high mileage oil for an older turbo car

[firebird72]

Originally Posted By: lexus114
Originally Posted By: firebird72
Originally Posted By: jayg
Looks like the image isnt showing up now. Here is the VOA specs for Maxlife HDD 15w40. Strong Zinc numbers. Do you daily drive this or park it outside? If not, I wouldn't hesitate to run it year round.


no daily driving, its a fair weather driver & a garage queen. but again, 15/40 is too thick for any use or purpose of this car & where i live. it calls for 10/30 & is occasionally driven/started in colder temps. while it looks like a great oil, i just dont see the need for a thick HDEO in it. maxlife will be more than enough.


personally, i`d go with mobil-1 10W30 high millage oil.


also a very good oil choice... but why would you go with full synthetic in this car when it sees under 500 miles a year & has a slow rear main leak? waste of money IMO & could make the leak worse, a full synthetic or thick HDEO just isnt needed. if i started driving it 1500-2000 miles each season &/or turned up the boost & started hot rodding it i would agree with a step up in oil... but for what the car does now, a standard or blend HM oil is perfectly fine.

my main concern was the turbo seals & using HM oil... & that has been addressed.

 

[semaj281]

Originally Posted By: firebird72

curious what you are basing that oil weight suggestion on? the car calls for straight 30 weight oil unless driven in temps below 40* then it calls for 10/30. back in the 80's GM's solution to avoiding coking was thicker oils but todays oils are much better & most all 10/30 oils will be ok for street use. i live in the midwest & the car gets driven or started in 40* & below days, the engine has very low miles & zero consumption or burning... so please explain why i would want or need a 10/40 or expecially a 15/50 oil for this car??? also, why does thicker oil "wick away heat?" always read that thinner oils, to a poaint, are better for coooling since they flow better around bearing etc... flow equals cooling, not thickness.


I'm not sure I follow the "flow equals cooling" logic. Flow increases with heat which also results in a fluid pressure drop. Flow suffers with more viscosity, but higher viscosity oils can help keep moving parts separated to dissipate heat. Oil technology has changed over the years and there are many examples of people running M1 0w-40 in engines that call for less viscosity. In a turbo car there is more to consider than the viscosity labeling, which should be taken with a grain of salt anyway because different brands of 5w-30 are going to have a different cSt rating.
I believe the people recommending a synthetic 10w-30 or 10w-40 are doing it because of their anti-shear characteristics which are important in a turbo car.

 

[Popsy]

What about a (probably) VII free oil like Delo 400 SD 15W30?
Or it's 10W30 counterpart, Delo 400 XLE...but this one is probably formulated with some VII

 

[firebird72]

Originally Posted By: semaj281
I'm not sure I follow the "flow equals cooling" logic. Flow increases with heat which also results in a fluid pressure drop. Flow suffers with more viscosity, but higher viscosity oils can help keep moving parts separated to dissipate heat. Oil technology has changed over the years and there are many examples of people running M1 0w-40 in engines that call for less viscosity. In a turbo car there is more to consider than the viscosity labeling, which should be taken with a grain of salt anyway because different brands of 5w-30 are going to have a different cSt rating.
I believe the people recommending a synthetic 10w-30 or 10w-40 are doing it because of their anti-shear characteristics which are important in a turbo car.


the logic is based on what i have heard from people much more experienced at engines & engine building than i am. for example, in a mild performance average american v8 car, an engine set up for street use & relatively tighter clearances (as opposed to loose race type builds) would usually call for lets say a 10/30 or maaaybe 10/40 oil, no fancy 0 weight or pure synthetic oils are usually used in these types of engines, especially older flat tappet cams. some people like the average armchair racer would say "you need to run 20/50 in that thing," or "thicker oil is better than thin oil" etc etc... that is not true IMO. a thicker than needed oil just causes increased drag, takes longer to circulate on startup causing engine wear, & in many cases doesnt flow as freely over bearing surfaces. a correct weight oil for the specific engines needs is always better than a thicker than needed oil based on the idea that it "seperates parts better." being able to freely flow & carry away heat is what i was refering to. too thick of oil doesnt do that as well as a correct weight for the application oil that is thinner. generally speaking.

for my specific car which calls for a 30 weight oil, i would much rather use that oil than experimenting with a 15/40 or even a 50 weight that someone above suggested. obviously a synthetic would be "better" since its a "better" oil vs a conventional oil. but keep in mind again the car is driven very low miles, never abused or overheated, does not burn or consume any oil, just a very small rear main drip, has excellent oil psi. its also ran in colder weather sometimes. i just dont see any valid reason to use a thicker oil or go to a pure synthetic, its a waste of money in this situation & could possible make the leak a little worse.

i will be using a good conventional or blend HM oil... in 10/30 weight.

