I have a 1999 impressa outback sport (2.2l SOHC). i've notice that there is oil present on the Spark Plug Hood when changing Spark Plugs. I have about 104K on the engine and have been getting Lousy Gas Mileage. Are the two related? also, since i'm getting to the 105K Timing belt replacement time, i'm thinking about pulling the engine completely to adjust and or replace O-rings and other gaskets. good idea?

thank you.

Mike-In-Ohio

I believe you have the spark plugs that go through the valve cover. I believe that started on the 2.2's in 99.

 

If that's the case, then you have O-rings sealing the spark plug holes. Those O-rings are most likely leaking.

 

You'll have to remove the valve covers to replace them, so you'll have to replace the valve cover gaskets and grommets too.

 

It's no emergency, but if you want, you can do it when you do the 105k timing belt.

 

The mileage could be a number of things:

1) What kind of plugs are you using?

2) What about plug wires? Replaced them recently?

3) Fuel filter done recently?

4) Do you have any CEL's (Check Engine Light) or have had one in the past? That could point to a number of sensors, from the O2 sensor to the MAF sensor.

Sounds easy enough. thank you.

I have a 1999 impressa outback sport (2.2l SOHC). i've notice that there is oil present on the Spark Plug Hood when changing Spark Plugs. I have about 104K on the engine and have been getting Lousy Gas Mileage. Are the two related? also, since i'm getting to the 105K Timing belt replacement time, i'm thinking about pulling the engine completely to adjust and or replace O-rings and other gaskets. good idea?

thank you.

Mike-In-Ohio

First i want to thank you again for your insight. the spark plug hood does go through the Valve Covers. Also, in answer to your other questions/statements:

the Spark Plugs are Bauch dual electro (or something like that) they were recommended by my local NAPA dealer (maybe because the cost more)

Yes the check engine light is on, and my local Autozone parts dealer used their computer to determine that it was a O2 sensor (about 80 USD) and was told it really wasn't important.

I haven't changed the Fuel Filter since I bought the car, but should do this we i start my tear down this week.

I haven't changed the spark plug wires yet either (i'm sure they are OEM and will cost some change to replace, but hey what's money?)

my Service Manauls arrived today (180 USD) and they even thru in the binders (11,12,&13). so thanks again and if you know of a "reputable "parts dealer, for the Timing Belt and o-rings/gasket set. let me know.

 

I believe you have the spark plugs that go through the valve cover. I believe that started on the 2.2's in 99.

 

If that's the case, then you have O-rings sealing the spark plug holes. Those O-rings are most likely leaking.

 

You'll have to remove the valve covers to replace them, so you'll have to replace the valve cover gaskets and grommets too.

 

It's no emergency, but if you want, you can do it when you do the 105k timing belt.

 

The mileage could be a number of things:

1) What kind of plugs are you using?

2) What about plug wires? Replaced them recently?

3) Fuel filter done recently?

4) Do you have any CEL's (Check Engine Light) or have had one in the past? That could point to a number of sensors, from the O2 sensor to the MAF sensor.

First i want to thank you again for your insight. the spark plug hood does go through the Valve Covers. Also, in answer to your other questions/statements:

the Spark Plugs are Bauch dual electro (or something like that) they were recommended by my local NAPA dealer (maybe because the cost more)

Yes the check engine light is on, and my local Autozone parts dealer used their computer to determine that it was a O2 sensor (about 80 USD) and was told it really wasn't important.

I haven't changed the Fuel Filter since I bought the car, but should do this we i start my tear down this week.

I haven't changed the spark plug wires yet either (i'm sure they are OEM and will cost some change to replace, but hey what's money?)

my Service Manauls arrived today (180 USD) and they even thru in the binders (11,12,&13). so thanks again and if you know of a "reputable "parts dealer, for the Timing Belt and o-rings/gasket set. let me know.

 

The O2 sensor being bad doesn't hurt anything, but it can make your gas mileage decrease. A generic O2 sensor is $20 or so for my car -- you just have solder the wire to it. I don't know if you can use the generic sensors for the newer cars (mine is '89), but you might look into it.

 

I've heard that subaru's don't like Bosch spark plugs. Wrong heat range. I use the higher end NKG ones now -- can't say I really notice a difference, but I did replace a set of worn out NKG plugs with nice new expensive Bosch ones once, and didn't get any increase in gas mileage that I expected with new plugs. Who knows.

NGK are the most loved for these engines.

 

NGK BKR6E-11

 

 

or BKR5E-11 if you do alot of low-rev, city driving. Those plugs are one notch "hotter" and will keep themselves clean under those circumstances.