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Author Topic: Engine Maintenance Tips: Additives & Oil  (Read 90483 times)

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Offline St Giles

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Engine Maintenance Tips: Additives & Oil
« on: December 12, 2025, 08:56:06 PM »
I recently watched a lot of youtube, and here's what I learned:

Sta-bil is probably the best fuel stabilizer (actually I already knew that having had very good success with it).

Hot Shot's is probably the best diesel additive by a lot.

Do use fuel additives such as fuel system cleaners.

DON'T use oil additives, except maybe a flush product minutes before an oil change and without driving with it. Oils are already specially formulated to perform as best as possible for whatever specific application they are designed for.

Don't frequently change the brand/formulation of oil, as different formulations can fight with the residue of the last one causing worse oil performance. This is the same reason to not use additives.

Don't use diesel oil in gas engines (women would never do that) or gas oil in diesels; the oil manufacturers know more than you about what works best in what, and doing otherwise really could be catastrophic in a few engines.

Amsoil Signature Series is the best there is in my opinion because it ranks lower high to upper middle across many specific tests and use purposes, which means it is not necessarily best at any one thing, but is plenty good enough at everything. It's an above average average oil such that using another formulation could compromise performance/protection in some areas while improving in others.

Don't use new oil that has been stored for many years (beyond 3-5 years). The fresher the better. Even sealed new oil can degrade, absorb moisture, and oxidize, significantly losing it's ability to protect the engine.

Do make sure the cap is tight on on your unopened oil, and store it on an upper shelf in the house (where it stays warm and the AC keeps the humidity down). Cold, and sitting for years, can cause the built-in additives to separate out, which are not easy to mix back in (shaking the bottle does almost nothing). Old oil still works, but is it worth shortening the life of an engine with as expensive as they are now?


Finally, there is no such thing as Lifetime Fluid. Antifreeze, Brake fluid, Transmission fluid, 20,000 mile motor oil all must be changed regularly and probably much more often than your car dealer recommends, if you want the systems those fluids go in to last more than just 150-300k miles. They attract moisture causing rust, change PH and become corrosive, break down or fill up with suspended sediment that becomes abrasive.

The cause of oil consumption in old engines apart from leaks is probably due to not just regular wear, but the oil rings on the pistons, which have a hard life with little oil flow, getting clogged with sludge, and failing to deliver oil to the cylinders. Sludge comes from old oil getting baked on. It's an indication of excessive heat or mainly not enough fresh oil with fresh detergent is flowing through that area. These lower oil rings may be one of the only places with any indication of sludge due to the harsh conditions they operate in.

A solution would be to use oil with a particularly strong cleaning ability, and changing it every 5k or less, with an occasional detergent engine flush. Sludge can start as soon as 20-30k and get severe enough to cause harm around 60k.



Re: Engine Maintenance Tips: Additives & Oil
« Reply #1 on: December 12, 2025, 10:07:55 PM »
What do you think about oil weights? I’ve had this argument with Guys on the 4g eclipse forum they tell everybody to run 10/30 when it calls for 5/20. I lived in the cold north east and I tried to explain to them the 5 weight is necessary because most engine damage occurs on start up. The 20 weight is necessary to work the variable valve timing properly. Of course it’s an eclipse forum so they beat the snot out of their cars in places like Florida so it makes a big difference they may benefit at 110*f when racing the things but under normal conditions the 5/20 the manufacturer recommends is probably more wise. The 5 weight when it is -10*f is more likely to save your engine for the long run. I change the oil in it 4 times a year usually every 2000 miles or so in the change of the season so heat related break down isn’t as much of a concern to me. But now I live in Knoxville so I think I’m still safe with the recommended oil. We had a flat earth style melt down in the forum over this discussion 🤣 i realize the 0 weight nowadays is mostly for fuel savings and newer engines may benefit from a 5/20 but the low numbers in the early 2000s like in my 06 eclipse was more about getting the oil flowing faster on cold starts. Cold starts kill engines! This new stop start technology sends your oil pressure to 0 now every time you hit a red light and that is ridiculous in it’s own way.


