And....... Never rotate the engine backwards. If you go a little past your intended stopping place, DO NOT turn it backwards to return.

 

I finally got a time to redo the leakdown test following the great suggestions here.

Yes, my previous leakdown was wrong. Taking out the engine valve cover helped a lot. This time, I confirmed both intake and exhaust valves were closed for #3. And it was much easier for me to find where the leakage was. I found the major leakage was from #1. I could feel and hear clearly the air flow from #1.

I believe this was because #3 had a worn piston ring, the air went down through the ring.
At the same time, #1 was kind of in the lowest position so the air came out from #1. Correct me if I am wrong.

If the root cause is the worn ring of #3, I guess I need replacing the engine. Any idea of the cost could be if including the "used" engine to be put in and the labor? I am in the PA and NJ area. Here is a website I found the used engine for HHR 2.2L ecoTec. 2011 Chevrolet HHR 2.2L (Fits: 2.2L (VIN W, 8th digit, opt LE8) Used Engines For Sale @ BUYUSEDENGINE.COM Buy cheap Used engines at BUYUSEDENGINE.COM

 

About $2,000, $800 for the engine $1200 labor. About 11 hours flat rate.

Check around your local junkyards, some of them install for reasonable rates. If they don't have a motor they can find one.

Don't bother asking at big box mechanic shops.

 

You were testing #3, and determined it was leaking into #1? What did that look like? I've never heard of anything like that.

 

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I took all the spark plugs out and also the engine valve cover. Then I used the leakdown tool to input air into the cylinder #3. I heard the leakage from the #1 hole. I felt the airflow from the top of #1 hole.

My guess was the piston ring of #3 broke and the compressed air went down the piston and somehow find its way from #1 hole which the piston was in the lowest position at that time. But I could be wrong on my guess.

 

If your issue is rings and blow back from #3 to #1 you might want to consider
A: new engine, hey, it’s cheaper and easier , plus faster then rebuilding the old engine.
B: a used low mileage engine from a recycler ( junk Yard).
C: well it’s not our choice , it’s your decision, sell it , as is, not recommended as it’s more expensive then you think to sell or trade then get another used car.

 

Hmm. I tried to think of a scenario where the air went from Cyl. #3 to #1.

If #3 had a burnt or leaking intake valve, the air would be pushed back into the intake manifold. And, if the #1 cylinder had it's intake valve open during the test then maybe the air could have been pushed out there thru the empty #1 sparkplug hole.
(Path of least resistance since the throttle body plate would be closed )

That's my guess for today.

 

Your thought is close to mine. Except exhaust. #3 at true TDC, puts #1 at BDC after power stroke(beginning of exhaust stroke). I don't know the camshaft profile, I'm wondering if the exhaust valves would be open yet in #1. Gotta be close to opening by then.

EDIT: I can't imagine the exhaust valves being open that early, and no way the intake valves were open. If a ring were broken in #3, leaking air into the crankcase... with the valve cover off, that air would be blowing around, through all the holes where the oil drains down into the crankcase, plus the PCV passages, you should have felt it everywhere.

And #1 and #3 are kinda too far apart to be a head gasket, which would have shown #1 bad compression also.

Maybe the air pressure pushed the crankshaft so that the exhaust valves were open in #1? How much air pressure are you using? Did you lock the crank like Cat Man HHR suggested? Just thinking aloud, trying to make sense of this.

 

I redid the leakdown test again with taking the valve cover out to clarify the questions being asked:

1. The air flow out from the #1 was very obviously heard and felt. When I put my hand to the top of the hole #1, the leakage became much less and the flow sound almost stopped.

2. There was a little bit air flow out from the tailpipe. It was not easy to be felt and I couldn't hear any leakage sound. But I used a thin plastic food wrap to it (sealed with tapes). I could see there was some air trying to make its way out there (not much, just a little).

3. I am pretty sure no air flow out from the oil dipstick hole, no air flow from the cylinder #2 or #4. And no anywhere I could feel other than #1.

4. I retested the compression of #1, 2, 3, 4. #1 was in good shape, had the same pressure as #2 and #4.

5. During the test, the #1 had the intake valve open.

I don't quite know how this engine works so my previous guess of the worn ring could be wrong. The above is my observation. Is this possibly caused by the broken intake manifold gasket, say the rubber ring of #3's intake?

 

There is a connection between the cylinders via the intake manifold. If 2 intake valves are burned/open/coked it could do that.