Red Line synthetic oil..anyone used it

[ZSaint]

If you valve cover leaks, it is not the problem with the Mobil 1, et al. I think they have very similar charactoristics, now, and do not know of any leakage problem.

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I would let the tranny drain for a day or over night. If you are serious, I would take the back cover off the diff to make certain it drains completely. If not, just drain out what you can and fill 'er up. Your gears will be very happy!

[DatsunZsRule]

I personally am a big Valvoline guy. I use the Valvoline Full Synthetic (SynPower) in my daily driver and regular Valvoline in my Z and I'm also a big Redline fan. Redline is all I use in my Transmission and Differential.

Synthetic is without question the best ONLY if the car is a newer car, or It has been used religiously since the car was yung with lower miles.

This is why I run just the regular Valvoline in my Z. The previous owner of my Z ran nothing but regular in it so for me, synthetic wasn't an option. Why? Because synthetic has higher detergents and if you start using it in an older car that has ran nothing but regular motor oil, it can loosen up any old sludge build up and can clog oil passages in the motor, cause oil seals to leak ect. My Z is a low mileage car but I just prefer not to take the chance. Plus it's only driven on nice sunny summer weekends only so really synthetic would be a waste.

Honestly, Oil has come such a long way compaired to what it was in the 70's. Regular oil today is damn good oil as long as you change it every 2,500-3,000 miles. True, Synthetic starts much better in cold weather, protects better in extream heat conditions ect. but in some cases it can be more harm than good when it's used in an older car that has never used it and a higher mileage car for the reasons I listed above.

weight-

I run 10W30 in my Z. It's slightly thinner than the 10W40 which is better IMO because it reaches the bearing surfaces more quickly and revs up faster, and will provide a little better oil pressure too and It's always held up great in the summer heat in my Z as well. Every time I check my oil she's always good and full

Anyways this is just MY $0.02 cents worth on the topic. Everyone has there own opinion about which brand oil is the best to use, which weight is the best ect. so no offence to anyone who has different opinions

[dhoneycutt]

I personally am a big Valvoline guy. I use the Valvoline Full Synthetic (SynPower) in my daily driver and regular Valvoline in my Z and I'm also a big Redline fan. Redline is all I use in my Transmission and Differential.

Synthetic is without question the best ONLY if the car is a newer car, or It has been used religiously since the car was yung with lower miles.

I Disagree. Any time is a good time to switch to synthetic!

This is why I run just the regular Valvoline in my Z. The previous owner of my Z ran nothing but regular in it so for me, synthetic wasn't an option. Why? Because synthetic has higher detergents and if you start using it in an older car that has ran nothing but regular motor oil, it can loosen up any old sludge build up and can clog oil passages in the motor,

Partially true,

It does have higher detergents that may loosen sludge and deposits that are currently in your motor and possibly HIDING potential leaks which is why they (synthetic oils) have been blamed for making gaskets leak. In reality, Synthetic oils do not react with gaskets and cause leaks. Synthetic oils prevent sludge buildup better and keep the internals cleaner and better lubricated.

My Z is a low mileage car but I just prefer not to take the chance. Plus it's only driven on nice sunny summer weekends only so really synthetic would be a waste.

If it will help it last longer with less wear, why is it a waste?

Honestly, Oil has come such a long way compaired to what it was in the 70's. Regular oil today is damn good oil as long as you change it every 2,500-3,000 miles. True, Synthetic starts much better in cold weather, protects better in extream heat conditions ect.

Again, why is it a waste?

but in some cases it can be more harm than good when it's used in an older car that has never used it and a higher mileage car for the reasons I listed above.

I don't see how?

Just my $.02 worth and IMHO

[Arne]

Synthetic is without question the best ONLY if the car is a newer car, or It has been used religiously since the car was yung with lower miles.

Well, I switched from normal oil (Castrol GTX) to Mobil 1 in one of my previous cars right after I bought it - with 150,000 miles on the original engine. This was in a graymarket 1981 BMW 323i, which had a 2.3 liter, SOHC inline six, very similar to the L-series in our Zs. I drove it on Mobil 1 for the next 5 years and another 75,000 miles. Never leaked, nor did the synth break loose any sludge that I could detect. So the above concern isn't valid - in my experience. YMMV.

