Running A Quart Over

[Merkava_4]

Yesterday I tried running a quart over the recommended fill of 5 quarts, bringing the sump up to 6 quarts. So far from what I can tell, there's been no ill effects as of yet. I contacted a machine shop before embarking on this adventure. The guy on the phone said he was pretty sure the Buick 3.8L could handle it. He warned me of the risks involved with having too much crankcase pressure and also added that he could see no reason why I would want to do such a thing. At that point I thanked him for his time and ended the phone conversation.

I'll keep you all posted on the status of this madness and let you all know if the engine blows the seals out or starves for oil due to oil pump cavitation.

 

[92saturnsl2]

I doubt you will do any harm.. Most manufacturers engineer at least a 1qt "buffer, knowing that if not, they'll lose tons of engines due the average Joe who mistakingly checks his oil level on a 7% grade, or otherwise adds that extra quart somehow.

 

[ATS-V]

The 3.8 takes 4.7 quarts, so you're more than a quart over. But I don't think you'll have any issues. I run a full 5 in mine and have been doing so for over 100k.

 

[CBDFrontier06]

I have to wonder why a machine shop technician wouldn't know that +volume does not = +pressure. At a given temperature, your oil pump produces the same pressure no matter how much oil is in your sump, unless you run it so low that it begins to suck air.

The likely first effects of too much oil is fouling of one or more spark plugs, followed by coking deposits on the valves, and catalytic converter contamination. One quart overfull would normally only have these effects on an engine that is already suffering from worn oil rings. You should be fine if that's not the case.

 

[Curious Kid]

Having too much oil in the crankcase can also lead to aeration which could lead to poor lubrication of parts should said air bubbles be present where only a film of oil should be. This aeration would come as result of the crank beating at or whipping the bulk oil in the sump, which also serves as another means of power loss. Such aeration may also increase the rate of oxidation, but I honestly don't know.

Is there too much oil in your case - I honestly don't know. I suppose you could compare levels if you knew the maximum crank radius and compare this to the running level of the oil in the sump???

Is there any special reason why one is wanting to run a higher oil level than necessary?

Take care.

 

[Dr. T]

It may reduce fuel economy too. I personally don't like it. Just put the right amount and call it a day. Now, I can see if it says 4.7 and you use 5qts, that's fine. But to put in 5.7 or 6...uuugghh...why experiement with your engine?

 

[Greggy_D]

I always go .5 qts over. Never have done a full quart though.

 

[kapps]

I know several Lotus owners with Europa twin cams who run a quart over due to a little fact that sustained high speed cornering to the right prevents the oil from draining back into sump

. Apparently, its not fun to look down and see zero oil pressure as you exit that corner

 

[Quattro Pete]

Quote:

---

and also added that he could see no reason why I would want to do such a thing.

---

Me neither. Care to explain why you did it? Are you trying to increase oil capacity of your engine? If so, why not start with a bigger/oversized oil filter?

 

[Merkava_4]

Quote:

---

Is there any special reason why one is wanting to run a higher oil level than necessary?

---

I'm thinking that more oil can dilute contaminants better and help the engine run a little cooler. I've always been envious of the BMW's and Jaguars with their large 8 quart + sumps.

 

[Patman]

I've been running a quart over on my Corvette ever since I got the car. It calls for 6.5 quarts but I put in 7.5. GM actually recommends adding one extra quart if you're racing your C5 or C6 Corvette, it even says so right in the owner's manual. So if it's safe to run when racing, it's certainly safe to run all the time. And my experience proves that, I've been doing it for 3 years now with great oil analysis results. Having extra oil means there is less stress overall on the oil so it will hold it's TBN longer and the wear metals are spread out over a larger volume, so in turn those wear metals won't cause as much wear themselves. When driving hard, the oil won't get as hot either.

I also run extra oil in my wife's Honda too, a half quart over spec.

The way I see it, there are no negatives to running extra oil, as long as you don't run beyond the safe limit.

 

[LouDawg]

Not saying running a quart over is going to cause any problems. But why are the manufacturers usually so specific about how much oil to use? Seems they must have a pretty good reason to say, for example, use 4.5 quarts not 5 or 5.5 quarts. If there were a lot of benefits, why wouldn't they just recommend more to begin with?

