Oil fill tube question

[mblackburnjr]

I have been looking at lots of original engine pics and noticed some have the fill tube, and some dont. So.....was this a factory option or dealer installed?

[geezer#99]

If you mean the tube by the thermostat, it was factory installed with the motor. It was part of the crankcase ventilation system. Depending on the year of the motor the cap on top was vented or solid. When they went to the pcv on the valve cover and a breather on the other cover around 1967, the oil fill tube was plugged.

[FirstOwner69]

Are you asking about the tube near the rear of the left valve cover or the tube at the front of the block above the water pump?
I believe geezer is referring to the one at the front of the intake that was used prior to emission controls. I think the one in the valve cover may have been just a 4x4 thing. If not, it was probably added in 71 or 72 to make it easier to add oil. Not sure. My 69 3/4 ton never had either.

[Coley]

Or....are you referring to the tall oil filler tube sometimes located on the back port of the drivers side valve cover?
I think this was used when the truck came with a/c. The backstory being the fact that the a/c brackets covered over the normal (front) fill location hole on the passenger side valve cover so they added that tall filler tube on the opposite side.
Correct me if I'm wrong on this guys....
Coley

[Bigdav160]

No idea, however, my '72 4x4 w/AC has the tall extension near the brake booster.

The '67 Corvette in my avatar has the filler tube in the front of the intake and has a PCV in the side of the tube.

[bMr]

Original owner of a '72 2wd, 350/TH350, A/C which also has the oil filler tube near the brake booster.

[71 super]

The extension was used on both 2wd and 4wd to allow oil to be added with brake booster option in place.

[FirstOwner69]

As I noted in post 3, my 69 3/4 on 2WD with A/C and power brakes did not have one since new. However, the power brakes were added by the dealer prior to sale. I have looked at a bunch of these trucks in junkyards over the years and don't think I've seen one in a truck prior to 71. I very well could be wrong about the year though. To simplify adding oil when there's a brake booster makes sense, but when did it start?

I did a forum search and didn't find a definitive answer.

[seattle gmc]

My 70 k2500 has the tall one by the brake booster.

[71 super]

No idea on intro. Def. seen more on 71-72 trucks than any other

[mblackburnjr]

Ooops! Guess i should've been more specific. I was refering to the one at back of drivers valve cover, near the booster. Is this an option listed on the spid? The few i've seen have been 71 or 72. So the booster reason makes more sense.

[jocko]

It is not a SPID option. While there appear to be cases where it was not installed on power brake cars, that seems to be the reasoning. Perhaps it was a new thing in 71 to help resolve the pain of filling with oil once everyone started ordering power brakes in those days. Remember that power brakes really weren't all that common (although available) in earlier trucks, so maybe GM finally got the word that folks were annoyed trying to fill up with oil with the big ol booster in the way - and they didn't get the fix incorporated til 71(?) Anyhoo, not a SPID option. Having said all that - I know of a few 71/2's with pwr brks that didn't have it installed. Always hard to tell what some POs have pulled off and tossed though.