Quick dipstick question

72T · 03-02-2009, 05:57 AM

I'm trying to get a sense of oil usage, and how much to add without overfilling. I've got the stock dipstick in th '72, which shows high and low lines about three inches apart. I can't find anything in my manuels concerning adding and how much equals rising level. Is it just a matter of: warm the engine, check, add, check, add, etc. until you get there? When filling, is it OK to go to the line, or do you need to let it circulate a bit and re-read? Sorry for the noob question, just want to do it right, and learn something.

Rot 911 · 03-02-2009, 06:23 AM

Full is actually mid-point between those two marks. The difference between the two marks is around a quart.

Paulporsche · 06:36 AM

And you are right: do this on level ground, w/ the engine @ 176F and running @ idle. Or if your engine stalls upon opening the oil filler I imagine you could check the level right away after the engine is off.

notmytarga · notmytarga's Garage

The 1972 is obviously different because of the position of the oil filler on the fender.

Oil level in the tank will change with idle speed and engine temp. It is not reasonable to assume that the level will not change quickly after the engine is off - because it does, significantly. to check the level - the engine is warm and idleing at 1200 ish, so there is no need for delay in reading the level.

There is a original decal in my 1975 engine bay that says that the difference between the top and bottom marks (about 3 inches) represent 2.5 liters - which are very similar in size to quarts. Since the oil level sender is the same - this calibration should carry.

Answer - Oil volume to take the oil level from the bottom to top mark is approx 2.5 Quarts.

Hope this helps.

72T · 03-02-2009, 09:00 AM

Thanks all. 2.5 quarts or 1 quart difference? I guess I'll just go slow and see what happens. Also, when I checked over the weekend, the oil temp was at or above 210 degrees, would that make it read lower, assuming that temperature can make a difference?

tharbert · tharbert's Garage

In my 72, I can't get a good "dip" on the stick as oil spashes over fingers and stick before I can get it out. I wonder if some diverter that redirects the scanvenged oil is out of place. I have been using the gauge to tell me when it starts getting low. The oil level gauge always shows "low" until the temp gauge lifts off the peg then gradually levitates to a true indication of the level. That is, true to the eyes as I look down into the tank.

S2GART · S2GART's Garage

Kurt V, if mid way beween points is full, then what is the upper mark for?

chrisgo17 · 03-02-2009, 10:43 AM

I have wondered about the upper mark for 25 years. I was always told in the middle but no more. Though I do not go by the Gauge, it puts it at 7 with 8 being in the red.

Rot 911 · 03-02-2009, 10:48 AM

Quote:

Originally Posted by S2GART

Kurt V, if mid way beween points is full, then what is the upper mark for?

Hell if I know. Funny German thinking. My BMW also has a dipstick with two marks and full is right in the middle.

72T · 03-02-2009, 10:48 AM

My mechanic recently told me "upper line, no more", maybe that is the drop dead line? It seems like there would be a line for "proper fill" somewhere. "In the middle" seems un-German.

tobluforu · tobluforu's Garage

I just go by the gauge in the car.

72T · 03-02-2009, 11:02 AM

A great idea, that dash indicator. Too bad mine's broken...!

S2GART · S2GART's Garage

Don't rely on that oil level guage. Mine fluxuates too much. Alot of times with the engine running it indicates in the red, when I know full well there is pleanty of oil. There is nothing more accurate than an oil mark on a dip stick.

To help me guage any oil usage, I actually made an additional mark in the middle of the 2 factory marks.

moneymanager · 03-02-2009, 12:45 PM

You guys have too much time on your hands. Level ground, warmed up, in the middle of the two marks. That's all anyone needs to know.

Paulporsche · 01:45 PM

moneymanager,

And add: "engine idling"

I'll go w/ notmytarga for now just to be on the safe side. What he has said is the factory procdure. I was hoping that the level wouldn't change in a few seconds, or that the mark on the stick would still be @ its previous, running level for a few seconds for those whose engines stall, but I have to admit I won't be able to verify this for a few weeks.

daepp · 03:05 PM

My 72 has so much splash it's difficult - but still possible - to read the stick. I keep it in the middle.

As for the gauge inside, I do rely on it. It tells me - in general - the level of my oil in the tank. I would guess that they are not comparable between cars, but if you get used to yours, you just about don't need the dipstick. With the gauge, it is very obvious when I am getting 1 to 1.5 quarts low, and similarly obvious when I've added a quart.

As for the inop gauge, check the leads where they attach to the sender at the tank. Mine fell off once.

moneymanager · 03-02-2009, 02:50 PM

Excellent addition, and very useful for those who were raised on Buicks.

pwd72s · 06:32 PM

I'd add that it's 8.5 quarts for an oil change on a '72...not the 10 quarts of other years. The forward oil tank has less capacity than the rearward mounted ones.

daepp · 03-02-2009, 05:13 PM

Paul - even on the S with the front oil cooler?

pwd72s · 03-02-2009, 06:31 PM

Quote:

Originally Posted by daepp

Paul - even on the S with the front oil cooler?

Front cooler or not...8 1/2 quarts per change. You see, the "dirty" oil stays in the lines and cooler when oil is changed. That's with the factory set up. IIRC, elephant racing lines now have a set up where you can use compressed air to clear all the oil...if so, that should equal about a quart.