Help: Procedure to replace intake manifold gaskets

[adroitboy]

Hi All. I have a new to me '94 legacy (non turbo) with an EJ22. It's started having issues at idle. It's lumpy, and barely manages to run. Above idle it seems fine although the gas milage seems to have gone down a bit to around 26-28 on the freeway (usually around 30).

 

I believe that the problem is the driver's side intake gasket as I can hear a lot of sucking sound there (using a hose). If so, it seems the gaskets are fairly inexpensive. Is this something that should be fairly easy to replace? I'm reasonably compotent as a home-mechanic. I'm just not sure what will have to be removed in order to get to the gaskets (besides the obvious answer of the intake manifold). Any suggestions and step-by-step disassembly directions/things to watch for would be most appreciated.

 

Thanks!

Aaron

[blitz]

On my '02, it was a matter of removing the manifold bolts, then prying the manifold up.

 

It should lift up enough to allow you to scrape gasket material off both surfaces. Just be sure to stuff paper towels into the intake ports first.

 

**** ******!

[adroitboy]

On my '02, it was a matter of removing the manifold bolts, then prying the manifold up.

 

It should lift up enough to allow you to scrape gasket material off both surfaces. Just be sure to stuff paper towels into the intake ports first.

 

**** ******!

 

Did you need to remove anything from the engine? Throttle cables? Electrical stuff? Fuel/vacuum lines?

 

I'm just not sure of what is attached and what is not.

[blitz]

Did you need to remove anything from the engine? Throttle cables? Electrical stuff? Fuel/vacuum lines?

I removed only the airbox. You'll find out when you lift up if anything is binding. The fuel lines will probably be the only thingthat gives you any resistance. You only need to come up about an inch or two.

 

**** ******!

[idosubaru]

always remember, you are only unbolting the intake, not removing it. so there's no need to disconnect all the goodies associated with it. once it's unbolted you only need to lift it enough to clean the old gasket off and slide the new ones in. there's no need to take all the stuff off of it. like he mentioned, be prepared to make sure nothing gets down the intake ports.

 

if the intake manifold has coolant passages (i think it does..i know the older EA and ER series do), then you may want to drain the coolant some so coolant doesn't pour down into the cylinder when you lift it off as well. very simple to do.

[blitz]

Now that I think about it, I also pulled the plug-wires off at the plugs because they're a tight wrap.

 

**** ******!

[Gnuman]

no coolant passages at the ends of the manifold. just right around the throttle body. 12mm bolts (4 on each side). Easy job, really.

[SaltCar]

Is this a common problem with the 2.2? I also have a rough idle sometimes when the car is fully warmed up and I have noticed that there is some greasy looking deposit around one of the intake runners on the head.

 

I have done nothing to diagnose this condition because it is really just an annoyance and I thought that I would do the timing belt first in case it is related. I have done no tune-up type work to this car besides filters and fluids.

 

Anyone have any thoughts for testing? I could run some propane at the joint to see if it smooths out the idle. Hook up a vacuum guage to check for irregularities.

[avk]

If the greasy looking deposit is at no. 1 intake runner, it might be from a leaking O-ring under the steering pump reservoir, or from some other connection at the pump.

[adroitboy]

Well, it's done.

 

It really wasn't that hard. The toughest part is a lack of a lot of room between the intake manifold and the engine. Here's what I did.

 

0) sprayed in some engine degreaser and tried to wash anything lose around the area where the intake manifold connects to the engine. Drove it around a bit to evaporate all or the water off. Make sure to let it cool for a while. I gave it 30 minutes and it was a bit uncomfortable heat-wise.

1) Disconnect spark plug wires, and ?injector wires?

2) remove the plug wire bracket on the passenger side (it interfered with lifting the manifold up.

3) Loosen the 4 - 12mm bolts on each side. Remember that you have 2 long and 2 shorts ones.

4) Lift the intake manifold up. I could only get it up about 3-4" on the drivers side and around 2" on the passenger side.

5) Stuff a little paper towel into the intakes so hopefully nothing goes in there.

6) remove the loose gaskets. They came out easily.

7) clean (as best you can...it's tight in there) the mating surfaces of the intake and the engine. Mine had a little dirt/oil on them.

8) Remove the paper towels!!!!!!!

9) Pop the new gasket in line it up somewhat (I used 2 bots in there loosely to hold it in place). I did the driver's side first and then the passenger side. I don't have a subaru dealer nearby, so I used NAPA. Gaskets cost me ~$13

10) Put the bolts back in. Tighten down. I didn't go super tight as I think torque is fairly light. I don't have a torque wrench though.

11) Re-attach the wires you removed in step 1.

 

The idle is fine now and mileage on the last freeway tank at 75mph cruising was 29mpg which is about average for that speed. It had been decreasing to around 25 and the idle had gotten very rough.

 

Thanks for the advice!!!

Aaron

'94 2wd Automatic Legacy with 140,000 miles (almost an engine donor)

'85 VW Vanagon with 2002 EJ25 (a bigger engine donor)