Hoping someone can help me. I have a 98 Regal GS with dual climate control. All of a sudden I get no heat. The hose going to the heater core feels hot, even though, I replaced the thermostat with no luck. What else should I be looking for? Any suggestions?

is it blowing air?

is it blowing air?
Yes, It is blowing air. The climate controls seem to be working. Except the air is luke warm, even if you turn it up to 90 degrees. The thermostat had alot of crude on it. I wonder if I have a plugged heater core?

Welcome to AF.

Is this both driver and passenger sides? Possible plugged heater core with sludge but a cooling system flush may be in order. How does the heater core outlet hose feel going back to the tensioner assembly? Check the coolant level at the radiator via peeking in the filler neck and at the reservoir tank. Make sure the engine is cool enough to remove the radiator cap. Also, do you have the original Dex-cool or what it ever replaced at 5 years or 150K miles, whichever comes first.

Welcome to AF.



Is this both driver and passenger sides? Possible plugged heater core with sludge but a cooling system flush may be in order. How does the heater core outlet hose feel going back to the tensioner assembly? Check the coolant level at , the radiator via peeking in the filler neck and at the reservoir tank. Make sure the engine is cool enough to remove the radiator cap. Also, do you have the original Dex-cool or what it ever replaced at 5 years or 150K miles, whichever comes first.

Hi,
Thanks for the reply. This is both sides. It seems like it is plugged. The thermostat was covered with crud. The vehicle has the original Dex-cool in it, with 99,600 miles, I had it from new. The outlet hose is not hot, which leads you to believe it is not circulating through the core.The radiator is full up to the neck.Is there some kind of electronically controlled servo or temperature control valve that controls the water input to the core?

No servo or valve. Coolant is always circulating in and out of the heater core regardless of the temperature actuators which control blend doors to direct heat within the HVAC system.

You are way overdue on Dex-cool replacement and it is sludging causing blockage/stoppage. It should have been replaced back when your Regal turned 5 years old since it is 5 years or 150K miles, whichever comes first. I would get the complete cooling system flushed and possibly consider having the radiator and heater core flushed separately.

Have you been having to add coolant? Hate to say it but if you have- then it's leaking- and could be an intake manifold gasket- or worse a head gasket- start with the flush- What engine?- I assume a 3800- which was part of the big intake manifold fiasco- all those failures were first recognized as "my heater doesn't work"

Have you been having to add coolant? Hate to say it but if you have- then it's leaking- and could be an intake manifold gasket- or worse a head gasket- start with the flush- What engine?- I assume a 3800- which was part of the big intake manifold fiasco- all those failures were first recognized as "my heater doesn't work"

Not really. Assume a 3800? You mean you don't know? FYI. The Regal GS has the L67 Series II 3800 engine and is not susceptible to the infamous upper intake manifold (plenum) issue like the L36 normally aspirated SII 3800 engine. The supercharger is the upper intake manifold. Lower intake gaskets (LIM) possible but uncommon based on my experiences. Supercharger coolant passage o-rings also possible.

I've seen Regals with the 3.1L engine- so I missed the GS part- please forgive me-

Rental car regals used the 3.1L all the time - a chevy engine was cheaper than a Buick engine- but that was back in about '94- things are probably changed now..

I've seen Regals with the 3.1L engine- so I missed the GS part- please forgive me-


Thats understandable so no problem and don't worry about it. True the Regals prior to 1997 came with various GM engine options but the rule of thumb on the '97-'04 models is the GS/GSE has the supercharged L67 SII 3800 and the LS/LSE has the N/A L36 SII 3800. This is one of the few forums where it is almost unnecessary to ask the engine size if the OP posts the model he/she has and if it is a '97 and up. The Vin "M" 3.1L engine was discontinued for use in the Regal by Buick except in the Century.

If you have noticed - I don't pay attention to the forum Car Model titles- I meerly hit the new posts and look for GM products-(as in carlines - W, C/H, N, M/L, etc). I am not a Regal enthusiast or a Grand Prix enthusiast- but I do know all the a/c systems by heart on most all the GM products- so I can't help but pick up on trends that span across the GM car lines and I generically watch for them- a/c related or not. So when I see Regal- I think okay - GM W-car- which includes Century, older ones like- Lumina, Cutlass, Grand Prix, and newer ones, Impala, Monte Carlo, Lucerne, LaCross- mostly built in Oshawa. I do the same with trucks- look for trends across all the truck lines etc... So now you know where I'm coming from.

Welcome to AF.

Is this both driver and passenger sides? Possible plugged heater core with sludge but a cooling system flush may be in order. How does the heater core outlet hose feel going back to the tensioner assembly? Check the coolant level at the radiator via peeking in the filler neck and at the reservoir tank. Make sure the engine is cool enough to remove the radiator cap. Also, do you have the original Dex-cool or what it ever replaced at 5 years or 150K miles, whichever comes first.

Just to follow up on this. My mechanic tried to flush the core twice. The heat came and went twice. He changed the core and all is well.