I have recently bought a 2003 350Z I got 200,000 miles on it got a pretty good deal so I bought it the problem is I don't know if the prior owner used Synthetic or conventional oil there's no stickers there's no records I've got nothing to back it up so I was wondering should I go with conventional to be safe or will synthetic if it was on conventional mess it up I don't want to start eating my seals away cuz right now I have zero leaks zero smoke and I want to keep it that way so anybody out there know conventional versus Syntec when you have no clue what was in it before thanks for the help

 

Use synthetic, you will be fine. Start with the recommended 5w30

 

As terrasmak says, fully synthetic 5w30 as this is what is recommended. If you have no idea when the car last had an oil and filter change checking how thick and syrupy it is will tell you its not been changed recently or regularly.

 

+1 ..I'd also stay away from the 'high mileage' oils and lubricants as well, as their additives can do more harm than good in the long run.. Four quarts of full synthetic oil with one quart Lucas Original Oil Stabilizer(not high mileage) with every oil change is a great habit to start.

 

mobil 1 5w30 synthetic with bosch 3300 filter is what i run.

 

Why dilute good oil with a stupidly heavy weight oil that has no additives (Lucas). You would be better off just getting a heavier weight oil to start like a 0W-40 vs the stock 5W-35 if you want a thicker oil.

 

Do you really need me to break this down into a science for ya', rancor, as to why I've chosen to recommend that additive for his specific application?.. No disrespect.

 

Please do also no disrespect I would like to hear why you prefer it. From my understanding lucas is strate heavyweight oil thicker than 250 weight gear oil and has no additives. All it does is thicken the oil you are adding it to and reducing the additive package of the oil by 20% if used as directed. What benefit does this have over running a thicker base oil like a 40 or 50 weight with is full additive package?

 

The Lucas product is primarily an oil stabilizer which claims also to reduce
friction and improvement oil lubricity. Unfortunately it ranked next to last in that respect. The Lucas product
received average to below-average rankings in every parameter but one. The only parameter it received an
above-average score in was low-pressure Non-Seizure scar (0.38 mm). However, it attained this scar only
at the lower Non-Seizure Load of 63 kg, making it inferior to products like X-tra Lube (0.38 mm at 80 kg) and
even Prolong (0.39 mm at 80 kg). The Lucas product also received a higher-pressure Seizure Load Scar
measurement of 2.75 mm, which placed it 5th among the ten product. However, like it’s other scar, this scar
was attained only at a Seizure Load level which was lower than other products – 160 kg. Lucas’ Seizure
Load Scar of 2.75 mm @ 160 kg is judged to be inferior even to the untreated base oil rating of 2.79 mm @
200 kg. Lucas was also one of only three product (STP, MotorPurr) to attain only 200 kg for Weld Load.
Lucas’ product cost of $12.00 per treatment is less than some of the other products on the list (though much
higher than both X-tra Lube and STP), but its overall results seem to call into question the value of its
lubrication-enhancing claims.

 

You're in Florida so maybe look into 10w30 as well. Better for summer months.

Always run synthetic. Lasts longer than conventional motor oil. Change every 6k instead of 3

 

You Tube

...I also like Five Guys burgers way better than McDonald's.

 

Lmao that is not regular motor oil. That's like a 0w50 aka olive oil haha

But thicker isn't always better. You need the oil to break down to get into smaller oil galleys and pat places when warm.

 

Why??

 

You know people have gotten killed over these 'what oil's better for whatever' debates...

 

It's interesting that out of all the posts here, nobody has mentioned this thread:

https://my350z.com/forum/engine-and-...-and-info.html

I still think it's one of the best ones on VQ engine lubrication.

 

You know, dk, I was going to post that very same photo of the oil ppm protection individual oil analysis chart today..heh.. I'm being serious.. It's an interesting read. How the marketing hype and product turnover obviously gets more focus than R & D.

 

Yeah, we really owe a note of gratitude to Resolute for creating that thread; it's full of good, factual information for new 350Z owners. It's been years since he sold his Z33 and moved on, but his thread is still one of the best reads on here IMO.