Oil level question after oil change by dealer

[Indy GT]

Just for Ralphie!

Indy -
The only potential problem with an overfill that I can see would be the coefficient of thermal expansion which might lead to an overflow from the tank (leaking out the dipstick hole) as the engine heats up which might then lead to a fire as it reaches the exhaust manifold. Otherwise, no problem.

Ok Ralphie, since I know you are a technical brother, I’ll bite. This is a valid question to ponder but IMO is not a problem with our dry sump system….But let’s prove it.

First, however, let me state my assumptions before launching into the calculations:
1. I do not know what the inside of our external oil tank looks like internally. The “full” oil hole on my dipstick is 10.75” from the top of the oil tank upper dome. The tank circumference is 25”, thus the residual volume in the tank (before fluid would be expelled out the dip stick opening from a “full” operating condition) assuming no internal structures above this full-level exist is calculated ((pi)((25”/(2*pi))^2)*10.75” = 534.96 cubic inches.
2. Coefficient of thermal expansion for our oil is 0.00039 1/F
3. Assume the starting oil temp is 70F and the final oil temp is 300F
4. Assume the oil system was previously filled to capacity i.e. the at-temperature oil level in the external oil tank was at the full mark before the extra one quart (32 fluid oz = 57.76 cubic inches) is added to the system.

Since the at-temperature standard oil fill is at the top of the dipstick level and all is fine, we need only worry about the extra quart of oil someone at the dealership may or may not have added to “overfill” the system. As Ralphie points out the oil will expand due to the (70F – 300F) temperature change (just like the air (or nitrogen) in our tires increases with temperature).
This fluid expansion is given by the formula dV = Vo*B*(T1-T0) where:
dV is the change in volume the oil experiences
Vo is the fluid volume which is to expand (in our case this is only 1 quart since the expansion of the initial 9.5 standard oil fill has already been accounted for by the Ford engineers in our as-designed external tank).
B is the coefficient of thermal expansion of the fluid (assumption 2)
T1 is the final fluid temperature and T0 the initial temperature.

Thus if we make the dV calculation using one additional quart or an additional 57.76 cu in of oil-

dV = (57.76 cu in)*(0.00039 1/F)*(300F – 70F) = 5.18 cu in of fluid volume change for the temperature increase

And the total at-temperature volume change in the external oil tank is the initial one quart overfill (57.76 cu in) plus the thermal expansion of this quart (5.18 cu in) = 62.94 cubic inches total.

Therefore since the external oil tank has extra volume capacity of about 535 cubic inches above the “full” dipstick mark (with the caveats stated in the assumptions) and the “expanded” extra quart occupies only about 63 cubic inches additional volume, it is no problem to have an extra quart.

 

[PL510*Jeff]

Thank You Kind Sir. I'm extremely thankful for this disertation explaning the thermal expansion of Ford Synthetic GT oil.

Ralphie un-neccesarily alarmed me with his "oil fire" post.

I lost most of one nigth's sleep, worrying about this potential problem.

I'll sleep better tonight.

Thanks Again!

Ok Ralphie, since I know you are a technical brother, I’ll bite. This is a valid question to ponder but IMO is not a problem with our dry sump system….But let’s prove it.

First, however, let me state my assumptions before launching into the calculations:
1. I do not know what the inside of our external oil tank looks like internally. The “full” oil hole on my dipstick is 10.75” from the top of the oil tank upper dome. The tank circumference is 25”, thus the residual volume in the tank (before fluid would be expelled out the dip stick opening from a “full” operating condition) assuming no internal structures above this full-level exist is calculated ((pi)((25”/(2*pi))^2)*10.75” = 534.96 cubic inches.
2. Coefficient of thermal expansion for our oil is 0.00039 1/F
3. Assume the starting oil temp is 70F and the final oil temp is 300F
4. Assume the oil system was previously filled to capacity i.e. the at-temperature oil level in the external oil tank was at the full mark before the extra one quart (32 fluid oz = 57.76 cubic inches) is added to the system.

