When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The question is what else, you can determine this by putting compressed air in the spark plug tube with cylinder 1 at TDC, and listen to where the air escapes from, doing the leak down test is only going tell you how much the valves are leaking however, so you don't know if it's worn guides that have ovalized the valve seat, toasted valves that aren't sealing right, pitted valve seats.
I'll do the leakdown test and will also listen for where air is escaping on cylinder #1.
Unfortunately, I do not know. I'm the 3rd (or maybe 4th) owner and have only put about 2,000 miles on the car. Judging from the PO's efforts and low mileage he put on the car, I doubt he ever adjusted them and I don't know anything about the prior owner or two.
Likely burnt exhaust valves due to extended use at tight clearance. All 06-09 should be inspected every 35k. Had a customer last week go from .011 to .009 in 33k miles. His car should level out and clearance should stabilize.
And to stress once again, do not mill the cylinder head. It's not needed now, or later, or ever. Doing so will only equate to skewed chain geometry and a lifetime of timing chain problems.
And to stress once again, do not mill the cylinder head. It's not needed now, or later, or ever. Doing so will only equate to skewed chain geometry and a lifetime of timing chain problems.
Got it. I don't even know what is meant by that but glad you guys pointed it out so I know to avoid it in case someone suggests it.
I didn't get to do the leakdown today as I'm using a combo of a compression tester and a friend's homemade leakdown tester and some pieces needed some modification. Hopefully I'll get to do the leakdown in the next couple of days.
Leakdown test performed this morning. Note that I'm using a friend's homemade leakdown tester in conjunction with a hose from an AutoZone compression tester -- I took out the needle from the end of the compression tester hose so that it would allow air to flow into the cylinder. The leakdown tester just has one PSI gauge -- no % gauge but I'm just noting the difference between pressures before and after I hook the tester up to the hose that is attached to the spark plug hole.
For all of these I had the compressor's regulator set to around 82 PSI and the leakdown tester regulator set to 60 PSI. I confirmed the piston was up by having a few ratchet extensions resting on top of the piston while I turned the engine. The engine was warmed up.
Cylinder #1
Pressure dropped to 10 PSI so I thought I was on the exhaust stroke with so much leakage. Rotated the engine 180 and re-did the test. Pressure dropped from 60 to 0 so I rotated 180 again and confirmed pressure on compression stroke went from 60 to 10.
83% loss.
Cylinder #3
60 to 42 PSI briefly then back up to 50 where it stayed.
16.6% loss.
Cylinder #4
60 to 53 PSI.
11.6% loss.
Cylinder #2
60 to 55 PSI.
8.3% loss.
Back to cylinder #1
60 to 10 -- same as before.
70 to 18 -- approx. 74% loss.
The numbers for 2, 3, and 4 don't seem great but they're a lot closer to each other compared to #1. Also, the gauge wasn't all that easy to determine exact numbers from -- same gauge from the compression tester which gave me different numbers each time.
Next, I tried to listen and feel for the air escaping from #1:
I put my hand over the 2, 3, and 4 cylinders and was pretty sure I could feel pressure coming out of #2. On 3 and 4, I could feel heat rising, which was expected, but it was evenly spread on my whole hand whereas on #2, I could feel a stronger pressure on the part of my hand immediately over the spark plug tube. I turned down the tester's regulator and back up to confirm that it did feel like air coming up out of the #2 spark plug tube.
I listened around with a stethoscope and could not hear anything when I touched the 2, 3, or 4 spark plug tubes or around them.
I could hear air when touching the bolt holes for the coil pack cover -- more air towards cylinder #1 than the ones over near 3 and 4.
I could barely hear something when touching the nut that attaches the PCV hose.
I could barely hear something when touching the tightening screws on the breather tube hose.
I did not hear anything around the coolant reservoir nor the radiator cap.
Nothing from the exhaust pipe.
Nothing around the headers.
Couldn't really hear anything from the bolts that hold down the valve cover.
Will go back and check again around the oil dipstick as I didn't think to listen there.
In the below pic, I've tried to highlight where I felt or heard air and where I did not. Green = felt air Brown = did not feel air Blue = heard air Yellow = barely heard air Red = did not hear air
Did some more listening. Note that this time the spark plugs were back in 2, 3, and 4 cylinders just a few turns to prevent things from going in there.
A little bit of sound from the oil dipstick tube -- I had to turn up the air pressure to really hear it. I understand there should always be a little noise here due to air leaking past the piston rings.
I was able to hear some air if I put the stethoscope tip right underneath the radiator cap but not on top of it.
Re-checked the exhaust with pressure turned up. Nothing from tip, center of pipe, cat, nor headers.
Nothing from oil filler cap.
I can hear consistent air from all 4 cylinders if I touch the listener to the inside of the metal holes that are in the valve cover.
Based on Rob Robinette's guide, I'm guessing this indicates a damaged head gasket and since I get nothing from the exhaust, either those exhaust valves are not burnt or the head gasket leak is big enough that I cannot detect the leak from the exhaust.
Got it. I don't even know what is meant by that but glad you guys pointed it out so I know to avoid it in case someone suggests it.
I didn't get to do the leakdown today as I'm using a combo of a compression tester and a friend's homemade leakdown tester and some pieces needed some modification. Hopefully I'll get to do the leakdown in the next couple of days.
It means to shave off material from the mating surface to make it perfectly flat. Unless you've had overheating issues I doubt it's warped enough to require it.
Are you still thinking it's a burnt valve? Would you mind explaining why you're doubtful about the head gasket having a leak? I only came to that guess based on where air seems to be leaking from and Rob's guide that suggests possible causes based on where air leaks are detected. Other than that, I've got little info and less experience to go on.
I looked at the oil and coolant and both look fine. The coolant has no black flakes. I did notice that my reservoir cap is cracked which I guess could cause a pressurization problem in the coolant system -- I think that's fairly new as I did a coolant flush a few months back and did not notice it then nor have I had any issues with the coolant system. Might have even cracked that cap today when re-tightening. When I opened the radiator cap (NOT the reservoir), the coolant was all the way at the top.
Also of note is that there were no symptoms that prompted me to do the compression test. No overheating, no oil burning, coolant level is always stable -- I just had a car with fairly high mileage and thought I'd check it. From there, I got down the wormhole of changing out the VC seal, spark plug tube seals, adjusting valves, and now trying to figure out why cylinder #1 has such low pressure.
Whatever I do, I was going to ask the shop to perform more diagnosis before repairing anything. Just wanted to attempt to diagnose it myself to see if a fix might be something I was up to. I don't think a valve job or a head gasket is something I will try to do.
01-02-2017, 09:40 AM
