heater tech or tbl

[Fuzpile]

'97 Legacy. No big deal. The weather has been blistering cold lately....

Heater valves redirect heated coolant thru the core, nbd. The extremity to how they do it with EJ22 (for they run very cool) is that they cut the loop so far to get heat out of the engine that the Fan comes on? Seriously. The engine runs fine and not hot except there is a little stink of Other parts being heated. So they are cooking one part to give me heat to where the fan comes on? I rarely does that in summer. I checked already the overflow canister which hasn't moved in months so remove the rad cap to see it's to the top.

That sorta computes because these are cool running. Any thoughts, anyone else's fan come on. ?

[nipper]

i have absolutly no idea what you are talking about, but that has never stopped me before.

 

Cars stopped using "heater valves" ages ago. They now use mixing or blend doors in the HVAC system to control temp and air flow. There is coolant constantly flowing through the heater core.

 

 

Maybe you can gear your question towards that. By fan I am going to assume you mean your main radiator fan?

 

In winter you may have things run that do not normally run in hot weather unless needed. This is done to keep them from seizing over winter. Ac compressors used to do this on some cars, along with fans etc affected by cold weather.

[hankosolder2]

Do you have the heater controls set to defrost or heat/defrost? If so, the AC compressor runs (as Nipper noted) to dehumidify the air in the cabin to reduce fogging. When the AC compressor runs, the radiator fans must run to pull air through the AC condenser.

[Fairtax4me]

Cars stopped using "heater valves" ages ago.

Nah, plenty of modern cars still have valves on the heater core hoses.

 

If the main cooling fan is coming on I would suspect the thermostat is faulty, or the bypass pipe or heater core is partially clogged.

 

Subaru cooling systems actually use the heater core as part of the bypass. Coolant is routed from the crossover, through the core, then to the back side of the thermostat. The idea is that the coolant is still warm enough when it reaches the thermostat housing, that it helps keep the thermostat open when the coolant flowing in from the radiator is below the thermostats opening temperature.

Improper coolant flow due to blockage would result in excessive heat being draw away from the coolant in the radiator and heater cores. Yet coolant inside the engine is still hot enough that it trips the fan.

[nipper]

Actually I havent see one specd out since the begnining of the OBDII cars. They usually are pricey to make as compared to a cheap liutlle plastic flapper door. Just iout of curiosity I would like to see a few.

 

I also wonder if he may be having a sticking thermostat.

[Fuzpile]

Thanks guys. I'm going to have to think about some things you said. The compressor wasn't on to my knowledge--although that's where i'm getting to if the fan fan came on. It was just the heat control turned way up and upper over heating worked great. That could be really simple and makes sense.

[nipper]

Thanks guys. I'm going to have to think about some things you said. The compressor wasn't on to my knowledge--although that's where i'm getting to if the fan fan came on. It was just the heat control turned way up and upper over heating worked great. That could be really simple and makes sense.

 

 

Then someplace we have failed you. We simply cant have things making sense in the last minutes of the unofficial i hate window thread time frame.

 

It may be autocycling just to keep itself from freezing over winter. Also some cars do have the compressor come on at startup just to get the lubricant in the coolant to circulate.

[Fuzpile]

I read it more and need thank you more. I'll be watching for this blockage stuff later. They are a different critter to me.

[Fairtax4me]

Actually I havent see one specd out since the begnining of the OBDII cars. They usually are pricey to make as compared to a cheap liutlle plastic flapper door. Just iout of curiosity I would like to see a few.

 

I also wonder if he may be having a sticking thermostat.

Off the top of my head, Lincoln, Jaguar use them. Mercedes Benz. Wanna say VW/Audi as well.

And yes, they are typically quite pricey.

This wonderfully byooteefull contraption:

The Lincoln part (motorcraft) typically ran about $300 from a dealer, but it was such a common failure the after market picked it up and Rockauto now sells it for $170. Probably more from a local parts supplier.

[nipper]

Cool. i just like to keep my mental database going.

 

well no pun meant cool kind of thing.

[Fuzpile]

I did say tech or trouble. If I was to sit here and think I know what you do then i'm an @hole yet there are other things. Just a passenger in a Subie with friends along the way. I hope to expire some knowledge along the way. because if I don't the input will destroy the atmosphere. emmisions

[Fuzpile]

Then again F'tax has displayed some along the line which could do this. It's Flyin great if you look at all the inputs and how they are governed by sensors. Remember this was similar to washing machine hot and cold valves and the solenoids there, triggered by timers. Never really got into that too much.