High Mileage?

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mykdee

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I tried searching and could not find anything.

So my question is, what do you consider high mileage on the 5.7 and what is the highest mileage motors on this site?

I have a 94 2-door Yukon with the 5.7 and 205k on it and would like to start using it for daily use. It runs great and has no leaks, previous owners kept it up.

Post up some of the highest mileage motors you guys have.
 

Toomanyhobbies

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Have you done a compression test? If good compression why not? Most say the rule of thumb on a 350 is 200K, but that's just conjecture.
 

SnowDrifter

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Have you done a compression test? If good compression why not? Most say the rule of thumb on a 350 is 200K, but that's just conjecture.
And at that timeframe, even minor variations in maintenance will cause a pretty major difference in the usable lifespan of the engine.


As far as inspecting a high mileage engine to get an idea of where its at, I'd do, at a minimum, the following:

1. Compression AND leakdown test
2. Check oil pressure with mechanical gauge
3. Get an oil analysis done
4. Open the oil cap and see how much blowby you have. Rule of thumb: When you place the cap upside down on the fill port, it should teeter a bit. If it's blown off, that's too much.
5. Monitor oil consumption. Good compression =/= not burning oil


Other things you can check if you'd like to go more in depth:

1. Drop the pan, inspect internals for sludge or varnish
2. While the pan is out, pull rod and main bearings, check clearance and give a visual inspection
3. Inspect the timing chain, verify if it's in spec or not.
 
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mykdee

mykdee

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And at that timeframe, even minor variations in maintenance will cause a pretty major difference in the usable lifespan of the engine.


As far as inspecting a high mileage engine to get an idea of where its at, I'd do, at a minimum, the following:

1. Compression AND leakdown test
2. Check oil pressure with mechanical gauge
3. Get an oil analysis done
4. Open the oil cap and see how much blowby you have. Rule of thumb: When you place the cap upside down on the fill port, it should teeter a bit. If it's blown off, that's too much.
5. Monitor oil consumption. Good compression =/= not burning oil


Other things you can check if you'd like to go more in depth:

1. Drop the pan, inspect internals for sludge or varnish
2. While the pan is out, pull rod and main bearings, check clearance and give a visual inspection
3. Inspect the timing chain, verify if it's in spec or not.


1. What should the compression be at, considering the mileage?
2. What should oil pressure read on a meachanical gauge?

3. I checked for blowby, there is very little blowby close to none. The oil cap is not blown off when laying on there.
 

Squirrelsmith

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1. What should the compression be at, considering the mileage?
2. What should oil pressure read on a meachanical gauge?

3. I checked for blowby, there is very little blowby close to none. The oil cap is not blown off when laying on there.
I believe 150 psi is ideal. Mine has 187k miles the compression was 135 - 150 psi. It's important that all the numbers are within a range of eachother.... %15 i think it is
 

Squirrelsmith

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Personaly im not worried about it. Stock crate engines are so cheap i'll just replace it when the time comes and still be way ahead financially of where i would be with a later model tahoe. Assuming you do the work yourself
 
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mykdee

mykdee

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Personaly im not worried about it. Stock crate engines are so cheap i'll just replace it when the time comes and still be way ahead financially of where i would be with a later model tahoe. Assuming you do the work yourself

I figure even if you pay a shop to install a new crate motor, you would still be in much better shape than buying a new Tahoe or Yukon. You could pay a shop to install a Motor, Trans & transfer case and still be in GREAT shape!
 

Squirrelsmith

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I figure even if you pay a shop to install a new crate motor, you would still be in much better shape than buying a new Tahoe or Yukon. You could pay a shop to install a Motor, Trans & transfer case and still be in GREAT shape!
That was my thought when i bought mine. I was looking at nnbs's and with 100k miles the damn thing were still like $20k. I figure i could totally rebuild a obs (or nbs for that matter) and have a brand new truck.
My theory assumed though that i could do most of the work myself and you need to have the cash to do it. A lot of people can get together $400 a month for a car payment on a 20k car but cant manage their money in such a way that they have several thousands dollars on hand when they do need a new engine.
 
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mykdee

mykdee

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That was my thought when i bought mine. I was looking at nnbs's and with 100k miles the damn thing were still like $20k. I figure i could totally rebuild a obs (or nbs for that matter) and have a brand new truck.
My theory assumed though that i could do most of the work myself and you need to have the cash to do it. A lot of people can get together $400 a month for a car payment on a 20k car but cant manage their money in such a way that they have several thousands dollars on hand when they do need a new engine.

If you are even somewhat responsible with your money and save that $400 a month payment, within 1 year you would have the money for a new motor & trans!
 

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