hello everyone

I have to top up my pink coolant about 16 ounces (2 cups) every month. I cannot find a drop of coolant anywhere. Any idea what it could be.

 

headgasket, valley pan gasket, throttle body heater, or radiator are a few places to look that aren't super obvious. The radiator should be easy once you pop off the top piece of plastic and often the screws that hold the rad on top have been over tightened and actually punctured the end tanks.

 

Try replacing the filler cap.

 

If you search forums, you'll find quite a few posts. I am about to reply to the one that I started, but I'll copy the reply here.

Long story short: you have a very minor leak that happens only at certain pressure. To detect the leak, you have to get a pressure tester and test the cooling system over a long period.

Symptoms: you flush and fill cooling to the max coolant level line. In a few days/weeks/months, your coolant level drops by 1/2 to 1" in the reservoir and stays at that level. Keyword "and."

Here is what happens, as evidenced by my testing over a year. With overflow tank full to the max cold level line, you pressure test and look for leaks everywhere with a flashlight and a mirror. The leaks can be extremely small and they may appear only when the tank is full. Crawl under the car, use mirrors and inspect every cooling hose connection. When the coolant level drops by a bit, there may be less pressure in the system and the leak won't manifest itself. That's why your level drops and stays.

What to do about it? Depends on where you have the leak. I spotted a small one in the place that is not easy to reach. I monitor my temp with Ultragauge and check the coolant level weekly. The initial leak has not been an issue and I'll address it during the cooling system overhaul (every 30K for me). To ensure that your coolant level settles, mark it with electrical tape/marker 2-3 weeks after coolant fill up.

 

Also, what level do you keep your expansion tank at? It’s possible that the Full Cold mark is a little too high for your engine. If you let the level go a bit lower does it then stay there?

 

It looks like Mr Choodles addressed this as I was typing.

 

My stable coolant level is about 1/2" below the Max line.

If your pressure is too high to handle for the coolant cap, you will see coolant leaking out via overflow pipe/outlet.

If the cap can handle the pressure but a part of the systems cannot due to a leak, you'll see the scenario described in this thread. Coolant will "disappear" until the pressure lowers to the point so that it does not cause the opening in a faulty connection.

 

The last time the coolant was at the very bottom of the res tank and i filled it back up to just above the full line, that was about a month ago. This morning it was back to the bottom of the reservoir and I filled it back up in the same manner

 

cap looks fine like new

 

Mine does not stay at the level and slowly decreases. If I understood all that you wrote this will be hard one to find