Plugged Heater Core.....Again

medicmandan · #1 12-19-2006, 11:23 PM

Today was the first really cold day this winter. Heat was working when I first
warmed up the car. Then it was lukewarm and only gets hot when I rev up the engine or get above 40mph. Got home tonight and sure enough the out hose on the heater core is only lukewarm. I just flushed the core the end of Octobe when I installed a new water pump. Heat has been great up until today.

I figure I will flush it again this weekend. I've read a few comments regarding eliminating that extra bypass before the heater core. Is this the problem from that setup or did the new water pump just stir up some crap and it has finally plugged the core?

mwt878991 · #2 12-20-2006, 07:08 AM

Quote:

Originally Posted by medicmandan

I've read a few comments regarding eliminating that extra bypass before the heater core.

I never heard of eliminating the bypass. One of the problems is they didnt have a bypass and the coolant didnt constantly circulate into the heater core.

Mike

medicmandan · #3 12-20-2006, 09:29 AM

Quote:

Originally Posted by mwt878991

I never heard of eliminating the bypass. One of the problems is they didnt have a bypass and the coolant didnt constantly circulate into the heater core.

Mike

Maybe I was misreading that discussion. How does having a bypass before the heater core make it so there is always coolant flowing through the heater core? Last year when I was having this problem, I clamped the bypass of with some channel locks and I ended up with more heat in the car. The hose I am referring to is the one that branches off between the thermostat and the heater core and then connects on the other side between the heater core and the water pump.

medicmandan · #4 12-20-2006, 10:07 AM

Someone mentioned a service bulleting regarding those hoses but I can't seem to find the discussion.

medicmandan · #5 12-20-2006, 10:17 AM

Would a regular flush from one of the service shops flush the core as well? It's only supposed to get to 15 degrees today. Aweful cold for standing outside with the hose.

dddcccmack · #6 12-20-2006, 10:48 AM

I posted comments on service bulletin two days ago. do a search under my name. this heater problem is becoming my obsetion. There is a post somewere here that suggest intalling a filter. there is a cheep filter on the web by ITT industries. A good fix would be an small elect pump intalled on the IN core line but I dont know of a 12v pump.
Question . . . . anybody know which line is in and which is out to the core? It looks like in is from the pump, out goes to the eng? But my pump side hose is cool and my eng side hose is hot. which tells me the pump side is the out. If the pump side is the return (out of core)then I would assume that pluging or restrickting the bypass would not damage the coolent needed to the eng . . . if its reverst (pump side in to core) then I can see a restriction of the bypass might cause a problem of coolent need at the eng side?? Any opionions? Thanks

medicmandan · #7 12-20-2006, 11:54 AM

Quote:

Originally Posted by dddcccmack

I posted comments on service bulletin two days ago. do a search under my name. this heater problem is becoming my obsetion. There is a post somewere here that suggest intalling a filter. there is a cheep filter on the web by ITT industries. A good fix would be an small elect pump intalled on the IN core line but I dont know of a 12v pump.
Question . . . . anybody know which line is in and which is out to the core? It looks like in is from the pump, out goes to the eng? But my pump side hose is cool and my eng side hose is hot. which tells me the pump side is the out. If the pump side is the return (out of core)then I would assume that pluging or restrickting the bypass would not damage the coolent needed to the eng . . . if its reverst (pump side in to core) then I can see a restriction of the bypass might cause a problem of coolent need at the eng side?? Any opionions? Thanks

I thought that the "in" came from the thermostat, which would mean the pump is the "out" side.

medicmandan · #8 12-20-2006, 02:25 PM

Ran home during lunch and flushed that core again. There wasn't a lot but some brown crud did come out. Seems to be working pretty good now. Hope it stays that way.

That's going to get old having to flush that every 2 months.

shorod · #9 12-20-2006, 02:28 PM

Quote:

Originally Posted by medicmandan

Today was the first really cold day this winter. Heat was working when I first
warmed up the car. Then it was lukewarm and only gets hot when I rev up the engine or get above 40mph. Got home tonight and sure enough the out hose on the heater core is only lukewarm. I just flushed the core the end of Octobe when I installed a new water pump. Heat has been great up until today.

I figure I will flush it again this weekend. I've read a few comments regarding eliminating that extra bypass before the heater core. Is this the problem from that setup or did the new water pump just stir up some crap and it has finally plugged the core?

Did you check the level of the coolant in the radiator/overflow bottle? Since you replaced the water pump recently, you may have trapped air in the cooling system that needs to be purged. That would certainly be the quickest and cheapest place to start.

-Rod

medicmandan · #10 12-20-2006, 02:30 PM

Quote:

Originally Posted by shorod

Did you check the level of the coolant in the radiator/overflow bottle? Since you replaced the water pump recently, you may have trapped air in the cooling system that needs to be purged. That would certainly be the quickest and cheapest place to start.

-Rod

The coolant was right at the top line of the bottle when I shut the car off. How do you purge the system of air? I couldn't find a bleeder screw anywhere. I did notice some bubbling in the bottle after I restarted the car and before I put the cap back on.

shorod · #11 12-20-2006, 11:03 PM

Ooh, how much bubbling? Bubbling coolant with the engine running COULD indicate compression is finding it's way into the cooling system, often through a bad head gasket or cracked head. Let's hope it's not that.

Probably the easiest way to purge the air from the system will be to drive the car and get it warm enough you are sure the thermostat is open, then park on a steep incline, nose up. The air will be displaced to the highest point in the cooling system. As the engine cools down, release the radiator cap. If the level dropped, that is probably due to trapped air. Top the system off again and see if that helps at all.

Some of the Taurii had purge valves, some do not. I don't recall which model years/engines had the purge valves. What year is yours, and which engine?

-Rod

medicmandan · #12 12-20-2006, 11:43 PM

Quote:

Originally Posted by shorod

Ooh, how much bubbling? Bubbling coolant with the engine running COULD indicate compression is finding it's way into the cooling system, often through a bad head gasket or cracked head. Let's hope it's not that.

Probably the easiest way to purge the air from the system will be to drive the car and get it warm enough you are sure the thermostat is open, then park on a steep incline, nose up. The air will be displaced to the highest point in the cooling system. As the engine cools down, release the radiator cap. If the level dropped, that is probably due to trapped air. Top the system off again and see if that helps at all.

Some of the Taurii had purge valves, some do not. I don't recall which model years/engines had the purge valves. What year is yours, and which engine?

-Rod

It wasn't a rolling boil or anything. Just bubbles on the side of the bottle closest to the engine.

I have a 99 SE with the 3.0 engine.

medicmandan · #13 12-20-2006, 11:44 PM

I've had them test the coolant for exhaust gases a couple of times after some overheating events. Both times it came up negative.

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