Do I trust the dipstick or the manual?

Patman

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Here is my dilemma. The manual for the LT1 f-body shows the oil capacity as 5 quarts with the stock oil filter. The long one I run takes maybe a 1/4 quart extra at the most. But when I change my oil I need to add 5.6 quarts to get it to the full line. Should I trust the dipstick and continue doing this? Or should I run 5.25 and see where that shows on the stick, and treat that level as the actual full line? I'm worried because other LT1 f-body owners have told me they only need to run 5qts with the long filter to have it show full on the dipstick. Why the large discrepency?
 

Al

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Well, you are less than a half quart different. Since you don't go over the full line on the dipstick I would stay with that number (5.6). It's unlikely that the dipstick is off. The dipstick tube could possibly not be pressed completely into the block-(probably a reach). You could check with the dealer. [freaknout] Again, I personally would go by the dipstick, but would be careful not to go above the full line. In my Nissan I tend to go a bit over the full line. But running less than 1/2 quart over on a 5 qt sys shouldn't hurt. But again I would be careful not to go over line. IMHO. [Happy]
 

Patman

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I've been asking around on the various F-body boards as to what others have found, and one more person told me his LT1 only needs 5 quarts with the long filter. But yet, a guy I know personally here in Toronto says his 95 Z28 takes 5.5 quarts with the long filter. Now I wonder if the Canadian cars might hold more oil? Although that wouldn't make sense, why would that be any different? Maybe I should just split the difference and run 5.3 to 5.4 quarts? I'm just worried that having it filled up a tad too high could be robbing me of power, and could possibly increase the oil consumption slightly, since my engine does leak oil out the back of the intake manifold.
 
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I don't think less than a half quart will be any problem. When I bought my new Silverado 4.3 in Feb. it was 1/2 Qt high. By the time the change oil light came on at 5711 it was down to the full mark. The dealer sent me a coupon for a free change so I took it in. 1/2 Qt low again. I asked the service man about it and he just said that they use 5 Qts. (the 4.3 uses 4.5 Qts). Next time I changed I put on a long filter and used 5 so now at almost 5K miles I am almost down to full with 5wSS. On one other truck I had, I put in 4 Qts and cut the dipstick with a file, added another qt and cut another line. I first thought the "imperial" qt might be different but then I realized that the oil companies are all packaging the same. Keep looking and someone will square you away. RW
 
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To find out what the exact amount should be try this..... First you should know exactly what amount with the standard filter takes. now take a standard filter, fill it, measure amount... now take new longer filter, fill it, measure amount.... You want to make sure that you completly fill the filters through the inside and outside holes. take the difference, add to the total beginning amount used in a standard oil drain. This should give you a very close approx of actual amount to be used. So if you know for a fact, 5qts for total oil change with standard filter, then by measuring two new filters(one standard one longer), so if the difference is 1/4 between the two, then difference between the two should obviously added giving you a total of 5 1/4. [ September 08, 2002, 08:43 AM: Message edited by: BOBISTHEOILGUY ]
 

Patman

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I know I think about these sorts of things way too long, but here is another twist to your idea Bob. How exactly do you figure it out when there is a difference between how much old oil comes out with a 5min drain of the oil compared to a 2 hour drain? Obviously even more oil comes out when you drain it that long. So is the manual taking into account the fact that most lube shops only let the oil drain 3-5min? Darnit, I think too much for my own good. [Freak]
 
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Well for what its worth, in my car in order to get a correct reading it needs to be warmed up, then off for about 5 mins and on EVEN ground. A slight incline will throw off the reading in my car by .5 litre.
 

Jay

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My car required more oil than the manual says also, but I attribute it to the fact that I let the oil drain for a couple of hours. So I get more of the old oil out than someone that goes to a fast lube place.
 

Patman

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Here is another bit of info to totally confuse things! Even though other people I know with LT1s have manuals that say 5 quarts is the capacity, I just double checked mine and it says 4.5 quarts capacity with filter change! So now I definitely don't trust the manual. There was no change to the oil capacity of the LT1 from 93-97, so why would some manuals read 4.5 while others read 5? I know the service manuals say 5. Wierd. [Confused]
 

Al

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quote:
Originally posted by BOBISTHEOILGUY: To find out what the exact amount should be try this..... First you should know exactly what amount with the standard filter takes. now take a standard filter, fill it, measure amount... now take new longer filter, fill it, measure amount.... You want to make sure that you completly fill the filters through the inside and outside holes. take the difference, add to the total beginning amount used in a standard oil drain. This should give you a very close approx of actual amount to be used. So if you know for a fact, 5qts for total oil change with standard filter, then by measuring two new filters(one standard one longer), so if the difference is 1/4 between the two, then difference between the two should obviously added giving you a total of 5 1/4.
I guess one of tghe problems is that he will still be unsure of the right amount even with the normal filter (probably is not 5quarts). I would just go to the full line and no fuller.
 

