Synthetic oil in an older car

[WyrTwister]

We have Dad's 1991 Chevy Caprice 5.0l . He always used Quaker State conventional oil .

I have been reading about the issue of flat tappets / cam and newer oils with lower zinc content .

I am wondering about the advisability of switching to synthetic oil ?

Your comments appreciated .

Thanks ,
Wyr
God bless

 

[Dyusik]

Used Edge 0w40 in a LB6 in my old Beretta. All was well, until I sold the car. That Zn you mentioned is higher than you average GF5 stuff too.

 

[BrocLuno]

Maybe Rotella T6 5W-40 synthetic. Has plenty zinc, easy start, a bit of viscosity for hot running.

Or 10W-30 Maxlife which has a very good add pak too

 

[901Memphis]

There's still some good oils if you don't want to go synthetic. Quaker State defy 10w40 should still have high zinc as well as Maxlife 10w40. If you go to any good 40 grade they are allowed more zddp than 30s usually although not all are formulated to take advantage of this allowance

If you do want to go synthetic there's Mobil 1 high mileage 10w40

 

[ARCOgraphite]

Cam is broken in. no Worries. It will wear. Should be a roller though!

Synthetic doesnt have better lubricity than conventional. Petro oil doent have batter lubricity than animal fats.

In America synthetic is a marketing tearm and has NOTHING to do with the oil being a majority Group iv or group v lubricant.

Most are just refined mineral oils or Mineral oil byproducts like slackwax.

No how do you enjoy being lied to by the industry? They are betting on the fact that you are ignorant.

 

[Dyusik]

Originally Posted By: 901Memphis
There's still some good oils if you don't want to go synthetic. Quaker State defy 10w40 should still have high zinc as well as Maxlife 10w40. If you go to any good 40 grade they are allowed more zddp than 30s usually although not all are formulated to take advantage of this allowance

If you do want to go synthetic there's Mobil 1 high mileage 10w40


No longer the case with the SN/CK-4, as they too follow the 800ppm P limit.

 

[RegDunlop]

IMO do not go full synthetic, continue with conventional ( if it were me, I would not use ANY SOPUS oil --try Castrol or Mobil or Valvoline white bottle) , or switch to Valvoline max-life in the red bottle.

 

[MichiganMadMan]

Originally Posted By: ARCOgraphite
Should be a roller though!

^ THIS
I had a 1992 Roadmonster with the L05 (TBI 350) and I know for a fact it was a roller. I think the cars switched to roller cams somewhere in the mid-80's while the pickups continued with flat tappets into the mid-90's.

 

[WobblyElvis]

About 3 years ago I had a 99 Caravan with a small oil leak. I switched to synthetic oil and the leak became much larger and a few more leaks developed. I tried Stop Leak and switched back to conventional oil but it made no difference. I kept a pan under the vehicle as it sat in my driveway. Switching an older vehicle to synthetic is something I'll never do again.

 

[bigt61]

OP - run SuperTech dino 10W-30, change very 4-5000 miles & keep it topped off - it will be fine. Synthetic is a waste at this point and your spring pressure is so low that the flat tappet issue doesn't apply.

 

[HerrStig]

Originally Posted By: WobblyElvis
About 3 years ago I had a 99 Caravan with a small oil leak. I switched to synthetic oil and the leak became much larger and a few more leaks developed. I tried Stop Leak and switched back to conventional oil but it made no difference. I kept a pan under the vehicle as it sat in my driveway. Switching an older vehicle to synthetic is something I'll never do again.
And maybe that leak was going to do that anyway.

 

[HerrStig]

Originally Posted By: 901Memphis
There's still some good oils if you don't want to go synthetic. Quaker State defy 10w40 should still have high zinc as well as Maxlife 10w40. If you go to any good 40 grade they are allowed more zddp than 30s usually although not all are formulated to take advantage of this allowance

If you do want to go synthetic there's Mobil 1 high mileage 10w40
This. It's why a lot of bikers use T6.

 

[benjy]

due to more additives for cleaner running even a group III refined CRUDE oil will clean out the "[censored]" left behind by lesser oils. real synthetics group IV + V likely clean more, a few drips hurt nothing. i ran group IV PAO that was blended with group V Ester oil in a 125,000 mile 64 olds cutlass, sold at 250,000 miles running well + still dripping!!

 

[Red91]

The 5.0 and 5.7 TBI engines produced for cars had roller cams starting in '87, whereas the truck versions remained flat tappet throughout their run. Either way, those era small blocks had good camshaft quality and a lower ZDDP oil won't hurt them.

I'm personally considering Synpower or Edge 0W-40 for the next change in my Roadmaster Estate.

 

[FCD]

86 and on GM Cars had roller cams, 96 for trucks, so zddp should not be an issue.
Use 5W-40 Shell Rotella T6 or Valvoline Maxlife.

 

[aquariuscsm]

Pennzoil Platinum high mileage 10W30 and an AC Delco oil filter.

 

[OneEyeJack]

A 1991 is not really an "older car". If you're doing well with conventional oil you might consider it's continued use.

Then, you could go part way there with a known good semi synthetic like Motorcraft.

And finally a "fully synthetic" labeled oil.

There is not a bad choice, here.

I drive a 1984 Civic with synthetic oil from new and have no lubrication problems. From where I see it a 1991 is nearly new. (lol)

 

[umungus1122]

I wouldn't use a full syn in it. If a small leak or dirt covering a leak is present, it may start leaking. I've had that happen several times. Go with a HM blend like Maxlife or Defy. Yes, it's a roller cam, and doesn't need anything special. As to the truck TBI 305s, my '95 is a roller cam.

 

[aquariuscsm]

Originally Posted By: OneEyeJack
A 1991 is not really an "older car". If you're doing well with conventional oil you might consider it's continued use.

Then, you could go part way there with a known good semi synthetic like Motorcraft.

And finally a "fully synthetic" labeled oil.

There is not a bad choice, here.

I drive a 1984 Civic with synthetic oil from new and have no lubrication problems. From where I see it a 1991 is nearly new. (lol)


Haha same here. To me anything made in the 90s is "newish"

 

[FCD]

1991 is definetly "older" in my opinion, doesn't the NHRA say once a car is over 25 it's a classic?