4,000 mile oil change interval (with Synthetic) from now on.

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I just wanted to share my "Zero-Sludge" strategy for oil changes going forward.
I'll be changing my oil every 4,000 miles with PUP Synthetic (5 quart jug from Walmart) from now on, and changing my PCV valve every 30,000 miles.
I started the regiment with an engine flush (Liqui Moly) to clean out the engine first.

I think oil testing labs that are telling people with 10k oil change intervals that their oil is still good for another X thousand miles, are missing the point.
The amount of sludge in your engine is proportional to how many miles you go between oil changes.
Sludge is that gooey black thick formation all over the inside of your engine which clogs oil passageways and causes lower oil pressure which can really
harm an engine over the long term.

I read so many posts on BITOG about people that are so proud that they are going 7500, 10000, 12000, 15000 OCI's and testing labs saying their oil is still good.
The focus should not be on how long you can go without an oil change, but instead how clean is the inside of your engine.

Think about it this way. If you were going to buy a used car, would you prefer the previous owner did 3k to 4k oil changes, or 15k oil changes.

Bill
 
I'm someone that almost always goes about 3-5K myself, usually using "conventional" which is syn blend now anyway. 90% of my driving is city/suburban and short trip, though.

That said, people have posted sludge free immaculate valve covers with 7, 8, and even 10K oil changes here. Even on a Galant I ran with Supertech conventional most of its life for 4-7k oil changes over 50K miles, I had only light varnish when I pulled the head. On that Galant, though, I always cleaned the PCV valve every oil change and bought 1-2 new ones, and was fairly religious with new air filters every year.

Sludge 99% of the time is related more to PCV valves than any other factor I think. The other thing that seems to cause sludge sorta regardless of the oil brand is if a car has been sitting for a long time and the oil just gets old sitting around in an engine (which is a different environment than a plastic bottle.)

So oil changes are a big deal for preventing sludge, but they're not the only factor, it's imo more about complete maintenance of the car. If you have bad spark plugs and o2 sensors, or a thermostat that's perpetually stuck open, those will eventually create more sludge even with a 3K interval than you would with a 10k interval on good oil, assuming everything else in the car is working properly, PCV isn't shut, air filter is clean, etc.
 
Think about it this way. If you were going to buy a used car, would you prefer the previous owner did 3k to 4k oil changes, or 15k oil changes.
To me that's a wrong way of thinking about used cars in general. 15K is obviously extreme and hyperbolic (though one of my friends does that and says it's been fine for him with good synthetic.) We'll use 10K for sake of argument.

I would go as far to say mileage in general is irrelevant with used vehicles past 4-5 years old (ie, buying 5-7 or so year old fleet vehicles with 100-150K on them already.) It's much more about how well everything stayed together over time. I had a friend that did religious 3K oil changes on his used cars, but would absolutely totally trash them, get into small fender benders, never replace any broken parts like tie rods, would destroy his suspension driving over curbs, etc, and then would complain "man, why aren't my cars lasting, I do oil changes every 3K."

So with used cars you can have absolutely trashed examples with 100K miles and 5K oil changes, or immaculate examples with 200K miles and 10K oil changes, you want the one that's not on the whole, trashed. There's other fluids that arguably matter more for change intervals, like coolant, transmission fluid, brake fluid, etc, that cost a lot more than $30 at Jiffy Lube to change that people don't change, that again matter more for the car as a whole than just oil changes.
 
I had a front valve cover gasket leak, and during repair, mechanic said he saw some sludge underneath it.
He also recommended doing a PCV valve change which I did. I have the Honda 3.5 VCM engine, which is prone to sludging.
So I chose to do a Liqui-Moli engine flush as well, to remove old sludge.

Many engines are prone to sludging - just google your make and model.
 
I had a front valve cover gasket leak, and during repair, mechanic said he saw some sludge underneath it.
He also recommended doing a PCV valve change which I did. I have the Honda 3.5 VCM engine, which is prone to sludging.
So I chose to do a Liqui-Moli engine flush as well, to remove old sludge.

Many engines are prone to sludging - just google your make and model.
How did that work out?
 
The Liqui-Moli engine flush went surprising well. I went to a Mavis Discount Tire (which we have in the North East).
They only charge $14 labor to do an oil change. I bring my own oil and filter.
I had them do 2 oil changes for 1 visit. They changed the oil and filter (using some cheap oil I bought a Walmart) so oil / filter was clean and new.
Then I had them add the Liqui-Moli, and ran engine for 10 minutes, then drain it all out.
The oil that came out after that drain was quite dark (10 minute old new oil with Liqui-Moli ran in engine for 10 minutes).
The darkness of that drain was really a good sign, that Liqui-Moli really cleaned out the engine.
Then they changed oil/filter again (last time with PUP and good filter).
I didn't have the valve cover opened again, so not sure what improvement there is, but the dark 10 minute old oil is a good sign.
 
I had a front valve cover gasket leak, and during repair, mechanic said he saw some sludge underneath it.
He also recommended doing a PCV valve change which I did. I have the Honda 3.5 VCM engine, which is prone to sludging.
So I chose to do a Liqui-Moli engine flush as well, to remove old sludge.

Many engines are prone to sludging - just google your make and model.
Even with all the Liqui-Moly in the world, your vehicle is still going to rust away long long before you have any sludge issues from a consistent manufacture specified oil change interval.
 