[gogriz91]

I run Castrol in the engine, but want to switch to synthetic in a high mileage trannie and rear diff. Anything I should be concerned about (leaks after switching) or just drain, flush, refill and go?

[ZSaint]

I agree with Honeycutt. When synthetics first came out, oil viscosity was a concern. They were thin, thin, thin. Now we have everything from 5# to 50#. If you have an older car or a high-mileage engine use the 20-40 or 20-50 wt. Just like using oil... You would not put 10# in a car with 100K. The same holds true for synthetics. You gain so much in oil temps, bearing drag and cold starting, it's no contest!

[bpilati]

I've never tried Redline, but I hear it's good. I've been running dino oil in my Z now for a while. I use Castrol 20w50 in the engine, standard gear oil in the tranny and diff. My Z mechanic I shouldn't put Amsoil in my 156K mile engine; that it should be rebuilt first. I think of changing the oil in the tranny and diff. I use Amsoil in my 00 Expedition engine now, and Mobil 1 prior to that since 6K miles. It's at about 110K miles now. I use Amsoil in my 89 Corolla tranny (rebuilt) with no problem. I may switch everthing that isn't leaking to Amsoil eventually. I have a 79 Toyota Corona with 78K miles that I may switch to Amsoil.

[DatsunZsRule]

I Disagree. Any time is a good time to switch to synthetic!

Thats fine if you don't agree. I know from experience that says otherwise. I had an old winter beater with high miles with NO leaks. I thought one day what the hell, I'll try synthetic even though it had high miles to help it start easier in the cold even though I knew of the risk and sure as sh!t what a mistake. After about a couple oil changes that poor car started pissing oil leaks like crazy. First it was the oil pan gasket so I replaced that. Then not long after that the valve cover gasket started pissing oil like crazy ect. later on I noticed the motor wasn't running like it used to due to the synthetic loosening up the old sludge and creating problems internally in the motor. That motor was strong and in good running shape when I had the regular and NO, I never "Beat the crap out of it" as I depended on it for work. This is just a fact wheather you want to agree or not. Ask any Auto Tech about starting Synthetic in an older engine with high miles. They will tell you NO for the same reasons.

If it will help it last longer with less wear, why is it a waste?

Why because I usually hit 3 months before I hit 3,000 miles so in that case, spending extra on Synthetic would be a waste of money. Like I stated, "Honestly, Oil has come such a long way compaired to what it was in the 70's. Regular oil today is damn good oil as long as you change it every 2,500-3,000"

So you don't see how in some cases it can be more harm than good when it's used in an older car that has never used it and a higher mileage car? Thats fine man, go ahead and try it out. Hope your car has better luck then my poor winter car did.

My Z mechanic I shouldn't put Amsoil in my 156K mile engine; that it should be rebuilt first.

EXACTLY!

[dhoneycutt]

I have switched several of my older high mileage cars over to synthetic with none of the issues. That is not to say you didn't. When you switch from regular oil to synthetic and your gaskets start leaking(bad/worn out), then your gaskets would have leaked with regular oil also except the leaks were plugged by all the sludge and crap inside. That sludge and crap can come loose anytime and cause internal problems, its just that synthetic does what it is suppose to. Keep it clean and well lubricated. So yes to a point, what you say can be true. I'm just saying it hasn't happened to me and it might not happen to the next guy either. I know you were just giving your opinion as was I and I mean no ill will to you!

[kenz240z]

Here's a link discussing the important points to consider when choosing a motor oil. Synthetics, and their benefits, are also discussed.

http://www.atis.net/oil_faq.html

[ZSaint]

I copied this article for my records. I have seen a similar piece done on filters. The only part of this I do not comprehend is the Viscosity Index. (VI) I do not understand what this means. (The hgiher the number the better) Can any one give me a simple explanation?

[gnosez]

I switched from Mobil One after my L28 cam started to show signs of wear after only 5,000 miles. In talking with Dave Rebello, he was not keen on Mobil One for L28 engines and I have since switched to Redline for all of my drivetrain needs.

I have since upgraded cams and have about 10k on it now with no signs of wear at all. The '80 tranny is fine and the quaiffe diff works like it should. I do oil changes at the 3k to 4k interval and change gear oil 2 - 3 times a season (April to end of November).

Dam cheaper than replacing a set of bearings.....