What engine oil?

[Mudsport96]

5w30 valvoline and ac Delco filters from New till roughly 100k miles. Then Orielly house brand oil and ac Delco filters till current.
Don't think that you need to run any special oil to get longevity, just be consistent with changes and a quality filter. It is actually at 415 now and needing another change.
As for the above comment of internals of engines running cheap oils... it was most likely poor maintenance that made the insides look bad.

This was at 396k miles. That is varnish not debris or sludge. Pan was pulled for pick-up o-ring replacement. Synthetic oil is alright, I have run it in severe applications. But for these vehicles, don't waste your money. Fun fact Orielly oil is made by Mobil.
Ad the mileage is up there, it gets 10w30 in the winter and 15w40 in the summer. The father-in-law did not catch the failed pick-up o-ring right away and I'm sure it did a little damage as it has low pressure in the summer with 5 or 10w30.

 

[Jonmurphy]

I have a 2005 Yukon XL with the 5.3. I have an oil leak problem, after 24 hours of sitting it will leave 2 small puddles of oil about 1.5 inch across, and one about 4 inches across. I added AT-205 to my oil a few weeks ago, and it completely resealed them and I lost no oil at all. I noticed that the puddles have returned tho, slowly at first but now they’re back to the same size. Anyways, I was wondering what brand of oil do you guys recommend? I’ve heard great things about both Mobil 1 full synthetic high mileage, but also valvoline full synthetic with the max life. My current plan is to do the oil change this weekend as it’s already needed, and then replace 8oz of oil with the AT205 to help seal up again. Also, any inquiries on the Bar’s stop leak specifically for the rear main seal? I’ve heard good things about it as well, and was wondering all of your opinions. Also was a little concerned it might be too much sealant additives at once. Thank you!

Edit: The vehicle has 203k miles and I go between 3-5k between oil changes.

Hello Hello McLaughlin? With 203,000 miles you need to use a heavier oil That helps your whole engine and slows down the leaks a bit., as any damn fool knows Or should know. thicker liquid Higher the viscosity Flows slower out tiny or big holes. Use 1 of the 20/50 oils. I don't like Mobil 1Synthetic because I have experienced The precipitation that is falling out of the additives. TheY form A white hard surface inside your engine. Mobil 1 representatives told me well there is a timeline you have to use these engines Oil Within some timeline but they don't tell you what it is .. I wouldn't store in an engine or the oil container it will precipitate the additives out And down Let an Container sit for a while and then see what happens on the bottom after a few Months.

 

[Jonmurphy]

id fix the oil leaks vs using snake oils.

Hi folks I gotta say again When your engine wears the clearances increase I am a mechanical engineer and a certified auto mechanic I've personally owned over 500 vehicles since I was 12 years old 20/50 weight oil, Is there a way to go Any engine over hundred hundred 50,000 miles Need this All ESAE test show there's an insignificant gas mileage difference, using the heavier oils and of course your engine parts are better protected, your spark plugs have less contamination.. Uss available 20 /50 oils and of course with the high mileage additive. look up what the high mileage additive does. SAE testss not your brother-in-law's sister says.. My favorite is valvoline Get the semi synthetic or the synthetic. And the big secret is what all All over the road engines use.?????? Put on a bypass, 1or 2 micron filter.. Napa, Frantz, Et cetera sells these. After 2 or 300,000 miles Tear down a engine, and there won't be ANY sludge. And as the GM test show it's the 1 and 2 micron Particles that wear your engine out, not the bigger ones Caught by the 10 and 20 micron filters that you normally buy, It's a tiny ones that Tear up your cylinder walls they hone up everything, And Leave clogging sludge, Drain brack holes and everywhere..

 

[Mudsport96]

Uss available 20 /50 oils and of course with the high mileage additive. look up what the high mileage additive does. SAE testss not your brother-in-law's sister says.. My favorite is valvoline Get the semi synthetic or the synthetic.

I dont need "brother in laws sister says" info. I have an engine with over 400k on it. And 300k is cheap oil with a quality filter.

Put on a bypass, 1or 2 micron filter.. Napa, Frantz, Et cetera sells these. After 2 or 300,000 miles Tear down a engine, and there won't be ANY sludge.

You just need a quality filter spun on the engine, no need for additional filters in 99% of what these trucks are used for. I literally posted pictures of cheap orielly house oil use in my oil pan and there is no sludge at almost 400k miles. Some varnishing, but I'm sure that is from over heating as I know it had blow a radiator twice in its lifetime.
Again 99% of these vehicles don't need fancy oil. It may give a placebo effect, but a API star oil will be fine. Most of the time, you won't need to up the viscosity till over 200-250k miles. Not this 100-150k you stated. Mine didn't need 10W40 till the father-in-law drove it with a bad pick up oring and starved it for oil. Even then, with 10w30 in the winter it still carries 40ish psi on the highway, and will climb to 75-80 passing at 5k rpm.

 

[SnowDrifter]

I dont need "brother in laws sister says" info. I have an engine with over 400k on it. And 300k is cheap oil with a quality filter.

