Changing Viscosity for Summer and for Cleaning?

[CANADADIY]

I'm not sure if I missed it but how many miles on the engine? The previous owner must have gone extremely long between oil changes.

 

[samiamz]

I'm not sure if I missed it but how many miles on the engine? The previous owner must have gone extremely long between oil changes.

60k miles

 

[McRightclick]

60k miles

Must've been about a 60k mile OCI for that amount of sludge haha

 

[wlk]

Engine & timing components had only 65K miles on them. Timing components worked fine prior to tear down. Just had low oil pressure code..which led to the sludge discovery

Timing chain sure but not guides and tensioner. They are wear items, I'd just replace them, just asking to do it again.
Great job on clean-up, VRP 5w30, HPL, Motul X-Clean 5w40, Amsoil SS or even a standard xW40/50 with some Gumout Multisystem Tune Up or Kreen @ 1oz/qt or HPL 40 cleaner ect will clean as well and give you the added visc you are worried about. Even LiquiMoly flush or BG EPR at the end of oci's will do as well

 

[scrllock]

Timing chain sure but not guides and tensioner. They are wear items, I'd just replace them, just asking to do it again.
Great job on clean-up, VRP 5w30, HPL, Motul X-Clean 5w40, Amsoil SS or even a standard xW40/50 with some Gumout Multisystem Tune Up or Kreen @ 1oz/qt or HPL 40 cleaner ect will clean as well and give you the added visc you are worried about. Even LiquiMoly flush or BG EPR at the end of oci's will do as well

Plus the thing that wears chains is soot/debris. That oil was about as dirty as possible, personally if I was gonna tear it down, the timing stuff is the obvious thing to take care of, way, way easier than doing it again on an accelerated timeline.

 

[wlk]

Plus the thing that wears chains is soot/debris. That oil was about as dirty as possible, personally if I was gonna tear it down, the timing stuff is the obvious thing to take care of, way, way easier than doing it again on an accelerated timeline.

I don't disagree, I would go all new regardless personally but giving him an option

 

[chazthespaz]

What do you mean by dismantle? Did you open the oil pan? Did you take the pistons out?


If your engine is spec'd for 5W-20 and your main concern in to continue the internal cleaning—you have 2 options:

1. Run VRP 5W-30 year round from now on for unspecified time. Most likely at least 3-4 oil changes.

2. Use the oil you like and also get one of the HPL engine cleaners and use them together for certain time, but for sure more than once.

HPL have 2 cleaning oils SAE 30 and SAE 40 that can be mixed with any oil:
https://www.advlubrication.com/collections/automotive-lubricants/products/engine-cleaner

The difference would be that the VRP is proven to clean not only sludge and varnish, but also to clean piston rings too. And the other engine cleaners are not specialized in cleaning specifically piston rings. But they may clean quicker the other engine internals.

If you had that much sludge in your engine I would inspect the oil filter every 1,000 miles (regardless of the cleaning oil I use), if it's cartridge filter and possible change it, if it has a lot sledge in it. If it's a regular metal filter, I would change it after 1,000-2,000 miles and cut it open to inspect any collected material and decide when to change the next filter.

I like the idea of an early oil filter change at 1,000 miles - I think the good synthetics discussed will help clean up residual sludge, which would end up in the filter.

 

[CANADADIY]

Would have been a great experiment to leave the sludge and just put VRP in it

 

[Japanese]

Must've been about a 60k mile OCI for that amount of sludge haha

It might be 6 OCI with Ford synt. blend 5W-20. But possibly fewer longer OCI.

Would have been a great experiment to leave the sludge and just put VRP in it

Don't worry, there is still plenty of sludge in that engine for the VRP. We'll see that in the first few oil filters.

 

[Nick Garrett]

The correct answer has already been given a few times but you're obviously obsessed with using VRP. Its Texas you dont need a 5W anyways. 10w40/15w50 would serve you fine as well.

 

[kschachn]

The correct answer has already been given a few times but you're obviously obsessed with using VRP. Its Texas you dont need a 5W anyways. 10w40/15w50 would serve you fine as well.

But on the other hand, a 5W winter rating does no harm either.

 

[Slick]

Thanks for reaching out. I have looked into this quite a bit and have come to the same/similar assessment you have experienced. Also, I should note that it's one thing for people to see a pic or video of sludge on the internet and claim "lack of oil changes"...but seeing the sludge in person and tearing down the engine and seeing the evidence of how different areas were affecting + knowing the backstory of past ownership habits and maintenance...starts to paint a story that maybe isn't just about a lack of oil changes only. You and I have the unique connection of both seeing the sludge face to face, seeing how it affected different areas of the engine, knowing the vehicle's history, and both dealt with cleaning it out...and with all that evidence we have the same/similar assessment of causation. I doubt that's a coincidence. I might be wrong, but in my studies & hands on experience, I think there's more to it than just "they didn't change the oil"...and I think you hit the nail on the head.

My studies & personal journey have me thinking it has something to do with...
1. Shear/breakdown of oil (either due to not changing oil and, crappy quality oil, or another element causing it to break down)
2. + Short trips (broken down oil starts to coagulate and never gets opportunity to heat up and flow properly)
3. + poor PCV design (exhaust gasses somehow play a role in oil breaking down or coagulating?)
4. + Could humidity (with the short trips) play a role...moisture in crankcase?

I do believe the PCV system has something to do with it because when removing the valve covers my passenger side (PCV side) sludge was twice as bad as my drivers side.

I also did extensive research on this truck's history, and it was apparently owned by an elderly man who hardly drove it avg 5-6K miles a year. I bought it in 2025...and from 2015-2025 he drove it only 60k miles. He would use it to make short trips to the store and back. Otherwise, It mainly sat in his driveway. It's my understanding that he changed the oil maybe 3-4x during ownership...so let's call it every 15-20K miles. And once again, this is Texas gulf coast hot and humid weather..much like Florida. Sounds like a very similar situation to your father's car.

I'm glad you were able to clean it and keep it running. That's encouraging, because most people have told me my engine is gone...do not resuscitate. But I have hope because I don't see evidence of damage...just normal wear. I as well have changed all PCV components, sensors, etc. I'm now just trying to decide what oil to refill it with. Thanks for your story, it helps a lot!

Wristcheck

I think your engine stands a good chance for normal life. You have cleaned/removed the heavy sludge and noted normal wear. My take the key factor is - did the sludge buildup prevent oil system flow to the bearings, valve train, and other. As long as the sludge would allow the unpressurized drain back oil to make its way back into the oil pan/sump; then the oil pickup and pump could keep flowing oil to the vital areas.

I agree 15,000 to 20,000 mile oil changes, while not what most of us here would do, still (with modern oils) would be flowing into the pump and pressurized oil system. I suspect even an elderly operator over time would notice an engine light illuminated due to low oil pressure. I suspect you did not see any "Service Engine Soon" when you first drove it.

(cringe case growing up - one of my friend's dad would change his oil filter each year and only top off the oil. Never asked why as he was not a pleasant person to be around. This was in the 1970s and 1980s. He alway had pushrod V8 GM smallblocks in a half ton pickup for himself and his wife a full size car. He kept them (likely) around 5 years/80,000 miles before trading for the new one. Never heard of any mechanical issues with his vehicles. )

Keep us posted but my take is you will be ok and spent your time well cleaning and removing the heavy sludge.