silverstone03

Hey guys Im planning on switching to a full synthetic oil tomorrow. My car is an 03 with 95k miles and I just read on another forum that switching to a full synthetic at high mileage can cause oil leak/burning problems.

Is this true? Thanks!

2004Black350z

iTrader: (37)

Im no mechanic but no never heard that. I have ran synthetic since the first change at 5k miles.

bobbyz350

iTrader: (4)

yup synthentic only thing i ever had in mine

flecko28

iTrader: (13)

youve been using conventional all this time, right? why do you want to change it now? you might as well keep using what has worked for 95k miles

Stock2Autocrozz

iTrader: (6)

+1 stick w success...i run and always have on syn mobil 1 despite what others say or believe from reading...if any consumption or burn iff exists it is from chemical makeup, not bc of engine nor mileage,lest those symptoms already exist

350ZTheStandard

iTrader: (4)

How could using synthetic oil be bad???

BrickyardZ2003

I got this, guys. OP, when you run conventional oil, especially in a vehicle up past 80-90k, you actually DO have 'sludge' in/around your motor. Common leaks such as front main, rear main, and valve covers are actually sealed up by small amounts of sledged up oil due to using conventional over the years. You know how high quality oils claim to break down even pre-existing sludge? They break down the 'seals' that were formed by using conventional oil over the years, causing oil to seep through those gaskets that are prone to failure at that mileage.

Long story short, stick with conventional. Are you tracking the car regularly? Do you truly require a full synthetic-filled crank case? Go with the norm - if it ain't broke, don't fix it.

350Zdj

iTrader: (3)

If this is true, then this must be the reason why engine started burning oil. My mileage was around 55k miles, when I had the engine reflushed (using the machine) every other oil change. About a year later on my engine would eat up 3 ltrs of engine oil every 250 miles. (Tracked the car hard several times)

mw9

iTrader: (51)

I was on the phone with Amsoil a few months ago about this question, got a 99 ford escort for a DD with a 132,000, I ask them the same question and they said no problem, just would have to change oil a little earlier.

davidv

iTrader: (2)

Motor oil is motor oil. Use one or the other or swap or mix. No rocket science here.

mvallejo

When is it safe to switch to synthetic? And what are the advantages of doing so. I have ran conventional in my Z since day one changing it every 3K miles. But I have been told lately that it woud be better to switch to synthetic. I have 37K miles right now on my 2007.
I just dont understand why nissan says to use convntional if it is true that synthetic would be better.

terrasmak

iTrader: (8)

I would swap to synthetic, there are many speculations and nothing proven that you can't swap over to it an any time.

silverstone03

Awesome explanation I really appreciate it. I also spoke with Forged Performance today about oil burning and leaking issues from switching to synthetic at 95k miles. They said its not a guarantee that I will run into these problems, kindve hit or miss, but they do hear about it happening from time to time. Not worth the risk if you ask me. Thanks again

BrickyardZ2003

No problem! A lot of cars do run into issues like this, and yeah it really is hit or miss.

b18ccivics

iTrader: (11)

I run mobil 1 synthetic in everything. I have an engine right now whit a least 250k miles that saw 8200-8400 rpm every day. The valvetrain is so clean it looks like a 20k mile engine. I have also swapped to mobil with a lot of different engines with different amounts of miles on them with no problems.

exZilaration

iTrader: (1)

OP There is some truth to this. Ive switched to synthetic on my maxima and it started leaking around pretty much every seal possible mind you ive NEVER had a problem with it before. I also tried this on my Supra i went pure blend then fully synthetic and the oil pan gasket leaks so its not all bogus

BrickyardZ2003

Glad someone else has experienced this. I wasn't just blowing smoke. My old 5.0 had the same issue. I bought it thinking Mobil 1 was all it'd see. After requiring an oil change MAXIMUM every 2k miles due to front main and oil pan leaks, it was right back to Castrol I went.

starbuck

iTrader: (7)

Exactly. Switching to synthetic at that millage COULD produce problems in the form of leaks. It 'probably' won't happen but why risk it? If you don't track the car often I don't see anything wrong with mineral based oil in a Z.

A lot of things that are not proven are still avoided. People started using hands-free cellphone devices before it was proven to increase the risk of cancer.

Bottom line, why risk it?

xthejokerx

iTrader: (1)

Wow never heard different oils could cause leaks. I thought leaks were due to malfunctional oil pan gaskets or something....

My car is sort of leaking oil and I have Mobil 1 full synthetic... should i go back to conventional? It's really worrying me seeing oil stains on the ground.....

BrickyardZ2003

Leaks ARE due to malfunctioned gaskets. Synthetic oil, however can and will break down the sludge buildup. It's no guarantee that switching back to conventional will help. On my old 5.0 it DID help out. Instead of leaving 3-4 drops EVERYWHERE, I maybe dripped out one droplet a week after a few changes with conventional.