Oil too heavy of a weight? Blown seals?

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Feb 21, 2008
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Ok, don't rib me too hard, but someone stated to me that they would never put 15w-50 in their engine because I am asking for blown seals. I have never heard this. Can some of you elaborate? Is this a conspiracy theory? LOL

I picked up a couple of 2-gallon containers of Mystik 15w-50 for my next change since it is easy to find and has a great price. Now I am wondering.
 
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So someone made the remark that they imagined it would happen, not that it actually did? I wonder what happened to the pressure relief in the system?

I once heard on here that someone once heard that someone said that an oil with a 0W winter rating would destroy an engine because it is too thin. These two guys should get together and form a collation to meet in the middle. Sounds like a match to me.
 
I was buying oil at the NS Norfolk Auto Service center a few years ago. I was grabbing a bunch of 0W30 Castrol Syntec SL for 0.99/quart.

One of the mechanics looked at my purchase and let me know that, "That oil is too thin for your car. You need a 10W30, or you will have no oil pressure on start up"
 
I was buying oil at the NS Norfolk Auto Service center a few years ago. I was grabbing a bunch of 0W30 Castrol Syntec SL for 0.99/quart.

One of the mechanics looked at my purchase and let me know that, "That oil is too thin for your car. You need a 10W30, or you will have no oil pressure on start up"
This dude was a"mechanic"? :ROFLMAO:
 
This dude was a"mechanic"? :ROFLMAO:
Yep. Wore the uniform shirt of the technicians that worked there. Was getting oil for a customer (they just got it off the shelf in the retail section).

People who work on cars and get paid for it are, in fact, mechanics.

Whether or not they know anything about cars or not, whether they understand, or have training, they are still considered mechanics...
 
I got a fairly new self propelled lawn mower from a "mechanic" last year, dude failed to diagnose water in the fuel tank and aparently screwed with the intake valve lash and caused the pushrod to bend.
So I take it your mower was having a hard time starting that's why it was there . So he screwed around with the valves . I hope that Einstein didn't charge you ?
 
So I take it your mower was having a hard time starting that's why it was there . So he screwed around with the valves . I hope that Einstein didn't charge you ?
I got it for free, he's some dude I known from school, he was complaining it wouldn't start, I suggested it had bad gas, but he wouldn't listen to me, he just went on about how craftsman stuff was junk and he was going to buy a honda, he said he was just going to throw it out, so I asked if I could have it so I drove out to the rural town he lives in and he had it sat out on the curb for me to take, I got it home and sure enough there was lots of water in the fuel system, it was fairly late at night so the next day I cleaned up the fuel system but it still wouldn't run, then I took a look at the valve lash and found the bent push rod, it had seeped oil around the valve cover gasket but he'd also changed the oil and "cleaned the carb" by spraying WD40 into it, so there was oily stuff all over so I wasn't sure if the valve cover was seeping or if it was just spilled oil and WD40 residue, I ended up putting a used push rod and a new head gasket on it since I had removed the head to verify the valves weren't bent. so I got a $300+ mower for like $20 in parts.
 
Yeah, I kinda figured it was a stretch. I have worked on vehicles for a LONG time and research quite a bit. I had never heard of such before, so I was a little stumped LOL....like maybe they know something I don't? Appreciate the feedback.
 
I personally would not use 15w-50 because I don't think the modern engine needs it.
Not because it blown the seal.

I did put 20w-50 in the 80s-90s in my 80 Toyota Celica.
I put 15w-40 Diesel rated oil in my diesel because that is what required, sometimes 5w-40 synthetic.
I used diesel rated 10w-30 once, it was not good because it was overheat, at least for my burb in the signature.

Newer engine is more tighter in terms of tolerance, so it can use thinner oil..
 
This dude was a"mechanic"? :ROFLMAO:
Most likely not certified for anything, by anyone. The military auto hobby shops exist due to the transient lifestyle of the typical military family that is living in an apartment or renting some place. They have lifts and tools, things active duty people who are in that town for 18 months don't usually have. You can change oil, do brakes and other general maintenance. They hire "mechanic professionals" to advise people on how to do general vehicle maintenance. Some even stock some basic parts behind the counter.
 
