2012 OB 3.6R - code PO128 - temp sensor question - crossover pipe

[craigmcd]

Howdy, I am working to repair the PO128 error code, and will replace the crossover pipe which runs below the intake manifold. As part of that  project I was going to replace both "sensor assembly - temperature", since part of the problem may be a bad reading of the temp.

There are TWO very similar temperature sensors: 22630 AA140 (36D) which is about $19, and 22630 KA140 (30D) which is $32.

Are these interchangeable? Can I buy the cheap one for both spots?

I am buying all new gaskets for the intake manifold. Is there anything else I will encounter or should consider as I replace this pipe and all the nearby hoses? I do not plan on touching any fuel lines.

Many thanks, Craig

2012 Outback 3.6 R Limited

[1 Lucky Texan]

one may be for the ECU, the other for the gauge  (or light?) - not sure on a 2012...?

[craigmcd]

So they are different ?

[craigmcd]

12 hours ago, 1 Lucky Texan said:

one may be for the ECU, the other for the gauge  (or light?) - not sure on a 2012...?

Lucky T,  I know you have done a few of these repairs. Would it be okay if I just do the crossover pipe (and hoses) for now -- and SKIP replacing the sensors for now?  If I still get the code I can always replace the sensors. I will do the thermostat since I have to drain the coolant anyhow.

[heartless]

6 hours ago, craigmcd said:

Lucky T,  I know you have done a few of these repairs. Would it be okay if I just do the crossover pipe (and hoses) for now -- and SKIP replacing the sensors for now?  If I still get the code I can always replace the sensors. I will do the thermostat since I have to drain the coolant anyhow.

make sure you have a Subaru thermostat! aftermarket t-stats are not recommended.

[1 Lucky Texan]

never done the repair! - only read about it.

If it's the dash temp sensor that's bad, you'd be in 'some' danger not knowing if the engine began overheating. If it's the ECU part of the sensor (if a single sensor, it's a moot distinction as they are in the same housing on newer cars, 2 separate sensore on older cars)) ,the ECU may incorrectly richen or lean the A:F mixture since it will have incorrect data on engine temp.

[Mike104]

It looks like there is only one temperature sensor installed (#22630) on that year.  Not sure why two different part numbers with the price variance though.  Did you put in your VIN to perhaps filter one of them out?

The only difference I can see in the two part numbers is one has a white connector and one has a black connector.  Not sure what impact that has though.

 

Edited October 4, 2019 by Mike104

[craigmcd]

Yes Mike, when I ordered parts online from my local Subaru, I started with the VIN number, and my car showed correctly. As far as I can tell, one is driver side at the front, the other is passenger side at the rear.  In the parts catalog - and I looked a few - the front one is shown as a good photo. However, the back one is shown as a stick drawing, so not helpful. The illustration above does not show the rear one - but I have seen that drawing.

Heartless, I did order a Subi thermostat. Thanks.

Craig

 

[craigmcd]

This is from my official repair manual - the highlighted one is the rear sensor.

[craigmcd]

Here is a different diagram only showing the one coolant sensor.  I will bring this with me to Subaru when I pick up parts tomorrow. Curious

[Rampage]

3rd and 4th pictures.

In the first picture I see the rear of the engine and the second picture I see the front of the engine.

I think I only see one sensor.

Edited October 4, 2019 by Rampage

[Mike104]

According to the picture posted by the OP #7 is an Oil Temperature Sensor  and #12 is an Engine Coolant Temperature Sensor they both appear to be on the left front of the engine

[craigmcd]

10 hours ago, Rampage said:

3rd and 4th pictures.

In the first picture I see the rear of the engine and the second picture I see the front of the engine.

I think I only see one sensor.

Rampage - THANKS - I had considered that I was seeing the engine from two different directions, but without the inclusion of some major components in the diagrams, I was not positive. On another close look, I can see where the transmission bolts on, and the oil filler and coolant inlet. Very helpful - thanks  again. One temp sensor.

[craigmcd]

So I did this repair yesterday and just thought I would do a quick review which might help others with this. My parts list was about $200, which included the black crossover pipe, small rubber hoses, thermostat, manifold gaskets, throttle gasket (not used), rubbery egr gasket (not used) and two jugs of Subaru coolant, but NO sensors. I should have bought the rigid egr gasket which connect the vertical pipe to the egr w two bolts. The repair took me 5.5 hours, which includes a lunch while the radiator drained out. I was working on a hoist. Subaru says I need the coolant sensor KA140, which is the more expensive one. They did not have one in stock. The one special tool I recommend is long plier designed to remove the rubber hoses - they are hard to reach. All the bolts are 8, 10, 12 and 14mm.

The main thing is that you should separate the manifold from the silver fuel lines assembly (4 bolts)  which run in the front and down the sides in an area under the intake manifold. I am NOT talking about the fuel rails which connect the fuel injectors, I did not touch those. Do not loosen or remove the fuel lines or rubber connectors, they are flexible enough to hinge up out of the way. You will take out two bolts so the egr is free of the pipe which runs down to the exhaust manifold area - the little gasket will fall down (it is hard to reassemble, I held it with needle nose pliers until I could get the first bolt started - buy a new gasket, and maybe a spare). Once you get enough vacuum tubes and a couple electrical connections undone, you will be able to tip the manifold / fuel lines back and lift a little. At this time, remove the right side bolt on the fuel line bracket which is hard to reach behind a/c component - the one on the left is super easy. Now wire the manifold back out of the way, and lift the fuel line assembly enough to access below it, but no so much as to twist or tear the rubber fuel lines you are hinging on. You do not need to remove the throttle or the egr valve, just move them with the intake manifold as a whole.

Now is a good time to drain the radiator fluid.

You should now have pretty decent access to the black crossover pipe, which runs left to right directly behind the alternator. It connects 4 rubber hoses, which you should replace (except for the large one in the rear which runs through the firewall - this is where the special pliers will help) - dont cut or damage the original. For the record, I did not see a significant difference between the original and the remodeled crossover pipe, it must be subtle.

On reassembly. Replace the 6 intake manifold gaskets. As you are lowering everything down into place, be sure to install the fuel line screw (front right) while you can still reach it. Lower the whole assembly into place and drop a few bolts into the manifold holes. Before tightening down the manifold, be sure to get that pesky little egr gasket back in place. After that, the rest of the assembly is pretty fast.

I replaced the thermostat, which of course drained more fluid. My refill was just under 6 qts, but I expect to top it off a little today.

So, just plan on plenty of time, don’t drop anything into the engine holes, and make sure to properly “burp” the coolant system by following Subaru’s instructions in the official manual.

I hope that helps someone. I will post a photo from my desktop in a little while.
 

[craigmcd]

Here you are - I highlighted the crossover pipe and the three bolt holes for it. Also, the hard to reach bolt I mentioned, which should be installed early in reassembly.