Can rebuilding an Engine drastically increase fuel efficiency?

[Bryan]

I've got a 2002 Chevy Express 2500 with 130k miles on it. It's in good shape and it was well cared for by a school disctrict. Drives great and as of right now I'm getting 18-19 mpg on the highway. Hypothetically if I were to get the engine rebuilt would that drastically improve my fuel efficiency?

Thanks for your help

 

[[email protected]]

Not really. If you are getting 18 to 19 now…I doubt it will get much better.

 

[NctryBen]

No... you may gain some... but rebuilding your engine would more likely just freshen the moving parts and bearings and such giving you more efficiency in maybe power and such. But cannot guarantee any drastic change in fuel efficiency. Best thing is to go through your systems... electronics, fuel, exhaust as far as the motor. Then make sure your drivetrain is maintained well as far as transmission, transfer case (if you have one), drive shaft and rearend. And your braking system... checking for calipers sticking or whatever.
You’d be surprised what you might find dragging you down. Air and fuel filters can be simple but ignored often. My mileage isn’t really suffering at 610,000 miles. But the maintenance is a top priority. I think in ten years I figure I’ve spent $7000 in oil changes alone. Haha. 7.3 diesel....

 

[GotSmart]

Drastically?

No.

If you changed out the entire fuel delivery system perhaps up to 25%. But the cost would be more than the mileage gain would justify.

Keep up on the oil changes, and use a fuel cleaner like Lucas every other fill up. That is the best way to help keep from getting worse gas mileage.

 

[bullfrog]

Absolutely the best thing is to keep the oil and filter changed at no more than 5,000 miles even with synthetic oil and using a high quality filter like WIX or NAPA PRO. Your present fuel mileage seems extremely good at present to me but should if it go down after checking things like tire pressures, brake adjustments and back pressure a cylinder leakage test will tell you the condition of the engine internals as far as combustion efficiently. An oil diagnostic test will also help verify you and your motor are doing things right. It has been my experience that new from the factory motors generally are better quality and last longer than rebuilds. Many people get sold a valve job only to find a little later they need a complete rebuild as renewing the top end of the motor increases the strain on the lower end and brings out problems that may have not been apparent previously so be careful about performance improvements without a total rebuild by a expert mechanic.

 

[rruff]

I've got a 2002 Chevy Express 2500 with 130k miles on it. It's in good shape and it was well cared for by a school disctrict. Drives great and as of right now I'm getting 18-19 mpg on the highway. Hypothetically if I were to get the engine rebuilt would that drastically improve my fuel efficiency?

18-19 mpg is fantastic for one of those. Are there any indications that you need a rebuild? 130k miles isn't a lot.

 

[FlipperFla]

Wow! That’s really good for an Express. What size engine? Mine is a 2000 w/ a 350ci. Depends on load and terrain but I’m around 16-17. I specifically bought it in my search for a hi top with a 350. It was the last year. Seems everything I ever owned had a 350, our boat had 2! Talk about a gas hog, it got around 1MPG. Great engines! Run forever. Workhorse of America! Parts available everywhere.

 

[user 2252]

18-19 mpg is fantastic for one of those. Are there any indications that you need a rebuild? 130k miles isn't a lot.

........unless you really love this stuff, just think, your rebuild purrs like a kitten every time you turn the key, and you can enjoy feeling the power as you step on the gas pedal heading out on the latest road trip with confidence. The choice is yours, only you know the shape it's in and will it be worth the time and money. I for one would rebuild and potentially gain another 20 years and 130000 miles if the body was solid. years ago, when i wore a younger man's clothes, you could buy a crate engine (complete block with pistons and crankshaft, cam, lifters and heads) for about 1500 to 2500 dollar and swap it out yourself.

 

[Zerpersande]

I've got a 2002 Chevy Express 2500 with 130k miles on it. It's in good shape and it was well cared for by a school disctrict. Drives great and as of right now I'm getting 18-19 mpg on the highway. Hypothetically if I were to get the engine rebuilt would that drastically improve my fuel efficiency?

Thanks for your help

Any gains will likely be small. Of course you’ll likely improve HP a bit through better compression, which will give better mileage. But notice I didn’t say ‘measurably better mileage’.

 

[FlipperFla]

Any gains will likely be small. Of course you’ll likely improve HP a bit through better compression, which will give better mileage. But notice I didn’t say ‘measurably better mileage’.

Everyone of my previous Chevy vans with 350s all went well over 300k. Rust was the major issues in earlier models. My 1st one, 78 G20 made to order from Chevy, $4700!

 

[AeroNautiCal]

The single most important thing which has the capability to improve one's MPG is to carry out a weekly tyre pressure check!

Underinflated tyres create drag in addition to negatively affecting the handling of the vehicle, but it also causes an increase in fuel consumption.

Obviously, the condition of the air filter, and other filters can adversely affect fuel consumption, but by far, the most neglected are the tyre pressures.


Insurance companies may reject a claim if the tyre pressures were found to be outside of the manufacturers approved range.


I would not consider an engine rebuild as a means of increasing MPG, as your engine is relatively low mileage and the vehicle was cared for.


