More problem's with my new Prime - Leaking rear hatch window :( *update 1.30.17*

I bought that deal for a new car and used it once over 10 years of ownership. It ended up not saving me money because Firestone will not work on rear alignment problems, and I buy long life treads ;-)

 

I understand and it is an individual decision:

• At 5k (this time 2k) - change engine and transmission oil with samples sent for analysis. Toyota.
• At 5k - change both with samples sent for analysis.
• At 15k - change both with samples.
• Thereafter, engine oil changes late Spring and late Fall. Alignment checks every Spring to deal with pothole effects.

It is how I am because of previous Prius performance.

Bob Wilson

 

And what has your previous oil analyses revealed?

 

I have only tested transmission oil since there is no filter, just a screen. I found at 5k, a remarkable population of early wear particles and sealant beads. The dissolved elements suggests a 20-30% carry forward. Some evidence of grinding down to smaller particles.

At 15k miles, the oil was not bad but for the ground particles. The oil looked not bad.

At 35k, it was pretty good without any significant particulates and excellent viscosity.

So this time I am starting the changes early to get the early particulate materials out.

Bob Wilson

 

See post 104 for your answer.

 

Part of the problem might be that a lot of the mechanics at Toyota dealership have not caught up to the Prime yet in knowing what to look for when things go wrong.

 

A con of the plastic panels on early Saturns was that they needed larger gaps than steel to allow for expansion. That's my first thought on hearing about your panel gap. It likely doesn't apply to carbon fiber, though. If it isn't normal, then it is probably related to the handles being reversed, and fixing them might fix the panel.

I feel you do to

Toyota's recommended 10k oil change could be excessive with a hybrid, let alone a PHEV. I go around 7500 miles on my ICE car following the oil monitor. A Volt can go up to 2 years between oil changes.

There were reports of the transmission fluid having a burnt smell in gen2 Prius. So some adopted 30k change intervals. I believe the fluid used is Toyota's standard automatic transmission fluid. Those are susceptible to heat, because they have to work as an hydraulic fluid in addition to a lubricant. The HSD transaxle isn't an automatic though, and I suspect the heat stressed fluid wasn't an issue for it. Either way, the gen4 has improved cooling of the transmission fluid.

If it helps your piece of mind, an early initial change on a new car won't hurt it, and only result in a little more oil used and cash spent.

 

I don't know about the Gen-2 as I've only owned a Gen-1 and Gen-3:

To me, it smelled of paraffin and was dark and opaque. Here is a photo of the oil sample, the dark bottle:

The full description including oil testing results are found here: 2003 Prius - Cold Weather and Transaxle Originally, I was interested in the cold weather performance of the Gen-1.

Based on the Gen-1 experience, we front-end loaded the transmission oil changes to get the early wear debris out early and then relaxed the interval because subsequent tests showed it was an effective technique (see attached oil analysis.)

Not my recommended practice. It looks like two early changes effectively flush the initial wear debris which appears to be the root cause. Without material to crush and grind into a fine, smoke-like material, the oil does not suffer the local heating and shear-down (loss of viscosity from mechanical action. There after, it becomes a +100k oil because it only has to deal with the distributed stresses of the excellent gear surfaces.

The type WS transmission oil has more in common with aircraft turbine oil than anything else I've found. It may have similar characteristics to hydraulic oils but this is not something I've studied. Just I've not found any hydraulic pumps or motors in the Prius eCVT transmissions. I really see it as a low viscosity lubricant.

IMHO it was the early manufacturing and wear debris that was the problem. One clue being the silicon-based sealant that was revealed in abnormally high silicon content in the used oil tests. Initially the relatively large particles, each time they pass through the gear surfaces, are crushed to smaller and smaller pieces and these fine particles cause local heating of the oil and stresses fracture the oil into a lower viscosity material (i.e., shear down.)

The methodology I followed was pretty important:

• Canadian fleet studies of hybrids quantified the effect of cold on hybrid performance.
• Testing Amsol claims (**EXCESSIVE YELLOW METAL WEAR**) led to an early change.
• Based on cold temperature roll-down metrics, I found a measurable reduction in rolling drag.
  
• Soliciting more samples from the "Prius Technical Stuff" community increased the sample size.
• This led to understanding the wear characteristics
  • A pivotal test revealed the silicon leaching into the oil.

I do not claim perfect knowledge and we've moved beyond our Gen-1 and Gen-3 Prius. We have a Prius Prime and BMW i3-REx on the driveway and limited windows for cold weather testing. But a sunny day, it has warmed up nicely and our doggies are interested in visiting the dog park.

Bob Wilson

 

I am planning:

• 2k
• 7k = 2k + 5k service
• 17k = 7k + 10k service
• 37k = 17k + 20k service (optional)

This is a log scale with oil testing. The accelerated rate is based upon what I saw in our Gen-3 oil changes with the goal of achieving a steady-state, low wear rate, earlier in the Prime life.

Bob Wilson

 

In the Prius it is a low viscosity lubricant, but it is also the fluid used in Toyota's automatic transmissions.

 

Interesting. I looked up 2010 Corolla Owner's Manual, and indeed: GENUINE TOYOTA ATF WS is the spec'd fluid for the automatic, and there's the caution that using anything else could damage the transmission.

 

I was just looking to see what other transmission fluids Toyota used, and it appears all their current models have been transitioned to WS. At least the automatics.