Oil in coolant with only 3,000 miles on the clock

Perhaps you should learn about cooling systems before publicly posting your ignorance/stupidity.

Thank you.
I would explain further, but he can do his own interwebs research.

Well, yes and no.
Yes- if this were a problem that I suspected was something that could lead to problems later. Things like coolant in the lubrication system.
No- since this is a problem that is one-way (oil in the cooling system). This type of problem does not lead to particularly bad long-term problems. Maybe a slight loss in cooling ability, as the heat exchanging properties between the coolant and the metal must now work through a less-thermally-conductive film of oil. But outside of that, a one-way passage of oil into coolant does not pose a significant enough problem to virtually any engine to warrant an emergency mindset.

It's very much still under warrantee. Which means it should not cost me anything. Doing what you suggest will certainly cost me, and likely quite a bit.
Even if I have to be a dick and keep chasing after Toyota, I know they will eventually be forced to deal with it. Thankfully, that is not the case (see next post of mine in this thread).

Seriously. Do your research first, before insisting you're an ass.
Pressure cap opens every damn day the truck reaches operating temperature for more than about 20 minutes (exceptions being only when the outside temperature is extremely cold, like sub-freezing). Why? Because after that time the system has equalized, and the coolant circulating through it never really dips below around 120*F. This means that the expansion of the fluid increases the pressure enough to overcome the cap's rating and spill into the overflow tank, where it is later sucked back into the engine when the temperature (and pressure) drops enough. Every single liquid-cooled internal combustion engine does this......unless the engine is without an overflow tank, in which case it does, in fact, lose coolant over time. It doesn't require maximum temperature to achieve this.

 

UPDATE!

So I took my truck back in to Tustin Toyota for its 20,000 service three weeks ago (21,000 miles in one year. Hell yeah!). I mentioned the oil in the coolant, showed them Irvine's service records. We agreed Irvine is a POS.

Turns out I struck gold that visit. A national Toyota rep happened to be in the shop when my truck came in, and, thanks to all the work I've done on it, he "just had to have a look at [my] awesome truck." He also looked over the service ticket, saw the oil-in-coolant issue, and told the tech that he had come across a few other cases of exactly this thing. Talked the tech through what to do and what to look for.

Tech inspected everything, couldn't find the source. Flushed the system and ran it for 30 minutes to see if it came back (of course it didn't). Told me to come back in 1,000 miles if the problem came back.

I was a little worried that, because it was so intermittent, and because the only other time it had happened was 13,000 miles ago, I wouldn't be able to duplicate the issue. Thankfully, it did come back -- I'm getting the sense that it's off-road related, because it seems to happen when I'm in 4wd extensively (went on a weekend trip to Mojave over those 1,000 miles).

Three weeks later (yesterday) I stop in to have them look at it again. This time I'm sent home in a rental car (fucking POS Yaris. Feels like I'm driving an underpowered matchbox made of tissue paper).

Today I'm told over the phone that they're having one of their specialist reps come up from San Diego to look into the problem. Apparently my radiator is on the shop floor right now. Dealership service tech is suspecting the same thing as I: the oil cooler sandwich adaptor.

So while I miss my truck, and the fact that I have it mostly equipped as a BOB and so am without any of my regular BOB gear/supplies, I am *really* freaking glad this is finally getting the attention it deserves.

I have made abundantly clear to the service writer that I want as much detailed info about what's going on as he can give me, including details about other instances Toyota knows about. If there's anything I can find out, I'll pass it along to TW.

 

Glad to hear! Looking forward to finding out what exactly is going on.

 

Got my truck back, after the dealer having it for three days.