 

[Hammer]

Quote:

---

I've been running a quart over on my Corvette ever since I got the car. It calls for 6.5 quarts but I put in 7.5. GM actually recommends adding one extra quart if you're racing your C5 or C6 Corvette, it even says so right in the owner's manual. So if it's safe to run when racing, it's certainly safe to run all the time.

---

Pat...I do the same thing in my Z06. BUT, i do wonder sometimes of it is bad when not racing because, IIRC, the owners manual also says to remove this extra quart afterwards. When racing, you will tend to have the motor in high rpms...which will tend to keep the sump pumped down. Normal driving will keep your rpms relatively low and the higher likely hood of potential crank through oil contact. But my hunch is that it's not an issue, I am just saying we should never assume it's OK for one circumstance and therefore Ok for another.

Hammer

 

[Quattro Pete]

Quote:

---

Not saying running a quart over is going to cause any problems. But why are the manufacturers usually so specific about how much oil to use? Seems they must have a pretty good reason to say, for example, use 4.5 quarts not 5 or 5.5 quarts. If there were a lot of benefits, why wouldn't they just recommend more to begin with?

---

I tend to agree. The high and low marks on the dipstick are there for a reason. If it was OK to put more oil in there, the high mark would have been placed higher.

In case of the original poster, he added about 28% more oil than the manufacturer specified. Sure, it may be beneficial for longer drains (exactly how long is your OCI?), but the risks to me are just not worth it. Like I said, there are other ways to increase the oil sump capacity.

 

[mcrn]

Quote:

---

Quote:

---

Not saying running a quart over is going to cause any problems. But why are the manufacturers usually so specific about how much oil to use? Seems they must have a pretty good reason to say, for example, use 4.5 quarts not 5 or 5.5 quarts. If there were a lot of benefits, why wouldn't they just recommend more to begin with?

---

I tend to agree. The high and low marks on the dipstick are there for a reason. If it was OK to put more oil in there, the high mark would have been placed higher.

In case of the original poster, he added about 28% more oil than the manufacturer specified. Sure, it may be beneficial for longer drains (exactly how long is your OCI?), but the risks to me are just not worth it. Like I said, there are other ways to increase the oil sump capacity.

---

Are there other ways to increase the sump other than a larger filter?

 

[Quest]

If I were the original poster, I would definitely check to see if the oil level is "high" enough to reach the crankshaft's lowest point during operation. The "churning"/"whipping" effect of the crankshaft with an overfilled crankcase will beat the oil like an egg whipper, adding air bubbles into the oiling system which may subsequently lead to crank/main bearing failures if the oil pump manage to suck enough air bubbles and pump it into the oil gallery --> leads to main/rod bearing wear.

Also: excessive whipping motion introduced to the oil may lead to premature oil oxidation too...

My 2c's worth.

 

[Quattro Pete]

Quote:

---

Are there other ways to increase the sump other than a larger filter?

---

Check to see if you can buy a larger aftermarket oil pan for your application. For some engines it is also possible to install a larger oil cooler that sits between the engine and the oil filter - folks used to do this on the VAG 1.8T engine.

 

[aquariuscsm]

Z-Doc ( a guy that works on nothing but Nissan Z`s) said putting a bit extra is good for alot of extended highway runs. My car holds 4.5 quarts,whick Z-Doc said I might as well put in 5 quarts. I never put in any more than the 4.5 though.

 

[aquariuscsm]

Quote:

---

Z-Doc ( a guy that works on nothing but Nissan Z`s) said putting a bit extra is good for alot of extended highway runs. My car holds 4.5 quarts,whick Z-Doc said I might as well put in 5 quarts. I never put in any more than the 4.5 though.

---

*which* Sorry about the typo.

 

[mcrn]

Quote:

---

Quote:

---

Are there other ways to increase the sump other than a larger filter?

---

Check to see if you can buy a larger aftermarket oil pan for your application. For some engines it is also possible to install a larger oil cooler that sits between the engine and the oil filter - folks used to do this on the VAG 1.8T engine.

---

Cool thanks! I am not concerned about my vehicle now because its a 2.3 4 cylinder and holds 5 qts which I think is pretty good for a 4 cyl. However for my next vehicle I will keep that in mind. I never thought about a bigger cooler.