Thermostat removal?

suberb · Post by **suberb** » Mon Jun 30, 2003 3:25 am

Allright, finally picked up the wagon(90 legacy L) today. It overheated which was a known problem, when it did I cranked the heater to help cool the motor. Well I wasn't getting any heat, this tells me that the thermostat isn't opening. Now how do ya get at the thing, looks like you have to remove the intake. Is this correct? And are my assumptions correct to overheating problem?

Thanks for any input.

magicmike · Post by **magicmike** » Mon Jun 30, 2003 11:52 am

Its not necisarilly your thermostat. Your heater core could be clogged. If there was a radiator leak in the past someone could have used some of that radiator sealer crap and clogged the whole thing up. Take it from me, I made this mistake when I had my first 87' GL sedan. I finally replaced the heater core after 1 winter of freezing my ass off and the heat worked perfectly. I would definately try the thermostat first though, cant hurt. As far as your heater core goes.....I'll pray for you, you DO NOT want to have to change that!

Mike

Post by **Legacy777** » Mon Jun 30, 2003 1:46 pm

Also, there is a little bleed/burp screw on the passenger side of the radiator. It is a very common problem for people not to know of this and therefore not get all the air out of the system and have trapped bubbles, and overheat the engine.

Try the burp screw first. Then the thermostat. If it's not trapped air the first time around, at least you have the knowledge of the burp screw when you do the thermostat.

Brat4by4 · Post by **Brat4by4** » Mon Jun 30, 2003 3:18 pm

Lastly make sure there is enough coolant to actually flow through the heater core. I had that experience. You have to check the coolant level in the inner circuit, not at the radiator. But thermostats are cheap and it's always good to have a new one, so definitely do that first.

ciper · Post by **ciper** » Mon Jun 30, 2003 7:01 pm

The heater has NOTHING to do with the thermostat. The heater core should ALWAYS be hot since it acts as the bypass circuit.

If the heater doesnt blow hot there are only three reasons:
The vent controls are in the wrong position
The coolant isnt hot yet
No coolant is in the core

I suggest checking coolant level then reading about leaking head gaskets on Nasioc. It could be that exhaust is displacing the coolant.

Brat4by4 · Post by **Brat4by4** » Mon Jun 30, 2003 9:56 pm

Good catch ciper. Geez, I just went through all of this not too long ago trying to figure out what was happening to my car before (coolant leak by turbo). No heat can tell you if the water pump is gone because it is not pushing it through the heater core. Overheating can be radiator/thermostat related... overheating AND no heat is most likely coolant and/or water pump related.

ciper · Post by **ciper** » Mon Jun 30, 2003 10:18 pm

Hmm, water pump. Never thought about it not pumping. What happened? Did the fins corrode and disintegrate?

douglas vincent · Post by **douglas vincent** » Mon Jun 30, 2003 10:24 pm

I suspected my waterpump was not working as well so to check it I just yanked the thermostat out and resealed it with no thermostat. You will be able to tell immediately if it works or not because now the water is flowing all the time and even thought the temperature gauge wont warm up for a long time, you will be able to feel the heated water running through the bottom and top radiator hoses. you should be able to tell withen 5 minutes or less.

suberb · Post by **suberb** » Mon Jun 30, 2003 11:24 pm

OK, more detail, the heater starts to blow hot in initial warm up, then when the temp spikes its blows no heat. It has recently had a new water pump radiator and thermostat in trying to solve the overheating problem. I pulled the burp screw and topped off the radiator but didn't cycle the engine while I did it so I will try that. I suspected thermostat because if water isn't cycling through the motor you won't get hot water in your heater core because it is part of the circuit. Perhaps it just needs to be burped to solve the problem.

I have a feeling it could be a head gasket but I don't feel like diving that far into it at the moment given my current project of motor and tranny rebuild for my truck.

And if I could get an answer on the thermo removal that would be great.

evolutionmovement · Post by **evolutionmovement** » Mon Jun 30, 2003 11:29 pm

Being all gloom and doom, there's another possibility: bad head gasket or cracked head. The first year N/A Legacies had a problem with cracked heads and the water pump might not be pumping coolant as air can build up in the housing after driving for a while, causing cavitation and eventually displacing the coolant and greatly reducing coolant flow without the external symptoms of a bad pump. This happens even if you remove the thermostat. I speak from experience, being forced to drive fifty miles in the red with the heat blasting cold air. Damned if the engine didn't kick over on the first crank the next day and run the balls until it reached temperature and then just kept climbing.

Steve

mTk · Post by **mTk** » Mon Jun 30, 2003 11:34 pm

suberb wrote:And if I could get an answer on the thermo removal that would be great.

The thermostat is in the water pump. If you follow the lower radiator hose to the engine block therer is an elbow w/ two bolts that can be removed, once that's out you'll see the thermostat.

MK

ciper · Post by **ciper** » Tue Jul 01, 2003 12:18 am

"I suspected thermostat because if water isn't cycling through the motor you won't get hot water in your heater core because it is part of the circuit"

Thats not correct! Doesnt matter if you SEALED the thermo housing, coolant will flow to the heater core at all times (as long as the coolant level is high enough and the pump is running).

Having heat to start then go cold is probably the number one two sign of exhaust in the coolant passages! The heater is one of the higher points in the system and the air displaces it. Also be careful of sudden temperature drops, this could mean that in reality coolant is now below the temperature sender but the engine is getting exponentially hotter in small areas.

Post by **Legacy777** » Tue Jul 01, 2003 1:50 am

I've never heard the first year legacies had cracking problems. No problems on mine.......

ciper · Post by **ciper** » Tue Jul 01, 2003 2:36 am

You had better be knocking on lots of wood Legacy777

suberb · Post by **suberb** » Tue Jul 01, 2003 6:01 am

mk750 wrote:
suberb wrote:And if I could get an answer on the thermo removal that would be great.
The thermostat is in the water pump. If you follow the lower radiator hose to the engine block therer is an elbow w/ two bolts that can be removed, once that's out you'll see the thermostat.

MK

Thanks for the info, just the answer I was looking for.

Post by **Legacy777** » Tue Jul 01, 2003 1:59 pm

ciper wrote:You had better be knocking on lots of wood Legacy777

I'll live. The way I've driven the car in the past and hadn't had any problems, I'm not too worried. Sure, anything is possible......and if it happens....I'll deal with it.

czo79 · Post by **czo79** » Tue Jul 01, 2003 5:05 pm

The symptoms described are practically word for word what happened to me when my headgasket went on my 97 GT...albeit they were notorious for headgaskets going...
Good luck
Micum

evolutionmovement · Post by **evolutionmovement** » Tue Jul 01, 2003 11:20 pm

I was informed of the cracked head issue with the early Legacys when my head cracked. My car's very early production (Nov '89). It's also N/A (open deck) and I would doubt the turbos had any problem. Of course with the way I drive maybe I should follow my own advice: Don't blame the car, blame the owner.

Steve

Post by **Legacy777** » Tue Jul 01, 2003 11:34 pm

my car was manufactured in 7/89

Not sure if that's after they straightened things out.

ciper · Post by **ciper** » Wed Jul 02, 2003 12:39 am

I have many legacy. Two of which are produced 10 or 11 of 89. Both over 150k and driven VERY HARD (to the point that I have broken many other parts of the car)....

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Thermostat removal?

Thermostat removal?