Why do you want a motor flush, is it pretty gunked up inside? Oil pan removal should be removed afterwards. I've seen many oil pickup screens plug up and destroy engines from using engine flush.

 

Yeah that’s what I was thinking after reading the motor medic directions... it says to drop the oil pan After the Flush because of aclogging issue.

Forget a "flush". Consider adding the recommened amount of seafoam to the oil fill and run the engine a couple hundred miles before an oil change.

You can also use seafoam in the gas to clean injectors, but if you use top tier gas, it's not necessary.

cool that’s what I was thinking maybe would be the best... I was going to do the intake seafoam cleanse again before next oil change...

 

Forget a "flush". Consider adding the recommened amount of seafoam to the oil fill and run the engine a couple hundred miles before an oil change.

You can also use seafoam in the gas to clean injectors, but if you use top tier gas, it's not necessary.

 

When I do use a motor flush, I use Gunk 5 minute motor flush. I have used this stuff for years. In the old days. it was 15 minute motor flush. so that is how long I run it, at idle only. Then do an oil change. If you use a good oil, this issue should not come back. What engine is this. Old cast iron block? aluminum block? all of this makes a difference.

 

Cool thanks. I don’t know exactly I need to look it up. It’s a 2000 Silverado 1500 LS Z71 5.3L

 

Here (in south Louisiana) where I live, it is hot most of the year. This effects sludge build up in your engine, as the engine stays hotter for a longer time after it is shut off. The oil tends to cook off as it sits in your hot engine. Any oil that has any paraffin in it will turn waxy and sludge as it cooks off in the heat. Quaker state, Penzoil, Castroil, all sludge up. Rotella is grate stuff, and can be used in your engine, although it is for a diesel engine. I used it for a while, but now use Valvoline. As for synthetic oil, just avoid the above mentioned brands and you should be good to go. IMO its not necessary to use synthetic oil in a cast iron block like you have, but that is just my opinion. People will argue about synthetic VS conventional oil, but keep this in mind. Cast iron engines have been around a lot longer than synthetic oil has. They were designed to use conventional oil. I am not saying that is better than synthetic oil, but IMO, it is just an added expense that is not needed.

 

he has the same engine I have not cast iron !!!!!!

my 96 Impala has cast iron block and your 97 is cast iron ..

my Impala LT1 has the same oil in it as the 2000 5.3L 5-30wt mobil synthetic...my 2000 came with dino ran like sh^t... at 10K miles all fixed .. then I dumped the GM dexron III @18K miles used synthetic tranny fluid increase MPG . more power faster shifts esp when cold ..

GM dexos spec oil is the best I have used .. I go 10K miles on my 2000 and use 1/2QT of oil .. oil still looking good no sludge cranks very fast when cold out .. cold out means below 20F ...

where you live if it got to 20F that would be like a total disaster LOL...

 

he has the same engine I have not cast iron !!!!!!

my 96 Impala has cast iron block and your 97 is cast iron ..

my Impala LT1 has the same oil in it as the 2000 5.3L 5-30wt mobil synthetic...my 2000 came with dino ran like sh^t... at 10K miles all fixed .. then I dumped the GM dexron III @18K miles used synthetic tranny fluid increase MPG . more power faster shifts esp when cold ..

GM dexos spec oil is the best I have used .. I go 10K miles on my 2000 and use 1/2QT of oil .. oil still looking good no sludge cranks very fast when cold out .. cold out means below 20F ...

where you live if it got to 20F that would be like a total disaster LOL...

first gen truck 5.3l not cast iron,,,, thats news to me, but what ever. As for the oil, sence you dont live here, then there is no way for you to know. Just because it did not happen to you, doesnt mean it doesnt happen at all. I just know what I have seen with my own eyes. I have been doing mechanic work sence 1976. And I was a mechanic at 2 auto dealers. I just learned I could make more money, and enjoyed welding better. I still do and never stop wrenching on my own equptment, and still do at work as needed.

