Service advice for Prius Prime after 2 year warranty ends

While the Prius and other cars have faster warm up times, and even ICE cars warm up faster than those of the past, it still takes time for any excess water to be driven off once the oil becomes hot. Induction cook tops start boiling water much faster than an electric or gas range, but once the pot of water starts boiling, it will take the same amount of time to boil dry on any burner.

Just reaching the engine temperature at which excess water starts boiling off the oil, and vented past the PCV, isn't enough to remove it. Time at temp is a factor.

 

And...there is no single "engine temperature." The temperature gauge on the instrument panel shows only the temperature of the coolant in the head. Especially in winter the oil sump can be much cooler even under steady operation. In older cars many of us have seen a mayonnaise-like emulsion of oil & water on the underside of the oil filler cap in cold winter weather caused by cool oil and moisture against the cold valve cover.

Marine diesel engines I've run have temperature sensors in the coolant to & from the engine, the oil to & from the oil cooler, sometimes the temperature of the coolant leaving each cylinder, sometimes the temperature of the oil leaving each main bearing, sometimes the oil caught in a catch-pan near each connecting rod bearing, and the exhaust temperature leaving each cylinder. It all matters. There is no single engine temperature.

 

Good point. But once the oil is warm enough for water to boil off, no more water is getting mixed in. Water from combustion only condenses and ends up in the oil when the engine and oil are cold. So with a fast warm-up cycle little water gets into the oil. And when you're in HV and the ICE is automatically switching on and off, everything probably only cools a few degrees during the off time (EV driving), so the time to warm up again is probably minimal or none at all.

 

I think it's the short engine runs that are so common to a car like the Prime that we need to be concerned about. In my case, there have been several times where the engine only needed to run for about the last 2-3 miles of a drive. The coolant was warm enough to let the engine shut off, but I doubt that the oil was hot enough yet to boil water.

 

That's a great marketing ploy, but I suspect you would have much difficulty collecting any money on a warranty claim.

 

We aren't talking about a hybrid here, but a PHEV.

Short trips aren't good for cars, for several reasons. One of them is that they could lead to water build up in the oil; more water from combustion is introduced into the crankcase, but not engine run enough time occurs to boil off the water ended up in the oil from the last trip. With a PHEV it is possible to be exposing the engine to short trip conditions when traveling over the 5 miles or so that qualify as a short trip.

Water in the oil uses up acid neutralizers. So if a PHEV is seeing few hybrid miles, the additives could be consumed faster than the miles on the engine imply.

 

One thing to watch out for--
--The drain plug gasket is fiber. No problem, but it may stick to the oil pan. It needs to be pried off and a new gasket used. We do not want two gaskets stacked under the drain plug. That's inviting a leak. The fiber gasket tends to harden and loose its resilience with heat. It may not seal completely if reused.

Why do it myself--
--The dealership gorilla who did the oil & filter change last time got the filler cap so tight that I had to use a 10" crescent wrench to loosen it. The plastic filter cap was so tight that I had a hard time finding a breaker bar long enough to get the leverage I needed but not so long that I didn't have any swing under the car to get it loose. The 25 Newton-meter (18-1/2 pound-foot) torque is enough to keep the cap from coming loose. (The seal is provided by the o-ring up in the barrel.) The cheapo piece-o-junk specialty wrench for the filter cap from Amazon didn't fit well but got the job done.
--And, in my case, I'm a hour from a dealership. I'd rather do it myself and get it done.

The oil looked quite clean when it came out. 4.4 quarts is a large sump for a 1.8 litre engine. That helps contribute to the oil's long drain interval.

The WIX 57064 filter looks just like the Toyota oil filter, but the picture doesn't show a drain plug gasket included. They don't list a spin-on filter. WIX also lists the WA10000 engine air filter and two different sizes of cabin filters. NAPA will have the same filters under their label.

