Subaru B9 Trifecta SUV Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
So I am hoping that its not worse case scenario.

What I have searched for:
- these things could have a head warping issue
- possible head gasket

What I see in my vehicle:
- no white smoke or puffing in exhaust
- no issues that I can see with the coolant (loss or bubbles)
- I have not used a coolant tester (but may do that for the $30-40 it will cost me)
- slight rough idle at start-up but goes away after 1-2 minutes
- temp gauge hoovers right at the high temp line with it going in to the RED often but always comes back down
- miss fire (often just pending, but sometimes throws light too) on cylinder 3 (always on same #3 so far)
- can go 1 day or 3 weeks before the pending code or an active code comes back after I clear it

What I am doing now as I don't know if connected or not, but would like opinions:
- Swapping #3 coil to #1 to see if code follows coil pack and that is an isolated coil issue (mileage is 170k)
- If it stays on #3 I will move the injector as well

After the swap above which is free and 30 minutes under the car, for cheap and 1st attempts at a fix, thinking of throwing $100 at it to see:
- OEM thermostat
- Throttle body gasket

Thoughts on anything else.
If really a head gasket, I'm not doing the work as we got the car for my daughter kind of cheap so not worth it.

Anyone use a $20 bottle of head gasket sealer for this "common" situation even if it only buys me a year?

Thanks
 

·
Registered
Joined
·
703 Posts
Wouldn't it be hilarious if we posted on the exact same thing on different threads within minutes of each other?


In short, before doing anything else, check to see if you have a pulse on Cyl 3 injector. If not, pull your ECM and follow the instructions.

If to no avail, replace coolant temp sensor before going any further. It's right next to Cyl 2, easy to access.

Unlikely that a bad HG is causing the misfire, although certainly not impossible. If that's the case, pulling/inspecting plug #3 is an easy way to confirm. If it is the HG, you could try pouring in a couple bottles of Subaru Coolant Conditioner to buy some time depending on how warped the heads are... I'm going on almost a year right now since I first started getting bubbles in the coolant again. Keep the acceleration under 25-50% if you have the Limited (or LCD monitor) with the acceleration gauge, and "burp" / fill the coolant from time to time to keep the problem from getting worse.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Thank I will swap my coil, check the injector, and see if the fault stays on #3 and if so will pull the ECM for the misfire issue.
Also check plugs for the possible HG issue if that could be an issue.

And yes, new coolant temp sender is also easy cheap fix.... Thx
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
So here is what I ended up seeing. After closer review, I did have bubbles in the overflow tank after car was at temp.

And on another post I saw that if I disconnect injector or plug for affected cylinder via the scanner, maybe I could see something else.

Disconnected the #3 inj plug and ran the car. Clearly white smoke coming from passenger side exhaust pipe and then after a few minutes coming from the cat converter so coolant clearly having an issue internally at #3.

I did not pay a lot for the car (as it’s my daughters) so HG repair is out of the question. So I also saw that Subaru started adding “Subaru coolant conditioner” to its maintainer schedule and it’s a HG repair type product.

So yes, I added a bottle of K-seal to the Tribeca’s radiator and topped it off along with the overflow tank.

Ran it for 3 heat cycles, 15 min each with the #3 disabled to prevent too much pressure and then 3 low power 15 min drives with #3 reconnected.

And results so far - temp gauge hasn’t moved past mid range at all and even was below it for portions of the drives.

And it was progressive like the bottle said that it would take 3-5 cycles and keep adding to the plugged area over time. And I did add coolant each time but seemed to be less.

So verdict is still out but I will post an update after next week. I will time the drives and measure coolant added in the hopes I see a trend and eventually do not have to add.

in the meantime, more comfortable with it not hitting temp max just below red line and will see how long it last.
 
1 - 5 of 5 Posts
Top