Dear All,

I purchased a used Subaru from a private party a couple of months back. Within weeks the CEL light came on. Took it to the dealer. They diagnosed a faulty plug wire. They replaced only one of the wires. Total cost: $140. Two weeks later the light comes back again, same code. I take the car back to the dealership. Two hours or so of the mechanic scratching his head and getting input from other mechanics in the shop, I am told the car needs a new head gasket. He had taken out the out exhaust manifolds (I suppose) and showed to me the valves in the back (nearest to the driver) in a reddish brown color, while those closer to the front of the car were whitish. Estimate: $1600+taxes + etc..= $2000. (they were cutting me a deal at $75/hour). I said I'd think about it. Drove it for a few days. One morning the light had disappeared. It showed up again a few days later. And that's been hapening ever since. I carefully monitor the engine temperature and I have never seen it go up and down. As far as I can tell, by the sound and the feel of the engine, the car runs fine.

 

Could anyone tell me how the cylinders are numbered? is #1 the front one on the passenger side, #2 front on the driver side, #3 back driver side, and #4 back passenger side?

 

Thanks for your ideas

I believe the pattern is like this:

 

 

Front of car

2-1

4-3

Rear of car

 

I assume you have the 2.5 liter engine that is more prone to head gasket problems. It would be good to know what the code is that is setting the warning light off. I would have a block check done to see if exhaust gases are getting into the coolant.

I forgot to mention the code is "cylinder #3 misfire" 0303 if I remember well.

You could try replacing or swaping the plug and wire to 3 from another spot and see if that helps. If that doesn't work I would swap coils next.

You could try replacing or swaping the plug and wire to 3 from another spot and see if that helps. If that doesn't work I would swap coils next.

 

Thanks! I am going to try that. I understand that the wires are resistance paired, which means that I cannot swap them randomly.

Is that correct?

If that is true, it is news to me. I don't see why this would be needed. It's just a spark wire and the resistance between the wire lengths would be pretty small compared to the wire resistance.

You can swap plug wires at least temporarily to diagnose the problem. I think wire 1/3 are exactly same, 2/4 are slightly different. You head gaskets are probably fine. Search for CEL misfire and you will gets lots of info on what you can swap/test.

You can swap plug wires at least temporarily to diagnose the problem. I think wire 1/3 are exactly same, 2/4 are slightly different. You head gaskets are probably fine. Search for CEL misfire and you will gets lots of info on what you can swap/test.

 

Thanks for the advice! Any advice on how to check the injectors with a screwdriver ? Is there a way to determine the code without a code reader? A code reader is +$150 and I don't want to go to Pep boys after each wire swap. On some cars you can make the CEL flash a number of times to indicate the code. Does that work on the subarus?