Dealer Says Grill Blocking is Burning Transaxle Fluid

Is it correct that the water temperature showing on my ScanGuage II is only for the engine cooling fluid and doesn't tell me anything about the inverter cooling?

PA P

 

Yes, the ScanGuage only shows the engine temp. If you had a CanView you could see the inverter temp. You can use the engine temp as a guide to inverter temps, but it is not perfect. Maybe Efusco or JimboK could give a better perspective of the relationship between observed engine temp and inverter temp.

Wayne

 

Isn't it designed to last 90K miles? Why change 1/2 way early?

 

I understand the NHW20 change interval is 60k miles and that matches what we've seen in the oil testing results.

The reason for changing early is that about half of the Prius are running above the "designed" driving profile, the average, and half are running below the "designed" driving profile. Not everyone drives like North Americans in the Midwest. This is where oil testing can provide valuable feedback for both keeping the vehicle in peak performance and maximum life. So far, oil testing indicates there are significant differences.

In areas of higher than average dust and speed, the transaxle oil tends to lose 15% of the starting viscosity before others. In contrast, folks in areas with less road dust and lower than average speed seem to meet the "design" target. Obviously, the 'design' does not change how the vehicle is operated in the field.

Bob Wilson

 

My question exposes my ignorance here? How does driving on dusty roads affect transaxle viscosity and life expectancy?

 

NO WAY the grille blocking caused that. I block mine once the temp is consistently below 50 degrees (F).

I've been doing it for three years since I got my '05. I changed the transaxle oil this summer at 80K and it was still nice and pink. I sent that for testing as I do with my oil each change (23K between changes using Amsoil). The tests always come back clean. OAI changed their lab locations this year and the new lab actually called me asking if I had sampled oil from a different vehicle with less miles (it was that clean).

 

Until we started testing the oil, no one had a clue.

It is a pattern, slight since we have so few samples, seen in the early results. Samples from Texas and Utah seemed to be worse than others with larger silicon and aluminum content. We know the seal leaches silicon but aluminum is the second signature of dirt/grit and it was also evident.

We don't have a definitive answer, yet. BTW, this was seen only in the NHW11 samples. We don't have enough NHW20 samples to draw any conclusions.

Bob Wilson

 

ddan may also not know that the transaxle is not a fully sealed system? It has an air pressure equalization valve, so it could possibly inhale.

 

Tochatihu,

Good point. That makes sense. Seems like Toyota should have protected it with a filter if airborne contaminants could affect the fluid's longevity.

dd

 

I had the transaxle fluid changed at 180,000klm[only because of PC]it was never mentioned to me by my dealer,when i did ask about it they said it's not on the service schedule,which it's not but just an ADDITIONAL INSPECTION every 3yrs/45,000klm,so how do you inspect it?....by changing it?

 

Inspection probably consists of the tech opening the fill plug, sticking his finger in, noticing whether he can touch the fluid, and if so then saying its good.

I change transaxle fluid at 30K mile intervals, based upon the results of my used fluid testing.

 

Ahem, it ain't easy but it can be done.

Bob Wilson

 

What do you use to block the grill? I used 1/2 inch charcoal pipe insulation, but it fell off. How to you attach it or is there a better product that looks good and is effective. I live in MN so it is already cold and want to block it now.

 

bwilson4web, (Bob)

Wow. That's all I can say. (except... thank you).

dd

 

i use 3/4" pipe insulation, its a bit big, so i cut it to just over 2/3 diameter, fold in half and pre bend it to get the curve of the grill, fold in half and stuff it in.

VERY small notches to match the vertical braces will allow you to stuff it in further. that should hold. occasionally, i will have the ends pop out a bit, but other than that, have never lost a piece.

 

You have discovered one of the pleasures of mods: they open the possibility of voiding the warranty and give dealers and Toyota a way to blame problems on you. Without the blocking they would have given you no argument.

 

I had lower grille blocked at the before start of October and full grille block at end of October. No cold (+1°C) mornings yet. Scan-Gauge II reports engine temps usually in mid 80°C's and a high of 90°C.
No mountain or long freeway driving,
Best tank ever after initial grille-block 48.1mpg / 4.9L/100km (Total miles on car 7775)
I guess best practice would be to remove all obvious mods before servicing so as not to provide dealer an excuse for voiding warranty.
It would be up to them to prove the issue was cause by a mod.
They will try any convenient excuse to NOT cover a problem, legitimate or not.