Best oil for 100K + engines?

[El Terrible]

Well Ive been using Castrol gtx high milage for years now and its been awesome to me...........

 

[samwilkie]

i just turned 150000 on my 03 tahoe but i just got it as well so im not sure what oil is in it.there doesnt look like there is any leaks anywhere and still runs great would it be safe to put in a full synthetic oil? the high miles kinda has me worried about that

 

[Wake]

i just turned 150000 on my 03 tahoe but i just got it as well so im not sure what oil is in it.there doesnt look like there is any leaks anywhere and still runs great would it be safe to put in a full synthetic oil? the high miles kinda has me worried about that

I would say yes. I've switched used cars I purchased with over 100K miles to synthetic and had no issues that I didn't have prior to switching.

The only thing with synthetic oil is that if you have a leak it will leak a little more, if you didn't have a leak previously then you might develop a small one. If you had sludge inside your engine keeping it from leaking then you will leak after the synthetic cleans out the inside over a few oil changes.

The good thing about trying synthetic oil is that if you don't like the results you can switch back to conventional.

Synthetics have changed over the last several years as well. You now have high mileage synthetics that are supposed to have seal conditioners to help prevent leaks.

 

[samwilkie]

Thanks Wake Ill pick some up this week.

 

[Johny_Vette]

I've got 167k In the hoe below me, And I've been using Royal purple since I got it with 98k back in 05. Nuff said, Synthetic over over thing. IMO Royal purple is the way to go. I change my oil every 2k Miles, But when I feel like changing it more often I do, The last oil change I did I did it at exactly 932 Mi because I love the fact that the truck has been good to me, the engine hasn't asked for anything besides, Gas, Oil, Engine Coolant, Brake Fluid, Wind shield washer, brakes, and shocks and a window regulator since 05.

 

[CEN2MENTAL95]

mobil 1 high mileage with mobil 1 oil filter for me

 

[robrr44]

Extra Virgin Olive Oil, 104K.

 

[CAResearch]

So are most over 100k folks doing home oil changes, or are folks paying 70 for synthetic at the local shop?

Also whats the typical cost to replace the front and rear differential fluid with synthetic at a tune up shop?

 

[robrr44]

I doing the home DIY thing. And I run whatever high mileage oil is the cheapest. I've been thinking of switching to synthetic though. Quick question, sorry to hijack the post, however, I have seen my oil pressure at idle sit at 40 but jumps pretty substantially under hard acceleration. Would switching to synthetic help with the oil pressure under heavy load?

 

[Freedom Motorsports]

While everyone has their favorite choice in synthetic lubricants, keep in mind that they are NOT all created equal. Also, changing from one to another often can be detrimental to the health of your engine. Some synthetics are made with lower quality base stock oils than others and you should do your research on the different types of synthetic oils available and make your choice according to that research. Not just marketing "hype". Regardless of the oil you choose to use, the number one thing to remember is to make sure to stay at or below whatever mileage interval that the particular company recommends for their oils. For example, AMSOIL has been offering Warranted 25K mile oil change intervals since 1972. These intervals have been tested in the real world and used by millions of people since and they have been able to continue to offer these warranted intervals because of the research and development into the technology involved in the formulation of synthetic fluids in general. They were the first company to offer full synthetic lubricants to the automotive industry and continue to be the leader in synthetic lubrication research and development. No other oil company can offer the same benefits or intervals, period.

AS for the oil pressures, keep two things in mind, when under load, it is common for these engines to run at around 60psi. The other thing to keep in mind is that the factory installed gauges in our vehicles are notoriously inaccurate. As an example, when you are at full operating temperature, your temp gauge will more than likely show that you are running at 210* when in actuality your engine is running at about 195*. The only way to get a fully accurate measure of what your vehicle is doing is to install an aftermarket gauge of some kind whether that be in the form of mechanical gauges or a monitor like the Edge Ensight monitors to get more accurate readings.

While synthetic oil can help with making sure that your oil pressure is more steady, they may or may not reduce the overall pressure under load. Every vehicle and engine is different and what one does, another may not do.