Preventative Maintenance on High Mileage '14 Sierra 4x4 5.3L

[2014HighMiler]

I have recently acquired a 2014 Sierra Crew 4x4 5.3L with over 200,000 kms

 

I have been thinking about installing a new vacuum pump. I did piles of reading on the different issues for the new engine(s). Mine looks like it has been there for a while and it seems like fallout from a failed one is brutal. Are there an better options? I heard about disabling the V4 mode and deleting the vacuum pump altogether. Any thoughts?

 

I have looked into the maintenance history of this truck and it appears it has had the rad replaced, but I will likely install the redesigned thermostat just to be safe as I am smelling some coolant after driving, but the reservoir is not noticeably depleting.

 

I also read about the GDI coking of intake valves. I have no history of a cleaning being done on this truck at all and no catch can either - over 200,000 kms! Truck is returning about 14.5L/100 for a mix of driving, but primarily short runs in and out of town. Highway driving 80-100 it seems to get into the low 13's. I'm not sure if this is good or bad for the truck. When the weather gets nice I will probably remove the intake manifold and have a look (need the Goldwing for back-up vehicle).

 

Oil - 0W20 - I am coverting the truck over to Amsoil. I have read the whole oil story, I get it, but I am wondering with this kinda Kms, how many of you would go up to 5W rather than the 0W. I care more about the motor than any fuel mileage loss. Oil pressure seems fine and the winter pour point of 5W full synthetic is fine. I had upgraded the 5W in my 8.1L to 10W full synthetic and it started easier in the winter.

 

Anything else you might consider on a high miler like this?

 

 

[Mike GMC]

Change all the fluids, engine, trans, transfer case, differentials, brakes and coolant.  Get the cooling system pressure tested and find the leak. If you smell it, it leaks.  I'd stick with the 0w-20.  Amsoil is good stuff, use it if it makes you happy.  Check the intake tube, throttle body and manifold plenum for oil.  If they are all dry, you may not need to worry about the valves.  If they are wet, clean up all you can and consider a top engine clean service.  Once clean, consider the catch can.

 

For the vacuum pump, if you're nervous about it, get a new one.  But consider this, if it's lasted this long, it's probably a good one.

[Sierra706]

I wouldn’t touch the transmission unless you know the previous owner did regular fluid changes


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[Kubs]

I agree that changing the fluids is good measure.  I do that on all used car I buy.

 

Just to clarify, the 0-5-10W does not change the weight of the oil.  They are indicators of the cold flow properties of the oil, and temperature in which it passed.  Switching from 0W-20 to 5W-20 would not change a thing. It's still 20 weight oil.

[2014HighMiler]

5 hours ago, Kubs said:

I agree that changing the fluids is good measure.  I do that on all used car I buy.

 

Just to clarify, the 0-5-10W does not change the weight of the oil.  They are indicators of the cold flow properties of the oil, and temperature in which it passed.  Switching from 0W-20 to 5W-20 would not change a thing. It's still 20 weight oil.

Sorry, senior moment...

[2014HighMiler]

6 hours ago, Bushleaguechew said:

I wouldn’t touch the transmission unless you know the previous owner did regular fluid changes


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Funny you mention that, it's the only part of the truck that I haven't ordered fluids for and according to GM, they hadn't serviced the transmission, but I am going to give the VIN to another service manager and doublecheck because if it's still on original fluid....geeez

[2014HighMiler]

6 hours ago, Mike GMC said:

Change all the fluids, engine, trans, transfer case, differentials, brakes and coolant.  Get the cooling system pressure tested and find the leak. If you smell it, it leaks.  I'd stick with the 0w-20.  Amsoil is good stuff, use it if it makes you happy.  Check the intake tube, throttle body and manifold plenum for oil.  If they are all dry, you may not need to worry about the valves.  If they are wet, clean up all you can and consider a top engine clean service.  Once clean, consider the catch can.

 

For the vacuum pump, if you're nervous about it, get a new one.  But consider this, if it's lasted this long, it's probably a good one.

I have always owned used higher mileage cars/trucks for the most part and had the same feeling that if the components lasted 200-300-400 kms, they might just hold out a bit longer yet. They came off the line on a good day, fresh tooling, and the right employees/QC!

 

As the weather warms up I will definitely have a look-see into the IM and report back. T'would be nice if it were dry......

[2014HighMiler]

Any comments regarding my fuel usage....pretty typical or should it be a bit better?

[Mike GMC]

I don't speak metric, so I can't comment on your fuel consumption. You might also want to replace the belts and hoses if they are showing signs of age.

[2014HighMiler]

Just now, Mike GMC said:

I don't speak metric, so I can't comment on you mileage.  You might also want to replace the belts and hoses if they are showing signs of age.

16-18 MPG

[Mike GMC]

I get an overall average of 18-19 on my '15.  That's about 2/3 highway miles.  Tires and driving style have huge impacts on efficiency, bigger LT tires are heavy.  I don't think I need to explain a heavy foot.

Is yours all stock or are there any mods?

[2014HighMiler]

2 minutes ago, Mike GMC said:

I get an overall average of 18-19 on my '15.  That's about 2/3 highway miles.  Tires and driving style have huge impacts on efficiency, bigger LT tires are heavy.  I don't think I need to explain a heavy foot.

Is yours all stock or are there any more?

All stock. I'm doing 4 hours of hwy driving this weekend and will be keeping an eye on fuel usage. I drive very relaxed. no rush.

[Mike GMC]

Well, if you land in the 18-20 range, I'd be happy with it.  I've also noticed that windy conditions can have big impacts on the mileage, positive or negative depending on direction.

[Mike GMC]

I've read stories on here about guys getting well over 20, even 25 mpg.  I've never been close to that.  I usually set the cruise at 80+ on the interstate and let her roll.  Even on the slower 2 lane highways at 65 ish, I barely see 20 mpg.

[2014HighMiler]

Yes I also heard about those claims and I don't know if I'll get there either. Maybe after the intake valves are cleaned and everything else is in tip shop shape, plus a good tail wind...