How long can you REALLY push syn oil?

[Hit Man X]

Well I've been wondering about this for a while. I run Mobil 1 in my Z and have in the past changed the filter and added ~1qt @ 5K mi, then change it all at 10K mi.

Now, I have 13K mi on the oil and am about to change the filter again here soon in 2K mi... I looked at it and it's still a medium to dark brown, not black at all.

Would it be safe to push it to 20K mi changing the filter and adding a quart every 5K mi? Or is that a big

The vehicle still runs strong and all...

Input is appreciated...

[kevindepot]

Not sure if I understand you. You add a qt. of oil every 5000 miles because it needs it or because you just do?
I change my oil and filter every 5000 miles. No questions asked!
OK, I just reread your post. I have never heard of anyone changing just the filter (and adding the qt. for the filter) and not changing the oil also.

[Hit Man X]

Well what I do is change the filter at 5K and add the quart to make up the difference the filter holds is all.

[GMCwantsLS1]

I'm pretty sure Moble 1 is rated to go up to 25K but will need a filter change at every 5K. I just change mine somewhere between 3K and 5K just to keep it extra clean.

[1TRUESS]

I run Mobil 1, but change my oil every 3K. I am not going to take a chance.

[Flyer]

http://neptune.spacebears.com/cars/stories/mobil1.html

That is an independant study on oil life. Very good readin. It might change some of your oil changing habits.

Someone told me that they look as oil changes as a very traumatic issue to an engine. When changed, the oil is completely drained from the engine causing a brutal cold start.

[Hit Man X]

See I prefill my filters w/ oil to avoid dry starts on the bottom end. Takes an extra few min but I have oil pressure almost instantly when the vehicle starts up.

Has anyone else done that?

I changed the filter and added a qt (plus another 1/2 due to the blowby) and took the truck for a spin around the block. Let it sit then check the level...

Oil looks like is has maybe 1000miles on it, that's how clean it is again. FWIW

[GMCwantsLS1]

I completly fill the filter and crankcase, then I remove a relay that disables the PCM so the engine won't start, I crank it until I show oil pressure (about 10-15 seconds just to be sure all the air is out) reinstall the realy and start and check for leaks. Whew that is one long sentence!

[8budfan]

i also use syn oil..have for years.used amsoil,mobil1 and now am using castrol syn.change filter every 5,000 and 10,000 and change the oil and filter at 13 to 15,000.have screwed up before and let them put reg oil in the truck,take off and ride 1 mile and notice a diff on how the truck is running...not the same power,even with the old oil in it . actually turned around and went back and had them change it back to syn. i know it would have been ok but did'nt like the way it was running...

[djkir23]

well seeing as that i do this for a living i think i know this pretty well. you can go 5000, 6000 or even 10 but would sure not go no more than that on mobil. Now if you used Royal Purple the so going 15000 or more would be good. And i have use both and Royal Purple is the best you can use. It will make a diffrence over mobil. In my old car i used it in trans and motor. I know alot of yall might think its expensive, but i can get it cheaper than mobil. So if anyone wants some let me know. I should be able to get it asap. And with mobil i always changed mine at 5000 to 6000