Engine failures?

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847
Location
Ozark Mountains
Anyone know of any engine failures or problems they believe happened because of using oil much thicker (like 10-40, 5-50 or 15-50) in an engined specked for 5-20?
 

JHZR2

Staff member
Messages
44,782
Location
New Jersey
Ive heard issues of oil pumps acting up/failing due to having to pump thicker oils than specified. I do not have any data for it, so cannot tell if it is a wife's tale or what. There are some general temperature/viscosity rules, which may vary slightly depending upon engine design, but are probably close enough for one size fits all. Using 15w-40 oils only above 4F, and using straight 30 weight oils only above 40F (this is actually labeled on the pennzoil HD30 bottle!) come to mind. Older cars had charts that recommended different oils for different temperatures. I think some (e.g. subaru) still have that to some extent at least. The real question is why do you think you need to do this, and what end are you trying to have more viscosity? It is pretty well established that for typical use, it is better to have a thinner oil at startup that flows easier. At high temperatures, it may be desireable to have a bit more viscosity at the bearings, but that said, the typical conventional 5w-30 oil may well shear to a 5w-20 spec oil before too long anyhow... 5w-20 oils tend to be pretty robust.
 
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313
Location
Lugoff, SC
Not directly related to the oil, but I have seen some Fords have problems with the oil failters blowing off when too thick of an oil is used. Which could lead to the failure of the engine.
 
Messages
6,987
Location
Michigan
Engines failures are rare in themselves and would be caused by a mechanical issue not oil. Cars are made to function with a wide range of oil viscosities for various conditions. Using a thicker oil mught cause a little sluggishness and slightly worse fuel economy.
 
Messages
39,806
Location
Pottstown, PA
 Originally Posted By: KLowD9x
Not directly related to the oil, but I have seen some Fords have problems with the oil failters blowing off when too thick of an oil is used. Which could lead to the failure of the engine.
Yeah. That was the relief valve issue on modular engines. The 5w-20 spec basically masked the problem.
 
Messages
4,998
Location
Milwaukee, WI
That chart is absurd. A 5w-40 is no good over 68 degrees? Weird. To the OP, all I've ever heard of is weird things happening with multi-displacment or fluid controlled (not just fluid actuated) valve timing systems.
 
Messages
3,756
Location
CA
 Originally Posted By: callbay
Anyone know of any engine failures or problems they believe happened because of using oil much thicker (like 10-40, 5-50 or 15-50) in an engined specked for 5-20?
You'll likely find no failures linked to thicker than specified oil. I run thicker than factory in all of my cars with absolutely no problems. With that said, I wouldn't get crazy and run a 15-50 in a car spec'd for 5w-20 in the middle of winter. I've also blown the filter off of my GN a couple times when I had to run a straight 60wt in the winter due to a bad rod bearing. I had to start it with it in gear so the rpms didn't go up and I still had 100psi cold at 800rpm. Couldn't think of touching the throttle until it was fully warm or the filter would shoot off. But that's hardly normal, it has a high volume, high pressure pump and relief and a straight 60wt dino in winter is just asking for trouble. Personally I look for the highest HTHS with the lowest viscosity. Sort of an HTHS vs 100c viscosity. Right now it's Amsoil ACD straight 30 with a [email protected] 100 and a 3.5 or 3.6 HTHS..... Maybe Gary can help me with the correct HTHS number.
 
Messages
22,602
Location
Dallas,Tx USA
 Originally Posted By: BuickGN
 Originally Posted By: callbay
Anyone know of any engine failures or problems they believe happened because of using oil much thicker (like 10-40, 5-50 or 15-50) in an engined specked for 5-20?
You'll likely find no failures linked to thicker than specified oil. I run thicker than factory in all of my cars with absolutely no problems. With that said, I wouldn't get crazy and run a 15-50 in a car spec'd for 5w-20 in the middle of winter. I've also blown the filter off of my GN a couple times when I had to run a straight 60wt in the winter due to a bad rod bearing. I had to start it with it in gear so the rpms didn't go up and I still had 100psi cold at 800rpm. Couldn't think of touching the throttle until it was fully warm or the filter would shoot off. But that's hardly normal, it has a high volume, high pressure pump and relief and a straight 60wt dino in winter is just asking for trouble. Personally I look for the highest HTHS with the lowest viscosity. Sort of an HTHS vs 100c viscosity. Right now it's Amsoil ACD straight 30 with a [email protected] 100 and a 3.5 or 3.6 HTHS..... Maybe Gary can help me with the correct HTHS number.
Man I bet that was insane seeing that filter shoot off!
 