Offline St Giles

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Re: Engine Maintenance Tips: Additives & Oil
« Reply #2 on: December 23, 2025, 06:31:01 PM »
I check the manual, and they show a variety of weights based on outside temperature. It seems modern engines do well with a 0w with how good the base oil quality is these days, but I'd prefer a higher number at running temps. There's a lot of engineering that goes into getting the perfect oil for a particular application, but with the quality of oil these days, just make sure you use it and keep it fresh. 

Something to keep in mind if you want thicker oil for more protection is that, a low winter/cold viscosity oil will likely break down and get thinner a lot faster than a thicker cold viscosity. Even though you could run 0w-50 (what sports cars recommend), that 50 will break down to 40 or 30 relatively quickly compared to a 20w-50 or SAE50. The base oil viscosity seems to be the most durable part according to my understanding, while the viscosity modifiers that get thicker as they heat up (less thin may be the better term, since even 50 weight may be thinner at 200F than 0 weight at 50F) are large molecules that get ripped apart more easily.

My plan is to use 0W-40 in the winter, and 10W-40 in the summer in my old engine that consumes some oil.

I really wish they had an oil pressure primer system on all engines, or delayed fuel pumping while the engine cranks to let oil circulate before the engine experiences high pressure.

I found some Valvoline Restore & Protect, I'm going to try to see if it cleans better than Amsoil SS. I took some before pictures to compare, and even though the Amsoil SS is supposed to clean better than their other blends, I think the Valvoline will clean better since that is the particular purpose of that formula. Unfortunately it only comes in 0w-20, 5w-20, and 5w-30.

I just ran some 5 year old e10 pump gas in a small engine with no problems, stored in a 5 gal can with Sta-bil. It's all I've used since I got it. I've gone through 10 gallons so far with some of it sitting in a 2 stroke tool for a whole year without use. 

Re: Engine Maintenance Tips: Additives & Oil
« Reply #3 on: December 23, 2025, 11:32:14 PM »
I check the manual, and they show a variety of weights based on outside temperature. It seems modern engines do well with a 0w with how good the base oil quality is these days, but I'd prefer a higher number at running temps. There's a lot of engineering that goes into getting the perfect oil for a particular application, but with the quality of oil these days, just make sure you use it and keep it fresh.

Something to keep in mind if you want thicker oil for more protection is that, a low winter/cold viscosity oil will likely break down and get thinner a lot faster than a thicker cold viscosity. Even though you could run 0w-50 (what sports cars recommend), that 50 will break down to 40 or 30 relatively quickly compared to a 20w-50 or SAE50. The base oil viscosity seems to be the most durable part according to my understanding, while the viscosity modifiers that get thicker as they heat up (less thin may be the better term, since even 50 weight may be thinner at 200F than 0 weight at 50F) are large molecules that get ripped apart more easily.

My plan is to use 0W-40 in the winter, and 10W-40 in the summer in my old engine that consumes some oil.

I really wish they had an oil pressure primer system on all engines, or delayed fuel pumping while the engine cranks to let oil circulate before the engine experiences high pressure.

I found some Valvoline Restore & Protect, I'm going to try to see if it cleans better than Amsoil SS. I took some before pictures to compare, and even though the Amsoil SS is supposed to clean better than their other blends, I think the Valvoline will clean better since that is the particular purpose of that formula. Unfortunately it only comes in 0w-20, 5w-20, and 5w-30.

I just ran some 5 year old e10 pump gas in a small engine with no problems, stored in a 5 gal can with Sta-bil. It's all I've used since I got it. I've gone through 10 gallons so far with some of it sitting in a 2 stroke tool for a whole year without use.
I threw that idea at a/i either a retrofit or idea for new engines with a heated oil pan and hot oil squirters placed near bearing surfaces and run it off an electric pump inside the pan with hard lines and flex lines running to the heads and block. You could shut it down after start up and just run off the mechanical pump
as normal. It told me it was an excellent idea but risk complexity and excessive cost of production and or installations. Haha but in the endless pursuit of green sustainability it was plausible. I guess if your getting 1,000,000 miles on Toyota engines built 10 years ago they are at the point of good enough. Now everything is putting turbos on small engines trying to keep the same power while torturing the little motors and that is proving to be unsustainable so maybe I can pitch it to Toyota after all. 

Re: Engine Maintenance Tips: Additives & Oil
« Reply #4 on: December 24, 2025, 04:24:19 AM »
The key to car care is going above and beyond with maintenance and repairs.