2011 Legacy Overheating Problems

[Valpo Subbie]

UHG!! Where to begin.

Chasing an overheat issue with this car. 2011 Legacy 2.5 SOHC non turbo engine. Latest is it overheated almost back to home on a test drive and had no heat from the HVAC system despite running HOT and pushing fluid out the overflow. It really seems like it has no coolant flow in the system but I could be wrong on that.

Been having issues with overheating for a bit now. Replaced hoses and t-stat (NON OEM). Replaced radiator as well. All new coolant. New temp sensor as well. Used the head gasket coolant test kit and they appear to be in tact at 153,000 miles.

Fans are coming on but only on low speed. Sitting in the garage I had my Foxwell plugged in to watch to the temps and once it comes up to temp (200ish F) then the fans kick in and do their cooling thing.

Todays plan of attack unless advised differently will be to drop the coolant again and pull the t-stat and test it with hot water. If it is stuck then I will get an OEM unit. Plan to pull the water pump as well and inspect the impeller.

Honestly I am at the limits of what I can think of with this car. Open to suggestions on what to check / test / replace.

Thanks in advance.

 

[Dick Foster]

My money is on the water pump.

 

[Valpo Subbie]

The water pump was my suspicion as well. I have always seen them fail and weep out the shaft seal but not on this car. Its dry at the moment. Gonna try to avoid dumping the radiator on this and pinch off the hoses with hose clamps, trying to avoid another $30 - 40 in coolant when the current coolant is basically new with less than 100 miles on it.

 

[Valpo Subbie]

Wellllllll SUMBITCH!!!!

I am not a new home mechanic but I am a new Subaru mechanic. The plan has just gone to crap. Watched a few videos on the platform that led me to believe I can take the water pump out relatively easily. Went out to look at the car and realized the videos LIED!!! Consulted the FSM and yup the pump is behind the timing belt. EFF ME!!!!

Time to regroup and add $$ to the parts list. Pretty sure the timing belt is original so there is no reason to pull the old belt to replace / inspect the water pump. Time to find a kit that encompasses both. I will go to the local Subaru dealer and get an OEM t-stat to swap all parts out at the same time.

Tired of throwing money at this car. Just put a new engine cradle in it as well.

 

[Valpo Subbie]

Last night I topped off the coolant and started it up to see what I got going on. I did not run it long enough to heat up and open the thermostat but it did produce heat into the heater core and both hoses were getting warm so that tells me the pump is circulating. It looks like a previous owner already had the head gaskets replaced as the gaskets were shiny and not graphite coated black ones. I did the combustion gas test again and no issues. Inspected the underside of the engine and there are no signs of current leaks at the bottoms of the heads. This is making me feel much better, just wish when the repairs were done and I would hope the belt was done then. Tomorrow I plan to change out the t-stat with an OEM and go from there. I will pull the timing inspection plate and see if I can find a name on the belt as well.

Tempted to pay for a CarFax to see what repair info I can find on the car.

 

[scubazteve]

when you refill did you pull a vacuum to pull the coolant backwards thru the thermostat or do the pull a vac on the whole coolant system (i'm less of a fan of that), or just fill and burp?

having no cabin heat then overheating the engine reminds me of the 2010 Pontiac Vibe/Toyota Matrix w/1.8L, and a -30 day even letting it idle for 15min, when driving the cabin heat would not get hot. Got on the highway and the temp gauge still barely moved. then all the sudden the temp gauge went up above normal while on the highway. by the time I pulled off i dont remember if it was steaming or not I think as least coming out the overflow.

I pulled to a dealer for service, after being parked in the bay and "heat soak", topped off with some straight concentrate i bought there, was fine ever since.

^^^what happend with this story there was a small air leak in the system (likely EGR in this case) from either the car cooling sys is not totally sealed and pulled air in when cooling in the evening via vacuum or a small small slight head gasket leak (like small small small bubbles) build up where the coolant wasnt totally full in the head.

If what you say is true I am imagining a small small small combustion leak that puts air into the system, or an air bubble that doesn't get worked out, or a small leak that relieves pressure when hot but then sort of seals when cold and pulls in air.

Since you are going thru the coolant anyways I would just fill with PEAK Global Lifetime ($10/gal for Concentrate) and is the single friendliest coolant you can put in there if you are worried about cost.


is it possible the thermostat is backwards....?

(good lord i ramble when drinking coffee)

in short do these;
- Thermostat (check/replace, compare differences, put the old one back?)
- New OEM radiator cap, no question on that.
-use vacuum source to pull coolant, i think the throttle body maybe higher than the heater core?
- if you really want to "see" flow you can swap out a chuck of hose like for the heater core with clear PVC suction hose... just dont let it get to full temp.. https://www.amazon.com/ZY-hosetube-...8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[Valpo Subbie]

New thermostat did not solve the issue. New radiator, new hoses, new temp sensor, new coolant. The only thing remaining is the water pump but that seems to be working. I know when I pulled the old radiator out there was a lot of funk on the front of it. I would not think that would obstruct the flow. I ran it in the garage to test the thermostat and got it up to 90 C when it opened and then took it around the neighborhood just 2 miles. Almost back home and it lit the temp gauge. That was 120 C which is about 245 F

Oil looks like oil. Did the combustion gas test in the radiator twice now and no signs of a problem. Bottom of the engine at the gasket is dry. The cooling system did push a bunch of coolant into the overflow and pulled it back once cooled but the system did dump its pressure in less than 30 minutes just now.

 

[Valpo Subbie]

Back from a short drive on a cold engine. Coolant was full in the radiator but down on the overflow. Topped off the overflow and went for a drive. First thing I noticed was LOTS of water sloshing noises behind the dash but they subsided as the drive and temp progressed. Hit the pre-overheat flashing temp gauge and my reader was saying 115C so yeah it got toasty. BUT I saw no bubbles in the overflow bottle and never saw the burning coolant fog chasing me on the drive. For now it’s cooling in the driveway parked at an angle with the car nose up. Let it fully cool and try again tomorrow. To see what happens while I await the leak down tester.

At this point I am hoping the issue is trapped air. I normally use my vac fill system to refill the radiator but I could not get a good seal in order to vac the Legacy