Since the at-temperature standard oil fill is at the top of the dipstick level and all is fine, we need only worry about the extra quart of oil someone at the dealership may or may not have added to “overfill” the system. As Ralphie points out the oil will expand due to the (70F – 300F) temperature change (just like the air (or nitrogen) in our tires increases with temperature).
This fluid expansion is given by the formula dV = Vo*B*(T1-T0) where:
dV is the change in volume the oil experiences
Vo is the fluid volume which is to expand (in our case this is only 1 quart since the expansion of the initial 9.5 standard oil fill has already been accounted for by the Ford engineers in our as-designed external tank).
B is the coefficient of thermal expansion of the fluid (assumption 2)
T1 is the final fluid temperature and T0 the initial temperature.

Thus if we make the dV calculation using one additional quart or an additional 57.76 cu in of oil-

dV = (57.76 cu in)*(0.00039 1/F)*(300F – 70F) = 5.18 cu in of fluid volume change for the temperature increase

And the total at-temperature volume change in the external oil tank is the initial one quart overfill (57.76 cu in) plus the thermal expansion of this quart (5.18 cu in) = 62.94 cubic inches total.

Therefore since the external oil tank has extra volume capacity of about 535 cubic inches above the “full” dipstick mark (with the caveats stated in the assumptions) and the “expanded” extra quart occupies only about 63 cubic inches additional volume, it is no problem to have an extra quart.

 

[paul b]

Ok Ralphie, since I know you are a technical brother, I’ll bite. This is a valid question to ponder but IMO is not a problem with our dry sump system….But let’s prove it.

First, however, let me state my assumptions before launching into the calculations:
1. I do not know what the inside of our external oil tank looks like internally. The “full” oil hole on my dipstick is 10.75” from the top of the oil tank upper dome. The tank circumference is 25”, thus the residual volume in the tank (before fluid would be expelled out the dip stick opening from a “full” operating condition) assuming no internal structures above this full-level exist is calculated ((pi)((25”/(2*pi))^2)*10.75” = 534.96 cubic inches.
2. Coefficient of thermal expansion for our oil is 0.00039 1/F
3. Assume the starting oil temp is 70F and the final oil temp is 300F
4. Assume the oil system was previously filled to capacity i.e. the at-temperature oil level in the external oil tank was at the full mark before the extra one quart (32 fluid oz = 57.76 cubic inches) is added to the system.

Since the at-temperature standard oil fill is at the top of the dipstick level and all is fine, we need only worry about the extra quart of oil someone at the dealership may or may not have added to “overfill” the system. As Ralphie points out the oil will expand due to the (70F – 300F) temperature change (just like the air (or nitrogen) in our tires increases with temperature).
This fluid expansion is given by the formula dV = Vo*B*(T1-T0) where:
dV is the change in volume the oil experiences
Vo is the fluid volume which is to expand (in our case this is only 1 quart since the expansion of the initial 9.5 standard oil fill has already been accounted for by the Ford engineers in our as-designed external tank).
B is the coefficient of thermal expansion of the fluid (assumption 2)
T1 is the final fluid temperature and T0 the initial temperature.

Thus if we make the dV calculation using one additional quart or an additional 57.76 cu in of oil-

dV = (57.76 cu in)*(0.00039 1/F)*(300F – 70F) = 5.18 cu in of fluid volume change for the temperature increase

And the total at-temperature volume change in the external oil tank is the initial one quart overfill (57.76 cu in) plus the thermal expansion of this quart (5.18 cu in) = 62.94 cubic inches total.

Therefore since the external oil tank has extra volume capacity of about 535 cubic inches above the “full” dipstick mark (with the caveats stated in the assumptions) and the “expanded” extra quart occupies only about 63 cubic inches additional volume, it is no problem to have an extra quart.

Would it make any difference if I use Castrol Syntec oil?

 

[Howard]

INDY, don't forget the effect of spirited cornering on the volume of oil in the reservoir. Centripital acceleration may throw the oil above the static thermal overflow condition in your calculation. Tidal forces will also exert an influence if the GT is aligned in an unfortunate orientation with respct to the moon. PL510Jeff, I recommend shipping the car to the GT Guys immediately for corrective oil level surgery.

