Low oil horror story

Wow I remember your oil usage was quite low. Like you were topping off 1 quart at 5000 miles and change at 7500 miles when the dipstick read half way between the marks. Did this increase happen suddenly?

 

I have had great luck with Castrol Edge 5w30 and low oil consumption. Prior to using the Edge, my Prius was burning Mobil 1 at a rate of 3/4 quart every 3-4,000 miles. Now at 7800 miles on the Edge oil, I have used such little oil I havent even needed to top off (went from right under the tip dimple of the dipstick to maybe 1/8" under it now. I change the oil at 8000 miles so I consider this a win.

 

That makes a lot of sense.

The mantra should be "Exchange oil every 10k miles, but CHECK oil level and top off as needed every month or 3k miles, whichever comes first."

 

I think too, at oil change time, either DIY or by pros, it's rare to check the oil level before draining. I've never thought to do it in the past, but it seems a good habit to get into.

 

Hmm, hard to say. I'm not too concerned about the oil usage so I can't say when the pattern changed or whether the change was fast or slow. I am pretty clear about the 1.7 qt/5K mile rate because I topped off the oil level before my wife took the 2004 on a 2K mile trip to southern CA and Lake Tahoe. I looked at how much the oil level had dropped when I changed the oil upon her return. The oil was 0.7 quarts low - hence (0.7 qt / 2K miles) x 5K miles = 1.7 qt.

This figure might be exaggerated to the extent that some of the oil had 6K miles on it before her trip started. So the average viscosity probably was somewhat lower vs. new oil.

 

I hate wasting good oil, I only change it when my oil dipstick reads halfway between the 2 marks. ... So I kinda check it before changing.

 

The "pros" have almost no incentive to check the oil level before they drain it during a regularly scheduled oil change.
This means that if your average Prius starts to have a drinking problem then the average driver isn't going to find it....IT's going to find the driver.

Sadly, it often works that way with people too, and for the same reason.

 

I was going to say: "what woke me up was a thread here...". Then, checked the OP's opening post in this thread, and yeah: there's a lesson here.

 

Access can be maddening. Especially when the bolt you're trying to get to is behind something and you're hitting the wall getting that item off.

Sometimes there's a somewhat higher than trivial torque spec on a bolt, but: good luck getting a torque wrench in there.

 

Just to add another data point to this thread, my Prius is at about 220,000 km (137,000 miles) and uses about 300 mL every 4000 km. That works out at about a pint every 4000 miles.

I'm using Castrol Edge 5w30, and I go six months and around 16000 km (10,000 miles) between changes. I check the oil every few thousand km and top off pretty regularly though.

 

How important is it to keep the level at the top dip ? my 2004 Prius', 231Kmiles, oil consumption rate seems lower when oil level is between 1/2 and 3/4. The consumption seems higher if it's topped. I need to increase my measurement precision.

The problem is oil consumption is that it kills the catalytic converter, then produce the dreaded P0420 code. Has any one tried Cataclean ?

Cataclean - lower your emissions - increase your performance

thanks

 

That is the opposite of what I've experienced with my 225K mile 05 Prius. If I don't "religiously" top off the oil to the full mark, my car will use more oil; especially if I don't top off until the halfway point, then it seems the oil consumption increases. I've also noticed that consumption is lower during the first 1000 miles after an oil change and increases until I do the next oil change at 5000 miles. My driving is 90% highway at 70 mph or faster depending on my mood.

Here's the typical top off I've been experiencing lately with Pennzoil Platinum 5W30 after an oil change (each top off is to the full mark)

1000 miles - add 6 0z
2000 miles - add 10 oz
3000 miles - add 12 oz
4000 miles - add 12 0z

At the 5000 mile oil change when I check the dipstick, the oil level usually is 12 oz below the full mark so the total consumption is 52 oz per 5000 miles or a little less than a quart every 3000 miles on average. When I didn't top off to the full mark the consumption increased to a quart every 2500 miles. And, as you can plainly see, the consumption is NOT linear.

