Niels67

Hi, I chaged the heater core, installed new heater hoses between pump and core and water walve and core. Filled the radiator several times, pumped on the upper lh main hose to get rid of air pockets from the radiator as far as possible. Fluid level is at the fill cap and when engine is running I can see the floud running when filler cap is removed. Hoses to and from heater turn warm to hot but still.... no matter how I currently still manually open and close the lever for the temperature door behind the glove box, there is no real hot or even warm air coming at me into the passenger compartment. The blower works in all positions, ac is without belt -deactivated and when I move the manual lever to heat position i can hear a "pff...." that tells that there is vaccuum in the lines. Vent door opens and defrost door moves as well. Any ideas what could be the reason ? Entrapped air in the heater core and hoses still evident ? Stuck water valve ? But hoses get warm ...and I read that it is open failsafe otherwise the hoses wont get warm... Any hint to check further would be hightly appreciated.. Would love to see some effect of changing the heater core... what a job...
Thanks, Niels

joe_padavano

The first question is, with the engine warmed up, are both heater hoses hot to the touch? If yes, then my money is on incorrectly routed vacuum hoses.

Niels67

Thanks Joe, I will check more detailed but I connected the vac hoses as it was before removing the heater assy under the dash to change the heater core so how can the vac be a problem ? You mean because of the water valve possibly ? Is there a good way to check the water valve for operation ? To answer your question, yes, with engine warmed up both hoses are warm to touch if this is what "to the touch means". Not hot but both are warm, the feeding one a bit more than the going one... they are different diameter and can I mix them up ?
It may sound stupid to ask but really knowing a bit I feel a bit lost about why the heater core does NOT get hot with this.. I would love to drill a hole in the highest section of the hose to see if there is no air entrapped honestly but....

2blu442

It sounds like you replaced the valve that screws into the back corner of the intake manifold. Do you still have the old one? If so is it in good enough condition that you can put it back in to see if that fixes your problem.

Joe, my memory may be wrong. But I thought there were more than one types of this valve, one that opens opposite of the other. If that's true could Niels have purchased the wrong one? So it's not opening when it should?

John

Yellowstatue

One type is normally closed and the other normally open with vacuum on. Depends on which year, which era. On an 80's Regency it is normally closed with vacuum on.

Niels67

Thanks again guys and I have to say how much i appreciate your support no matter what, its really great and I will hopefully soon be able to also give good advices but as knowledge increases the tinge comes to do so.... As for my heater problem I have NOT replaced any valve yet. Just the heater core came new and both hoses connecting to it where installed as they were simply cut off. The car cam from LA and I guess no one needed a heating there. Here in Hamburg I do ;-) Tomorrow I will see if the hot water valve at the top rear of the engine has vacuum and if it is in open or closed by pulling off the hose and starting the engine to see if coolant flows from it... if so the only chance is there is a air bubble entrapped in the heater core that avoids it from getting hot coolant.

Niels67

Ok, checked the vacuum line and found that there is no vacuum at the water valve I believe white striped line even if I set the lever at the control to heat. Question now, is the water valve open or closed without vaccuum applied to the membrane there ? Cheers, Niels

Niels67

Found this post https://classicoldsmobile.com/forums...rol-valve.html and now I would want to ask if someone had repaired the water valve when it was found stuck closed..

76olds

I replaced the heater core last spring in my 76, I had a hard time getting my heater box to seal properly back in place, this prevented heat as well. After I had the heater box in place without insulation in the way I had heat. Hope this helps.
Eric