I personally would not use 15w-50 because I don't think the modern engine needs it.
Not because it blown the seal.

I did put 20w-50 in the 80s-90s in my 80 Toyota Celica.
I put 15w-40 Diesel rated oil in my diesel because that is what required, sometimes 5w-40 synthetic.
I used diesel rated 10w-30 once, it was not good because it was overheat, at least for my burb in the signature.

Newer engine is more tighter in terms of tolerance, so it can use thinner oil..
Clearances (the distance between parts) haven't changed much in almost 100 years for production engines. Tolerances (the allowed level of deviation from spec) have indeed improved due to better manufacturing practices, but that doesn't change the oil grade requirement.

An anecdote:
Back when the Ford Windsor 302 "HO" engines were being assembled, they were hand-built. The engines were bored to a nominal size and the appropriate size piston was determined, then ground down to a specific weight by removing material from around the wist pin area (this is part of balancing) and then the rods received the same treatment, and were stamped with the cylinder number they were intended for. Because of the hand-assembled nature of these engines, the tolerances were quite tight.

When the LSx truck engines were being produced, GM went with bulk fit piston/bore configurations. That is, there were "binned" parts that were slapped together, the block was bulk machine bored and honed and they used shorter piston skirts to reduce friction. This process (the piston to bore fitment) had some rather loose tolerances and, combined with the short skirted pistons, meant that some engines had some pretty loose piston/bore assemblies. When cold, these pistons would "slap" the bores, which is why the early LSx truck/SUV engines became somewhat notorious for being piston slappers. It had no real impact on longevity, but it was an annoying byproduct of that bulk-fit process. Later on, they put a teflon coating on the skirts to reduce (or eliminate) the noise. I don't know if they tightened up the manufacturing tolerances or not or if the same level of deviation was still allowed with the updated pistons.
 
I've also read that too much oil may blow a seal, and that an oil pump with too much pressure would do the same. But it seems to me the areas where seals are would not be affected by pressure.

I can't think of anything 'blowing a seal', I can only see seals drying out and cracking or shrinking.

Am I wrong?
 
Clearances (the distance between parts) haven't changed much in almost 100 years for production engines. Tolerances (the allowed level of deviation from spec) have indeed improved due to better manufacturing practices, but that doesn't change the oil grade requirement.

An anecdote:
Back when the Ford Windsor 302 "HO" engines were being assembled, they were hand-built. The engines were bored to a nominal size and the appropriate size piston was determined, then ground down to a specific weight by removing material from around the wist pin area (this is part of balancing) and then the rods received the same treatment, and were stamped with the cylinder number they were intended for. Because of the hand-assembled nature of these engines, the tolerances were quite tight.

When the LSx truck engines were being produced, GM went with bulk fit piston/bore configurations. That is, there were "binned" parts that were slapped together, the block was bulk machine bored and honed and they used shorter piston skirts to reduce friction. This process (the piston to bore fitment) had some rather loose tolerances and, combined with the short skirted pistons, meant that some engines had some pretty loose piston/bore assemblies. When cold, these pistons would "slap" the bores, which is why the early LSx truck/SUV engines became somewhat notorious for being piston slappers. It had no real impact on longevity, but it was an annoying byproduct of that bulk-fit process. Later on, they put a teflon coating on the skirts to reduce (or eliminate) the noise. I don't know if they tightened up the manufacturing tolerances or not or if the same level of deviation was still allowed with the updated pistons.
International measured the bores and stamped the deck next to each with an A,B,C or D. Same with pistons. They select fitted each piston to each cyl that way.
 
only crankcase pressure would blow a seal out and oil pump pressure is limited by bypass valve. I've seen failed bypass valves causing oil filter bursting, but not seals popping.
An ex co worker of mine said his Yaris engine with 30k miles blew a seal about two weeks after having added a bottle of Lucas synthetic oil stabilizer, which is of course pretty thick. So who knows. His dipstick level read full before the addition of the Lucas. Not saying that was the cause but he believes it is.
 
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