 

[05LGTLtd]

Keep in mind that a synthetic 10w-30 wil have less VII than a conventional oil. Also lower noack and better teost. All good qualities for a oil cooled turbo engine.

 

[firebird72]

Originally Posted By: 05LGTLtd
Keep in mind that a synthetic 10w-30 wil have less VII than a conventional oil. Also lower noack and better teost. All good qualities for a oil cooled turbo engine.


fully agree with that... but keep in mind that those qualities arent really needed for car that sees less than 500 miles a year. sometimes barely 300. i dont feel paying 2 times as much for full synthetic is really needed at this point due to the previous stated use/purpose of the car. i would be dumping the oil with only 1000-1500 miles on it after ~3 years.

im always open to hearing any oil suggestions but i think this thread has served its purpose & answered my concerns about the turbo & HM oils. thanks again guys.

 

[BrocLuno]

I have been a proponent of Delo 400 15W-40 in lots and lots of older engines. It's good oil that sees many of these engine out to close to 300K. And it serves turbos very well, and has for decades. All good

But, things are a changing as they always seem to when we get to a comfortable spot. The diesel and mixed fleet oils will be changing again this January. New formulations and new rules for add paks.

I just ordered enough Delo 15W-30 SD off Amazon to keep me going for the duration for hot motor build break-in oil. But that's not where you are at... Your motor is broken in and running happily

I would however consider Rotella T6 5W-40 in your situation. It's synthetic (USA style anyway), but it's pretty inexpensive. It's readily available and it's on the thin side for 40 at op temp. To me it's really a 35 at temp. Slightly to thick to be classed as a 30 ... But still not as thick as the average for a full on 15W-40 HDEO.

It's well proven and is great in turbo bearings. There is not great howl of anguish from truckers running it and turbo failures. Works fine in my turbo gas cars. Lots of Subie turbo owners swear by it. It's been run in more than one Grand National

I'd add it to the list of appropriate oils for your application.

 

[firebird72]

i use the 15/40 delo400 in my other car with a mild flattappet cam. good stuff. i will have to stock up on some before it changes.

havent looked at the rotella 5/40, i went with the delo after they changed the rotella back in 07, but sounds like the t6 is a good oil & might consider it for the turbo car. this has the same basic turbo as the grand nationals.

 

[Charlie2015]

Valvoline Maxlife

 

[ChrisGuerrero]

Originally Posted By: firebird72
hi, first post here but been a reader for many years...

i have an older 1981 pontiac turbo v8 engine & was wondering what the opinions on using a high mileage oil in it are? my main concern is the seals in the turbo, would the HM oil have any negative effect on them? like swell or harden them?

the car doesnt technically have high miles, its original 29,000 miles but the car is 35 years old & has a very minor rear main seal leak, just a drop or 2 when parked so its not bad at all but i thought using a HM oil might help seal it up & HM oil is usually a "better" oil as far as thickness & zddp levels which would be a benefit to this older car with a flat tappet cam. i am considering the synthetic or blend HM versions to benefit the turbo, but not sure if i trust the leak with synthetics.



Hello firebird72 — A good high mileage/high zinc motor oil would be great for your 1981 Pontiac Turbo V-8 engine. The seal conditioners in a high mileage conventional or synthetic motor oil should not harm the seals in your engine or turbo. Since your Pontiac has a flat tappet cam engine that requires a higher zinc (ZDDP) motor oil, we suggest that you use Shell Rotella T4. It’s not a high mileage formulated oil, but it does have a high level of zinc. Shell Rotella T4 Triple Protection 10W-30 would work best. It’s not just for diesel engines either; it's API service rated for gasoline engines as well. It’s formulated with 1200 PPM of zinc which is perfect for older flat tappet and performance engines. It targets high temperature and high-wear surfaces where they are needed the most. Hope this helps! - The Shell Rotella Team

 

[turboseize]

Originally Posted By: firebird72
yes i always do a cool down for a couple minutes if driven hard & also drive easy for the last 5-10 minutes.

Originally Posted By: jayg
Old school oil lubrication for that journal bearing should have at least a 40 wt oil to wick away heat. My recommendation would be M1 HM 10w40 or if you have no noticeable consumption or leaks, M1 15w50.


curious what you are basing that oil weight suggestion on? the car calls for straight 30 weight oil unless driven in temps below 40* then it calls for 10/30. back in the 80's GM's solution to avoiding coking was thicker oils but todays oils are much better & most all 10/30 oils will be ok for street use. i live in the midwest & the car gets driven or started in 40* & below days, the engine has very low miles & zero consumption or burning... so please explain why i would want or need a 10/40 or expecially a 15/50 oil for this car??? also, why does thicker oil "wick away heat?" always read that thinner oils, to a poaint, are better for coooling since they flow better around bearing etc... flow equals cooling, not thickness.


