Hey everyone i have a 2005 2500HD 8.1 with 30,000MI
And wondering if i can put sythetic( I see no harm in it)?
And should i use 5w-30 or a thicker oil?

Thanks in Advance for hte help

 

I have to assume you do it yourself, good 4 u. GM started your engine from Factory w/Synthetic oils in your entire drivetrain and you drove off the lot w/Mobil 1 FULL Synthetic it. GM went to full Synthetic oils in all it cars/trucks starting in 1995. Before Mobil 5-30/10-30 came out, most people I know from the TaraDelSole to Moab crowd used nothing but Castrol GTX Synthetic, the first widely available. This isn't saying straight oils are a mistake, they are a preference. I use nothing but Synthetics from my engine, front axle, transfer case, Tranny, to Rear end and have never used anything but. Again a preference. I recommend for the drive train, Tranny/Transfer case Dex III(50k between changes) and for the Front axle and rear end, Almasoil (50k between changes), used by everyone from Defense to Caterpillar to Rock Crushers. As for the engine, it's you who must decide if you want to add the extra buffer Synthetics offer. I just wanted you to know; GM started your truck off with Mobil 1 Full Synthetic oil for a reason, longevity. Hope this helps. If you do go to Mobil 1, you can, again a preference, get the extended life oils, 5k -> 15k between changes(you would still need to change oil filter every 3k-5k). You should stay away from BLENDS that is one thing I strongly believe in. It's all up to you but as one of our members says, you break it, you pay and Synthetics add protection you will never find in any standard 30w oil.
GL
Greek

 

GM DOES NOT use synthetic engine oils in every vehicle since 1995. The Corvette is one that uses Mobil 1 from the factory. As far as the drive train, don't assume it is all synthetic. For instance, my 2005 Silverado Crew Cab 4X4 Z71 did not use synthetic in the front differential from the factory. I changed it to synthetic right away. By all means use a synthetic lube in everything you can, it is a far superior lube to petroleum based lubes. Testing at GM shows Mobil 1 to be far better than many other synthetic lubes. As far as viscosity, use what is recommended in your "Owners Manual".

 

I will give you a Half A$$ apology for the flame I am going to give you. I left GM after 26 years just for this reason. Upper management doesn't get their hands dirty, believes everything their told, and treats the public like idiots. They like having the A.S.E card, looks good on resumes. BTW; thanks for the Parking Brake, DriveShaft, Warping Rotors, Steering Wheel Lockup at Speed, SunGear, Poor Swiches, Poorly Designed Heads and every other POS screw up you guys in Engineering and Warranty have just let pass in your rush to get the back 9 in!@! You had since 1985 when you Engineering Heros started the C5 project to get all the bugs out; Christ man, 2 years after it came out there were still 288 TSBs active, just on the 1999 C5!@! Getting facts straight my friend is important. Since the 95 z28/ss, GM has used Mobil 1 from the Factory. Maybe I should have added that in all the trucks and performance cars I have bought, I made sure that all oils were Synthetic BUT!@! the motor came with Mobil 1 (pick apart is weak man; WE are talking about MOTOR OIL. After 26 years with them, I would like to believe I know my oils and my facts. If your dlrshp tells you different, find another. Mobil 1 has been the staple for GM for 11 years now. Then again, I am in Ca where our requirements and standards demanded from GM may be a little higher do to the Punk *** Democrats who run this state.
Again, it is all about preference. Having owned a number of Corvettes, Z28/SSs and 1 Truck since 1995 (I currently have a 99C5-02Z28/ss and my 00/Z71), each has started its life w/Mobil 1. When you go in for your oil change next time at a GM dlrshp, ask them what oil they use. The answer will be, Mobil 1.
Thanks for the debate; that is what this forum is for.
26 years with General Motors.
Retired General Manager 9 years /Service Manager 10 Years / 7 years prior Wrenching. A.S.E. Certified as well. Real Glad your here,,,,.
Greek

 

