thicker viscosity oil on High Milage?

Question

Is it a good idea to use a thicker viscosity oil on a High millage car? For example, lets say that the car manual suggest 5W30 oil, should I upgrade to a 5W40 or 10W40 just because the car has 75,000 or 100,000 miles on it? What are the advantages to using a thicker oil?

Answer 1

Dear Juan-

On the higher milage cars its better to go with the heavier oils like 15w-40, or 20w-50.

The reason the lighter oils were developed is because the machining standards are much tighter on today's engines. But the other reason is for fuel efficency.

However, as the engines are used the tolerances open up due to the natural wear of the moving parts. This includes piston rings, valves, bearings and other such parts in the engines.

As these parts wear-in the parts become looser and hence need a thicker oil to better protect them for the future miles they may encounter.

Here is the rule of thumb that we use at our Chevrolet Dealership.

New, (0 to 30,000 miles): 0w-20, 5w-30, 10w-30

Intermediate, (30,001 to 75,000 miles) 10w-30, 10w-40,
15w-40

High Milage, (75,001 to 100,000+ Miles): 15w-40, 20w-50

Just be sure to keep the oil and the filter changed every 3000 miles or 90 days. This is the absolute best way to keep oil related engine damage from happening.

Also stick with the same brand of oil, do not switch brands on every oil change. This can and has been known to cause engine sludge build-up.

If you are not sure whay brand of oil was used in the car last, that is OK, just pick a specific brand and stick with it for as long as you own your car. You will be just fine.

For the record, if the vehicle manual suggested a particular type of oil, you can stick with that if you like, but the chances of that engine burning oil becomes greater as the engine wears.

The normal burn ratio for Oil Consumption is about 1 quart of oil to every 75 gallons of fuel, (Basically one quart of oil between oil changes). This is considered "normal" oil consumption.

As for the advantages of using a thicker oil, better engine protection, but its at the cost of a little fuel efficency.

Good Luck and I hope I was able to help you out!

Answer 2

if an engine has over 100,000 miles then yes you need to use a slightly thicker oil to lube all moving parts. you can also use a good heavy duty oil such as shell rotella-t , chevron
delo, or chevron delvac 15w40. all 3 oils mentioned come
in 15w40 and 20w50. these have more anti-wear additives than normal oil you would use in your car.i use 15w40 shell rotella-t in all my vehicles. i has a 1988 lincoln MKVII LSC
H.O. 5.0 with 187000 miles, a 1983 AMC eagle4x4
I-6 258 with 230000 miles, and a 1988 GMC V-2500
suburban 4x4 v-8 350 with 40000 miles on a new crate 350
engine. oils like rotella-t and delo are for commercial semi's
and are excellent in high loads and temps. my father also
uses rotella-t in a 1988 olds 98 regency with 300,000
miles on it and has no problems.

Answer 3

I'd go to 10w40. The thicker oil takes up a little more space in your worn bearings and other moving parts.

Answer 4

If it is 5W30, use 10W30, you dont need higher vicosity, just more weight, but if it is around winter time, than stick with 5W30 for high milage cars, as the cold weather makes it thicker anyway.

Answer 5

10-40 NO!
The major oil co's have special blends out for cars with high mileage. Stay with the manufacturer's recommendations.

Answer 6

why would you want to do that ? so the oil takes longer to get to the internal parts that require lubrication , the thicker the oil the slower it will flow . stay with the manufactures recommended wt

Answer 7

depends on the wear in the engine ,,do ya have low oil pressure? 235,000 miles on 10-40

Answer 8

i would recommend 10w30. after your car gets above 75k the tollerances get larger, therefor the lighter oils will not have the correct lubricating properties

Answer 9

no,its not a good idea, and there are no advantages,unless your moving from fargo to death valley, then you might wanna think about it.