I'm only saying this: If you love your car, treat it well.
I have a Honda Odyssey which some mechanics criticize as having a problematic transmission.
From reading the forums, some people say they do a drain/fill of their transmission fluid annually, which is much more frequent than
the owner's manual says to do it. They say it makes their transmissions last from 200k to 300k.
A transmission failure can cost $3k to $4k.
My mechanic charges me $40 labor and I give him the 3 quarts of genuine Honda ATF for the annual drain and fill.
Many people would say I'm wasting my money, but I feel good about the over maintenance. It can't hurt and might well save me $3k to 4k.

I'm am a very frugal person, but sometimes saving money in short term can be catastrophic in the long term.
 
I'm only saying this: If you love your car, treat it well.
I have a Honda Odyssey which some mechanics criticize as having a problematic transmission.
From reading the forums, some people say they do a drain/fill of their transmission fluid annually, which is much more frequent than
the owner's manual says to do it. They say it makes their transmissions last from 200k to 300k.
A transmission failure can cost $3k to $4k.
My mechanic charges me $40 labor and I give him the 3 quarts of genuine Honda ATF for the annual drain and fill.
Many people would say I'm wasting my money, but I feel good about the over maintenance. It can't hurt and might well save me $3k to 4k.

I'm am a very frugal person, but sometimes saving money in short term can be catastrophic in the long term.
Conceptualize it however you'd like, its still a waste.
 
I could go 60k without a transmission drain and fill, and go 10k without changing my oil, and claim I am saving money.
But if you really love your car, treat it right.
Think of it this way. It's like having a wife, and taking her out once a year to a McDonalds on your anniversary.
Much better to take her out every week to an expensive restaurant - Might cost more in the short term, but a lot cheaper than a divorse.
 
Depends on the kind of driving you do-a 3-4K OCI, in winter, with short trip driving would likely be worse for sludge than me blasting around town & country for 7500-10K hauling 7-8K in summertime with the company Transit. My MIL used to have an ;83 Cavalier 2.0 OHV (not that old at the time) that she insisted on driving 1/4 mile to work and back, 5 days a week, and NEVER anywhere else! It knocked the pin out of the camshaft timing gear TWICE because of too much sludge/friction! Not much fun fishing in the oil pan to get it back out, either (I fixed it both times, would have been late 1980s).
 
Do whatever you want with your money. Also who changes a non broken pcv valve just use a can of brake cleaner and clean it.

i go 8-11k on my engines using a ll-01 or vds 4.5 rated oil and have almost no consumption so i don't have to add oil. I checked inside my valve covers before and there's no sludge. i have over 500k+ on my gmc's combined since new and never changed anything inside of them. Smooth and quiet engines.

I don't do flushes either. I get that going 15k on a gasoline rated synthetic blend is definitely bad but 4k on Pennzoil Ultra Platinum and a liqui moly flush every oci is actually kind of absurd.

Also whoever buys it is probably gonna abuse the heck out of it anyway. What vehicle is it and when do you plan on selling it.

Also do you constantly grease the joints, change the trans fluid every 25k, change air filter every 10k, flush radiator coolant and brake fluid every year and change the belt and spark plugs every 3 years too?

I hope you're not the kind that goes hog wild on maintaining just one aspect but doesn't care about the rest. If you're gonna go hog wild about the oil please do the same for everything else so there's no hypocrisy. I still respect when someone goes all out on what they believe in even if I don't believe in it as much myself.
 
I could go 60k without a transmission drain and fill, and go 10k without changing my oil, and claim I am saving money.
But if you really love your car, treat it right.
Think of it this way. It's like having a wife, and taking her out once a year to a McDonalds on your anniversary.
Much better to take her out every week to an expensive restaurant - Might cost more in the short term, but a lot cheaper than a divorse.
You are right on one point, 60K on an Odyssey transmission is a bad idea! My wife just figures she'll hopefully be able to eat something after I'm gone from all those OCI & restaurant bill savings!🙃
 
I just wanted to share my "Zero-Sludge" strategy for oil changes going forward.
I'll be changing my oil every 4,000 miles with PUP Synthetic (5 quart jug from Walmart) from now on, and changing my PCV valve every 30,000 miles.
I started the regiment with an engine flush (Liqui Moly) to clean out the engine first.

I think oil testing labs that are telling people with 10k oil change intervals that their oil is still good for another X thousand miles, are missing the point.
The amount of sludge in your engine is proportional to how many miles you go between oil changes.
Sludge is that gooey black thick formation all over the inside of your engine which clogs oil passageways and causes lower oil pressure which can really
harm an engine over the long term.

I read so many posts on BITOG about people that are so proud that they are going 7500, 10000, 12000, 15000 OCI's and testing labs saying their oil is still good.
The focus should not be on how long you can go without an oil change, but instead how clean is the inside of your engine.

Think about it this way. If you were going to buy a used car, would you prefer the previous owner did 3k to 4k oil changes, or 15k oil changes.

Bill

Why 4K and not 3, or even 2 if a super clean engine is the most important thing?

What data, info or logic did you use to come up with 4K?

If you dont know what was under the valve covers before the flush how do you know how well the flush did or didnt work?
 
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