You just need a quality filter spun on the engine, no need for additional filters in 99% of what these trucks are used for. I literally posted pictures of cheap orielly house oil use in my oil pan and there is no sludge at almost 400k miles. Some varnishing, but I'm sure that is from over heating as I know it had blow a radiator twice in its lifetime.
Again 99% of these vehicles don't need fancy oil. It may give a placebo effect, but a API star oil will be fine. Most of the time, you won't need to up the viscosity till over 200-250k miles. Not this 100-150k you stated. Mine didn't need 10W40 till the father-in-law drove it with a bad pick up oring and starved it for oil. Even then, with 10w30 in the winter it still carries 40ish psi on the highway, and will climb to 75-80 passing at 5k rpm.

Echoing this

Putting thick 20w50 oils in this is..... Ridiculous. There is literally no data to support running oil that thick in this application. What do you expect a high mileage additive to do?

Where are you getting this information? Can you back this up in any way?

I don't mean to sound harsh. But like, this is something that has the potential to cause damage to our reader's engines, so that needs to be properly addressed.


Bear in mind that:
- Thicker oil will raise pressure because it's harder to pump
- The oiling system in these is pressure capped on account of a bypass valve in both the oil pump and the filter
- Bypass in the pump reduces flow, bypass in the filter reduces filtration
- Low flow = sad
- High viscosity = slower pumping speed = less oil sling onto splash lubricated parts like cylinder walls
- High viscosity at start = more time distant parts in the oiling system are running without oil
- High viscosity = slower drainback into the pan
- High mileage = ????

Only real use case I see for high viscosity oil is as a limp-fix for something catastrophically wrong. e.g. you have rod knock and need to limp a few thousand miles out of the motor. If you're at the point of reaching for thick stuff like that, your engine is on its last legs



From my own experiences:
- Thinner oil tends to produce less cylinder wall wear but more bearing wear. The opposite is true for thicker. Too thick increases wear across the board and the engine sounds like death on startup (this testing was done on a Subaru and may not be 100% applicable)
- Thinner oil tends to help quiet piston slap at startup, as does a high flow oil pump. Theory: more oil slung to cylinder walls mutes the sound



For myself.... I run 0w40 euro spec oil in mine. BUT, I also have a different oil pump that can move that stuff around without issue. I also run a larger filter with flow rates more appropriate for slightly thicker / higher volume. Also of note, the oil I run is 'thin' for the 40w side of things, barely thicker than a 30w. I have lab tests to back my choices

I'll die on my hill that if you really want to fiddle with oils... Run a 0w30. They pump better when cold, they don't thin out as much when hot. Better than 5w30 in literally every metric. Context of the time: 0w30s in the 90s/early 2000s sheared down, and were a 'rare' oil. So 5w30 was chosen. 10w30 chosen for severe duty because it resisted shear-down more. None of that applies with modern synthetic viscosity modifiers, which are stable for many thousands of miles.

 

[Mudsport96]

While we are getting away from the original post, fix the leak OP and the leak will stop. Father in law had a leak on his 06 body style 07 (classic) 5.3. Tried high mileage oil ( at 60k miles), tried blue devil leak stop, tried STP. I fixed it with w 4 dollar gasket for the oil cooler bypass....
As for the above post I agree. Higher Weight oil for an engine under 300k is pointless. If you have low pressure hook up a mechanical gauge and recheck. I know I should have checked the in pump bypass when I did the pick up tube o-ring... but I didn't want to pull the front cover. I know the pump itself is good as at higher rpm it makes killer pressure. I think the spring is weak letting it bypass at a lower psi at low rpm, but cannot bypass as much at high rpm so that is why I see more than 70psi passing. It could also be the more than 415k miles on it too.

 

[OR VietVet]

While we are talking oil myths, my $.02. I have never seen synthetic oil cause an engine to leak oil.

 

[SnowDrifter]

While we are talking oil myths, my $.02. I have never seen synthetic oil cause an engine to leak oil.

So, that one *was* true. But context of the time. PAO base stocks cause seals to shrink a touch - so it causes leaks. We pretty quickly figured out that if we mix in some ester based oil, it 'evens out.' But that was in the 70s. It literally hasn't been an issue in the last 40 years.

Much like how using unleaded gas will blow up your engine... It had merit at one point, but these days, it should be relegated to either a memory or the history books.

 

[OR VietVet]

So, that one *was* true. But context of the time. PAO base stocks cause seals to shrink a touch - so it causes leaks. We pretty quickly figured out that if we mix in some ester based oil, it 'evens out.' But that was in the 70s. It literally hasn't been an issue in the last 40 years.

Much like how using unleaded gas will blow up your engine... It had merit at one point, but these days, it should be relegated to either a memory or the history books.

I started in the garages in 1976, so it stands to reason that I may have not seen the synthetic oil leak problems. For once, I am not as old as I thought. For once.

 

[Mudsport96]

So, that one *was* true. But context of the time. PAO base stocks cause seals to shrink a touch - so it causes leaks. We pretty quickly figured out that if we mix in some ester based oil, it 'evens out.' But that was in the 70s. It literally hasn't been an issue in the last 40 years.

Much like how using unleaded gas will blow up your engine... It had merit at one point, but these days, it should be relegated to either a memory or the history books.

True on the oil.
And the unleaded thing was more of extra valve seat wear not sure if a blown engine would result.
However, the addition of ethanol to fuels in the 80s did contribute to the damage of older (50s into the mid and I would argue late 70s) carbed vehicles. The jetting was designed for 100 percent gasoline and then the ethanol would also eat the gaskets and float causing further fueling issues. So it starts going lean and causing spark knock so you back timing off to avoid that. So you get lack of power. Damn I could go on all day lol, off topic