Never Change Oil - Delvac Challenge

Pennzoil motor oil
Carlostrece said:
It would include 1 or 2 per month country highway drive(s) for 30 min at 55 mph. The car is stored in a dry heated garage. So never very cold when started. I do a visual inspection of oil condition every 3 months when I check oil level. I check oil color and verify that oil is dry (not frothy).

For 15 years I've been having a 3 year OCI using Maxlife using an ordinary oil filter. The old oil still looks almost new when changed (only 1200 miles on it). When my certified mechanic recently changed my valve covers gaskets, he said my valvetrain looks very clean.

He said in his opinion I could use a 4 year OCI using blend oil, or 5 year using a full synthetic oil.

I'm going to try 5 years OCI using a full syn. For extra protection I'll use an ext OCI full syn. Quaker State Ultimate Protection Full Synthetic is an ext OCI oil that claims 20K mile OCI. I will only have 2K miles on the oil when it's changed. I'm confident it will be fine for 5 years. It'd probably be fine for many more years, but I don't want to push my luck.

I see no reason to change the filter at 5 years because it would only have 2K miles on it. So I'll leave the filter in place for 10 years. I'll use an ext OCI filter (even though that might be overkill). NAPA Gold filter is rated for ext OCI use.

When I change oil at 5 years, I'll send a sample to a lab for a used oil analysis.
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I am not sure what brand filter you plan to use. As stated, if you are using an "ordinary oil filter", most likely it made of cellulose-synthetic blend media. Not sure regarding how it's integrity would hold up if you leave it in for 10 years?
I have no idea, but it seems like an awfully long time. I suppose that when oil filters started advertising longer drain intervals along with synthetic oils - i.e. 10,000 and 20,000 miles, I would think that they meant over maybe a 1-2 year time period, but maybe not 10 yrs?
Just wondering:unsure:
 
samiamz said:
I am not sure what brand filter you plan to use. As stated, if you are using an "ordinary oil filter", most likely it made of cellulose-synthetic blend media. Not sure regarding how it's integrity would hold up if you leave it in for 10 years?
I have no idea, but it seems like an awfully long time. I suppose that when oil filters started advertising longer drain intervals along with synthetic oils - i.e. 10,000 and 20,000 miles, I would think that they meant over maybe a 1-2 year time period, but maybe not 10 yrs?
Just wondering:unsure:
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I was using Maxlife Syn with an above average quality Baldwin filter for 3 years OCI. The Baldwin filter was rated 40 microns @ 99% and was built like a tank.

I'm currently using Maxlife Blend with an Oreilly Microgard Select filter made by Premium Guard in it's Vietnam factory. It's more efficient at filtering finer particles. Rated 25 microns @ 99% and designed for extended OCI with silicon gasket and anti drainback valve. I don't know the details of the filter media, but I know it's designed for extended OCI. I will use this filter 3 years until my next OCI.

At my next OCI, I'm going to switch to Quaker State Ultimate Protection Full Synthetic and NAPA Gold filter. The Quaker State Ultimate Protection Full Synthetic is an extended OCI oil. The NAPA Gold filter is an extended OCI filter. It's the same filter as Oreilly Microgard Select, except the NG has slightly more filtration material (according to a side-by-side filter dissection video I watched on Youtube).

Also, for $1 more, I buy an extra long filter that's compatible. It's double the normal length with double the filtration material and holds double the oil. So it should have double the capacity before clogging. It'll never even come close to clogging for me, especially with my car only driving 400 miles a year. In 10 years it will only have 4000 miles on it.

Do I need a double length filter? No, but for only $1 more, why not?

If anyone has a Buick 3800 Series 2 engine, the compatible double length filter is:
Baldwin B35-S (excellent build quality)
Oreilly Microgard Select MSL51036 (fine filtration, extended OCI, above average build quality)
NAPA Gold 1036 (fine filtration, extended OCI, extra filtration material, excellent build quality)

Each of the above filters is double the normal length for a Buick 3800 Series 2 engine. So double the capacity compared to normal length filter of same brand. You can find a double length filter in any brand. Baldwin and Microgard Select are the brands I've used in the past decade. NAPA Gold is what I plan to use in future.

I don't know if Buick 3800 Series 1 or 3 use same size filter as Series 2. If they do, then my part # info above could also be used for those engines too.

I think prefilling a new filter before installing is helpful, especially when using a double length filter. Do as you wish.
 
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Hey, still driving the car but just to and from work now. I need to top up the oil so I'll take some new pictures when I do so tomorrow. I'm sitting at the 267,000 mile range. I've stopped changing the filters since whenever the last time I mentioned doing it on here previously.
 
267,776 miles. It honestly doesn't look that bad to me. I added another half quart.

IMG_20260408_175346093.webp


IMG_20260408_175341661.webp


IMG_20260408_175141203.webp
 
Conspicuous consumption. Not a fan.

Could not watch Cash for Clunkers videos of government mandated destruction of running vehicles either. Maybe it’s just me.

You do you, of course. I understand why this would be interesting.
 
I've detailed it before but the rust on the vehicle is such that I'm on a limited pitch count with the car anyhow. One way or another the car doesn't have much longer left so it was a good prospect to run this experiment.
 
lazarus55 said:
This doesn’t really meet the definition of conspicuous consumption lol
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Close enough for me, like when The Who smashed up their instruments after a show. That was called conspicuous consumption at the time, which I thought was an apt description. Even being a Who fan.
 
I am consistently adding oil as the engine burns a little, and it was super super sunny out today when I took the pictures so I think that was a factor, but the oil still looks pretty dang good. I'm not an engine expert but it must not be very hard on the oil. There is some sludge in the oil filler neck and in the oil cap, which I tried to get pictures of, but otherwise all seems well. The fact this has lasted as long as it has tells me it's likely moreso a product of a well designed engine. I change my wife's Sienna's oil religiously and will continue doing so.
 
Just to sum this thread up for any new folks, I last changed the oil in my Prius in early 2022 at about 233k miles. I'm now at 267,776 and things are still fine. I use full synthetic 5w40 Mobil delvac for topoffs and have also stopped changing the filters but that's a relatively new development over the past year or so.
 
Stop calling this exercise an experiment.
You can't possibly replicate it.

I honestly see the value and appeal of driving your car into the sunset anyway you want.
Seriously, getting your "money's worth" out of the replaced battery pack alone could be motivation enough.

However, all that value back in your pocket via selling it to a food delivery person could be much greater.

This kinda reminds me of those Russian guys who replaced an engine's oil with Coca-Cola.
The engine ran and died and the guys stood there and looked stupid.
 
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