Hello again -

After traveling a few miles in my 99 Legacy, often the heater suddenly stops working and the engine temperature dramatically rises. If I stop the car for a few minutes the engine temp goes down quickly and the heater activates again. What do you suggest please?

I tested the coolant with a hydrometer and the antifreeze is much too weak. (All the floats sank!). Do you think icing initially caused the problem?

Gil

Hello again -

After traveling a few miles in my 99 Legacy, often the heater suddenly stops working and the engine temperature dramatically rises. If I stop the car for a few minutes the engine temp goes down quickly and the heater activates again. What do you suggest please?

I tested the coolant with a hydrometer and the antifreeze is much too weak. (All the floats sank!). Do you think icing initially caused the problem?

Gil

 

My mom's '98 foster did the same thing. The guys at the subaru place said that she blew her head gasket and she had that all replaced. It still acts up on her once in a while. Unfortunately on the days that it is the coldest. Sorry I can't really help. I would love to hear what the real problem is though.

Air lock, the head gasket prolly didn't need to be replaced, but whoever did it, didn't burp the cooling system correctly. Get the air out or you WILL blow the headgasket.

 

Search and you'll find lots of info. I can't do it, my network settings blocks all seaarch functions but Google ... don't ask.

what do you mean by "the heater stops"? it doesn't stay hot, or it shuts off altogether? "heater stops" sounds like the fan quits running...but that doesn't make sense, so i'm thinking you mean you just don't have heat?

 

how is the coolant level? is that okay?

how old is the thermostat - is it a Subaru thermostat?

i'd replace the thermostat and keep an eye on the coolant level.

no leakage anywhere?

I am in agreement with this, you probably need to add more coolant. When engine is cool take off Radiator cap and start engine with heater on, let idle and keep putting more coolant in every time some is sucked down. Their is other ways to do this but this has worked for me. This process will take some time.

Air lock, the head gasket prolly didn't need to be replaced, but whoever did it, didn't burp the cooling system correctly. Get the air out or you WILL blow the headgasket.

 

Search and you'll find lots of info. I can't do it, my network settings blocks all seaarch functions but Google ... don't ask.

Actually he needs to replace his coolant, thats first. Secondly you need to make sure there is no air in the system. As long as he's doping that, replace the radiator cap too.

It's possible that its a HG issue, but i am not feeling it right now.

 

nipper

An easy test for air lock/air on my '90 Legacy was to get the car warmed up and open the bleeder screw/valve on the passenger side of the radiator. If steam comes out, you've got it; if coolant flows out, you don't. Look for a post by Setright to replace/fill the coolant w/the best results.

 

Good luck and hope it's not the HG.

When I said the heater stops I should have said that the heat stops, not the heater fan.

Thanks for your advice I will have a look at the thermostat and flush out and replace the coolant and let you know.

If this is the case then you do have air in the system, you should not have to do anything with the thermostat unless you just want to change it because of age.

When I said the heater stops I should have said that the heat stops, not the heater fan.

Thanks for your advice I will have a look at the thermostat and flush out and replace the coolant and let you know.

I am in agreement with this, you probably need to add more coolant. When engine is cool take off Radiator cap and start engine with heater on, let idle and keep putting more coolant in every time some is sucked down. Their is other ways to do this but this has worked for me. This process will take some time.

 

Thanks tcspeer this worked fine.

Gil