I don't apologize for the flame you are about to get, you don't know what you are talking about! I can see why you are no longer with GM with the attitude you have. Jason2500 was told by you that his engine came with synthetic oil and that is not true. If it did the Owners Manual would specifically say to use synthetic engine oil which it does not say, I own one of those trucks. You said GM went to full synthetic in ALL the cars and trucks in 1995 and that is incorrect. Most vehicles use petroleum based engine oil as factory fill. Some higher performance or high heat applications come with a factory fill of synthetic and those vehicles recommend in their owners manuals the continued use of synthetic engine oil. An example of some 2006 cars that use synthetic as a factory fill is the Cadillac STS, Corvette and Chevy SSR. Vehicles such as the 2006 Impala and Silverado have non-synthetic as a factory fill and their owners manuals specify petroleum based oils as the standard service fill. I personally recommend synthetic be used in everything. You assume you know who I am like we met on the back 9 somewhere. You don't have the slightest idea who I am or of my vast "in the trenches" experiences which total about 40 years. As far as a debate, I don't debate with idoits so get off your soap box and stop acting like you know what you are talking about because you don't. I also enjoyed your posting on Dex-Cool. Do you really think GM would continue using a product that causes all the problems the greedy blood sucking lawyers says it causes? My investigation of vehicles that owners claimed had the so called Dex-Cool problems showed most vehicles were operated low on coolant. This caused the unprotected areas of the cooling system to react with oxygen and cause corrosion. Often times the failed part was the radiator pressure cap which didn't allow coolant back into the radiator when the system cooled down. I intend to just sit back and chuckle as you hand out your expert advice. I just hope you don't convince many others that you know what you are talking about. SUBJECT CLOSED.
[quote]ORIGINAL: makoltd

I will give you a Half A$$ apology for the flame I am going to give you. I left GM after 26 years just for this reason. Upper management doesn't get their hands dirty, believes everything their told, and treats the public like idiots. They like having the A.S.E card, looks good on resumes. BTW; thanks for the Parking Brake, DriveShaft, Warping Rotors, Steering Wheel Lockup at Speed, SunGear, Poor Swiches, Poorly Designed Heads and every other POS screw up you guys in Engineering and Warranty have just let pass in your rush to get the back 9 in!@! You had since 1985 when you Engineering Heros started the C5 project to get all the bugs out; Christ man, 2 years after it came out there were still 288 TSBs active, just on the 1999 C5!@! Getting facts straight my friend is important. Since the 95 z28/ss, GM has used Mobil 1 from the Factory. Maybe I should have added that in all the trucks and performance cars I have bought, I made sure that all oils were Synthetic BUT!@! the motor came with Mobil 1 (pick apart is weak man; WE are talking about MOTOR OIL. After 26 years with them, I would like to believe I know my oils and my facts. If your dlrshp tells you different, find another. Mobil 1 has been the staple for GM for 11 years now. Then again, I am in Ca where our requirements and standards demanded from GM may be a little higher do to the Punk *** Democrats who run this state.
Again, it is all about preference. Having owned a number of Corvettes, Z28/SSs and 1 Truck since 1995 (I currently have a 99C5-02Z28/ss and my 00/Z71), each has started its life w/Mobil 1. When you go in for your oil change next time at a GM dlrshp, ask them what oil they use. The answer will be, Mobil 1.
Thanks for the debate; that is what this forum is for.
26 years with General Motors.
Retired General Manager 9 years /Service Manager 10 Years / 7 ye

 

Alright, this is a pretty much retarded fight. Who gives a **** who's wrong!? At lest he's got the important facts straight. Apparently the point is Mobil 1 Synthetic is the best type of oil, in whatever recommended viscosity is in the owners manual?

So if I'm running Castrol GTX petrolium based oil at the moment, what's it gonna take to switch to Mobil 1 synthetic?

 

Correct way. This is how we did it at our dlrshp. If you do it yourself, even better.
1.) Empty pan - DO NOT REMOVE FILTER YET.
2.) Jack up front end of truck high and let it sit for 15- 20 mins draining.
3.) Drop Truck and Add only 3 quarts of Castrol GTX synthetic or Mobil 1 synthetic.
4.) Start motor and run for 2 mins, running new oil past old filter; a push
5.) Remove filter, jack up front end of truck again, drain pan, let stand.
6.) Replace Filter, drop truck for release of residual oil
7.) Add new oil. Remember the drain plug,
The easy way, just remove filter, drain, and change oil.
This is just the same procedure we would use to flush your radiator correctly to remove the RED Dex-Cool for Green Pennzoil. Only you would jack up the rear of truck after draining radiator, removing both hoses and running water into the top hose feed directly into engine. Then using a flush and do it again. If you want to do it right, it just takes a few extra steps.
HvFn
Greek