Dealer Says Grill Blocking is Burning Transaxle Fluid

Very unlikely. The transaxle is cooled some by the inverter coolant and the rest by air cooling on the case. The transaxle case is exposed under the car. Grill blocking would only have an affect if it blocked inverter cooling, and then your inverter should be toast about now.

Wayne

 

hmmm..where is the transaxle fluid at anyway?

 

And I'll remove mine before I take it in for the 100k service tomorrow.

PA P

 

Fibb222,

Did they actually show you some of the fluid?
Note to self: Take along a small bottle and ask for sample when getting the
tranny fluid changed.

Since you were there for a fluid change, they weren't trying to sell the
change. Why in the world would they say such a thing? Or, could it be that
the tech got "stuck on stupid" and rattled off of a standard service dept.
profit generator without thinking?

 

Hi All,

I have my license plate down covering the middle third of the lower grill year round, along with upper grill blocking. When temps get below 40's in the morning I add a block to 2/3's of the engine side of the license plate of the lower grill during the spring and fall. And when I do block in below 10 degree F weather, I still leave some crevices between the pieces of foam.

I read in one of the National Labs papers that the Prius transaxle is only cooled by air flowing over it, unlike other automatic transmissions which have a oil heat exchanger tied to the radiator. There has to be a pretty good blast of air from the radiator back at highways speeds for cooling.

I am not doing any mountain driving, I do not exceed 60 mph in the morning, or about 45 in the evening in my regular driving. My average speeds for the 23 mile commutes are never over 40 mph. If I were doing moutain/desert driving, or 70 mph cruising in the east coast hilly terrain, I might rethink my license plate blocking.

My engine temps run in the high 80's C, with some peaks up to 92 C. I have never seen it hotter than that.

I am probably going to do the tranny oil change before 45 K miles. I am at 35 K now, and the next oil change will be in April. I did my oil change this week, and the oil was black, but transucent brown on the edges of a drip. So, not that full or particulates at all.

 

Hi Fibb,

I think your telling a fib. Ha! . My Saturn SL2 at 3000 miles on the oil change would have pitch black oil. Not even brown on the edges.

 

"hell no."
-DH

 

i check my oil all the time, change it at 5-6000 mile intervals and worst ive seen it was a clear medium brown. nowhere near black.

 

Did you get a sample?

The data suggests a relationship between a dusty environment, rural, and worse transaxle oil. My first change at 52k miles / 83k km strongly suggested NHW11 oil has about a 30k mile / 48k km. So far, the NHW20 model transaxle oils have come out better.

There is a second effect, micro-dieseling, that I'm starting to look at but we don't have a good assay method worked out. It also turns out that rural areas tend to have higher speed operation that increases micro-dieseling effects.

My recommended practice is for folks to get their first transaxle oil change at 5-10k miles / 8-16k km. This purges the manufacturing and early oil seal leaching. If you have an NHW20 and do a lot of high speed, 70+ mph / 112 kph, and live in a rural, dusty area, an earlier change would be a good idea.

We found the NHW11 has about a 15% carry forward of transaxle oil. You might consider treating this first change as a 'flush' and after 5-10k miles / 8-16k km, doing a second change to get the last of the 'stuff' out.

Bob Wilson

 

Grill blocking will affect the inverter cooling also. The lower third of your radiator is dedicated to inverter cooling. My point was that IF the grill blocking contributed to your transaxle fluid being dark/burnt smelling then your inverter had to have over heated. But neither happened. You did the right thing and got that transaxle fluid changed.

Wayne

 

Actually there is a small area of the transaxle casing that has circulation of inverter coolant. But it so little area that it doesn't contribute much to cooling, probably more for warming the transaxle than cooling it.

Wayne