Engine Problem in a 1500 Tahoe L31 GM
- Thread starter Dufus2
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really outrageous clearance issues. Bore not straight, heat checking caused by overheat. Wrist pin.
And my favorite, inadequate lubrication.
And my favorite, inadequate lubrication.
Quite clean. I'm guessing the bore is out of round.
A mechanical expert told me there was nothing wrong with this engine. The temperature pellet was still intact on the freeze plug. The crankshaft was rough and the machine shop gave me these parts back. It's a L31 GM in a 1500 Tahoe. Just looking for other opinions of the cause.
Is there pitting on some of those bearings?
Maybe it's just the photo, but those bearings look pitted.
Regarding the pistons, what do the cylinder bores look like?
Regarding the pistons, what do the cylinder bores look like?
Overheated or not enough bore to piston clearance. Since the pellet was ok im going with #2
You may find something with this..
http://download.ms-motor-service.com/ximages/ks_50003973-02_web_leseprobe.pdf
http://download.ms-motor-service.com/ximages/ks_50003973-02_web_leseprobe.pdf
Do the piston skirts look like that on the other side?
Looks like this engine was under high load..alot. Lugged ,pitted shells=contaminated oil, high particulates.
39K on a rebuild or is that OEM? Those pistons look aftermarket to me and if it was rebuilt, then I would say that the machine shop didnt get the clearances right.
A little PU will clean that right up...
Any updates on this?
Those were definitely damaged by too little clearance or overheating. As the piston expands it takes up all the clearance and scuffs them. If this is a stock engine, then it was a design/manufacturing problem if it didn't everheat.
This is the result of multi-grade oils that don't protect the same as a full-film 30w oil. 5w30, never again! This oil was drained at 2,196 miles and the oil was full of grit. The particle count was 26/25/22 with 2% fuel dilution. Wear metals were at normal levels. Blackstone did the testing.
ls1mike
$50 Site Donor 2025
Was it a rebuild?
Originally Posted By: Dufus2
This is the result of multi-grade oils that don't protect the same as a full-film 30w oil. 5w30, never again! This oil was drained at 2,196 miles and the oil was full of grit. The particle count was 26/25/22 with 2% fuel dilution. Wear metals were at normal levels. Blackstone did the testing.
Do you know what oil was in it? I don't know how you can blame it on a multi-grade oil unless you can prove what oil was in it?
This is the result of multi-grade oils that don't protect the same as a full-film 30w oil. 5w30, never again! This oil was drained at 2,196 miles and the oil was full of grit. The particle count was 26/25/22 with 2% fuel dilution. Wear metals were at normal levels. Blackstone did the testing.
Do you know what oil was in it? I don't know how you can blame it on a multi-grade oil unless you can prove what oil was in it?
A qualified machine shop built this engine Feb/2010. 36,000 later the vehicle was sold by a dealership. The auto dealer serviced the engine with a Purolator PureOne filter and 5w30 motor oil (brand not specified). If the rebuild was faulty, it would not have lasted more than a few months. The engine was not tight, eliminates bore clearance issues.
The crank was ground down and very rough along with piston seizure on all load bearing surfaces. It was determined by the machine shop the oil caused the problem. Oil pressure dropped 15 psi on one 100 mile trip and fuel mileage also dropped significantly.
Boundry lubrication is the problem with this oil, it won't adhere to the metal.
The crank was ground down and very rough along with piston seizure on all load bearing surfaces. It was determined by the machine shop the oil caused the problem. Oil pressure dropped 15 psi on one 100 mile trip and fuel mileage also dropped significantly.
Boundry lubrication is the problem with this oil, it won't adhere to the metal.
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