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YES -
it's the wrong oil for your car -

there is a reason the developers say to use 5W30 -

quick to get proper lube at start up -
and thick enough to give proper lube at operating temp -

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if the reason you are asking about thicker oil
is to either slow down oil leaks or oil consumption -

it won't help either - not even a little bit -

 

No, I was asking because I can get Valvoline Full Synthetic racing oil for $1.00/quart. I thought it would be a cheap oil change.

 

Downside - poor lubrication, poor oil flow. Thicker is not better. No reason on earth to use a motorcycle oil in a Northstar - the engine's tight tolerances just won't handle the thick oil.

Matter of fact, this sort of oil question is directly addressed in your owner's manual.

 

when u start your car on a cold morning u will hear alot of knocking do to the fact that the sludge in the bottom of ur oil pan will remain sludge until about the 4th of july upon witch time ur motor will be junk
THICK DOES NOT LUBRICATE!

 

Regardless of weight range - 0W-20, 5W-30, 10W-30 or 20W-50 - there would be NO "sludge" in the oil pan - with 20W-50 only cold, very thick oil.

Which brings up another downside to thick oil: Filtration. When ANY engine oil is cold it's too thick to efficiently pass through the oil filter media - so a LOT of (cold) oil is simply bypassed by the oil filter's built-in internal valving - straight to the engine oil passages. So, whether you like it or not, automotive engines do not receive full oil filtration until the oil warms to operating temperatures - about 180 - 210 degrees, about 10 - 15 miles of driving.

houg, THIS is "sludge", caused by improper crankcase ventilation ....................... before PCV came into use ...............and after it arrived, due to improper engine maintenance ...............many drivers actually let their engines get this bad, then we see them in here.

https://www.google.com/search?q=aut...ch&tbo=u&source=univ&sa=X&ei=XRCfVN-_OIycNtGFgtgC&ved=0CB8QsAQ&biw=1366&bih=620

 

That is one nasty looking engine!

 

You should be OK with 10W30, I still use it, but I wouldn't go any higher than that.

 

what i meant by sludge was thick goopy peanut butter like oil / sludge

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when i was a teenager i owned a 1970 plymouth duster, i got a case of straight 30w oil for free so i put it in the motor, the motor wouldnt even crank over in the morning winter in ne

 

Racing oils are not designed for longevity of the engine but designed to produce the optimum results for racing only.

From Page 5-16 of the owners manual

SAE 5W-30


As shown in the viscosity chart, SAE 5W-30 is best


for your vehicle.


These numbers on an oil container show its


viscosity, or thickness. Do not use other viscosity


oils such as SAE 20W-50.

 

I have been using 20 50 oil in the hotter months of the year in all my cars and never had trouble with oil flow. I didnt use it in winter obviously. May be different for the Northstar, but for the small block Chevies and similar, it was fine. Poeple always said tge same thing, new engines are designed with clower tolerances, wont work, blah blah. If you look up the tolerances of a old sbc from the 60's and the last LT1 in the Camaro(1st gen style) of the late 90's, they are the same or very close. Only reason maker advised using thinner oils was for gas mileage, thats all. The thinner oil containers even say fuel saving on them. Engine tolerances were pretty much tightened up as much as possible by then. BMW and Mercedes use 5 50 oil in a lot of their cars, you think they use sloppy tolerances in their expensive high po engines? I bet the northstar has similar clearances as the chevy, or any other standard vehicle engine.

 

=======================
The thinner oil containers even say fuel saving on them.
oh - then it MUST be true -

because everyone knows -
they CAN'T print anything that isn't TRUE - :histeric::histeric::histeric:

 

oil that reads 'fuel savings' EC energy conserving or RC resource conserving" is a slicker oil.
That type of oil has so much friction modifier in it will cause the wet clutch to slip on a motorcycle that share engine/clutch/trans. oil.

 

I use 10-40 in my car for the winter because whenever i use anthing less, my engine light comes on saying "low oil pressure shut off engine". My local mechanic says its fine and should worry about it. Any second opinions on that?

 

Depends on what engine/year your car is, and how many miles it has on it.

It should be just fine on 10W-30, year-round. 10W-40 in hot summer, trailer towing, heavy mountain driving.

"Check oil pressure" lights in the Northstars are usually due to an iffy oil pressure sending switch - on the side of the oil filter adapter - they sometimes trip the warning at hot idle. Replace with an AC Delco switch. $15. (labor extra).

Look at the thermometer and oil recommendations in the owner's manual ................... 10W-40 is not recommended for a Northstar.