K&N oil filter versus Purolator oil filter
 

Oil filter not air filter. I run the K&N oil filter on my '95 Vette, and run a Purolator brand on my '94 Dakota. Even though my Vette is running to spec (19 mpg around town about 28 on the hwy, so its not running rich or anything) the Mobil One turns pretty dark and murky fairly quickly (dipstick check). However, the cheapo (Advance Auto house brand) dino oil I use in the Dakota still looks honey gold after 2000 miles (dipstick check). This tells me the Dak is still running within spec as well (mpg is as expected), BUT it makes me wonder how good of a job of filtering the expensive (by comparison) K&N Gold oil filter is really doing. It appears the Purolator filter is doing an excellent job of keeping the Dak's oil clean. Better job than the K&N seems to be doing in the Vette. Both the Mobil One and the cheapo dino oil have close to the same tint out of the bottle, so something's going on on the filtration side of things for the oil to look that much cleaner in the Dak.

I use Purolator myself but as afar as your cirumstances go, there is an awful lot of variables involved... doncha think? Thingas like cylinder out of round... ring condition... oh well.. maybe I'm talking out of my behind.

Mobil1 oil
 

Mobil1 if it is the syntheic it has a ton more cleaners than the cheapo dino oil. That's why you engine stays clean of deposits is because of the good detergents in the good oil. If the oil is as clean when it comes out after 2 or 3 thousand miles I would change oils.

I've been using Pure One filters for awhile now, they seem to have a great rep for the price.

You're not comparing apples to apples.

Next two changes, buy a K&N for your truck and put the PureOne on your vette and then compare.

I remember a while back tests for filtration and durability the Pure One filter came out ahead. The K&N wasn't in the test from what i remember.

[QUOTE=CentralCoaster]I've been using Pure One filters for awhile now, they seem to have a great rep for the price.

QUOTE]
:iagree: What I use as well...

When I first got my vette I used the OEM filter on my first oil change...then I heard about Mobil 1 filters so I tried that one...then I heard about K&N so I tried those and have used them for about 5 years now...

With all three my oil goes dark pretty quickly...if you change your oil regularly I can't imagine you will have a problem...

I would use Amsoil oil and Amsoil EaO oil filters.

Oil filters will only filter down to a certain particle size. The particles that discolor new oil are far smaller than any filter can capture.
Your Dodge's oil is staying clearer because there is less wear (or blowby) going on in that engine, not because the filter is better.

(let me guess: you have a K&N AIR filter in the Vette, and a paper filter in the Dodge???:D )

Larry
code5coupe

This is a good point and probably one of the largest factors in your case. Most synthetics contain high levels of detergents that keep the inside of the engine clean. So while your Dakota oil may look good, I'll bet the inside of your Vette engine looks better.

Another thing to consider is the design of the filter. In general, the K&N filter flows well, but doesn't filter well. Flow vs filtration is a trade off of design philosophy. However, the relatively new AMSOIL Ea Oil Filter (and AMSOIL Ea Air Filter) provide a very good compromise of filtration vs flow.

Correct part number for the 1995 C4 oil filter is EAO23 for those that are interested.
:cheers:

IMO it has more to do with the detergent package in the oil than the filter you use. I use Valvoline All Climate in all 4 of my vehicles and the oil is dark in all the vehicles when I change the oil at 3000 miles. I use different filters on the cars.

Lone Ranger, I think you bring up a good point to consider, is it possible that the Purolator is doing a better job of filtering and that is influencing the change in color state? Obviously basing the evaluation on color change is pretty un-scientific, since as AZC4Guy said, there are a lot of variables involved, particularily blow-by and state of tune issues. It may also be as others have said that it is just a sign that the Mobil-1 oil is doing a better job of cleaning.

That being said, a while back I found specs posted on the web for some of the more popular oil filters. I'm not saying these are facts as of today, but there were accurate at one point with respect to these two brands and I believe still are.

Purolator PureOne PL34631
* Average largest pore size: 42 µm
* Smallest pore size: 10 µm
* 30W 70F Oil flow @ 10psi: 5.3 oz per minute

K&N 3002
* Average largest pore size: 63 µm
* Smallest pore size: 27 µm
* 30W 70F Oil flow @ 10psi: 14.7 oz per minute

Purolator PremiumPlus L34631
* Average largest pore size: 57 µm
* Smallest pore size: 22 µm
* 30W 70F Oil flow @ 10psi: 17.2 oz per minute

Maybe there is something to your color change observation after all.
I use a Purolator on my Vette.

I doubt this is a filter problem. You are comparing apples and oranges between an old Vette and a new Dakota. If your oil is turning dark quickly something else is going on. Only way to be sure if there is a problem is to have oil analysis done on the Vette. BTW, the smaller the pore size the faster it clogs up.

How could you possibly know that without knowing what oil he is actually running. Chances are it's a major "energy conserving" oil with a good level of detergent additives sold under private brand. When I bought my C4 this year the PO had run nothing but Pennzoil dino for 18 years and 47K miles. This car doesn't burn any noticable amount of oil and has normal compression. Question...when did GM start recommending Mobil 1 in our Vettes?

He says he is using Mobil 1 in the Vette in the first post. :cheers:

FYI, the info pasted by Mike above shows what I was trying to explain above in that the K&N filter flows very well but doesn't filter as well. However, there is some evidence to show that this is actually beneficial for the LSx motors. For some concrete data, here is a used oil analysis report on a 99 C5 using AMSOIL Series 2000 0w30 and a K&N 1007 filter:
Corvette C5 AMSOIL Series 2000 0w30 Used Oil Analysis Report

The results show that the wear products in his motor are well below the fleet average for that lab and this motor family at similar time in engine life. While I think most of that is due to the oil, it is clear that the filter isn't hurting the engine either. So for those running the K&N oil filter, I wouldn't lose any sleep over it.

GM started recommending (actually, requiring) Moblie 1 (or an oil that meets the same specs) with the LT1 motor in the '92.
The reason is supposed to be that Moble 1 will withstand higher temperatures without breaking down, and the LT1 does not have an oil cooler from the factory.

Tom Piper

I've always thought that Mobile 1, especially since they went to super-syn, is darker right from the bottle.

Tom Piper

I use Castrol synthetic oil (as well as all other fluids in the car being Castrol) and i buy AC Delco filters in bulk for bugger all.

It is.

If your oil is still clean after 2000 miles, I would be a little worried. Oil that darkens up generally means that it is doing its job.

OIl, and I use the Pure One. Lower cost and effective. :cheers:

Paying extra for K&N or Mobil 1 filters is like pissing in the wind. But I suppose its all good for the "nothing but the best for my baby" crowd. I hope you wouldn't mind if I stole your wallet at the same time?

I use Purolator Pur-One.