Rrassi300zx

Im just wondering what synthetic oil does these cars seem to like best? Mobil 1? Maybe? And on a 150k mile car would 10w30 go well? Or 5w20? I live in Miami so the most cold we see here on a great cool day is about 50 degrees, and that's once every couple of years.
Thanks.

Mycarispurty

Oil is oil is oil to an extent. The important thing for a daily driver car is that you change it when it's time rather than letting it run for thousands of miles when it's already past time to change it.

I personally run Amsoil in my twin turbo. If the motor is original and no oil seals have ever been replaced, it may not be wise to switch to synthetic. When I had my 120k service done along with injectors, clutch, etc all oil seals were replaced so I felt more than safe to switch to synthetic.

Christiankustom

The real question is have you always used synthetic oil? You can't switch between the two. First off if you have been using regular oil you can not switch to synthetic. It will hurt your engine. Second if you have been using synthetic you have to stay on it. Thirdly if you have not been using a synthetic and your looking for a good product use ZMAX. I have been using it in my customers cars, my personal cars, my shops race cars and our drift cars. It's the best stuff. And lastly if you have been using synthetic a good brand to go with is Royal purple, Amsoil, Valvoline SynPower or Torco MPZ SR-1.

I will end with this. Be sure you want to use synthetic. The main reason to go synthetic is to prolong intervals between oil changes. Synthetic will make your engine leak oil like a SIV. That's its nature. It's good oil but your gaskets can't withstand the chemical and molecular properties and allow the synthetic oil to creep past seals, o-rings, gaskets and anything else meant to keep oil in. I have been running my shop for years, I'm certified and I have been doing this for over 17 years. Trust me when I say it will leak. And on these cars there are no easy and simple leak repairs.

I hope this helps.

Rrassi300zx

Thanks guys, I guess since I haven't changed the oil yet, i havent had the car long enough, I first have to find out what kind of oil was used previousely synthetic or non synthetic, the car has no leaks, I've changed the fuel pump, coils, spark plugs, alternator and now I'm planning on doing the timing belt along with water pump and anything else that maybe old.

One thing is for sure, the oil that it has now is really light? Don't know why but it along with the transmission oil is light looking? That's one thing that has always caught my attention, ive done alot of oil changes but never seen such light oil before, the guy I bought the car from said he had just changed the fluids but i didnt ask him what he had used before.
Thanks again for your input, it's very much appreciated.

Christiankustom

That's not a problem. I'm glad I could help. Keep up on this post and let me know what you find out. If you need something specific just PM me directly. These cars can be very temperamental. Also ask the previous owner as well when the last service maintenance was done. ie. timing belt, plugs etc.

flynismo

I registered just to say that this is completely untrue.

You absolutely CAN switch between conventional and synthetic. In fact, you can run both in your motor simultaneously with no harm. FAQs for Oil Products

In addition, switching to synthetic from conventional oil will not cause your motor to leak, unless there was an issue to begin with.
Switching to Synthetic Motor Oil in 'Dry' Engines

No offense, but I'd expect much better advice from someone who claims to be a certified shop owner of 17 years.

KSpakes87

In total agreement with Flynismo. Every car I have ever owned I have switched to synthetic.

My first car I bought from my mom when I was 16. She used conventional in it the entire life of the car when she had it. 150k miles later I change it straight to synthetic. No leaks

A 94 Ford Ranger I bought when I was 17 had 200k miles on it. Switched and no leaks.

Here it is 10 years later and I have yet to have an oil leak due to changing to synthetic.

If its so bad to switch why is there an SAE procedure to switching? (All this is, is letting it drain for 2 hours with oil filter off.)

How do you switch to begin with? Change all the seals in the motor then switch?

PredatorZ

I have to agree with the last 2 posts, I changed to Royal Purple when I got my Z31 at about 78K, only put 12k on her in 4 years, no leaks. I also changed my trans to Royal Purple and noticed it shifted a bit smoother. I'm sure Christian feels strongly about not changing, and maybe in a hi miles old dried out motor you might have a leak fest. But to just say it can't be done is a bit to final, and perhaps close minded of an opinion, imho, your mileage may vary.