Is 5W-20 to thin for my old Buick engine?

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I have an older Buick 215 with 150k miles. It's the V8 version of the ubiquitous 3800 V6. Traditionally, it would have called for 10W-40 or 10W-30 in my climate, but I've been using 5W-30 for better lubrication when starting it in the winter. It's parked outside and while it's rarely below 0 deg. F, startups were noisier with 10W. Years ago, I tried the 0W-40 that I use in my two other cars but it made too much valvetrain noise. I do a lot of short trips so the oil doesn't come up to temperature. The 5W-30 would only very rarely result in a lifter ticking.

I just filled it up with 5W-20 Mobil 1 High-Mileage. I bought the wrong weight by accident but had filled it before I knew. It should be no issue through the winter, but I typically put 5000 miles a year on this engine so the oil will only have a couple thousand miles on it before summer and 90 deg. F. I suppose I'll just wait and see if I get valvetrain noise on hot days and change it out if I do. Or should I change it out at the end of Spring?

I know what happens if I go to low viscosity in the first W-number -- with 0W I get lifter noise until the oil is hot. I'm not sure I understand what will happen if I run a low-viscosity in the second number -- 20 weight -- in hotter weather like 90 deg. F. The thermostat is 190 deg. F and on some hot days on steep grades or with low air-flow, the coolant temperature gets to 212 F on a digital gauge.
 
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that's very odd. but if you want the best cold flowing 30 grade pennzoil platinum 5w-30 will be fine.

5w-20 doesnt really do damage unless it gets burned faster so if the engine doesn't burn you can use it.
 
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My experience running 0w-20 in a 2002 Silverado 5.3 that called for 5w-30 was no issues. This was even with it having 150k on it at the time. It didn't change anything. Even my UOA didn't change. So I would say you are good to go to leave it in until your next oil change.
 
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OVERKILL

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that's very odd. but if you want the best cold flowing 30 grade pennzoil platinum 5w-30 will be fine.

5w-20 doesnt really do damage unless it gets burned faster so if the engine doesn't burn you can use it.
The best flowing 30 would be a 0w-30... But flow is irrelevant as long as you are using the proper grade for the prevailing ambient conditions.
 
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It would be nice if we knew the year, make and model of the car this engine is in as well as the location of the OP.
 
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I forgot about the Rover version-yeah, 5W20 would be too thin. I wouldn't go thinner than a 10W30, and a 10W40 or 15W40 sure wouldn't be out of range.
 
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As long as you got oil pressure I don't think that engine cares. The 3.8 / 3800s just needed some kind of oil in them. They aren't stressed out, the timing chains are short, and they have a decent oiling system. The Supercharged ones at least running synthetic is advisable.

That is what I've picked up after owning a few of them, and friends owning them in different flavors. We would joke they would run on corn oil if you tried.
 
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Those old Buicks had low oil pressure problems @ low engine speeds. The aluminum cover that through pump gears are in would wear.

Many would blink the oil light on a hot day idling. Might be ok in winter.
 
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all of the buick small block engines with a distributor have marginal or poor oil pressure

the 3800 V6s and later rover V8s have a crank driven oil pump mounted on the timing cover instead of distributor drive

the 94-99 rover front cover fits buick engines before the 3800
 
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colab

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The winter rating doesn’t work like that nor does most of what you’ve stated.

You sound a lot like somone who used to frequent this board.

I've never posted here before this thread.

Do you care to explain the difference between the winter rating and the second number? My own understanding is rather oversimplified. I believe the first number to be to cold flow viscosity and the latter number to be the viscosity when the oil is hot.

What determines an engine's need for viscosity at operating temperature? My uninformed speculation is that in times past (say 40 years ago), thicker oil was used to prolong the life of the oil while it endured viscosity break-down. I further speculate that more modern lubricants (say in the last 10 years) don't break down as much in 5000 miles. I also speculate that thicker oil has been used where hydraulic lifters would leak out a thinner oil and pump down causing valve lash and noise. Lastly, thicker oil leaks less, not only out of the hydraulic lifters, but out of valve seals, crank seals, valve cover gaskets and so on.

Why have some manuals specify heavier weight oils in hotter climates? Understandably, oil temperatures in engines operating in environments of 100 deg. F ambient are going to be higher than those of engines operating near freezing ambient temperatures -- because thermostats, oil coolers, and so on aren't likely to maintain operating temperatures perfectly.

My personal experience in this engine is that 0W oil was noisy, probably because it was leaking out of the lifters. It probably also weeped more out of seals and gaskets. I've run 15W oil in this engine and had none of that, but more metal-to-metal at startup in the winter. 5W seems to give good startups in all conditions and it doesn't weep out as much -- still more than 15W.

I have a crank-driven pump and should have good pressure. Unfortunately, I have only an idiot light for oil pressure, no gauge. The light is only ever on one or two seconds after startup (and one time when the pickup tube came loose).

I don't really understand why some engines can use -20 oil and others might need -40 or exactly why it might vary with climate. Correct me if my understanding is flawed or I'm mistaken somehow.
 
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The W stands for winter. The number before that W has no bearing on the thickness of the oil. The second number is the grade. Whether it is 0w20 or 5w20, it’s still a 20 grade oil.

What year is this engine? It’s like pulling teeth.
 

FZ1

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I have an older Buick 215 with 150k miles. It's the V8 version of the ubiquitous 3800 V6. Traditionally, it would have called for 10W-40 or 10W-30 in my climate, but I've been using 5W-30 for better lubrication when starting it in the winter. It's parked outside and while it's rarely below 0 deg. F, startups were noisier with 10W. Years ago, I tried the 0W-40 that I use in my two other cars but it made too much valvetrain noise. I do a lot of short trips so the oil doesn't come up to temperature. The 5W-30 would only very rarely result in a lifter ticking.

I just filled it up with 5W-20 Mobil 1 High-Mileage. I bought the wrong weight by accident but had filled it before I knew. It should be no issue through the winter, but I typically put 5000 miles a year on this engine so the oil will only have a couple thousand miles on it before summer and 90 deg. F. I suppose I'll just wait and see if I get valvetrain noise on hot days and change it out if I do. Or should I change it out at the end of Spring?

I know what happens if I go to low viscosity in the first W-number -- with 0W I get lifter noise until the oil is hot. I'm not sure I understand what will happen if I run a low-viscosity in the second number -- 20 weight -- in hotter weather like 90 deg. F. The thermostat is 190 deg. F and on some hot days on steep grades or with low air-flow, the coolant temperature gets to 212 F on a digital gauge.
OK so does it exhibit lifter tick with the 5-20? If no tick it's OK.
 
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