2001 Oldsmobile Alero

With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both too hot to hold. If they are..........

The heat in that vehicle is controlled by a blend door that regulates heated air flow. it is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

Hi Wrenchtech,
The heater hoses were not to hot to hold, which I thought was odd. I had wondered if there might be some sort of electrical part that might be not letting it circulate properly. I will research a little more when I have the car again. Thanks for the info on the actuator. I am sure it won't have easy access to check it out.

If the hoses are not both hot, then you have a restriction in the heater core.

Thanks wrenchtech. Unless it's a new restriction ( which it had a restriction when I started all of this )I flushed the heater core out backwards then the normal direction and before I reconnected the hoses to the engine and I had normal flow through the heater core at that point. I guess it's possible that something else might have came through the system to restrict it again. No type of stop leak or anything has been used in this cooling system that I am aware of. Thanks again

That doesn't mean the core has good flow. It can be 75% restricted and still act that way.

Oh, good point ! Might just be going in one fitting and right back out the other ? I have never thought about that. I really hate the thought of pulling the core, but I might be looking at that in the near future. I did get some heat after flushing it compared to blowing cold air before I started all of this.
Thanks again for the responce. I guess I know what I will be doing this weekend if not before :( I just hate messing with taking the dash apart unless it's absolutely nessessary !

Would there be a chance I could just disconnect both heater core lines from the engine and dump some radiator flush into them and let it sit for a while, and expect it to clean up the core ? Just a thought.

That's what I would try. I had the same problem with my own Blazer and I eventually got it cleaned out after numerous flushing. It was caked with Dexcool sludge which is probably what yours has too. Flush the rest of the engine too because it may just plug right back up again.

Thanks again !
I do know that they used dexcool until they heard that it was bad on head gaskets and a few other things, so you might be onto to something there. I will probably try flushing again when possible.
What anti-freeze is acceptable for a replacement of the dexcool, when the manufacturer recommends the dexcool ? We have ran that in my wife's Grandam for quite a while ?
Thanks Wrenchtech ! I will post what ends up fixing this problem to help others that encounter this.

There is nothing wrong with Dexcool. The problem is the maintenance on the vehicle. Dexcool is 5 year maximum and it has to be changed and if the system has any leaks, the introduction of air into the system causes big problems. Your car is a 2001 so if that coolant is original, that explains your problem.

I know they changed the antifreeze about a year ago, but may have been after the damage was done already.They have only owned this car a little over a year. It's starting to get to be a headache with all of the repairs it's needed in the past couple of months. The previous owners didn't keep it up to well, I think.

You may have some leaks show up after flushing too. The sludge may be holding them back while it corrodes the metal.

DON'T SAY THAT !!!! Oh well, I know that is a realization that might have to be dealt with....first come first served.