Amsoil Engine Flush? Should I Do It?

Schurkey · Feb 25, 2020

SAATR said:
What purpose does a bypass filter serve if it's only run for a few hundred miles?

The first few hundred miles on a new engine is when all the metal bits are getting friendly with each other. The bypass filter removes the wear particles from the oil, so that the oil doesn't have to be removed from the engine.

Why buy ultra-expensive "break in" oil, just to dump it at ~20 minutes, and again at 500 miles or so? With a bypass filter, the full-flow filter might be changed, but the oil is merely topped-off and continues in service.

Yeah, if you're not using thick Moly-based paste assembly lube because you've got roller lifters, you probably wouldn't have to change oil and filter at 20 minutes.

BNielsen said:
I'm wanting to install one of the dual-filter bypasses but I don't know a good spot to mount it

There are some remote-mounted dual oil filter assemblies that include a bypass filter. Most don't, they're just remote-mounted full-flow oil filters.

Erik the Awful · Feb 25, 2020

If you perform regular oil changes, there's nothing preventative about an oil flush. Maintaining the most perfectly clean oil does nothing above maintaining adequately clean oil. If you bought a truck that hasn't had regular maintenance, then an oil flush is preventative.

The poor man's flush is to change the oil, put in cheapo oil with a quart of ATF, drive 500 miles, then change to good oil.

I run Valvoline or Castrol (because I can find them anywhere around here) and change the oil every 3000-5000 miles.

Finally, if you're endurance racing, it pays to change the oil every race and send samples in for analysis. If your daily driver is a $200k over-engineered money sucker (which a GMT400 certainly is not!), it probably pays to have the same oil analysis.

Rick Gill · Feb 25, 2020

I have had 2 of these trucks. I put 165,000 on the first, 193,000 on the second. I am at 100,000 miles on a new engine in the second truck and going strong! Having been in the Automotive Parts and Service business for 47 years, I can speak with confidence. Many times I have witnessed the use of an engine oil flush and it does not work out well! Usually sludge releases and clogs the engine oil pump screen resulting in damage to the engine! At 115,000 miles your engine should be pretty clean inside unless the previous owner just never changed the oil. I would just do an oil change every 1500/2000 miles for a few times with a good quality oil and then start changing the oil every 3/5 thousand miles depending on how your truck is used. City/Highway miles? Your engine is one of the best ever built! Don't mess with success!!!

someotherguy · Feb 25, 2020

Just remember, "chunks" end up in the bottom of the pan, where your oil pump pickup screen is.

Richard

Redneckgeriatric · Feb 25, 2020

Erik the Awful said:
If you perform regular oil changes, there's nothing preventative about an oil flush. Maintaining the most perfectly clean oil does nothing above maintaining adequately clean oil. If you bought a truck that hasn't had regular maintenance, then an oil flush is preventative.

The poor man's flush is to change the oil, put in cheapo oil with a quart of ATF, drive 500 miles, then change to good oil.

I run Valvoline or Castrol (because I can find them anywhere around here) and change the oil every 3000-5000 miles.

Finally, if you're endurance racing, it pays to change the oil every race and send samples in for analysis. If your daily driver is a $200k over-engineered money sucker (which a GMT400 certainly is not!), it probably pays to have the same oil analysis.

lol you are right! these trucks are not! they are however, $2000 under engineered money suckers! rest of your post is right too!

Stillruns · Feb 26, 2020

Like anything else, it is a matter of personal preference. At 115 k, I would not think a flush is needed unless the previous owner was neglect in their maintenance duties, or you are unsure of the truck's history.

Having said that, I can share my own experiences...
4 different trucks...
88 c3500, 7.4, sold at 350k, tired but running well.
89 k5 blazer, 5.7, 145k and running great.
94 k1500, 5.7, 294k, a little tired but running awesome-ish, (daily driver).
98 1500 Tahoe, 5.7, 160k, runs great.

Each was flushed at 100k, (and every 100k since as it applies).

In all 4 I drained and filled with fresh dexron ATF, and a fresh WIX filter.

ATF is about 5 wt and very high detergent so it really scrubs stuff and is dirt cheap.

Let motor warm up then drive GENTLY for about 40-50 miles... nothing over 50 mph or about 1800-2000 rpm. A nice stretch of road without stop lights is my suggestion.

Once home, IMMEDIATELY drain thoroughly and discard filter. Install new filter, (I'm preferential toward WIX). Fill with Valvoline high mileage and you're good to go.
I've done this a bunch of times with no ill effects and will continue to do so...

Amzoil is good stuff... I'm just old school and trust this process.

Good luck...

someotherguy · Feb 26, 2020

RE: neglected engines; had a customer forever ago bring his squarebody truck in for oil pressure issues, turns out it had CHUNKS between the rocker arms, old sludgy oil that had cooked in and was interfering with oil drainback from the heads. This guy was a notorious cheapskate and wasn't about to pay for a teardown, rebuild, replacement, or anything. I did what I could, blocking the drain holes then using a shop vac to suck the chunks up while carefully chiseling them out. You can't get every single piece without tearing down the valvetrain but as I said this guy wasn't gonna pay for it. The engine lived, don't know for how long, but I can only imagine the mess in the pan that would have resulted had anybody simply just put an engine flush product in there.

Richard

Erik the Awful · Feb 26, 2020

Mind if I engage in Storytime?

When I was a Nissan tech, we had a customer bring in a 40k mile Altima that had never had the oil changed. The tech who had the job pulled the valvecover, and everything had a nice film of black oil on it. He touched the oil and it crumbed. The service writer told the customer that if she could provide proof she'd had the oil changed at least three times, he would replace the motor on warranty. She came back the next day with three receipts from the garage down the street with no dates and "vehicle serviced" scribbled on them. The car sat on the back lot for a solid year until she finally hired a lawyer. Nissan got a letter from the lawyer and instead of going through $10k worth of litigation they spent $5k on the motor swap. She got what she wanted, but it took the expense of a lawyer and her vehicle depreciated by sitting in the sun for a year.

kwslvdo96 · Feb 26, 2020

Thanks alot guys, I've owned this truck since 41K miles and the last 5 years, and ive always taken great care of it I change the oil every 3 to 4 thousand miles so with your advice im leaving it alone. Im just going to change oil to the Amsoil 10w30 and leave it be. Again thanks for your opinions

Aparke4 · Apr 1, 2020

I always put in Seafoam for the last 20-50 miles before an oil change... its mild and assists with cleaning but like mentioned above, the best is to run a oil change for 500 miles and change filter and oil afterwards with marvels, seafoam or a little ATF. Safe and easy.

Amsoil Engine Flush? Should I Do It?

Schurkey

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Erik the Awful

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Rick Gill

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someotherguy

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Redneckgeriatric

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Stillruns

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someotherguy

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Erik the Awful

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kwslvdo96

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Aparke4

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