Hello! 2007 GL 450
05-23-2023, 01:21 AM
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2007 gl450
Hello! 2007 GL 450
i am new to this forum, I have read some great posts with great feedback! I have a situation, maybe somebody has dealt with the same...?
2007 GL 450 with 70,000 miles. The truck looks like a 2018! In the last year, I changed spark plugs, vacuum hose, oil change, every fluid serviced and/or changed, front & rear suspension, brakes front & back, battery, fuel injector service, replaced intake manifold, both air filters, purge valve, charcoal canister and ignition coil. Now I have a misfire on cylinder 8 with compression of 120psi. I was told I needed a new engine because of Ringland failure on cyl 8 but I am having a hard time believing it. Don’t know how they see Ringland failure if they didn’t open the engine. Has anyone experienced and/or has heard of anything like this?
2007 GL 450 with 70,000 miles. The truck looks like a 2018! In the last year, I changed spark plugs, vacuum hose, oil change, every fluid serviced and/or changed, front & rear suspension, brakes front & back, battery, fuel injector service, replaced intake manifold, both air filters, purge valve, charcoal canister and ignition coil. Now I have a misfire on cylinder 8 with compression of 120psi. I was told I needed a new engine because of Ringland failure on cyl 8 but I am having a hard time believing it. Don’t know how they see Ringland failure if they didn’t open the engine. Has anyone experienced and/or has heard of anything like this?
05-23-2023, 08:50 PM
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2007 GL450
First, it's "ring land". Basically they are diagnosing compression ring failure. I am not familiar enough with such diagnosis to say whether it is reasonable. The general method to check for compression ring integrity is to squirt oil in the cylinder to see if the compression improves.
Unfortunately, low mileage can be a result of a short trips, not infrequent long (enough to bring the engine to full operating temperature).
The fuel injector service is a little peculiar for that mileage. The Bosch injection system is robust and seems to practically be a lifetime item. If the injectors were removed, it is possible the mechanic did not clean adequately around them beforehand, and junk fell inside. If it did, and got trapped between the piston and wall, above the ring, it could scratch the cylinder wall, resulting in a junk motor.
If you need a motor replacement, get a used 550 motor. They drop right in.
Unfortunately, low mileage can be a result of a short trips, not infrequent long (enough to bring the engine to full operating temperature).
The fuel injector service is a little peculiar for that mileage. The Bosch injection system is robust and seems to practically be a lifetime item. If the injectors were removed, it is possible the mechanic did not clean adequately around them beforehand, and junk fell inside. If it did, and got trapped between the piston and wall, above the ring, it could scratch the cylinder wall, resulting in a junk motor.
If you need a motor replacement, get a used 550 motor. They drop right in.
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texas008 (05-24-2023)
05-23-2023, 08:54 PM
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What maintenance action preceded the misfire?
The only way to really tell is to get a endoscope a camera in there and look for a scratched cylinder walls to confirm said diagnosis, which we have no idea how they arrived at unless they told you how. Industry standard is to do like Erik said, test compression warm and then squirt oil in there to see if compression improves -that would indicate a ring failure. If it didn’t improve, likely have a stuck or burned valve.
it comes down to trusting the evidence that your shop gave you. I I would put a 550 motor in this one as well, if the rest of the car is nice. If not, you have a $3000 parts car.
But sometimes given it the old Italian tuneup, will bring that cylinder right around.
The only way to really tell is to get a endoscope a camera in there and look for a scratched cylinder walls to confirm said diagnosis, which we have no idea how they arrived at unless they told you how. Industry standard is to do like Erik said, test compression warm and then squirt oil in there to see if compression improves -that would indicate a ring failure. If it didn’t improve, likely have a stuck or burned valve.
it comes down to trusting the evidence that your shop gave you. I I would put a 550 motor in this one as well, if the rest of the car is nice. If not, you have a $3000 parts car.
But sometimes given it the old Italian tuneup, will bring that cylinder right around.
05-25-2023, 07:59 PM
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If the compression improves when - if you squirt oil in there? Yes.
If not, the likely suspects, as Maximus noted, are a sticking (intake) or burnt (exhaust) valve. You really need to get an endoscope in there. If you were in southwestern Idaho, I'd offer to loan you mine, but I am guessing ... odds not good.
Now, in fairness, when I have used crummy gas &/or driven my beast infrequently, varnish has built up on the intake valve stems, making them stick when cold.
It all depends on the diagnostics that shop did. Dealerships are not above outright lying. So take a good look at the estimate information. And in the meantime, while it's not a generally good idea, you can operate the vehicle with a cylinder disabled. In fact, the ECU will do it for you.
If not, the likely suspects, as Maximus noted, are a sticking (intake) or burnt (exhaust) valve. You really need to get an endoscope in there. If you were in southwestern Idaho, I'd offer to loan you mine, but I am guessing ... odds not good.
Now, in fairness, when I have used crummy gas &/or driven my beast infrequently, varnish has built up on the intake valve stems, making them stick when cold.
It all depends on the diagnostics that shop did. Dealerships are not above outright lying. So take a good look at the estimate information. And in the meantime, while it's not a generally good idea, you can operate the vehicle with a cylinder disabled. In fact, the ECU will do it for you.
