The best non synthetic oil for a older engine

[ChainLightning]

I have a 1992 GMC half ton Sierra with a 350 in it. I was wondering what the best non synthetic oil you would recommend for it. It has 220,000 miles on it and does not burn any oil from what I can see. I just put 10W-30 Castrol GTX in it and a Wix oil filter. I have ran it for probably 30 miles and it has had a lot of idling time on it since I flushed the radiator. oil is getting pretty dirty so I know it is cleaning right. Thanks
(the reason I don't want synthetic is because I have witnessed it eating seals and gaskets in older vehicles several different times. And have heard a lot of stories. Would use it in newer cars but not anything under the year 2000)

 

[old_soul]

my 95 sierra uses Pennzoil 5w30 and a cheap fram filter every 3500 miles or so.

Still runs fine after 18 years lol

Does leak about a quart out between changes, from rear main seal but thats nothing to do with the oil

 

[Festus]

Detergent type oils do not "eat" the seals and gaskets. They can, however cause engines to leak that have ran cheaper grade, or non detergent oils for a long time. It does this by cleaning, and loosening up the old dirt and sludge deposits that were left in the engine over time. When these old deposits are removed it can cause leaks. If you know what type and brand of oil has been used in that engine, you should be safe sticking with it. If it has run a better quality oil, you shouldn't have a problem with whatever you choose. A look at the API label on the bottle will give you an indication of quality, not to mention, you usually get what you pay for. If you still believe in changing oil every 2-3000 miles, you're pretty much wasting money on the more expensive oils. Conversely, if you do run a non detergent oil, you should make sure you change oil every 2000 miles at most, and use a darn good filter, like Wix or Hastings.

If you choose to run a non detergent oil, you may find you won't have a lot to choose from. I've never even heard of it in a multi-viscosity oils. When I've heard of issues like you're worried about, it's usually with cheap store brand oils, or base grade Pennzoil, or Quaker State. I'm talking about their cheapest oils.

GM's recommended oil is 10W30. That is probably all it has ever seen. That will be a detergent oil. With that many miles on an engine, eventually it will have a leak or have a failure. It's called entropy, and you can't stop it. You hear a lot of BS out there from people who don't really know what they're talking about.

Also, Valvoline makes a special oil for higher mileage engines. Supposedly, it has additives to help the older seals and gaskets. I think it may just be a way of marketing their oil to people with your concerns, but I feel Valvoline is a good oil for the money, although nowadays I run Amsoil. IMHO, the benefits of running a multi grade, detergent type oil outweigh the risk of running a non detergent oil.

 

[ChainLightning]

Detergent type oils do not "eat" the seals and gaskets. They can, however cause engines to leak that have ran cheaper grade, or non detergent oils for a long time. It does this by cleaning, and loosening up the old dirt and sludge deposits that were left in the engine over time. When these old deposits are removed it can cause leaks. If you know what type and brand of oil has been used in that engine, you should be safe sticking with it. If it has run a better quality oil, you shouldn't have a problem with whatever you choose. A look at the API label on the bottle will give you an indication of quality, not to mention, you usually get what you pay for. If you still believe in changing oil every 2-3000 miles, you're pretty much wasting money on the more expensive oils. Conversely, if you do run a non detergent oil, you should make sure you change oil every 2000 miles at most, and use a darn good filter, like Wix or Hastings.

If you choose to run a non detergent oil, you may find you won't have a lot to choose from. I've never even heard of it in a multi-viscosity oils. When I've heard of issues like you're worried about, it's usually with cheap store brand oils, or base grade Pennzoil, or Quaker State. I'm talking about their cheapest oils.

GM's recommended oil is 10W30. That is probably all it has ever seen. That will be a detergent oil. With that many miles on an engine, eventually it will have a leak or have a failure. It's called entropy, and you can't stop it. You hear a lot of BS out there from people who don't really know what they're talking about.

Also, Valvoline makes a special oil for higher mileage engines. Supposedly, it has additives to help the older seals and gaskets. I think it may just be a way of marketing their oil to people with your concerns, but I feel Valvoline is a good oil for the money, although nowadays I run Amsoil. IMHO, the benefits of running a multi grade, detergent type oil outweigh the risk of running a non detergent oil.

Thank for all that good info. My buddy had a 94 Silverado with a 350 in it and it had about 450,000 on it. Suprisingly when it finally died the engine was not the cause.

 

[Festus]

It really isn't worth over thinking, although you can maybe tell, I've given it some thought. Lubrication related failures are almost unheard of. Lubrication related failures are usually due to low oil, or contaminated oil (anti-freeze). It's common for people to spend a lot of time worrying about engine oil, but most failures are due to overheating, or cooling system failures. Nobody gives their cooling systems a second thought, but if your coolant is over 10 years old and has over 100k miles, you can bet, the additive package in that coolant is totally spent, causing corrosion, and system deterioration. If you seriously overheat your engine, even if it doesn't immediately fail, it may contribute to a future failure.

 

[Icehouse]

Non detergent oils and non synthetic oils are 2 different cats. You are right Festus finding non detergent oils can be almost impossible, difficult at best. Gunked up radiators have caused many "oil failures". Synthetic oils can be like ethanol on old style gaskets, o-rings and fuel lines. ChainLightning the GTX you have in it now should do just fine, I us Castrol in most of my equipment. Have a good evening.

 

[MSgtBob66]

Festus and Icehouse are right on...

Oil ain't the reason most engines fail, heat is. Especially a '92 Chevy (or GMC). Run what they suggest (mine liked 10w30) and ignore what the snake oil sellers are telling you. The cheapest oil that you find that meets the OEM standards is what you should run, and if this truck is a work truck, change it and the filter at the severe duty limits according to the owners manual (someware around 3000 miles).

You have an old beater that you should take care of, because I have only heard of one 92 chev that died from engine failure. The rest of the truck took a poo before the engine did (I do live in the rust belt). Change your engine oil every 3000 miles with the cheapest oil that meets OEM specs.

Now you need to worry about the tranny....

S/F & Good Luck!

Bob

PS. I use Fram filters. They are cheap at Fleet Farm...