 

my eyes the 2000 5.3L is a silver color ya no paint on the engine LOL.......

on the 96 black paint and some rust .......2000 5.3L no rust perhaps a little white fussy color in spots...

when the temps drop down to 20F and lower you will not be happy as the engine will not run good with dino oil ..

also we up here use 30 below zero washer fluid .... I had a very hard time finding 30 below zero washer fluid in sw florida ..

I guess you never lived in the cold north east ... cold does screw things up I mean real cold not 50 F ..

I watch the weather channel every day reason is in winter we have to deal with hurricane snow storms .. you only have to deal with rainy hurricanes not too bad ..

storm number 3 coming this tuesday prehaps 12-24 inches with hurricane winds and no power again for a day or two ...

 

my eyes the 2000 5.3L is a silver color ya no paint on the engine LOL.......

on the 96 black paint and some rust .......2000 5.3L no rust perhaps a little white fussy color in spots...

when the temps drop down to 20F and lower you will not be happy as the engine will not run good with dino oil ..

also we up here use 30 below zero washer fluid .... I had a very hard time finding 30 below zero washer fluid in sw florida ..

I guess you never lived in the cold north east ... cold does screw things up I mean real cold not 50 F ..

your rite, I have loved in south Lousiana all my life, and will never live where it is real cold. You can have all of that. As for your engine, IDK what you have. I do know that GM made a lot of different 5.3L through the years, and IDK 5 or 6 different ones each year. My whole point about oil is that your climet will have an effect on your oil. Even you just said so.

 

Here is the info on first gen LS (genIII) engines straight from wikipedia.

Generation III (1996–2007)[edit]
Generation III
Overview
Manufacturer General Motors
Also called Vortec
Production 1996-2007
Layout
Configuration V8
Displacement

• 4,807 cc (293.3 cu in)
• 5,328 cc (325.1 cu in)
• 5,665 cc (345.7 cu in)
• 5,967 cc (364.1 cu in)

Cylinder bore

• 96.01 mm (3.780 in)
• 99 mm (3.9 in)
• 101.6 mm (4.00 in)

Piston stroke

• 83 mm (3.3 in)
• 92 mm (3.6 in)

Cylinder blockalloy

• Aluminium
• Cast iron

Cylinder headalloy

• Aluminium
• Cast iron

Valvetrain OHV
Combustion
Fuel system Sequential multi-port fuel injection
Fuel type

• Gasoline

Oil system Wet sump
Cooling system Water-cooled
Chronology
Predecessor

• Generation I
• Generation II

Successor Generation IV
The GM Generation I and Generation II (LT) engine families both derived from the longstanding Chevrolet small block V8. The Generation III small-block V8 was a "clean sheet" design, which replaced the Gen I and Gen II engine families in 2003 and 1996 respectively.

Like the previous two generations, the Buick and Oldsmobile small blocks, the gen III/IV can be found in many different brands. The engine blocks were cast in aluminium for car applications, and iron for most truck applications (notable exceptions include the Chevrolet TrailBlazer SS, Chevrolet SSR and a limited run of Chevrolet/GMC Extended Cab Standard Box Trucks).

 

I do have an extended cab standard box truck... I wonder if it’s aluminum... how can I check? And definitely on oil, manual says 5w30 for all weather hot or cold and 10w30 Only for temps Above zero degrees Fahrenheit.

 

The easiest way to know for sure, is to put a magnet on the block. If it sticks, its cast iron, if not its aluminum

 

....engine flush....

I add a quart of diesel to oil and idle it for 5 mins. Best flush.

If you're looking for something you can drive and clean the inside add a quart of trans fluid to oil then drive gently for about 100 miles before oil change.

Been doing both for years and I've tried just about any other commercial flush. None are more effective just more expensive.

Seafoam in the intake and gas tank. I saw no discernable results in the crankcase.