1972 Olds Cutlass

[Kestas]

Read your owners manual. I have a 71 Cutlass conv 350 auto, and the manual categorically states it can run on unleaded. This strongly suggests the valve seats are hardened. These engines have been ready for unleaded since at least 71, if not earlier (69?).

In addition, I've run my car for 60K miles on unleaded and recently rebuilt the engine because the seals were old and brittle. I saw no damage or seat recession on the valve seat. With 170K on the engine, I simply lapped the valve seats (among other work) and put the engine back in service with no problems.

If you are now the caretaker of a 72 Cutlass, you should hook up with these guys: Oldspower.com

 

[LTVibe]

"... GM-corporate edict that required engines to use lower-octane regular leaded, low lead or unleaded gasoline beginning with the 1971 model year."

It appears all GM vehicles starting in 1971 could safely use unleaded gas.

Sources:

web page1
web page2

(In both links, page down to 1971 year info)

 

[kerryf]

Hi

I've got a 1972 Olds Cutlass Convert, 350 engine and auto transmission. I did a search, but didn't get an answer to the following:

The previous owner insisted that a lead substitute like CD-2 was essential to prevent the valve seats from being damaged. I've since read that GM engines from 1972 had hardened seats installed at the factory to anticipate the phase out of leaded gas. It's not all that expensive to use the CD-2, but I wonder if it is necessary. Could it also be harmful?

What do you think?

Kerry

 

[TheTanSedan]

There was, at the time, note to distinguish between low-lead and no-lead. I haven't heard of anyone having problem with no lead so long as they weren't running 90 mph for extended periods or towing/hauling heavy loads, also for extended periods.

Keeping the coolant system like new (and most aren't at that age) is the most important item, IMO. I replaced the radiator on my '71 Chrysler after several flushes/rinses, and ran SCHAEFFERS #158 "Clean & Cool" with a hotter-than-factory thermostat.

I also ran M1 15W-50 in the 383. At a teardown to replace gaskets, the valves showed no signs of recession (99m), just a light coat of varnish on lifters, pushrods and in lifter valley.

 

[mechtech]

What has it been using since lead was phased out 20 years ago?
It must be OK.