How much antifreeze consumption needed to show in oil report?

[Bullet]

Two weeks ago I changed the oil and opened the radiator cap and didn't see anything. Granted you can't see far in there and can't say the last time I did check it - maybe two years? The prior oil change was in 2017 with 11k miles on the oil. I purchased a gallon of Asian Zerex and added a quart. My truck is a 2006 Tacoma with the 1GR-FE V6 engine which is known for head gasket failures. There doesn't seen to be anything concrete regarding when in/for 2006 Toyota began using a different head gasket. All I can find is what others claim - it was changed in 2006, was changed in 12/2005, etc. Two have mentioned they seen a technical service bulletin that it was changed in 2009, but I've been unable to find it. I bought new in 1/2006 and Toyota reports my truck first entered service 12/5/2005. So if the head gasket was changed in 12/2005 who knows which gaskets were used in mine.

So far the truck runs well, is not throwing any codes, or anything. But that antifreeze went somewhere and I've not found any leaks. This past weekend I added a couple ounces of antifreeze, but I don't think that means anything except maybe there was air in the system. I did an oil analysis the prior oil change specifically asking about antifreeze and Blackstone stated there were no traces. This oil change I had already dumped the old oil in a collection drain pan that had residuals of many other oils so an analysis probably would show just about anything.

I'll be watching it closely. How soon should I have a sample tested? thanks

 

[danez_yoda]

I have a 2007 Tacoma and a 2014 sienna. Every so often it need a slight top-up. Look at the overflow valve on the white tank in front for pink residue. Im thinking when the tank refills some of the antifreeze is lost through this vent. a little at a time over the years it adds up to a quart or so.

I have 60K and 110K on the two vehicles. They have always been like this. I also changes my radiator cap from the stock one to one with silicone seals. The orignal one was leaking and had pink residue all down the radiator. Stopped after changing the cap.

 

[Leo99]

I had a defective radiator cap that caused my coolant to disappear without a trace. New cap and the problem went away.

 

[Purpfox]

As for your question Bullet, you could do a crackle test at home, but testing can be quite accurate. .001%

 

[Garak]

Originally Posted by Leo99
I had a defective radiator cap that caused my coolant to disappear without a trace. New cap and the problem went away.

This is far more common than people think.