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Discussion Starter · #1 ·
I have a 11 cruze with the 1.4 turbo. Recently did a compression test due to burning oil that I thought was a bad turbo but not so sure now. Cylinder 3 has 210 cylinder 4 has 205. But cylinder 2 is 170 and 1 is 155. Could that be enough to cause blow by. Should I be worried about it. And should I just rebuild or replace the engine. Btw this engine has 190000 miles on it so yeah getting a little tired lol.

Thanks guys
 

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That is a fair spread in your compression results. They should all be within about 10% of each other. It is likely you could be getting blow by from Cyl. 1 and 2, assuming that the cause of the compression loss is the rings/cylinders being worn. With 190,000 miles it would not be a surprise that the engine is worn.

You will have to look into the cost of a rebuild vs. new or used replacement engine.
 

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With the mathematical formula. AT sea level. 170 is as high as it will go.
Compression ratio (9.5) X Atmospheric pressure (14.7) + Atmospheric pressure (14.7) equals compression pressure(154.35). Although the actual number is usually an additional atmospheric pressure added to the equation. (169.05)

Add oil to cylinder #1 and see if it goes higher. If it does, that's the rings. If not, it be the valves. (Generally speaking). Check #3 and #4 to see if there isn't anything in there causing higher pressure.

In the old days before the turbo got so popular. You could figure on what's causing oil consumption.
If your burning oil with foot off the pedal. You're sucking through the piston rings.
If your burning oil with heavy pedal. You're sucking through the valve seals.

If you got blowby. That's caused by worn piston rings.

the gen1 motor has a lot of quirks though that could be any type of abnormality. Causing any type of sympton. You'll find all kinds of posts with bad pcv, front main seal, top end gaskets, even turbos.
 

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Before going too far, tell us how you were blocking the throttle open during the test.
If you were testing without the throttle open (supposed to remove throttle body for testing but blocking is OK) the test is not valid.

If you were testing as suggested, the low cyls are way out of range. That much variation would have me pulling pistons with the anticipation of finding broken rings (and ring lands) or stuck rings that cannot expand to the bore.

Rob
 

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Discussion Starter · #5 ·
Thanks guys. I put oil in the cylinders and 1 and 2 jumped about 20psi. It smokes only when I run it hard then after the run it will start puffing smoke on acceleration and start to hesitate. As far as the compression test I just put it in clear flood mode while cranking it. Which is the gas pedal to the floor. I did notice unevenness while cranking.Other then the smoking it runs pretty smooth.
 

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As far as the compression test I just put it in clear flood mode while cranking it. Which is the gas pedal to the floor.
Which is fine for a car that has a mechanical throttle, but a bit iffy if it's throttle-by-wire like the Cruze. You're hoping the computer is cooperating. The results may vary as the battery wears down as well.

The 2011 was prone to crack pistons, so, I'd consider that.

All in all, it's probably time to do some shopping. At 190,000 miles, I don't know as anything other than a junkyard engine would make sense. From a bluebook value, I'm not sure as anything makes sense. (I'm seeing "private party" price of $3,700 for a LT in "good" condition.) I'm more of a "car is worth what you can get out of it" kind of guy. You might want to think about the life expediency of the rest of the car (as well as how long before you might have a life change) and plan accordingly.
 
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Discussion Starter · #7 ·
True. Yeah it isnt worth alot but the boy is in good shape with no rust. And me and my buddy where going to change the engine at his house if I do it. So no labor just parts.
 

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FYI.

Don't remember who but someone posted their readings not to long ago. 170 in all 4 jugs. I think he only had 60k miles.

IIRC. There's another thread posted down the line with the exact same problem.
 

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If the cylinders were filling up with oil or water would be about teh only way. Or possibly carbon buildup.

Look for that other thread and see if anything was figured out.
 

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It's got 190,000 miles on it. Just drive it and not worry about it. 155 on #1 doesn't indicate anything is broken or cracked. So you have to add some oil now and then, big deal. Wait until something blows or it smokes badly to do anything about it. There are so many of these cars in junkyards so used engines are cheap. Took me months and months to get even $300 for the 66,000 mile engine in my parts car.
 

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Before going too far, tell us how you were blocking the throttle open during the test.
If you were testing without the throttle open (supposed to remove throttle body for testing but blocking is OK) the test is not valid.

If you were testing as suggested, the low cyls are way out of range. That much variation would have me pulling pistons with the anticipation of finding broken rings (and ring lands) or stuck rings that cannot expand to the bore.

Rob
Before going too far, tell us how you were blocking the throttle open during the test.
If you were testing without the throttle open (supposed to remove throttle body for testing but blocking is OK) the test is not valid.

If you were testing as suggested, the low cyls are way out of range. That much variation would have me pulling pistons with the anticipation of finding broken rings (and ring lands) or stuck rings that cannot expand to the bore.

Rob
Hi Rob.
wanted ask you something, I did the compression test on my 2015 Chevy Cruze 1.8 (55k miles) and pretty much got similar results in all 4 cylinders.
I ran 3 tests on cylinder 1 and 2 tests on remaining cylinders.
Test 1. Test 2. Test 3.
1. 225 255 265
2. 265. 265
3. 265. 265
4. 270 270
I ran it with the throttle body on and didn’t know I was supposed to leave it open.
My first question is:
Are these readings to high?
And
Could having the throttle body closed be the cause?
 

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Yes I know it's not a diesel. Is there an engine problem you're concerned about? If not, it's fine. With the low miles, maybe there is a lot of carbon buildup raising the compression. Could just need an Italian tuneup.
 

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Yes I know it's not a diesel. Is there an engine problem you're concerned about? If not, it's fine. With the low miles, maybe there is a lot of carbon buildup raising the compression. Could just need an Italian tuneup.
Car is overheating but I replaced almost every part on the cooling system, was trying to see if a cracked head or blown gasket was the issue.
 
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