Patman

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[LOL!] LOL! Use the Schwartz! [Smile] I wish I knew for sure exactly what to do here, on one hand I want to run more oil in order to lessen the overall stress on the oil, but I also want to make sure I'm not losing horsepower by having too much oil. I wonder if there would be more engine wear if I ran 5 quarts vs running 5.6? [I dont know] Like I said, I just think way too much for my own good. [Bang Head]
 
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Patman, let it drain like normal for 5min(or whatever) into the drain pan. Then stick some kind of clear graduated measuring cup under there and let it finish draining into that, and then you will see how much extra your obsesive behavior gets you! [LOL!] j/k. Actually I think I may try this. I don't normally let it drain that long because I don't think it will be much, maybe 15mL. But it would be interesting to know.
 

Patman

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Now I'm thinking the next oil change I'll just put in an even 5 quarts and call it a day. Wherever that shows on the dipstick, I will then treat that as the full line. Now I wonder if I should take the oil filter off and perhaps put on a new one (without filling it too much) so that it gets rid of some excess oil? Or should I just leave it alone so I don't change too many things around (for oil analysis comparison purposes that is, since this interval is supposed to be identical to the last one to compare Maxlife to Schaeffer)
 

MolaKule

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Patman, You're correct. I should have added that I check the oil 15 seconds after shutdown when I am doing this "maximum" fillability test. I found that on the '92 Burb, I can actually run almost 650 mL above the full mark and 400mL above the full mark on the Nissan before oil whip and cavitation set in. On the '86 Burb, I can run almost 700 mL before bubbles appear. [ September 09, 2002, 11:07 PM: Message edited by: MolaKule ]
 
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Never run over the full mark. At that point you will have spashing and foaming. Better to be half quart low than half quart over. Standard procedure when we change oil is fill what we think it holds or what the book says, check the dipstick, and fill to full. My Mitsubishi says to fill with what the book says, start the engine and run a minute at idle, turn it off and wait 30 minutes to read the dip stick, then fill to full mark. (I don't know how a 10 minute oil change can follow this procedure). Oil capacity varies within engine series. Toyota puts an extra quart and a little in 4x4's over what is in a 4x2. I guess they figure we will contaminate it more.
 
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Widman, are you saying Molekule is doing it wrong or are you just replying to the thread start? [Smile] My own feeling is he's doing it right. I would be uneasy initially for fear some foaming could occur but not show on the dipstick. It'd take time to build a comfort level. Also, how did the mfg originally determine "full"? They probably leave more than 1pt margin for fear people will idle while parked on a hill. My perfect method would be an identical volume oil pan but with a window. Hmmm... David
 

Patman

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I checked my dipstick as soon as I pulled into my driveway and shut off my engine, and saw no evidence of bubbles in the oil, so it appears I'm ok. I'll leave it and not worry about it, although I will wait for the level to get a little bit lower than usual before topping it up, and I won't be topping it up to the top of the stick anymore. I was talking with a friend of mine and he reminded me that when he took delivery of his Mustang GT back in 96, Ford (or the dealer) had overfilled his crankcase by 2 full quarts! He immediately drained that oil as soon as he found out, and changed it, however he did drive around for about 500 miles like this. It never caused a problem. I also remember now when another friend of mine did the first oil change on his new Saturn (back in 99 or 2000) and he overfilled the crankcase by only about a quart, and TONS of smoke came out of his tailpipes. He lives in Michigan and was visiting me here, and he said it smoked all the way home for the whole six hour drive!
 

MolaKule

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I think Widman's concern is that overfilling will cause foaming, and of course, it does. Foaming creates air bubbles which may reduce film thickness. If in doubt, don't use my Max "fillability" procedure. But it has worked for me and does provide a little more oil capacity, albeit only slightly more than 450 mL than the max dipstick reading. [Cheers!]
 
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