08 GMC with a 1000 miles on it how long should I wait before changing
to synthetic motor oil. thanks :rolleyes:

Whenever you want to switch over. The old wait till xx,xxx miles is an old wives tale that will probably never die.

most people wait till their out of the break in peroid 3-5k miles. its a waste of money to switch to synthetic during that peroid.

is it true that once you use synthetic you cannot use regular oil again?

is it true that once you use synthetic you cannot use regular oil again?
That's another old wives tale.:rolleyes:

Agree with all, switch whenever you want and you can go back and forth, but the question would be why??

I was told to wait 10,000, until the rings seat. Other wise they will not seat as well with the slicker oil.

That is the theory but not sure how true it is today. And worse case, it may take a little longer, but they will seat.

Go with your gut switch over when you feel comfortable doing so.

Boost will seat the rings, switch when you want. I switched right @ 1000 miles. Going to change again at 3,000, then every 5,000 after that....Good Luck !!!!

this is getting ridicolous, no where in town can i find a synthetic CJ-4
and when i ask the clerk at the counter at auto zone or carquest they have no idea, i went to a big truck shop and all they sell is dino. and dont deal with syn

so i heard delo makes a syn and so does delvac(mobil) but i cant find any in town,
im not against amsoil, its id hate to pay shipping on motor oil, it cant be cheap to ship several gallons?

this is getting ridicolous, no where in town can i find a synthetic CJ-4
and when i ask the clerk at the counter at auto zone or carquest they have no idea, i went to a big truck shop and all they sell is dino. and dont deal with syn

so i heard delo makes a syn and so does delvac(mobil) but i cant find any in town,
im not against amsoil, its id hate to pay shipping on motor oil, it cant be cheap to ship several gallons?
Rotella syn 5W-40 can be had at Wal Mart and it's CJ-4 rated (look at the API donut on the back of the jug). Mobil 1 Turbo Diesel Truck 5W-40 is also a syn oil that can be had at Wal Mart and it's CJ-4 rated. By the way, the Mobil 1 Turbo Diesel Truck is Mobil Delvac 1 relabeled.

Delo 5W-40 and Mobil Delvac 1 5W-40 are both synthetics, but can only be had at jobbers.

Rotella 5W-40 or Mobil 1 Turbo Diesel Truck 5W-40 are proven performers and can be had locally.

i think the previous versions are still on the shelf in my area. on the rotella and mobil oils it does not say cj 4 on them, i guess i have to still wait for the supply to run through?

I also haven't seen any 5w40 Mobil-1 TDT or RotellaT with a CJ-4 rating .. also not listed on their respective websites ....
Mobil-1 Turbo Diesel Truck (http://www.mobil1.com/USA-English/MotorOil/Oils/Mobil_1_Turbo_Diesel_Truck_5W-40.aspx)
RotellaT 5w40 (http://www.shell.com/home/Framework?siteId=rotella-en&FC2=/rotella-en/html/iwgen/products/zzz_lhn.html&FC3=/rotella-en/html/iwgen/products/product_rotellasynth.html)


AVlube has a listing for a Delvac-1 that's CJ-4 ...
http://www.avlube.com/fonfacsizcol.html

Many new cars (Corvette's for one) come from the factory with syn motor oil. I changed the oil in my then new 03 GMC d/a at about 5k. Just traded it in for my sig Chevy with 78K on it, and even towing at over 23K GCW, wouldn't use enough oil in 8K miles to put any in. I will go back to Valvoline syn when I decide to change the oil. The oil change will happen probably just before I start towing the 5er again, maybe 5K, but not because of breakin concerns, just no sense to do it sooner.

I also haven't seen any 5w40 Mobil-1 TDT or RotellaT with a CJ-4 rating .. also not listed on their respective websites ....
Mobil-1 Turbo Diesel Truck (http://www.mobil1.com/USA-English/MotorOil/Oils/Mobil_1_Turbo_Diesel_Truck_5W-40.aspx)
RotellaT 5w40 (http://www.shell.com/home/Framework?siteId=rotella-en&FC2=/rotella-en/html/iwgen/products/zzz_lhn.html&FC3=/rotella-en/html/iwgen/products/product_rotellasynth.html)


AVlube has a listing for a Delvac-1 that's CJ-4 ...
http://www.avlube.com/fonfacsizcol.html
This is quite interesting, 'cause Mobil's own website for Delvac 1 5W-40 (http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobil_Delvac_1_5W-40.asp) doesn't say anything about it being CJ-4 certified. The only API certification they show are API CI-4 PLUS/CI-4/CH-4/CG-4/CF-4/CF/SL/SJ.

Also, Mobil states in their website that Mobil Delvac 1 5W-40 and Mobil 1 Turbo Diesel Truck are the same oil, only packaged differently.

This is quite interesting, 'cause Mobil's own website for Delvac 1 5W-40 (http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobil_Delvac_1_5W-40.asp) doesn't say anything about it being CJ-4 certified. The only API certification they show are API CI-4 PLUS/CI-4/CH-4/CG-4/CF-4/CF/SL/SJ...

Here's the link to the new ESP version of Delvac-1 .... it has the CJ-4 cert .. Mobil Delvac 1 ESP 5W-40 (http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobil_Delvac_1_ESP_5W-40.asp)

Here's the link to the new ESP version of Delvac-1 .... it has the CJ-4 cert .. Mobil Delvac 1 ESP 5W-40 (http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobil_Delvac_1_ESP_5W-40.asp)
Great!

Thank you. :)