Heater core replaced, now more issues

281pony · Sep 13, 2009

i replaced the god damn heater core again and now i have even weirder issues.

i am getting NO heat still. i let the car idle, it takes roughly 5 minutes to get warm. it hits 178 on my autometer gauge. then surges to 200, 210 within 2 seconds. i turn on the fan, and it slowly creeps higher. it did this before the heater core swap, but would immidiately drop back to 180 when the thermostat opened once it touched 195-200.

one hose going to the heater core is hot, one is not. im getting no leaks.

the radiator is ice cold. thermostat is less then 2 weeks old, worked great before this. seems weird it went bad without touching it?

what could this be? air in the coolant system? thermostat? all my vents inside the car are now functioning.

any ideas? im about to lose it..

edit; just felt radiator after its been sitting 5 minutes. its barely warm now.

281pony · Sep 14, 2009

im so confused..

i went out and fired it up again. it was down to 160. slightly warm radiator, like room temp. i started it, it slowly went to 180. hit 180, thermostat opened, it fell back down to 176ish.

then slowly went to 180... 182, then i turned on the fan. it worked properly, brought the temp back down. then the air got warm, then fairly hot.. it seemed to stay there, its not smoking hot air. its definately started to work properly though.

was this just air in the lines? should i just burp the system from here? never had to do more with my cooling system aside from a new thermostat. i understand how it all works, but im kinda confused here.

Shaolin Crane · Sep 14, 2009

possibly, did you burp the coolant system when you added the new fluid?

BlownFiveLiter · Sep 14, 2009

That definitely sounds like air in the system. I always jack the front end up nice and high, so I'm absolutely certain it's the highest point and the bubbles will rise.

67coupe · Sep 14, 2009

^ +1

Now that its been through a few heat cycles, check the coolant level. Sounds like it has purged air from the system.

LarsD · Sep 14, 2009

Sounds like air to me.

281pony · Sep 14, 2009

i thought it was air also. it acted fine, then it did it again today when i checked once more.

im going to jack the front end up and let it warm up with no radiator cap.

90lxcoupe · Sep 14, 2009

i always fill myne and start the car with no cap on and fill it up as needed from there. May not be the "right" way but its never failed me

Lawbreaker5.0 · Sep 14, 2009

definitely air in the system

liljoe07 · Sep 14, 2009

90lxcoupe said:
i always fill myne and start the car with no cap on and fill it up as needed from there. May not be the "right" way but its never failed me

X2

Thats how I've always done it. Matter of fact, did Head Gaskets last night. Never got above 176-180° after it was full.

1987stangman · Sep 15, 2009

281pony said:
i replaced the god damn heater core again and now i have even weirder issues.

i am getting NO heat still. i let the car idle, it takes roughly 5 minutes to get warm. it hits 178 on my autometer gauge. then surges to 200, 210 within 2 seconds. i turn on the fan, and it slowly creeps higher. it did this before the heater core swap, but would immidiately drop back to 180 when the thermostat opened once it touched 195-200.

one hose going to the heater core is hot, one is not. im getting no leaks.

the radiator is ice cold. thermostat is less then 2 weeks old, worked great before this. seems weird it went bad without touching it?

what could this be? air in the coolant system? thermostat? all my vents inside the car are now functioning.

any ideas? im about to lose it..

edit; just felt radiator after its been sitting 5 minutes. its barely warm now.

So what happens IF you bypass the heater core with a bypass tube? The same outcome?

281pony · Sep 16, 2009

i had to drive the car in for an alignment. it ran fine, temp didnt surge. ran right where it should be.

however, the heater seemed to fluctuate temp? i would crank it on and it would start semi-hot. then it seemed to almost fade a bit to warm air? the air does not feel as hot as it should by any means.

i am going to burp the system while im replacing my steering rack tomorrow however, could these symptoms indicate air in the system? seems like it since i get somewhat of a temp fluctuation. both heater core lines are hot. radiator is full, thermostat is opening.

LX Tails · Sep 16, 2009

Replace the thermostat and gasket. I had the thermostat housing on mine ground flat too. There should be a check valve (hole) on the t-stat, it should point straight up at the 12 o'clock position. The spring should point toward the engine. A good one will open up gradually. A bad one wont.

P.S. Wise words of wisdom. Use windshield glue to keep the t-stat in place the first time, (in the housing) this is an old redneck-tech tip that made it so much easier.

I had the same exact problems earlier this summer. I thought it was a HG or a faulty water pump. It was just a bad t-stat.

On burping: you might have to take it for a few full temp runs, and keep filling it up. But after that it should be OK.

Heater core replaced, now more issues

281pony

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