Yamaha thermostat mystery!

[fairdeal]

so I've never seen this question addressed here or elsewhere,

but surely I'm not the only person who's wondered:

what's with the blue "magic marker" stripe on Yamaha thermostats ?

every one I've seen has it.

My guess, its done "at the factory" to show the device has passed some QC performance test?

[boscoe99]

If I told you what the blue stripe is for I would have to kill you.

I like you so I won't tell you.

Actually I don't have a clue.

Your guess is as good as any. I like it.

[99yam40]

probably means it was out of spec, but we need to sell it anyway

[greasyshaft]

I always remove the mark before installation as a precaution.
Would hate for that blue ink to damage the cooling system...

[fairdeal]

The vents are those three dimples

[boscoe99]

The vents are those three dimples

Winner, winner, free chicken dinner.

Now the question for those with an inquiring mind (talking about fairwinds here) what is the volume of water (in gallons per minute) that can make it across those dimples when a pressure of 30 psi is applied to the garden hose flush fitting for a period of 15 minutes. In other words, how effective can the motor be flushed using the garden hose flush fitting when the thermostats are closed?

Let's see if Mr. Pratt can take us up on the challenge.

[fairdeal]

what is the volume of water (in gallons per minute) that can make it across those dimples ?

The short answer: not very much

Of course, those little "bleeders" are only there to let air pass - so that the thermostat is surrounded by water when the engine is operating, not insulated in an air pocket.

but I happen to have some data!

With city water supplied to the "garden hose flush port" - at an indicated ~40 psig supply -

in one minute, only 200 milliliters exited the starboard thermostat of my F225txrd

"gallons per minute"? - that's one-half of a tenth of a gallon.....




My current thinking is, that the most efficient method - minimizing water use while "flushing" the thermostat and its housing -

is a repeated series, of short applications of flushing water, with draining in between.

I imagine that should flush the block side of the thermostat fairly well; I'm not much concerned about the "downstream" side of the thermostat.

I turn on the hose full blast, until the "telltale" is flowing well (and all the various "holes" on the LU) but then shut off the water until the engine stops draining.
Then repeat - 3 or 4 times.


But I'm still mulling over how to make an inexpensive, simple way to "measure the salinity" (or conductivity) of the flush water leaving the engine

[boscoe99]

Would it have made too much sense to plumb the flush fitting hose so that it connected to the block at the top of each cylinder head? So that fresh water enters the block at the top and then via water pressure and gravity flows backwards down through the block removing any contaminated water and possible any sand, silt or other debris?

[TownsendsFJR1300]

Back to the original question:

"what's with the blue "magic marker" stripe on Yamaha thermostats ?"

[robert graham]

Back to the original question:

"what's with the blue "magic marker" stripe on Yamaha thermostats ?"

Likely a QC mark for tested units...and I'd expect each unit is tested for function...Maybe Rodnut knows for dead sure???

[zenoahphobic]

Would it have made too much sense to plumb the flush fitting hose so that it connected to the block at the top of each cylinder head? So that fresh water enters the block at the top and then via water pressure and gravity flows backwards down through the block removing any contaminated water and possible any sand, silt or other debris?

Some time back on a thread I suggested, atleast with the 2st V6 motors that the bolt/plug at the top of the heads could be used this way. Had no one dispute or enlighten this. I have not made a fitting yet as I think too cumbersome to have to unscrew these plugs everytime, so requires more sophistication with a tap.

In response to fairdeal that 200ml a minute could be useful (if you gave me that "glass" of beer every minute, I'd be done well before the third).
I use the taste test from the pee stream everytime I flush (now, now, watch your wandering imagination!)

That blue streak dissolves in water at 200 degrees, so if it is no longer there after a suspected overheat, then it was caused by this faulty thermostat! I got no idea My car is full of all sorts of paint dabs, stickers, stamps and unrecognisable numbers - thousands of them. Should we all be worried about this ever increasing phenomenon?

[TownsendsFJR1300]

Curious minds want to know!

I suspect, it may be a marking for an operating temp range.

Not much else it could be.

[Sequoiha]

I use the blue stripe for orientation of the thermostat, with it at the top it keeps the sides horizontal in the hole so the water runs off the supports, if it was vertical the water would sit in the bottom support and offer quicker deteriorating of the thermostat.

[TownsendsFJR1300]

I use the blue stripe for orientation of the thermostat, with it at the top it keeps the sides horizontal in the hole so the water runs off the supports, if it was vertical the water would sit in the bottom support and offer quicker deteriorating of the thermostat.

Is that one indentation (of three) larger than the others?

And wouldn't it be best to have one (or the largest vent) at the very bottom to fully drain?

[boscoe99]

I use the blue stripe for orientation of the thermostat, with it at the top it keeps the sides horizontal in the hole so the water runs off the supports, if it was vertical the water would sit in the bottom support and offer quicker deteriorating of the thermostat.

Did Yamaha ever mention anything about this or did you come up with this on your own?

Pretty clever if it makes the thermostat last longer. Is that what you have seen?

How many instances of the thermostat bore corroding in F200s/F225s do you see?