thermostat stuck?

[0perose]

I drove almost 100 miles on saturday... got back into the town where I live (10 miles from home)... stopped to see my girlfriend at work for about an hour..

left there, and headed home.. about 5 miles into the trip, I was following behind a slow moving minivan on a downhill grade in a 35mph zone.. noticed temp gauge starting to rise.. turned on the heater, and it was blowing ice cold. temp gauge still rising, I pulled over and shut the car off. let it cool down to about 1/4 way up the temp gauge (usually holds halfway under normal operation)

after it had cooled "sufficiently" I put some more coolant in because it had boiled some out of somewhere.. no cracked hoses or anything like that, radiator was cold but fan was running.

hopped back in the car, and drove less than a mile before the same thing happend (5 miles away from home)

let it cool down again, made it another mile, and the temp gauge started going up. pulled over, let it cool down, and made it another mile. repeated this all the way home, with temp gauge starting to climb after a mile, and me pulling over to let it cool down.

finally got home, pounded some beers, and went to sleep. I'd been working on the xt6 all day and really didn't feel like digging into the legacy.

woke up sunday, and called dad to see if he concurred with my diagnosis of a stuck thermostat. he said "yank it out and drive around.. see if it happens again"

it was sunday so I couldn't get a thermostat from the dealer, and I didn' t have a car to drive if I wanted to.

I took the thermostat housing off, and took out the thermostat. put it all back together, but didn't have any RTV or a new gasket

after I got it back together, I started putting coolant back in and the bastard was leaking.

took it apart and slapped some "household silicone" on the mating surfaces to see if that would help.... when reinstalling, one of the bolts twisted off because it was bent for some reason......

now I'm driving a '94 buick with 36k miles and an expired inspection that I borrowed from my friend that got hauled off to the physciatric center...

but my question is..... did the thermostat stick shut?

(planning on going to dealer today on break to get thermostat and gasket.. and some RTV from the auto parts store.. then get a bolt and put it back together)

[0perose]

7 views no replies!!! if it's not the thermostat I'd rather not buy one on my lunch break in 20 minutes LOL

[Splinter]

I had similar problems a few times while I was going through my coolant system nightmare.

I had air trapped in a hose somewhere, everything fixed itself after I took a speedbump way too fast.


I'd imagine that a stuck thermostat would do about the same thing.

[vrg3]

It could be the thermostat, yes. You really should use Subaru thermostats, since aftermarket ones don't always fit right and are more likely to fail by seizing shut than OEM ones.

But if you somehow leaked a bunch of coolant before this whole thing started, it could be air stuck in the system, like Splinter's saying. You probably didn't manage to burp the air out when you topped the level off, right? What's the level been doing lately?

[0perose]

I didn't notice any coolant leak before this happened... to be honest I haven't checked the coolant level in a while... but the first time the car overheated on saturday, when I pulled over, I popped the cap on the overflow and it was full... when the car had cooled down to about 1/4 of the temp gauge, I checked again and it was almost empty. I put enough in to get it back to "full" and let it sit some more and it sucked a bunch of that down in as it cooled some more...

I do plan on using an OEM thermostat, that's why I didn't hitch a ride to town on sunday... I could've gotten an autozone or advanced auto version, but I've heard they don't seat right and fail often, so I figured I would wait until today to get one from the dealer with a new gasket...

I'll put everything back together with a new thermostat and gasket, hopefully it won't leak, then I'll burp it and see if it overheats

thanks guys

[0perose]

just got hosed for $17 by the dealer for a thermostat and gasket, and they didn't even have the bolts for the housing...

hope it's not a weird thread because I really don't feel like rethreading it

[vrg3]

It's a bit high, but if it saves your engine...

I am pretty sure the threads are plain old M6x1.0. They're just fairly long.

[0perose]

cool

[douglas vincent]

If you were blowing cold air, that means there wasnt enough coolant in the system to make it to the heater core. While I hope for your sake it was the thermostat, I suspect that isnt the problem.

[0perose]

doug wins with his diagnosis of "it's not the thermostat"


got a new noise, though, once I got it all back together and running.. before it overheated again..

nasty bearing noise from front of engine that increases directly with engine rpm

....water pump failure?

....clogged heater core?

what do YOU think?! (I'm drivin' a buick man!!)

[Splinter]

I'd vote for an airpocket in the system somewhere

A blocked heater core shouldnt make the car over heat, just the heater not work.

You could probably try bypassing the heater core with a straight through hose and see if that fixes the problem.

[0perose]

You could probably try bypassing the heater core with a straight through hose and see if that fixes the problem.

my thoughts exactly.... but I'm leaning towards the water pump... how "hard" should the upper radiator hose be with the car running (with regards to pressure from coolant being pumped through?)

with the car running, before it overheated, the upper radiator hose was getting hot, but it was still almost as "squishy" as it was with the car not running.. I figured there would be more pressure in there... brand new radiator hose a couple thousand miles ago btw, so it's still pretty pliable...


I just don't see why there would be an air pocket in the cooling system all of the sudden?

what's the "recommended" burping procedure? I couldn't get any more coolant to go in


<edit> also, how hard would it be to bypass the heater core? could I use the existing hoses? what are the fittings it uses to connect? (sorry, at work right now, not in front of the car)

[Legacy777]

Are you bleeding the air out of the cooling system correctly?

Are you opening the bleeder screw on the passenger side of the radiator. (assuming you have a n/a engine)

[0perose]

Are you bleeding the air out of the cooling system correctly?

Are you opening the bleeder screw on the passenger side of the radiator. (assuming you have a n/a engine)

yes, I completely removed the bleeder screw on the pass. side when adding coolant. let it sit for 10 min, put the bleeder screw back in, started it up for 5min, couldn't get any more coolant in. let it sit another 10 with bleeder screw out, and still couldn't get any more coolant in

[Richard]

Whare is this supposed bleeder screw located?

[Splinter]

Whare is this supposed bleeder screw located?

Its only on N/A rads

[0perose]

so I guess that means tear into the water pump eh?

[0perose]

last night my friend matt came and drank wine with me.. then this morning before work we took out the fans, took off the belts, and removed the timing belt covers.. didn't have time to do anything else because I was hung over and woke up late

[entirelyturbo]

When you remove the bleeder screw, you're supposed to keep pouring coolant in until you see it come out of the hole for that bleeder screw. THEN all the air bubbles are out.

[0perose]

I couldn't pour coolant in until it came out the bleeder screw, because it wouldn't go down the filler neck anymore. the filler neck was full. I guess I could have added it through the bleeder screw, but it was at the bottom of the threads already, iirc. and like I said, I let it sit like that for 10min, then started the car for 5, and let it sit again for 10, and the filler neck of the radiator was still full and the coolant was still at the bottom of the threads on the bleeder screw....

how could I add more?

guess it doesn't matter now as the car is torn apart.