Checking to see if you're carrying stuff you don't use may lead to you hauling less weight and using morefuel

 

[rruff]

Found this regarding tire pressure, in an article about fuel saving tips : https://www.edmunds.com/fuel-economy/we-test-the-tips.html

Test #5 Check Your Tire Pressure
Result: Important for safety and to reduce tire wear
Cold Hard Facts: No measurable effect on the vehicles we tested
Recommendation: Check your tire pressure often but don't expect a big savings.

Lots of statements say low pressure is bad, but they don't reference actual tests. With modern radials it doesn't make much difference.

Best pressure for handling and tread life? That's where weight is evenly distributed across the tread. If you have different tires or wheels (dimensions) than stock or are carrying a load (aren't we all?), you can't go by the door sticker, either. Best to measure using the "chalk test". https://www.tundras.com/threads/tire-pressure-chalk-test-how-to-guide.2114/

Offroad things get even more complicated since flotation and absorbing bumps comes into play.

 

[Zerpersande]

I've got a 2002 Chevy Express 2500 with 130k miles on it. It's in good shape and it was well cared for by a school disctrict. Drives great and as of right now I'm getting 18-19 mpg on the highway. Hypothetically if I were to get the engine rebuilt would that drastically improve my fuel efficiency?

Thanks for your help

There is one proven way of improving your gas mileage. This trick requires two people, any friend with a couple of hours free time will do.

- Open the hood
- Have your friend remove the radiator cap and hold it
- Back your current car and take it it the dealership
- Trade your car in on a vehicle with better gas mileage
- Drive back home and tell your friend to throw the radiator cap in the trash

 

[eDJ_]

Good responses here. Before anything, a good tune up and even replacing the spark plug "wires". (which don't have wire inside them but rather carbon impregnated fiber...and should be replaced every couple of years) There are computerized tuning Pro devices that can be used in such a good tune up. Next, I would suggest making sure your brakes are functioning properly and not dragging. (causing friction that will draw down your fuel mileage)

From what others are saying it sounds like you are doing well as you are. It is tempting to invest in a new vehicle when you first get it, but rather than spending money to modify it spend some money to first have it analyzed to know what you got.

And one last thing. The PCV (positive crankcase valve) should be replaced once a year if YOU can get to it. They aren't expensive and can limit unnecessary oil consumption. A stuck PCV, or a PCV with it's seat not sealing due to wear, or a PCV with a plugged up hose can lead to above average oil consumption. And this lead an owner thinking it is the fault of a worn engine.

 

[Happy Camper]

All good advice, well most of it, given. Unless you're engine is dying and you're fully aware of that, the cost didn't justify any savings on fuel.

A broken motor gets great mileage as far as you can push or tow it. A running full sized van getting 19 mpg is something a lot wish they were getting with theirs.

Love the one you're with until it tells you it's done. Air filter is a bigger deal for mileage than people think. Oil and filters of course.

 

[kazak9999]

One method for improving MPG that has not been mentioned is to drive slower. Works just about every time.

 

[Happy Camper]

In fact, if you don't drive at all, you get even better mileage.

 

[kazak9999]

In fact, if you don't drive at all, you get even better mileage.

Lol!

 

[Spaceman Spiff]

In fact, if you don't drive at all, you get even better mileage.

Unless you idle your engine. Then you get 0.0 mpg.

 

[LargeMarge]

I've got... if I were to get the engine rebuilt[,] would that drastically improve my fuel efficiency?...

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Bore and stroke plus compression ratio are the major determinants for fuel consumption.
For a gasoline engine, another factor is carburetor versus injection (although the computer(s) controlling the injection system are subject to tinkering).
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A certain amount of fuel is needed for the combustion cycle.
Using the 'bore times stroke' formula, not much can be done to alter physics.
(Unfortunately, after about 2006 or so, many vehicles get worse fuel economy than an identical older sibling.
In an effort to reduce tail-pipe emissions, more fuel is required.
Weird, eh?)
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Instead of re-building your engine -- as long as it is functioning reasonably-well -- I suspect the 'nut behind the wheel' is still the primary influence on mpg [recently chided -- and still stinging (Yee-OUCH!) -- for using an abbreviation instead of stating the complete phrase, let it be known to all:
* 'mpg' is my personal shorthand for 'miles per gallon'].
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Another point:
* recouping your investment at a few fractions of something something per daily use... I think you are looking at decades.
A lot of fedbux, very tiny reward.
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This discussion ignores the vehicle down-time.
R&R [removing and replacing] an engine assembly is a significant undertaking, requiring specialists and specialized equipment.
Can you do without your rig for a month (if everything goes perfect (a yuge 'if'!)), potentially missing a few festivals or a hot-date with the next Forever Mate?
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And you risk fumbling one strategic wire, bumping one of the computers just the wrong way at just the wrong time, or introducing contaminants into the fuel system or the wiring system or the cyber-system.
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Perhaps a different vehicle might suit your RequirementsStatement?
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An aside:
We full-time live-aboard.
We rarely travel more than a hundred miles a month.
Fuel is a very minor part of our budget.