@Subharu Welcome to the forum from DFW, TX.

Several questions/issues come to mind:

1. Is the vehicle still under warranty from Subaru? IMHO you should have paid the $150 for diagnostic fee.
2. Why is there soooo much coolant stains outside the radiator?
3. Did anyone check the radiator cap?
4. Coolant level should be checked cold and at the high mark in the plastic coolant bottle.
5. Is the mechanic you took the vehicle to have worked done a Subaru Specialist or familiar with Subaru's.
6. CEL? What code was read? What was determined to have triggered to CEL?

IMHO, I would NOT trust your mechanic that you took this vehicle to. Something is not adding up.

 

Thanks @bman400 for the question.
1. Since i didn't bought the extended warranty. my assumption was no more warranty.
2. I don't know, most properly the mechanic, either at the dealer or the one that fixed check engine. This is the first time i open up the cap.
3. Yes i checked when it was cold. Car had been sitting on driveway more than 4/5 hrs.
4. i have seen him working on forester. when i took my car to him.
5. code was P2682 / P26A3

 

So, the Thermo Control Valve (AKA bypass valve) was covered under your power train warranty, which goes to 5/years/60,000 miles. You were way past that when the problem occurred, so yeah, no further warranty coverage without an extended warranty. The price you paid for the repair wasn't out of line.

The radiator is a separate, probably related, issue. What you saw is not normal. Hopefully your mechanic simply did a sloppy/poor job refilling the system, and what you saw is a result of that. Worst case is the system is leaking from somewhere. Any puddles under the car?

Here's what I would do. Top off the tank like you planned, AND fill the radiator, then drive until the engine is fully warmed up. Run the heater as well for a bit. After it fully cools, check the reservoir fluid level. You'll probably have to add more fluid, maybe 3-4 times. Repeat the drive-cool-refill process until you you don't need to (i.e. the reservoir is at the full mark after everything has cooled). If you need to keep adding fluid day after day, and the amount you need to add each time isn't getting smaller, pay a visit to your mechanic. The coolant is leaking somewhere.

You may want to clean up those areas where there is coolant residue. That will make it easier to spot a leak.

Your pictures make it look like the radiator cap could be leaking, since there's residue everywhere. Is the seal in good shape? There's a whiteish area in the six o'clock position of your picture. Is that just a reflection?

 

@boureesub yea it seems and hopefully it's just poor job. I don't see any puddle underneath the car.
Will update on it once i get the coolant and follow the procedure. Will definitely clean those area.
Thanks again

 

Subaru covered my thermo control valve at 85,000 miles without questions. I do not have an extended warranty. You may have had luck getting Subaru to cover the repair at a dealer, but not likely at an independent shop.

I would claim the problem under the federal emissions warranty that goes to 80k miles…

 

Hi guys,
Yesterday morning, while driving to work (approx. 33 miles) the whole time there was no heat even though I have the heat on maximum. At that time I have yet to fill the coolant. So later that evening , I fill the coolant both the reservoir (upto the full mark) and the radiator. I squeeze the hose, the top one, to let the air out . After that I run engine for few min. until the engine warm up with heat on to the maximum. And in-between rev up a little bit. Turn of the engine . And this is what I saw

Is that normal?
This morning, with topped of coolant. The heat came back after 5-10 min. I let the engine to cool of for like 3 hrs or so. Upon checking reservoir tank, it was empty like below low. And this is how the bay looks.

I topped off the reservoir tank back to the full again. Drove for like 35 min. or so. let the engine cool for like 2-3 hrs. and check the reservoir tank and this time it had dropped probably like an inch or so from the full marked and I didn't see any wet spot underneath the fan ( the same spot i took picture of earlier). I'll check again tomorrow to see the level of coolant in reservoir and how it all look in bay.
Thanks

 

There shouldn't be any wet spots, unless you spilled a bit during the refill?

 

I did spill a bit while when taking out the funnel after running engine for while to let the air out.

UPDATE: 1
After topping off the reservoir last night. This morning after reaching work, I checked the engine right after I parked the car. Reservoir had dropped like a centimeter or two. And no wet spot like it was before. Seems like it is trying to even out the coolant level in the system. I may be wrong ..

 

Hey all, just wanted to share recent experience. I have a 2019 Subaru Forester with 48,000 miles and I just went over the five-year mark for the warranty. I got the p2682 code and while driving to the dealership, blue cold engine indicator came on. Anyways, they said it was the thermal control valve and Subaru extended the warranty on this. They didn’t say how long or anything, but mine was covered. After reading all the threads, I was worried whether it would be covered or not, but just so everyone knows, there’s a good chance it is covered. Thanks!