should i fix this motor from a 90 gmc siera?

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stan

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90 gmc siera s15 2,5L 4tech oil pump came lose and rod bearings went bad halfway locking the engine sometimes..

took out the spark plugs and the were kinda black which means oil. so im thinking the rings are bad but i dont know for sure.

had metal shavings in oil when drained.

not sure condition of main bearins and not sure what i should do

i paid 400 for this and didnt know about the issue until it was to late.

cudnlt offord a mechanic to look at it.

i bought the rod bearings but what should i do? i got the motor half way taken apart so i cant test the pressure
 
I would have took the truck to a car auction and sold it for what i could get out of it and buy something else personally. But the only way you can check it is get you a manuall and get the measurements on the cylinders and check it against the specs thats about all you can do if its already apart good luck.
 
If youve got an oil fouled spark plug the engine is no good. One question: I thought a SIERRA was a full size half ton truck (1500). Was this four cylinder in the truck when you got it? Cause ive never seen that motor in a full size. Anyway, if it burned up the rod bearings you need to change the main bearings too, sicne you have to tear it down that far anyway. The bearings wont cost that much. But be sure to check your main caps/journals as a spun main bearing will cause wear here and cause a clearance issue with your crank, negating all your work. Plastigage is a great thing. But someting to think about: A black spark plug could be carbon fouled (incomplete combustion) due to various problems with the injection or ignition system, but only if its dry. If the plug is wet/black with oil youve got a punched piston or REALLY bad rings. So make sure, but it sounds like youve got a pretty good handle on it already as you know enough to diagnose a rod bearing problem. But seized mains will cause engine lockup too, and would kill your crankshaft. Or cam bearings. Gotta check it all in this situation. If it were me I would get another motor, maybe another 2.5, but 350's are cheap too if you get them from the right place. Many salvage yards stock engines that are still good. It may be cheaper than buying a full rebuild kit and rbuilding that 4 banger youve got. You would probably get better fuel mileage and engine life too as a bigger engine wouldnt have to work as hard to move your full size truck. If im wrong and you have a GMC sonoma (S10) you can still buy another motor, but the biggest you could swap in without custom fab work would be a 4.2 V6. ood luck and hope this helps.
 
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