Subaru Outback Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 20 of 21 Posts

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #1
I've had my outback for about three months, and I had noticed some peculiarities about the way the heater and engine temperature acted. Once it got cold, the engine took forever to warm up, and the heater would only blow hot when the throttle was open. I chalked this up to a thermostat issue, and boy was I right. When I pulled the old one out, there was nothing but the bracket! The rest of the valve assembly was gone! But now I've replaced it with a thermostat that I've tested and know that it works, and I now get no heat blowing at all and the engine overheats after a few minutes of driving. I'm afraid that there is some kind of blockage but I don't know where to begin looking. Please help save my baby!
 

·
Registered
Joined
·
22,802 Posts
I've had my outback for about three months, and I had noticed some peculiarities about the way the heater and engine temperature acted. Once it got cold, the engine took forever to warm up, and the heater would only blow hot when the throttle was open. I chalked this up to a thermostat issue, and boy was I right. When I pulled the old one out, there was nothing but the bracket! The rest of the valve assembly was gone! But now I've replaced it with a thermostat that I've tested and know that it works, and I now get no heat blowing at all and the engine overheats after a few minutes of driving. I'm afraid that there is some kind of blockage but I don't know where to begin looking. Please help save my baby!
#1 NEVER EVER use a parts store off the shelf thermostat for the subaru. Only Dealer sold OEM thermostats. Very well known issue which causes lots of issues and costly over heats etc.

#2 Unscrupulous sellers will remove the Tstats if the cooling system is suffering some type of issue most commonly a HG leak which allows air into the system and causes the Tstat to close up in air pockets.

So did you use an official subaru Tstat? Yes or No? If no go to your local subaru dealer and get one. Start with that.

Make sure you burp the car well - ie idle it with the radiator cap off and top it up as the air in the system is worked out. Then see how things go
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #4
Ok, no parts store stats, roger. I'll give burping a try and get back to you. Thank you!
 

·
Registered
2013 OB 3.6R Limited, Black Silica
Joined
·
383 Posts
Never seen a Subaru thermostat to know if it's possible, but have seen more than one person put them in upside down in other makes.
 

·
Registered
2014 OBW 3.6R Limited, 1997 OBW 2.5L Auto (sold, but not forgotten), and 1991 Ford F150
Joined
·
1,525 Posts
Never seen a Subaru thermostat to know if it's possible, but have seen more than one person put them in upside down in other makes.
OEM Subaru ones are too long to install upside down ... the shorter aftermarket ones can be, though.
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #7
Yeah I made sure to double check which way to put it back in. But just to be sure, the spring and valve go up into the engine side and the bracket prongs go towards the hose in the bottom right?
 

·
Registered
2013 OB 3.6R Limited, Black Silica
Joined
·
383 Posts
My first subaru so I won't say for sure. Need one of the others here to answer for you.
 

·
Registered
Joined
·
288 Posts
......... But just to be sure, the spring and valve go up into the engine side and the bracket prongs go towards the hose in the bottom right?
^Yes.

Stant's new Xacstat #48457 is a direct match for the oem unit.

O.
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #10
Ok. So I burped her until she wouldn't burp anymore, still no luck. The issue definitely stems from outflow. The hose from the top of the radiator leading into the engine got hot once the engine was warm, but the hose leading from the thermostat back into the radiator was cold. Any thoughts?
 

·
Registered
2013 OB 3.6R Limited, Black Silica
Joined
·
383 Posts
First thing to mind is, you said the old thermostat was missing the guts. Did something flow down and cause a blockage?can you run without the new thermostat to see if there is flow and isolate the new thermostat as an issue?
 

·
Registered
Joined
·
22,802 Posts
Ok. So I burped her until she wouldn't burp anymore, still no luck. The issue definitely stems from outflow. The hose from the top of the radiator leading into the engine got hot once the engine was warm, but the hose leading from the thermostat back into the radiator was cold. Any thoughts?
Are your running the OEM Tstat? I wasn't clear if that was the case or not?
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #13
Still using the parts store stat. I can't make it to a subie dealer until tomorrow. Running without the stat was my next thought to see if there was something up stream blocking flow. I don't think that the guts could have gone anywhere. I checked the inside of the block just above the stat housing and it was clear, and don't think that any of it could have gone up against the flow, or gotten past the cage of the bracket. We'll see what comes of the run without the stat.
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #14
Ok, the test went exactly how I didn't want. Nothing comes out of the thermostat port when it runs. When the throttle is applied a little bit trickles out, but that's all. I'm at a bit of a loss. Could something be blocking the flow somewhere inside the coolant channels? Tomorrow I may close it up without a stat and see if still runs like it has before.
 

·
Registered
Joined
·
22,802 Posts
For sure dont even bother messing with the parts store tstat. That will cause you heart burn and problems on its own. Lack of coolant flow? Busted pump vains caused by iced up coolant?
 

·
Registered
01 outback 2.5h4 5mt 217k
Joined
·
8 Posts
a trickle flow is scarey as all heck. First thing I would look at is a bad water pump.. and if that is ok... then I would be doing a test to see if anything head or blockwise is cracked and causing issues in that manner.:(
 

·
Premium Member
01 VDC, 05 R Sedan, 06 BAJA EJ257
Joined
·
15,462 Posts
+1 on the water pump.

Without removing the front cover, you can remove the upper hose from the radiator, remove the thermostat housing and run a hose through the upper hose. If it comes out the bottom, get yourself a timing belt kit and a water pump.

If it comes to a TB and pump, Gates has a good kit with pulleys and any new water pump from the aftermarket will suffice. The thermostat, definitely stick with the OE from Subaru. Its only $25 with the seal. The belt tensioner for this year is costly, but an aftermarket will work for this also. It may be available with the kit by now. I haven't needed to get on for a 2.5 older than 01 for a while.
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #18
OK, update. I unhooked the upper hose and ran water through the block, and it flushed straight through to the bottom no problem. So I guess its looking like the water pump eh?
 

·
Registered
1998 outback 2.5
Joined
·
9 Posts
Discussion Starter #19
Alright, now I put in an OEM thermostat, burped the system back full, still overheating. So its really pointing towards the water pump theory. :( Any handy tips for that I should know since I've never worked on subarus before?
 

·
Premium Member
01 VDC, 05 R Sedan, 06 BAJA EJ257
Joined
·
15,462 Posts
If you have done repairs on other vehicles, have tools, mechnically inclined, can read and follow printed instruction, its gravy.

I will give you a tip. If you have access to a 3/8 impact wrench and air, it makes removal of the crank bolt much easier. And, take the radiator and fans out for more workspace.
 
1 - 20 of 21 Posts
Top