What did you do to your NNBS GMT900 Tahoe/Yukon Today?

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George B

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I’ve been getting an average of 12mpg e85. I changed my tune to 89/91 BBP tune and on the way to the airport I was getting 18mpg, we’ll have to see what the average turns out to be over time but so far I’m a fan. Lol
I was thinking about the higher octane tune on E85 too. Will be watching for your report.
 

RooTBeeRthe1st

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I get about 50mi less per tank on e85.

While parts shopping the last week or whatever, I started thinking that my oil consumption could definitely be partly due to last summer when the radiator blew up and I overheated the engine, so now if I'm taking everything apart anyway, I should probably just actually rebuild it in case cylinders are slightly out of shape and or something else has an issue and needs to be machined before I throw a bunch of nice parts in a bold block...
Unfortunately that means the job will take a lot longer if I have to send stuff out to a machine shop.
 

Doubeleive

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I get about 50mi less per tank on e85.

While parts shopping the last week or whatever, I started thinking that my oil consumption could definitely be partly due to last summer when the radiator blew up and I overheated the engine, so now if I'm taking everything apart anyway, I should probably just actually rebuild it in case cylinders are slightly out of shape and or something else has an issue and needs to be machined before I throw a bunch of nice parts in a bold block...
Unfortunately that means the job will take a lot longer if I have to send stuff out to a machine shop.
define overheated, as in how much did it over heat and for how long?
if it only happened once and you noticed the problem right away and pulled over stopped and shut it off, then you are fine
if you drove it and never noticed any problem and it gave you a warning on the dic and you then pulled over and stopped, then you are probably fine as well
if it overheated and you continued to drive it and it made any weird knocking sounds and was over the red line for a while and or noticed a big drop in power, then it's possible you damaged something.
or if it overheated several times and you continued to drive it anyway like a stop-n-go when it cools off kind of thing then it also possible you damaged something.
 

RooTBeeRthe1st

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define overheated, as in how much did it over heat and for how long?
if it only happened once and you noticed the problem right away and pulled over stopped and shut it off, then you are fine
if you drove it and never noticed any problem and it gave you a warning on the dic and you then pulled over and stopped, then you are probably fine as well
if it overheated and you continued to drive it and it made any weird knocking sounds and was over the red line for a while and or noticed a big drop in power, then it's possible you damaged something.
or if it overheated several times and you continued to drive it anyway like a stop-n-go when it cools off kind of thing then it also possible you damaged something.
Couple miles no coolant.
I knew it was hot, but hoped there was still something in the system.
Whatever air was against the temp sensor was reading like 280.
This was last summer, I've put probably 10,000 miles on it since then, the only issue I've noticed is that higher oil consumption.
I'm starting to get a ticking noise but that's only come in the last couple months, and I'm honestly not sure if it's the dod lifters, potentially worn out lifter buckets, or just an exhaust leak.
 

Doubeleive

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Couple miles no coolant.
I knew it was hot, but hoped there was still something in the system.
Whatever air was against the temp sensor was reading like 280.
This was last summer, I've put probably 10,000 miles on it since then, the only issue I've noticed is that higher oil consumption.
I'm starting to get a ticking noise but that's only come in the last couple months, and I'm honestly not sure if it's the dod lifters, potentially worn out lifter buckets, or just an exhaust leak.
well that's probably going to have to be a personal call on that one, I haven't driven that far with no coolant since I had my 1st car lol I drove that one to the levy so to say, melted 2 sets of spark plug wires and it was puff the magic dragon at 10 15mph max in the end, young and dumb...... lesson learned
oh ya and i got arrested in it and it got towed away... in the bitter end long story...
 
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RooTBeeRthe1st

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well that's probably going to have to a personal call on that one, I haven't driven that far with no coolant since I had my 1st car lol I drove that one to the levy so to say, melted 2 sets of spark plug wires and it was puff the magic dragon at 10 15mph max in the end, young and dumb...... lesson learned
oh ya and i got arrested in it and it got towed away... in the bitter end long story...
Literally the only issue of noticed, besides the elevated oil consumption, is that either exhaust leak or valve train noise, and the exhaust leak is completely unrelated if that's what it is, and the valve pick, has slowly been getting worse over time and didn't happen until maybe 6 months after it overheated when I noticed, so likely also unrelated.

I'll probably just measure the bore both directions down every cylinder in the top middle and bottom just to check for uniformity and make sure that's not an issue, just trying to save down time when I rip it all apart.
 

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