AuAltima3.5

I want to switch to synthetic. I read the Oil Sticky. I am still unsure how to switch. Car is 02 VQ35 with 55k miles.

I can do one interval of 2quarts synthetic and 3 dino, OR do the Auto-Rx thing. I am just worried about getting leaks.

Anyone else switch over their motor past 50k?

mzmtg

iTrader: (11)

I switched straight from dino to syn at 195k miles. No issues.

You dont need any complex plan, just switch.

Larrio

iTrader: (10)

yep yep. Drain out dino oil and pour in synthetic. Your done

Torkaholic

Your concern for your engine's health is commendable, but reflects the concern about syn-caused leaks that is as persistent as it is incorrect. It comes, essentially, from two sources, both of which are unlikely to apply to you. First, when syns first went into wide public use, their additive packages were not nearly as well matched to the base oils as they are today. In 1975, for example, the refiners enjoyed about 75 years of experience brewing dino motor oils. In particular, they knew how to make them so that engine seals would hold up well. Not so with the new syns, some of which allowed seals to shrink a little, leading to leaks, even in new engines. Today, this is just of historical interest, as the syns are just as good at conditioning seals as dinos are (probably better, actually).

Second, in neglected engines, a coating of varnish, sludge, or both, will accumulate everywhere in the engine, including over critical seals. ONce this happens, the seals are deprived of a constant supply of fresh oil and the conditioners the oil brings with it. But the engine may not leak for a long time, as the sludge/varnish will act as a seal. Then, when you add a synthetic, which will typically clean much better than a dino, the sludge/varnish coating may be quickly (relatively) cleaned away, exposing the dried out, shrunken seals. Leaks are the predictable result, but often this type is temporary, as the seals will re-swell, if not too far gone.

If your engine is even close to clean, you'll have no worries. I switched my VQ35 (G35) to synthetic at only 6k miles. Eight thousand miles later, I'm having no problems, and specifically no leaks or consumption at all. Make the switch if you're inclined to do so and go enjoy your car!

AuAltima3.5

Well, I have only owned the car for the past 2 thousand miles. Neglect was what I was worried about.

I did a really lazy "sludge check" - I pulled of the oil cap and looked around beneath for build up around the internals, none seen.

bladerunr

iTrader: (14)

Please switch immediately to syn. No additives are needed. You'll love it. check bobistheoilguy.com for more on oil and related topics.

Free

I know I have said this a lot here but please consider using Lube Control in your oil even if it is sythetic and Fuel Power in the gas.

Many systhetic UOA's show great results with LC. Read up www.bobistheoilguy.com

imported_Max_TL

[QUOTE=AuAltima3.5]I want to switch to synthetic. I read the Oil Sticky. I am still unsure how to switch. Car is 02 VQ35 with 55k miles.
I can do one interval of 2quarts synthetic and 3 dino......QUOTE]

OK, another noob (similar) question -

'03 3.5 38K miles, second owner. Unsure of past maintanence.
In converting to syn - don't want to run 'cleaners RX etc.
should i run a 50/50 syn/dino oil for 1K miles & dump again - because of all the sludges & varnishes loosened & floating about?

2002 Maxima SE

iTrader: (3)

Just drain and put in synthetic. If you're worried about sludge you could do a 2000 mile filter switch.

konak85

iTrader: (10)

Briefly, what do you have to check before you make the switch? Leaks, ...what else?

mzmtg

iTrader: (11)

Did you read the damn thread you just posted in?

You don't have to check anything that you wouldnt normally check in an oil change.

Torkaholic

Yeah, there's really no need to get overly mystical about this; it';s really very simple, no magic involved. Drain oil, secure plug, install new filter, fill with correct amount of your chosen syn, then go enjoy your car.