Oil Leaks?

[MCNPathfinder]

Hey everyone, I know everyone has a different opinion on this, but I'd like to hear them all. I have a 2001 Pathfinder LE with ~118,000 miles on it. I just had it into the dealership. I love my truck, but when we've got problems, boy do we have some serious problems. LOL! Just like my other cars... Anyways, aside from all the belts needing to be replaced, I have a little leak on the oil cooler apparently. I know there's 2 o-rings there that should be replaced. The dealer wants like less than $10. No biggy. What I am concerned about it the oil. I'm FINALLY off the "free" oil-changes that the dealer offered me when I bought the truck. I figured I'd start putting 10w-30 full synthetic in there in the summer months and bump it back down to 5w-30 in the winter. What's your opinion on full synthetic oils? What are you rockin' in your PFs? I ran it in my Subie Legacy 2.5GT, but that thing had so many problems by the time I picked up my PF, I never really saw too much of a benefit. I'm just a little concerned given the age of the vehicle and the mileage that I might start leaking some serious oil being that it isn't as thick as the conventional stuff. Finally off these dealer oil changes, can you believe they go 5,000 miles? 5,000 miles on regular oil? Risky risky. If I wasn't so freakin' poor I would of skipped it all together. BTW, how much oil does the VQ35 take then, being a decent size 3.5 in the PF? My plan is the Valvoline full synthetic over 100,000 miles stuff with a FRAM tough guard filter.

[Towncivilian]

See here on instructions how to fix your oil cooler leak. It's a pretty easy DIY job.

I don't like the cardboard endcaps on most of the Fram oil filters. Purolator PureONE PL14610s can be had for $7 at Advance Auto Parts, and there is currently a $3 mail-in-rebate ($1.50 off of Purolator Classic filters) for them through October. Combine them with a 20% discount code or other code and they are quite cheap and excellent filters.

The base oils used in today's conventional oils are very close in terms of quality to supposed "full synthetic" oils (of which most are actually highly refined "dino" oils). Personally I'm not convinced a synthetic oil is worth the extra money especially if I'm paying $5-10 more but can't use the oil for twice as long. Our VQ35DE engines shear oil out of grade pretty quickly so personally I would run a thicker 30 weight or a 40 weight on the thin side. I know HDEOs (heavy duty engine oils) are designed to be more shear-stable and have excellent additive packs, so any diesel oil such as Rotella, Delovac, etc. that has an API starburst certification is suitable for use in any gasoline engine. You can find a lot of information about oils as well as virgin/used oil analyses over on Bob Is The Oil Guy, among other automotive topics.

I'd run 5k on any good quality conventional oil without a second thought today (as long as I pick an oil on the thicker side as I said before, or an HDEO). Anything longer I'd want a used oil analysis for some insight.

Our VQ35DE engines take 5.25 quarts of oil.

[MCNPathfinder]

Thanks a lot! That helps out a bunch! I was watching some YouTube videos on FRAM filters after you said they had cardboard ends. I did not like what I saw there. I've used FRAM since I was 16, just because everyone else in my family did, but I think I'm going to switch it up. I suppose if I ran regular oil and changed it every 3,000 miles, that's probably going to be pretty good. When I ran synthetic I still changed it every 3,000 which was probably a little overkill. I'm mainly just wondering if there's any benefits like from the various additives in synthetic oil that is going to help an engine in it's mid-life last a little longer than normal. Also, what's your opinion on Seafoaming? I've heard it's not good to do on cars this age that have never had it done before.

[Towncivilian]

3k intervals on any quality conventional will produce good results. You can also step it up to 3,750 miles which is the severe service interval recommended by the owner's manual to get a bit more from your money with no ill effects. Of course the more expensive synthetic oils will have more loaded additive packs, and this can speed up cleaning etc but if you always change your oil at a reasonable interval, you should not have any sludge or significant varnish problems. High mileage oils may be of benefit if you have oil consumption problems or leaks, and HDEOs also help minimize oil consumption. HDEOs are also very good cleaning oils due to their more stout additive packs. Honestly, the best bang for the buck in my opinion is an HDEO. I'm not sure if any are offered in 5W-30, however. I know Rotella T6 is offered in 0W-30 but that's on the expensive side as it's a full synthetic. But as I said, as long as you change your oil around 3-4k pretty much any API SM/SN oil will do fine.

I have not personally Seafoamed my PF. As with any oil additive or "tune up in a can" or whatnot, some praise it, some say it's useless. I personally think it's a bit too harsh as it contains a lot of solvents, and if your engine contains a lot of crud it supposedly can loosen up big chunks of sludge/carbon and potentially clog the oil pickup screen or other passageways, killing your engine. Slow cleaning using some Marvel Mystery Oil in the crankcase seems to be a slow, safe process, at least that's what the general consensus over on BITOG is. I've never used MMO in the oil though. Browse the Oil Additives section on BITOG and be stricken with confusion and uncertainty, and a lot of reading material!

Something else you should be aware of: I've read that Nissan OEM filters are now being sourced from China, so they may be of inferior construction and material compared to the Japanese filters that were previously being supplied.

The recommended interval for spark plug replacement in the FSM is 105,000 miles. Have you changed them yet? Also, are you the original owner?

[esy]

most car manufacturer's have Honeywell make their filters now (have been for quite some time now). Honeywell owns and makes FRAM.

[MCNPathfinder]

This is awesome! Thanks for the help everyone! I think I'll just go for regular oil now and change it every 3,000 miles. I know it was well taken care of, I'm it's second owner. The first owner got EVERYTHING done at my local dealership (where I take it now for warranty work), so they have a history of everything. The only thing that concerns me is that while it's a clean vehicle, the engine might not be especially if the dealership is changing it only once every 5,000. Who knows too, I mean, I'm not that proactive to bring it in RIGHT away either, it may have slipped to 6,000 or 7,000 too. I mean I would never let it get that high, but I don't know the previous owner. By that time I would have changed the oil twice! I'll ask the dealership what they put in when I go there to get these oil-cooler o-rings I need. I think I'll stay away from these seafoam products for now, and just put in some Lucas oil stuff. I used to use that on my Honda, and it appreciated it. Thanks again for the help!

[Towncivilian]

I hope you'll be using the Lucas product (Oil Stabilizer?) temporarily until your leak is fixed, because it's mostly just thick gear oil that thickens up your oil and doesn't even contain any additives. If I recall correctly it also causes foaming in some cases. I would not use it in my engine for any extended period of time. In fact, if you can manage your leak by keeping it topped off until you can fix the leak, I would do that rather than put that oil "stabilizer" in your crankcase. Lucas chose a poor choice of verbiage for that product too, as who wants a "stable" or a "firm" oil? I sure don't, I want it flowing!