YACT: Engine with 100k miles versus one with 200k miles.

[Red]

I'm curious, if a car has been properly maintained, what is the difference between an engine with 200k miles and one with 100k mikes?

Reason I ask, there is a Lexus in my area with 200k with proper maintence its entire life and selling pretty cheap with that mileage. What is the difference between this car and a car with 100k miles that is also maintained properly? After 200k are the pistons out of shape or warn down or what? I've been looking at high mileage reliable vehicles to save money, and as long as they have been maintained, and I can't see a problem.

 

[Rent]

There could be damage to the pistons, or other parts of the motor, though its highly unlikely with proper maintenence. You just have to realize that there is certain wear and tear on the rest of the car. A chassis @ 200k is not the same as it was @ 100k or when the car was new.

 

[Mill]

At 200k I wouldn't be worried as much about the engine as I would everything else.

 

[StageLeft]

Steer clear, redhot If the engine keeps going without big work soon surely the rest of the car will need work.

 

[radioouman]

How about other issues like rust, hardened hoses, worn bushings in the suspension, etc.

 

[Red]

But that is what I'm saying... what if the 200k mile car has new struts, belts, water pump, etc, etc...doesn't leak or hesitate or anything...

just like a 100k mile car...

where is the difference?

 

[StageLeft]

Originally posted by: Redhotjrm
But that is what I'm saying... what if the 200k mile car has new struts, belts, water pump, etc, etc...doesn't leak or hesitate or anything...

just like a 100k mile car...

where is the difference?

Diff is that the engine has twice as much wear as a 100k engine

 

[radioouman]

The transmission would be my biggest concern.

 

[Eli]

Originally posted by: Redhotjrm
But that is what I'm saying... what if the 200k mile car has new struts, belts, water pump, etc, etc...doesn't leak or hesitate or anything...

just like a 100k mile car...

where is the difference?

All engines wear over time. Oil does not completely prevent metal to metal contact, and wear occours.

An engine's mechanical condition is measured by how well it can hold air(a leakdown test).

At first, the engine needs to be broken in to mate all the moving parts perfectly. After this initial period of heavy wear, the engine is mature and enters its long service life. However, as things progress.. the cylinder bore and rings wear, along withthe valve faces and seats, cylinders become oval shaped(due to the side to side forces of the piston/connecting rod relationship), etc. All this does is let air leak, and make the engine less efficient, robbing you of power.

As for the bottom end, all bearing clearances increase. This is bad because on each power stroke, the top side of the big end connecting rod bearing is slammed into the crankpin. If it gets really bad, we call it rod knock. Main bearings also wear, allowing the crankshaft to hammer away. Once these things start, it goes downhill rapidly as the engine literally beats itself to death.

However....... milage isn't really a very good indicator of an engines condition.

An engine with 200,000 highway miles would probably be in better shape on the inside than a car with 100,000 city miles, all else being equal.