I guess the car calls for straight 30 as early multigrades were prone to shearing, and an 1980s 10w-30 or 10w-40 would relatively fast have an HTHS of "too low". But a quality modern oil should not have these issues any more.

Originally Posted By: jayg
Originally Posted By: UltrafanUK
2 or 3 minutes is enough to avoid hot shutdown damage to the turbo bearings in most older vehicles. Modern ones have a follow on electric oil puimp.
Cold starting with your boot on the accelerator causing a sudden jump in the revs as the engine fires up is more of a bearing killer.


It really isn't though. In an older vehicle that is water and oil cooled then yes but the idle oil pressure on a strictly oil cooled turbo BOP that isn't enough to avoid coking. I've had so many old school turbo vehicles and I've learned the hard way on tricks to make them last.



On my previous Saab 900 turbo 8V (Garrett T3, only oil - no water), the turbo would take roughly 5 minutes at idle after a spirited short Autobahn drive just to go from "bright orange" to "no longer visibly glowing" (at daylight). You really had to take your time to cool this car down before shutting it off.
On my more modern 16V with electronic fuel injection and deceleration fuel cut-off, this is much easier. I use downshift and engine breaking as I go from 5th to 2nd gear to pump cool air through the engine when on the off-ramp, and then I let her idle 30 second, so that the turbo does not spin as fast when shut the engine off. A guy in the german Saab forum who, besides being a Saab enthusiast, happens to be an engine developer for an automotive engineering contractor once did some test runs with several different engines, in which he simulated driving under full load, and then several downshifts an deceleration fuel cut-off until stand still. Deceleartion cut-off and engine braking through several gears brought down temperatures from to 300-400°C relatively quickly, and while further idling took down temperatures further, it did so only very slow and the absalute temperature decreases where minuscule.
Obviuosly that is only going to work with deceleration fuel cut-off, so in a mechanical fuel injection or carburator car, nothing beats calm driving and looong idling.

Originally Posted By: firebird72
Originally Posted By: lexus114
Originally Posted By: firebird72
Originally Posted By: jayg
Looks like the image isnt showing up now. Here is the VOA specs for Maxlife HDD 15w40. Strong Zinc numbers. Do you daily drive this or park it outside? If not, I wouldn't hesitate to run it year round.


no daily driving, its a fair weather driver & a garage queen. but again, 15/40 is too thick for any use or purpose of this car & where i live. it calls for 10/30 & is occasionally driven/started in colder temps. while it looks like a great oil, i just dont see the need for a thick HDEO in it. maxlife will be more than enough.


personally, i`d go with mobil-1 10W30 high millage oil.


also a very good oil choice... but why would you go with full synthetic in this car when it sees under 500 miles a year & has a slow rear main leak? waste of money IMO & could make the leak worse, a full synthetic or thick HDEO just isnt needed. if i started driving it 1500-2000 miles each season &/or turned up the boost & started hot rodding it i would agree with a step up in oil... but for what the car does now, a standard or blend HM oil is perfectly fine.

my main concern was the turbo seals & using HM oil... & that has been addressed.


The turbo seals are labyrinth seals, no nead for sel conditioners there. As for the bad rear main seal... well, there is only one way to fix this, and that is to fix the seal.

Originally Posted By: 05LGTLtd
Keep in mind that a synthetic 10w-30 wil have less VII than a conventional oil. Also lower noack and better teost. All good qualities for a oil cooled turbo engine.


This is also a good point.
There was another point made in this thread (but I blw the quote): that you have a flat tappet engine and thus want high levels of ZDDP.

And to bring it all together:
- the manufacrurer specced a straight 30, as he was afraid of the early VIIs failing. So the manufacturer obviously wanted a relatively high HTHS (even though the term HTHS wasn't in use by then) and a shear stable oil.
- but you do not want to viscous oil, as sometimes you cold-start the car on colder days.
- old turbos can produce absurd heat.
- mineral oils coke easily.
- a synthetic oil has less VII, higher NOACk, is less susceptible to termal degradation and oxidation
- you want relatively high ZDDP, so no mid- or low-SAPS oils.

If I were you, I'd look for an POA-based synthetic with european manufacturer certifications, especially MB 229.5 (shear stable VII and low NOACK) and Porsche A40 (includes a hot-shut-off test in a turbocharged engine to control coking). Taking into account the manufacturer prescribed a straight 30, I'd choose a heavy 0w-30/5w-30 or a lighter 0w-40, and the higher HTHS, the better. Most manufacturers just tate HTHS >3.5, but if we find something more specific, that is what we want. There are some o-30 and 0w-40 that have 3.68, some even 3.8 - which would be in the same range as a straight 30. All the protection you need, better cold start.
The two fully synthetic Castrol would be the first to come my mind. There are a few others, but if you want PAO, the air is getting thin, and Castrol would probably be the easiest to get.