Yikes! Headgasket time.....

[brianl703]

The ATF cooler circuit is low-pressure. If it were hundreds of PSI it'd be using high pressure hoses like that used for the high-pressure side of the power steering. It does not, so it isn't.

Also there should be almost no restriction on the return side of the cooler circuit, regardless of the pump's capability to actually develop significant pressure if there were a major restriction.

 

[Master ACiD]

sounds logical, but why did i have to empty quarts of atf out of my radiator overflow tank when mine went bad. literally quarts came out. there was even more in the actual cooling system.

 

[Tim]

My atf cooler lines on the Sienna are low pressure. They are high-pressure flared fittings with metal tubes on my Volvos, however.

I have a message in to Butler regarding a coolant analysis. I was thinking about putting a couple heat/cool cycles on it (it has mostly distilled water in the cooling system and fresh atf) and then taking an atf sample and jabbing it with a hot soldering iron to see if there is any water in it.

Just got in from working and have to get up at 0500 tomorrow, so no time tonight...maybe Sunday.

Thanks for following along and playing devil's advocate guys.


Tim

 

[mechtech2]

Many intake manifolds have coolant passages which can leak into the oil, and sometimes the other way around.
This is only one idea, not a certainty.

 

[The_Jeff]

As far as overflow bubbles, the overflow/vent tube empties when you open the radiator cap to check underneath it. So the first startup you'll see bubbles as the radiator coolant expands and burps the line clear of air again.

Am also hoping it's an ATF mix within the rad, cheaper for you.

 

[Tim]

I am going to do a quick and dirty test for water in my atf.

I have drained the rad and block and re-filled with distilled water.

I am going to run the vehicle for 3 or 4 heat cycles and maybe 50 miles. Then I'll drain the atf and dunk a hot soldering iron into a sample and see if I get any hiss.

I teste this by dunking the iron into a pure virgin sample...only smoke.

Then I put one small drop of water into about 4 ounces of atf and stirred vigorously for a minute. When I put the iron in, I heard a hiss.

I had been told by one of my chemists that this soldering iron trick is sometimes used when a lab has many samples to test for water...it seems to work.

Tim

 

[Oldmoparguy1]

Good trick. I'll have to remember that one.

 

[Tim]

Well, I continue to be baffled.

After running about 40 miles in 4 hot/cold cycles, I took a 3 oz sample of atf and did the soldering iron trick...no water.

Did it twice to make sure!

So, I am going to flush the cooling system a couple more times with distilled water and will watch carefully for any change to the coolant or atf.

I have continued to watch the half-gallon sample of the offending coolant. It has maintained its burnt orange color and has not phase separated in almost a week. This tells me the color is not coming from atf.

I hate to admit this...but the only explanation I can come up with is when I flushed and switched over from Toyota red three years ago, I must have "missed" some. IIRC, I did about 4 distilled water flushes and then topped off with Prestone all makes/models. Then last year I drained the system and re-filled with the same coolant. It looked fine then as I recall.

It wasn't until just last week I noticed the color change. And I am under my hoods several times per week on average (yes, I am a loser!).

Even my best answer is not very good...I really have a hard time believing some residual Toyota red took 3 years to start discoloring my Prestone and making some goo.

I don't know what else to say....