Toyota L Weak and Overheating Engine-Newly Overhauled

We have overhauled a Toyota L engine just this week and came to a puzzling issue on why it lost its power and is overheating.

Prior to overhauling the engine had overheated due to the radiator hose bursting.  It was immediately addressed during that day and everything was fixed and we used the car onto the occasion we went through.

However, after going back home the owner noticed that the coolant was being mixed with oil. The oil cooler gasket was replaced and to make sure everything was fine the cylinder head gasket was also replaced. Those steps did not solve the issue, the more the car emits thick white smoke.

This time the owner decided to let the engine overhauled.

The car was brought to the mechanic and the engine disassembled. Noticeably, the four cylinders were having the same uneven and marked sides.

The mechanic recommended that the cylinders be replaced with a standard size or oversize it with a 0.50mm.

The owner happened to decide on the 0.50 sleeves be oversized. He brought the block to the Machine Shop for oversizing and went ahead and bought all the 0.50 piston, piston rings.

Weak and Overheating Engine-Newly Overhauled-0.50 size piston

After one day he went back to the Machine Shop because he was called to decide on what will they do. On the image below they have shown the owner that the sleeve has a crack around near the top and they don’t recommend it for oversizing rather it should be replaced with a standard.

Weak and Overheating Engine-Newly Overhauled-oversize cylinder

Since he bought all the oversize piston and piston rings through an order, it cannot be returned and the only remedy is to buy a standard sleeve then oversize it. It was an unexpected additional expense, however, the parts have to be utilized and no other choice.


The four standard sleeves were rebored and honed

After these sleeves were rebored and honed the engine is ready to be assembled. With new overhauling gasket, it includes the cylinder head gasket, the oil cooler gasket, new crankshaft oil seal, new camshaft oil seal, new cylinder head cover gasket, new crankcase cover gasket and others. New sets of 0.50 sleeves, 0.50 piston, and piston rings.

The engine assembled with a new look, freshly cleaned inside and outside.

The engine attached to the body and the new engine life is first started successfully.  The sound is fine enough and you are contented with what you have done. The noise is just fine and it needs breaking-in for hours before it is normally used again for services anywhere.

Road Testing

After one day we tested it on the road and upon climbing up the hill there was no power even to the first gear.  It could just move on a plane lane and when you forced it to an elevated road it overheats and stalls.

The coolants are obviously circulating both oil and water that clearly puts impression that the coolant pump is working fine.

This is the first time I experienced a newly overhauled engine with no power.  It’s a puzzle I and the mechanic have to discover.

I wish my readers could help in the solution of the issue at hand.  Please kindly post your comments down below the comment box.

What do you think is the reason behind why this engine has no power instead of a renewed strength and life? What steps and solutions should be done to restore this engine to its power?





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