 

Honda filters are the same dimensions, and they have a simple oil filter socket, heavy gauge steel, that works well. Toyota has one too, though I've no experience with that. Part numbers:

Honda: 07AAA-PLCA100
Toyo: 09228-06500-02A

Be sure to completely oil soak the new O-ring (with new 0W20), and after install on the housing, apply a little more.

 

That is fairly typical in today's cars with engines of that size.

 

what filters are you guys using ?
i have the spin on type, not the cartridge type.
i saw that mobil1 m1-103 is still cross referenced.
if we are talking extended OCI, would an oversized filter with higher filtration be a good idea?

 

I doubt it. Filters in modern cars that have been properly maintained rarely get any debris in them, so even the stock filter would be effective through multiple oil changes. The only reason the oil is ever changed is that the additives become depleted - the oil still lubricates fine.

That said, the last thing I would do with my expensive car with a long powertrain warranty is to extend the oil change interval. Oil changes are dirt cheap, and without sampling and testing (as expensive as the oil change), you are only guessing on whether the oil should be changed at whatever extended interval you choose.

By my quick math - 5 quarts synthetic in jug at Walmart $25. Good quality filter $8 or less. Crush washer less than $1. One hour of my time (I'll assume that's free, since I'm probably doing other stuff to the car at the same time - check other fluids, pressures, inspection).

 

+1 (more like +1,000!) In fact, I change more often than specified since I'm a little suspicious of planned obsolescence being part of the factory OCI calculations. I've never had an oil burner or bearing failure.

 

I better not divulge the kms between our oil changes. Suffice to say up here it's 6 months or 8K kms, whichever comes first. And we're not putting on the miles like we used too...

 

I always use OEM filters during the warranty period. In the unlikely case of an engine warranty claim, I don't want any chance of rejection due to a non-spec filter. The oil can be lab tested to show that it was OK at the time of the failure. Not so for the filter.

Oil filter specs are not published by the engine maker the way oil specs are published. Aftermarket filter makers reverse engineer the OEM filters. They may make something that matches the OEM filter, or they may pick something out of their catalog that they feel is "close enough" to the OEM filter. I trust WIX and a couple of other filter makers. Mobil 1 labeled filters (and K&N & Royal Purple) are made by Champion Labs, owned by Fram. Probably OK, but I'll stick with OEM.

One of the Rank organizations, an investment group from New Zealand, owns Fram & Champ Labs. Purolator is owned by Bosch & Mann+Hummel. WIX is owned by the Affinia Group. Baldwin & Hastings is owned by Parker Hannifin.

 

Do your dealerships customarily take 4 - 6 hours to perform the service? Mine do. Add to that my 25,000 miles per year and it means if I don't do it myself I have the pleasure of spending half a Saturday at the dealership every 8 weeks.

 

Oil changes every 3,850 miles?

 

Service every 5,000. 8 weeks is the typical summer interval when there's more family trips to the beach, etc. 110°F is also when it's the most fun waiting at the dealer because the waiting area is full and outside is miserable.

 

1hr 2 max. Or I get a loaner, ride to/from home, work, store etc. My choice. No extra charge.

 

I'm probably going to change my oil every year. We're at ~6000 miles after 2 years of ownership (we have a few cars, so usage gets spread out a lot) and since usage is ~85% EV (we're at ~160MPG since new) there's not enough engine use to justify it.

Now, about the concerns about the additives breaking down: one of our performance cars (with a somewhat big turbo, compared to what you see on most cars today) had the same oil in it for 3 years, and had only seen very occasional engine starts having driven only ~8 miles in the past 2 years (life was very challenging for a short few years). When I did an oil change, I had a sample of the Mobil 1 sent to Blackstone labs - the report showed that the oil was basically like-new, indicating that there was little/no chemical breakdown over the period when the car was just left sitting.

Don't know where you're located but our most often-used dealers on the north shore have pretty long wait times (regularly 2-3hr) for simple oil changes and they don't do loaners unless it's a pretty big job.

 

I wouldn't recommend waiting two years to change your oil.

If I didn't drive as much, I'd still change the oil every year. Think of it as cheap insurance.