Would anyone know what type of motor oil is needed/recommended for a 1972 Cutlass S?

Another question, my car has a consistent whistle, especially at idle, I’ve tried to locate all vacuum ports and found a couple that I had to plug but the whistling continues. I’m not sure what it is as it doesn’t seem to affect performance or idle rpms. Any help/suggestions would be greatly appreciated.

 

10W-30, possibly 10W-40 for hot weather or a worn engine. Make sure that it's formulated with adequate ZDDP content for a flat-tappet cam. Don't use synthetic unless the car has already been using it.


Test with a vacuum gauge to definitively rule out vacuum leaks.


Welcome to CO!

 

Thanks for the info. I’m an admitted noob at this. If I get the gauge are there directions on where to connect it or would you know?

 

Welcome to the site. A good 10/30 should be sufficient. A lot of guys like the Valvoline vr1.

You can connect the gauge to just about any vacuum source, but I'd suggest one of the nipples on the intake manifold.

Any chance the whistle pitch changes when you press on the brake pedal? I'm referring to the brake booster being an issue but its probably something else. Keep looking, and make sure the carb is tight to the manifold too.

 

 

I had a 600CFM Edelbrock Carb (1406) that whistled at idle, give it some throttle it would stop . Off the throttle the whistle returned.
What carb are you running ?

Eric

 

 

If at all possible, take some video and audio as the engine is running and whistling, upload it to youtube, and put the link here. Then people can actually hear the sound themselves and would have a much better chance of identifying the cause.

 

No , not between the intake.
I found mine to be coming from one of the idle mixture screws. I must have turned one of them in too tight at some point before backing them out when setting the vacuum.
It actually became intermittent and seemed to stop eventually.
Hope this helps
Eric

 

Whistle from the oil fill tube cap? Do you have a PCV valve installed?