Howard

 

[Indy GT]

LOL, Good one Howard! I did forget the gravitational forces of the moon....

And thanks Jeffy. Glad you are able to now sleep at peace!

Would it make any difference if I use Castrol Syntec oil?

Paul, the calculations are only valid for Motorcraft oil.











NOT!

 

[Derry]

Also while the flashpoint of oil is in the 400-500 degree range, without an open flame the metal would need to be 750+ degrees to be an issue of concern.

 

[junior]

The OP asked what time it is,..., and Indy GT showed us how to make a watch :cheers

 

[Empty Pockets]

Guys, come on...in the real world, "a half qt over" in the 'tank of a dry sump system doesn't really mean squat...even when one factors in "the gravitational forces of the moon". :lol Now, in a conventional OIL PAN....................


(I'd be willing to bet that the guys at Ford factored in the possibility of someone dumping in 10 qts and calling 'er good when they designed the tank.)

 

[doc4140]

OK. so that was the oil......................so i checked the coolant in the reservoir and it was level with the top rung of the coolant reservoir instead of level with the bottom rung of the reservoir................................... I guess doesnt matter? The intercooler reservoir was correct. So I guess that means that either it doesnt really matter even though the owners manual from Ford that comes with the car says that overfill of the oil can cause possible engine damage. Food for thought.

 

[Indy GT]

Wow Scott, 22 posts and you have been a Forum member since 10/06. How about joining us more often...?

Not "food for thought" at all. Those caution words are probably vestiges from owners manuals past. How many dry-sump lubrication systems has Ford OE supplied in the past? Probably boilerplate prose the marketing/maintenance/lawyers made the writer include to cover situations when gross overfill occurred (like filling the external tank to the top of the tank).
I would not worry about it, nor should you if it ever happens to you.

Junior, hope you view it as a Rolex.:biggrin

Sometimes I have to build the watch as other owners remain skeptical from the opinions presented. Hopefully one can see the factual answer based on basic calculations.

 

[Silverbullitt]

The next thing to ponder is if you overfill it could be better for the motor. If you overfill then each unit of oil should make proportionate fewer trips through the system, therefore lasting longer and protecting the engine with more anti wear additives.

 

[Empty Pockets]

The next thing to ponder is if you overfill it could be better for the motor. If you overfill then each unit of oil should make proportionate fewer trips through the system, therefore lasting longer and protecting the engine with more anti wear additives.

Hey, 'bullitt, I think we may be :dead:! :rofl

 

[fjpikul]

IndyGT, are y0u using the letter d to represent the Greek letter delta?

 

[Indy GT]

IndyGT, are y0u using the letter d to represent the Greek letter delta?

Morning Frankie!
I was rather expecting a "watch" comment from you too...:thumbsup

But to answer your quesion, it really could be either. In the equation "dV" one could use the Greek letter "delta" as that symbol means "the change in" just as "d" in the expression "dV" or "dT" generally is understood to be the change in V (volume) or the change in T (time). The fonts available to us in the Forum are limited and I did not see any symbol fonts which came out in the text looking correctly. Thus my use for "pi" for the circumference to diamater relationship (3.1415926535).

 

[GTRob]

I was rather expecting a "watch" comment from you too..
The fonts available to us in the Forum are limited

Stick to making watches:biggrin

π = Alt+227
⌂ = Alt+127

Use them constantly.

 

[HOOKED ON GT]

Is checking oil level done after engines warm.... turn off for 1min and check stick for actual level?

I couldn't find anything in the workshop manual.

Stu

 

[fjpikul]

Yes

 

[GT Tech]

The engines were originally filled with 2 qts when they arrived at Wixom from the Romeo engine plant. On the Wixom build line, station 5 or 6, an additional 10 qts were added. I know this because I set up the oil and fluid fill machines. On a normal oil change, every drop of oil will never be drained out. I usually add 9 qts then do the normal routine for checking the level. I can't recall ever having to add more than an additional 1/2 qt.