One thing is for sure, asking a question like that is definitely sure to get a lot of opinions. The answer is that there is no clear cut answer.

Myself, I use Pennzoil Platinum and will likely switch to Pennzoil Ultra once I do some reading up on it. You really have to read up on things and form your own opinions. BITOG.com has oil analysis' of various different oils and some really smart folks that know their stuff when it comes to tribology.

 

30 days? How far do you drive your rig a day? I work from home so the only driving I ever need to do is school (20 miles round trip, twice a week), gf's (6 miles round trip), and deliveries (usually within 20-25 miles round trip also). When I was on conventional I never made it to 3k miles so I had to go by the 3 month rule.

 

I personally run castrol gtx with wix filters.

 

I own a 1986 S10 with the 2.5 4cyl.
I switched to RP 2 years ago and noticed a deference with MPG and horsepower.

I used the K&N and RP 10w30 with Lucas synthetic oil stabilizer. i can go almost twice or triple the amount of mileage on RP, before changing the oil.

I do not use RP in my 4.3 i use wolfhead 10w30 and a wix oil filter.
I might switch here very soon.

 

If you haven't ever had an OLA (oil life analysis) done, you really don't know how far you can go on any particular oil. You might be surprised what the bargain bin dino oil can do...

But without numbers, generalizations are worthless.

 

Thanks for all the advice from everybody. Here is the thing though with me switching to Royal Purple: I am not looking to:

1. Get more power or MPGs (I have a CAI for that and I only installed it because the new oil lines were rubbing the stock airbox. I installed the CAI only to protect the oil lines. I do notice an increase in power, so that is a good bonus.)

2. Extend oil change intervals (I get it done it every 2500-3000 anyway. I am only on 2000 on this oil with the Lucas and the last oil change was in January. The next time the oil is changed will be my first time changing my own oil. ).

I AM looking to:

1. Extend the life of the engine
2. Improve engine reliability
3. Slow down engine wear
4. Clean out any engine sludge.

I actually ordered a test kit from Blackstone Laboratories a few days ago so I can send them an oil sample to find out any hidden problems with this engine so I can any hidden problems fixed BEFORE I get stranded waiting for a tow truck.

 

My comment wasn't directed solely at you, but kudos for getting an OLA done!

In this day and age, there is very little reason to change your oil every 3000 miles (aside from all out vehicle abuse and/or VERY extreme conditions). For the vast majority of cases, this is an old wives tale and you are just pissing money down the drain. If you are using any one of the quality oils available with a quality filter, 5000 miles shouldn't be a problem at all.

My recommendation would be to find an oil that YOU like after researching a few different ones. Run it in your vehicle for a length of time that you are comfortable with and get an OLA done. This will give you an indication of how much further you can safely go. At the next oil change using the longer interval, do another OLA and see how things changed.

About your list... 1,2,&3 are the same in terms of what oil does for your engine. With 4, most modern oils are already loaded up pretty good with detergents. I doubt you actually have a problem with sludge if you have been religious with 3000 miles OCI's, but if you were really worried about it, there are a number of products (SeaFoam, Marvel's Mystery Oil, etc) that will make short work of cleaning out your engine.

 

Is PR synthetic oil? im thinking of switching to synthetic in my 2000 ZR2 Blazer, good idea, or bad idea you guys tell me what i should do. Also i got a little of the good old 4.3 liter tick, what be best to get rid of that??? thanks guys let me know asap. Im trying to do this today

 

i throw in some Lucas product whenever that "tick" appears. works great.

as for the swap to synthetic.personally, not yet. but i plan on goiung to the Castrol Edge by the time Winter rolls around. that should help out with the monthly oil changes.

 

I run RP 5W-30 and the K&N filter on my '98 Blazer, 157k miles.

As for switching straight to RP from conventional, I don't know if it would affect anything. I went conventional > semi-synth > full-synth> then RP. Never used Lucas in the oil though. Only time I'll pour anything except oil in the crankcase is when I seafoam 100mi before oil changes.

Can't say I noticed any power or mpg gains or that it was quieter.

Personally, with RP and the K&N filter, I change every 10k miles. Although I'm going to start changing the filter more often, every 5-6k (K&N filter doesn't have a bypass valve so if it gets clogged your oil is gonna stop flowing).

I've heard a lot of bad things about Fram filters. With a little googling you can find where people have cut open Fram filters and the insides look rather, cheap.
http://www.dslreports.com/forum/r218...-FILTER-REVIEW