Messages
22,602
Location
Dallas,Tx USA
 Originally Posted By: ZZman
Using a thicker oil mught cause a little sluggishness and slightly worse fuel economy.
When I had my first 3000GT,I changed the oil to a 10W40 from a 10W30 and I could definitely feel the sluggishness. Fuel economy didn`t appear to change,but it definitely affected her aceleration in 1st gear. Those car have a hellacious powerband (sort`ve like the powerband in a 2-stroke dirt bike)and it was definitely more responsive on the 10W30. Those cars seem to have "finicky" engines.
 
Messages
3,756
Location
CA
 Originally Posted By: aquariuscsm
 Originally Posted By: BuickGN
 Originally Posted By: callbay
Anyone know of any engine failures or problems they believe happened because of using oil much thicker (like 10-40, 5-50 or 15-50) in an engined specked for 5-20?
You'll likely find no failures linked to thicker than specified oil. I run thicker than factory in all of my cars with absolutely no problems. With that said, I wouldn't get crazy and run a 15-50 in a car spec'd for 5w-20 in the middle of winter. I've also blown the filter off of my GN a couple times when I had to run a straight 60wt in the winter due to a bad rod bearing. I had to start it with it in gear so the rpms didn't go up and I still had 100psi cold at 800rpm. Couldn't think of touching the throttle until it was fully warm or the filter would shoot off. But that's hardly normal, it has a high volume, high pressure pump and relief and a straight 60wt dino in winter is just asking for trouble. Personally I look for the highest HTHS with the lowest viscosity. Sort of an HTHS vs 100c viscosity. Right now it's Amsoil ACD straight 30 with a [email protected] 100 and a 3.5 or 3.6 HTHS..... Maybe Gary can help me with the correct HTHS number.
Man I bet that was insane seeing that filter shoot off!
It was the noise that got me. I learned it very well lol. I was at the parents' house one time and you could follow the blowoff trail and my 3 point turn back into the house perfectly. My father wasn't too happy.
 
Messages
22,602
Location
Dallas,Tx USA
 Originally Posted By: BuickGN
 Originally Posted By: aquariuscsm
 Originally Posted By: BuickGN
 Originally Posted By: callbay
Anyone know of any engine failures or problems they believe happened because of using oil much thicker (like 10-40, 5-50 or 15-50) in an engined specked for 5-20?
You'll likely find no failures linked to thicker than specified oil. I run thicker than factory in all of my cars with absolutely no problems. With that said, I wouldn't get crazy and run a 15-50 in a car spec'd for 5w-20 in the middle of winter. I've also blown the filter off of my GN a couple times when I had to run a straight 60wt in the winter due to a bad rod bearing. I had to start it with it in gear so the rpms didn't go up and I still had 100psi cold at 800rpm. Couldn't think of touching the throttle until it was fully warm or the filter would shoot off. But that's hardly normal, it has a high volume, high pressure pump and relief and a straight 60wt dino in winter is just asking for trouble. Personally I look for the highest HTHS with the lowest viscosity. Sort of an HTHS vs 100c viscosity. Right now it's Amsoil ACD straight 30 with a [email protected] 100 and a 3.5 or 3.6 HTHS..... Maybe Gary can help me with the correct HTHS number.
Man I bet that was insane seeing that filter shoot off!
It was the noise that got me. I learned it very well lol. I was at the parents' house one time and you could follow the blowoff trail and my 3 point turn back into the house perfectly. My father wasn't too happy.
Man that would`ve scared me sh**less!!!!!!!!
 
Messages
782
Location
Alberta
If your car spec's 5W-20, I probably wouldn't go any thicker than a 15W-40. The current HDEO CI-4+/CJ-4 rated Group II based 15W-40's are so good, I just don't see how there could ever really be many situations where a 50 weight would provide any significant benefit or protection over these oils. As far as hurting the engine -- no. Just a little less power and gas mileage over a 5W-20.
 
Messages
8
Location
N.E. Florida
FWIW,I switched from 10w30 to 15w40 in my '02 Dodge ram 4.7 at 9k and have never had any problem.Vehicle has 123K on it now and still gets the same fuel economy when it had the 10w30.
 
Messages
19,479
Location
Chicago Area
I don't get those posted charts at all. They don't seem to make consistent viscosity sense. A thick oil can cause problems with oil controlled cam and valve systems, on new cars. On a cold day, the pump won't be able to pump it to the bearings, either. Tough on the starter, as well.
 
Messages
3,756
Location
CA
 Originally Posted By: mechtech2
I don't get those posted charts at all. They don't seem to make consistent viscosity sense. A thick oil can cause problems with oil controlled cam and valve systems, on new cars. On a cold day, the pump won't be able to pump it to the bearings, either. Tough on the starter, as well.
Won't be able to pump it to the bearings? No way, unless it's way out of it's acceptable viscosity vs temp range. If it's even close, oil will arrive at the bearings very quickly.
 
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