Home Forums Gear Hunting Trucks and Four-Wheel Drives Castrol Synthec or Mobil 1?

I'm going to switch over to synthetic oil at my next oil change. I want to go with a brand of oil that I can buy locally. That's pretty much Castrol Syntec or Mobil 1. Is there any difference between the two? Is one better then the other? Thanks.

You have the right idea to select one readily available oil and use it.

Either one, I am sure, has passed the API tests and other tests.

You might check your vehicles warrantee to see if some oil or other is required or not allowed.

Use the grade of oil thats required by the manual.

I can't say if one is better than the other. The sellers provide plenty of marketing to us for sure.

I sold lubricants for a long time made by a custom blender. When there is some special or unusual application indeed a unique lubricant might indeed improve things. In your case its just another engine. Select one brand or the other and stay with it.

I ran Mobil 1 in all my trucks from 1998-2005. When I traded from a Ford F150 to a Toyota Tundra, I went with regular Castrol GTX. Go with the one that is most readily available. I did run Pennzoil synthetic oil once, and can't say I really cared for it.

Thanks guys. Both Castrol Syntec and Mobil 1 are readily available in my area. I have a 2007 Ram 1500, 4x4, Hemi, auto, anti spin rear end. I want to switch the engine oil and front and rear differential fluids to synthetic. I'm not sure about the transmission and transfer case fluids. I also want to use the best air and oil filters available. I'm probably going to have this truck for a while and want to keep it top shape. Quality oils, fluids and filters are a great place to start.

I'll take all the advise I can get on filters too. Purolator and Fram are the most popular in my area.

Castrol isn't a synthetic oil. Its a highly refined dino oil (group 3)

Castrol won a lawsuit that enables them to call their Syntec oil synthetic.

Mobil 1 is a true synthetic oil (group 4)

They are typically priced very close. Why some one would pay the same for an oil thats not truly synthetic is beyond me.

A couple other true synthetics are Royal Purple,Amsoil,and Redline.

ATF is the fluid I'd most want to be synthetic.

Fram filters suck. They used to be ok,but have gone downhill. People still buy them because they're a well known name.

Purolater,Mobil 1,Donaldson,Wix,AC Delco are good choices.

What Mossy said.

rb

I use the Mobil and a K&N air filter in my 01 Cherokee and get up to 24MPG on longer trips and almost never get less than 20 on short trips.

Thanks for the replies!

NYH,

Changing the differentials to synthetic is smart. I had a 2001 F150 4x4, and when I made the switch to synthetic, my MPG went up 1 mpg. I thought it was a fluke, but knew someone else with a trck identical to mine at the time, and they had the same thing happen when they swtiched over. I know some that have claimed 2-3 mpg difference when they swtiched the transmission fluid as well as the diffs.

In regards to the oil filter, if they don't carry Wix where you are at, the NAPA Gold filter is the same thing (made by Wix). I run the NAPA Gold in all of my vehicles (even the ATV).

I perform engineering tech support for semi trucks where miles per gallon ratings average 6.5 Every fleet I know uses synthetic lubes to boost their fuel economy. As far as filters go, the K&N air filter is ideal as you win on multiple fronts. Not only does it breathe better than a pleated paper media filter, but it has a million mile warranty. Thats just the ticket for the truck you said you wanted to keep for a long time. The oil filter is less critical as you will be replacing it at every oil change interval. That being said, some oil filters are obviously better than others. The less expensive oil filters will utilize a cheaper paper media and the bypass valve inside can open up because of oil pressure and not because the paper is saturated with debris. Any brand name should be adequate. Fram quality is not rated as highly as in years past, but is still better than the economy brands used at the quick lube oil change shops.
Groovin61

In regards to changing the rear-end oil, you may want to do some research on your anti-spin differential before changing lubricants. I know Mopar recommends The following each time the rear end oil is changed:

In Sure-Grip Differentials 4 ounces (.1183 litres) of MOPAR Hypoid Gear Oil Additive Friction Modifier, Part No. 4318060 equivalent must be included

I am not a lubrication expert, but just wanted to point out that the anti spin may require a little different viscosity than typical 90 weight.

I use Mobil 1...been thinking about the K&N air filter switch...they really increase gas millage?

For the record: 2005 F150, 5.4L

Tony

Go to Bobistheoilguy.com

I ran Mobil 1 in my wife's 96 Pont. Grand Prix from day one for 8 years and 140ishk miles and even with those high miles it still got 28-30 mpg on the highway and 22 in town. I sold it to my mother-in-law and she's still driving now. The enigne is still runs great. I think its close 200k now. I used to use Castrol Snytech in my trucks and it is good also. I just keep the Grand Prix longer than the trucks. I think either would be a good choice.

Moble One 5w30 is all I use in my two 4x4 Tacomas and Chev 2500 HD 4x4 crew 6.0 gas....K&N oil filters.....and air...

There is no way I'd run a K&N air filter on a turbo diesel, especially on a rig I wanted to last a million miles. I did not used to think that way, but here is waht opened my eyes........

http://www.duramax-diesel.com/spicer/index.htm

As to oil, consider this concerning running synthetic oil in the engine. While a synthetic's viscosity last significantly longer than dino oil, the sythetic oil gets as dirty as the dino oil. Unless you have a way to keep the synthetic oil clean, then you need to change it at the same frequency as the dino oil.

The only way to keep the synthetic clean is to run an oil bypass filtration system. These systems require changing the oil filters something like every 6000 miles and adding a quart or so of oil to top things off. This way you can run 24,000 miles with the synthetic. However, when I did a cost analyst, I found that the extra cost of the synthetic oil at oil change time, coupled with the buying of filters and quarts to top off, was a wash with using dino oil and changing it every 3000 miles or 3 months.

Add in that when Amzoil tested a bunch of diesel engine oils (IE 15W40) for viscosity breakdown, Rotella (a dino oil) was rated #2 over all ahead of several synthetics.

One of the advantages to a synthetic is thet you can normally run a lighter weight oil, which should mean better effficieny. However, with a diesel rig you can't do that. You need to run an oil that is no less than 15W on the bottom end. Lighter viscocity oils get "squeezed out" of the rod bearings during the compression stroke with the high cylinder pressures a diesel produces.

Also, given how many--if not most--gassers recommed 5W30 nowadays, I am not sure you can run a lighter synthetic.

I am NOT anti-synthetic, as I think they are the best choice for differntials and manual trannys. However, I have never found an application where an synthetic engine oil was an advantage.

Misc. Many modern engines will go 5000 miles between oil changes on dino oil. Also, some feel that modern engines keep the oil cleaner, and if they do a synthetic engine oil might be more useful than with older engines.

Costco has Mobil 1 on sale at about $22.00 for a 6qt case using their coupon. I'm going to pick up my 6th case later today! Sale ends tomorrow.

MtnHtr

Then you haven't had to start your engines at -40 degrees or colder.With 5w30 Ams oil or Mobil 1,my engines turn over much easier and much quicker than with 5w30 conventional oil.It can make the difference between an engine starting or not starting in very cold weather.The oil pressure also builds much quicker on the gauge with synthetic oil.