I don't consider this excessive for a 4 cylinder engine with 225K miles. Sure it could be better but if oil consumption is my only worry I'll gladly accept it since it's such a low cost problem with my $1 per quart full synthetic oil stockpile (ask me how!). A traction battery that fails with less than 200K miles is a big problem that I luckily didn't experience. Every mile past 200K has been gravy. No mechanical failures of any sort since 200K. The only DTC I've ever had in my four years of owning this Prius is P0A93 which was 45K miles ago.

 

I don't think there's any reason for it to use more oil when topped off, unless it's overfilled. It's fairly common to see reports of overfills causing oil in the throttle body and intake manifold. So I'd assume that overfill can definitely cause increased oil consumption, but anything under the top dimple should be fine.

Remember that a dipstick isn't necessarily "linear", so make sure you judge it more by what you need to add rather than just how it looks on the stick.

I'm like Jadziasman, the main thing I notice is slightly lower oil consumption in the first few thousand km after a fresh oil change. It might seem a bit obsessive, but I top off any time I can fit about 250 ml (8 oz) in there. The reason for this is that I have several small bottles (that previously held an oil additive) that are easy to pour without a funnel, so I just keep them filled with about 8 oz of oil for top offs. Since I check my dipstick every few thousand kms anyway, and the 8oz bottles are always there at hand I figure I may as well add one any time the stick is lower than 3/4 (of the way between the empty and full marks).

Typically I end up adding this 8 oz at approximately this schedule:

After the first 4000 to 5000 km - add 8 oz (240 ml)
about every 3000 km thereafter - add 8 oz (240 ml)

As to why the fresh oil always seems to last a bit longer before a top off is needed I don't know. It could be due to the oil breaking down or thinning as it accumulates miles, but the synthetic oil I use seems to hold up pretty well so I don't think there's any major fail or anything going on there. One other theory I was thinking of is this. Most used oil analyses I see have a small amount (couple of percent) of fuel contamination, which could correspond to about 2 or 2.5 oz in a Prius. Maybe this is just something that builds up in the first few thousand km (before reaching steady state) and masks the first 2 oz or so of consumption.

 

good point on the dipstick not necessarily linear.

I also notice a general increase in consumption as the oil darken. I think it is due to reduce viscosity, since the basic reason for the oil consumption is due to the partially clogged drain holes in the piston oil grooves. It's a common problem with the older Corolla engine as well. So as the oil ages and looses viscosity, it is not able to drain fast enough back into the crankcase. I am actually rather upset with Toyota about this. All that was needed was to make these holes slightly larger, or have more of them. I am contemplating dropping the oil pan to see if I can get to these holes and do a roto-rooter job.

 

As the engine oil ages, I agree it loses viscosity. That means it gets thinner. If the fluid is thinner then it should drain faster through a hole of a given size, compared to its draining speed when the oil is fresh.

 

I heard some sage advice in the "car parts store" (no free advertising from me) about oil weight and vehicle age. It goes something like this. For every 100,000 miles on the vehicle, increase the resting weight of the oil you purchase by 5. So, new Prius, use the factory recommended 5W30. At 100K on the ticker, up that to 10W30. And so on. From what I've read in the threads, and I have studied them well, I should expect a slight drop in MPG, especially in winter. I put in 10W30 on my last oil change. I noticed a slight drop in oil consumption, which may or may not hold until the next change (non-linear consumption as noted above). And no change in MPG. In case someone wonders, total mileage right now is 186,399.

 

what happens when you reach 500k?

 

Straight 30W, like a lawnmower. It might even sound like a single cylinder Briggs & Stratton about then also.

 

i see your point, and I agree with you. I was thinking about clean versus dirty oil. The oil itself may loose viscosity, and thus easier to flow. But can the absorbed dirty carbon particles effectively slow the flow ?

I am currently resisting from adding oil with the level still above the half mark between the dips on the oil stick.