So it seems that the coolant is getting to that valve but the valve isnt directing it to the heater core. Is there a way to manually operate the valve?
 
#6 ·
The valve is vacuum operated, if you disconnect that little line on it and connect it to a vacuum source, you will be able to open it.

If you then get heat, it will either mean that the valve is bad, or worse, something in the HVAC unit is not working.

Also why did you have a cylinder head replaced?
 
#7 ·
The head was replaced when I had the leaking head gasket replaced. It must have overheated at some point enough to warp the head.(It happened before I bought it) The machine shop couldnt resurface it because it was too warped. It was coverd by a warranty so I diddnt have to pay for it.
 
#9 ·
Well I was wondering about the thermostat and even asked the dealer to change it but they said the cost would be astronomical and that since the car was getting to operating temp, it wasnt bad. I assume its expensive because the thermo. is under the intake somewhere. where is the actuator for the heater core?
 
#13 ·
Ordered a heater control valve today. Usually $90 got it for $63 w/ my bros shop discount. I am cautiously optimistic. Should be fairly simple to replace. Do you have to drain the coolant or can I just kink the hoses? I'll let you guys know if that was the prob.
 
#14 ·
I replaced the heater control valve and still low heat. As before, it will get to 100 after about 10 miles of driving. Which is should be getting hotter much faster. I tested the old valve and it functioned properly. I hooked a vacuum hose to it and the plunger raised. I hooked the vacuum line that goes to the heater control valve and the plunger raised when I set the climate control to 60. And then it went back down when I set it to 90. Which confuses me because I would have thought it should do the opposite. But I hooked a constant vacuum line to the new valve and it still didnt get hot

So the only other thing I can think of is the heater core. All the hoses are hot so there must be a blockage at the heater core right? I am at a loss at this point. But I know I'm not paying $250 to have the heater core flushed like the dealer recommended.
 
#15 ·
Some thoughts, are the hoses on the contol valve in the correct position, is the elec. heater pump working (you replaced it)?, can you get the proper response when you move through the various HVAC modes, is air moving correctly?is there a temp deferential on the control valve hoses which would indicate flow, the vac line holds the valve closed to reduce coolent flow to the core... disconnect the CV hoses and blow some compressed air through the core, see what happens??? let us know.
 
#19 ·
"if it was stuck open, wouldnt it take a long time to warm the motor up? "

In my case it never went to half on the gauge, so yes it would take a long time depending on your definition or warm engine... Mid-gauge is supposed to be engine operating temp (about 180 F), mine got close but never to it...

essentially with the T-Stat open... coolant is continuously flowing through-out the rad...angine and heater core. Normally the T-Stat stays closed UNTIL the engine temp is right and requires cooling.... then it opens, regulates the engine temp...

Found my thread:
http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/96106-low-non-existent-heat.html
 
#20 ·
u made sure ur heater matrix is bled?

when the car is cold, take the filler cap off the header tank and set the fan settngsto blow on the hottest setting.

then start the car and let it tick over, watch the level of the coolent in the header tank and top up as necessary.

once the car hits normal opperateing temp (normally about 95degrees) chuck the cap back on and see if it warms up!
 
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