Oil leaks

[honschoppt1]

I have had my 02 QX4 for about a year now, and have already put about 20,000 miles on it, (at 188,000 now). I've only replaced rear shocks and trailing arms, along with a serpentine belt. Now I'm noticing pretty significant oil leaks in my driveway. I looked under the car and it looks like it may be coming from the oil pan gasket or the rear main seal. There definitely seems to be oil coming from the small notch between the engine and the transmission, which I believe is the rear main. I've been using synthetic 5w30 on my oil changes, but is there another oil I can change to in order to slow the leaks? Maybe conventional rather than synthetic? I have no problem spending the money on VC gaskets, oil pan gaskets, etc, but would like to hold off on the rear main for as long as possible because of how expensive it is. I plan on taking the car in for service (undecided on where) before I take a road trip in a few weeks to CO. Another question is how much should I expect to pay for a rear main once I have it done? I was quoted 1900 at my local Infiniti dealership to repair the RMS. Thanks for any input.

[atraudes]

There's all sorts of additives out there you can try if you're up for it that will be a lot cheaper than getting that seal replaced, but no personal experience with any of them. I had my transmission rebuilt for not much more than you were quoted for that seal (you can probably get it replaced for a lot less if you shop around), and the guy did the seal for almost free since it was right in front of him If you have any transmission flares or anything that might be hinting at a rebuild, maybe you can get both taken care of for the price of one.

When you do get the seal replaced, pick a good shop that will stand behind their work and keep an eye out for leaks after the work is done. I've read about folks having to have theirs replaced multiple times because the mechanics couldn't get it quite right (apparently it's kinda tricky). Any shop worth their salt won't charge you for reattempted work like that, and you wouldn't want them to.

Here's a good discussion on the rear main seal (with pics!).

If you're seeing leaks, check your oil cooler (in the front of the engine) too. It's very common for it to leak with as many years as we have, and it's really simple and cheap to fix. You can find the write-up here.

[04pathse]

I've been using synthetic 5w30 on my oil changes, but is there another oil I can change to in order to slow the leaks?

Are you using high mileage synthetic or regular synthetic? switching to high mileage may or may not help...

From what I have read, Valvoline full synthetic Maxlife is good stuff.

http://www.valvoline.com/our-products/m ... c-max-life

[yeldogt]

My Pathfinders have all leaked using synthetic oil -- all three .. and all 2002's. I use regular oil in mine -- normally the high milage oil. The high mile oil has additives that are designed to swell the seals a bit .. and have a bit more coating action for the top end. I could always tell the difference in my Nissan V6's and out Ford V6's with the high mile oil ,,, even in engines not all that high.

My current 02 has about 70k on it.

[honschoppt1]

So even though I've been using synthetic I should go ahead and switch to conventional high mileage? What kind does everyone recommend?

[04pathse]

So even though I've been using synthetic I should go ahead and switch to conventional high mileage? What kind does everyone recommend?

Most recommend not switching over from conventional to synthetic if conventional has been used in older vehicles or vehicles that have over 30,000 miles on them, some say its fine so who knows...
Also some say switching back and forth from conventional to synthetic is not a good idea, again, some say the opposite.

You stated you have only had the vehicle for a year and have been using full synthetic, do you have any idea what the previous owner/owners were using?
The answer is probably "no". If that is the case maybe you should consider a synthetic "blend". Castrol and Valvoline both make a high mileage synthetic blend oil that you may wish to consider.

There are a few threads on this forum that pertain to conventional vs synthetic oil in their Pathfinder / QX 4. Some say they have been using full synthetic without any issues or leaks and some say the exact opposite.

You should check out the 'bobtheoilguy" website for more information on different types of motor oil.

Everyone has their own opinion on what is best to use so you are most likely just going to have to do some research and make a decision on your own.

[AlanAZ]

I've been using synthetic 5w30 on my oil changes, but is there another oil I can change to in order to slow the leaks?

Are you using high mileage synthetic or regular synthetic? switching to high mileage may or may not help...

'High Mileage' synthetics contain conditioners that swell seals and help prevent leaks. I would try that first before switching back to conventional oils.

"Mobil 1 High Mileage oils are designed to help extend engine life and prevent engine oil leaks. To help prevent wear in higher mileage engines, this advanced, fully synthetic high mileage oil features:

Higher base oil viscosity to help reduce leaks and provide better high temperature protection.
With a boosted level of seal conditioner to protect engine seals in all vehicles because over time, rubber seals can harden or shrink, resulting in oil leaks."

https://mobiloil.com/en/motor-oils/mobi ... gh-mileage