According to the specialist they brought in from San Diego, the oil was actually transmission fluid.
He said there was a TSB for 2009-2010 MY Tacomas for precisely the problem I had, because the oil cooler would have a visible crack in it that would allow the fluid to mix with the coolant.
Problem was, my truck is a MY 2011, and the VIN fell outside the range of affected vehicles. I commented that its Date of Manufacture was November of 2010, and it was likely that it had a few transitional parts......like a 2010 transmission fluid cooler. He said it was possible, but that the fact remained that my truck was no included in the TSB, no matter what way one argued it.
The other problem was that neither he nor the mechanic could find any trace of a crack where there would normally be one (according to the TSB). They thoroughly inspected the system, and couldn't find where the trans fluid was coming from. This doesn't surprise me, since the problem was so intermittent -- I suspect it was a hairline facture that would only show up with some sort of Magneflux-type test, and was not visible to the eye, and would only leak under higher-than-average pressures (i.e. very hot transmission fluid under high RPMs).
However, he decided that since I had a history of the problem dating back to before the first oil change, and that the problem was identical to the TSB, he would authorize the TSB to be performed on my truck. This, of course, was what I would have stood on my head demanding, and I suspect he sensed that.

Here's what was included in the TSB service:
"Replaced radiator with thermostat, fan shield with resirvoir [sic]. See notes."
"Radiator assembly, Large capacity" (including integral transmission fluid cooler)
"Hose, Radiator to reservoir"
"Inlet sub-assembly, Water..." (text cut off). (Not sure what this is......I'll poke around under the hood when I get a chance and try to determine)
"Shroud, Fan" (including overflow reservoir)
"Super Long Life Coolant" (flushed the system)
"ATFWS" (WS Trans fluid) (flushed the system)
Hand-written mechanic's notes indicate the thermostat was also replaced. Perhaps as part of the "Inlet sub-assembly" where the text was cut off?

I'm happy I finally got this taken care of, which is to say that I'm happy I found a dealership that doesn't blow me off and try to tell me that what I'm looking at is mud.
If I have any more problems with this, I'll let y'all know. But I do hope and expect this to be the last of it.

 

MACH375. If you do some internet searches for Strawberry Milkshake for Toyota vehicles you'll find photos of where the failure is occurring.

Many owners, not so much 2nd gen Tacoma owners have gone to an aftermarket oil cooler and done away with the POS radiator trans cooler.

Hearing this wants me to pick up the pace on installing my cooler and stuff sitting in the box.

Off-road, you likely got the temps up in the trans and made the goofy fitting leak inside the radiator.

For most of these situations, it also puts coolant into the trans and wipe it out also.

http://www.tacomaworld.com/forum/technical-chat/227415-auto-tran-faliure-due-radiator-fail-2.html

PK

 

Well, it's back. 36,000 miles on the clock this time......though only ~8,000 miles on the engine (see my rollover thread).
Took it into the stealership this week, managed to time it such that the same factory rep that authorized the repairs last time would be in the very next day. They now don't want to touch it, saying I have a "heavily modified vehicle," and that "the modifications may be the cause of the problem." Gave me the Toyota number for opening a claim.
Thing is, the only modifications I've done are suspension, extra battery, OBA, lighting, my "hidden snorkel," and wrapped the exhaust when I had the engine out. The drivetrain and cooling system are bone stock (transmission has never even been out of the truck). The rep and dealer never mentioned anything about the engine, which means they didn't check to see if it's the original.
My concern is possible damage to the transmission. I don't want to have to rebuild or replace it if this is a factory problem (it is). I don't mind replacing (upgrading) the radiator, but the transmission is a whole other story.
I'll be calling that number soon.

And yeah, I now know what circumstances cause this: using Low Range for extended periods. I'm able to monitor my transmission temps (as well as all other OBD2 parameters) in real-time, and I did see the torque converter output temp sensor hit 240* for several minutes on a recent trip. But I had the oil/coolant mix prior to that happening -- happened on another trip where I had it in Low Range for a while and torque converter output temps were 215* for quite some time. These were with new coolant and new trans fluid.

In the meantime, anyone got any leads on a good replacement radiator with trans cooler? Preferably something aluminum.