I’m perplexed. Coolant loss stopping!?!?!

I’m confused.
How long does it take these systems to “burp?”

Ever since I finished timing belt install, and radiator flush had been adding about a cup of coolant every trip to town and back to keep it to full level; 24-35 miles round trip. (Probably added 1/2-3/4 gallon Since started driving it after replacing everything.)

Assumed it’s the crossover gasket, or water bypass o-ring not seated good.
Got all parts coming to replace everything coolant line/gasket related under intake.

Have about 1K miles since timing belt, radiator flush, and replacement, and after replacing rack bushings this week end, took it out, and really pushed it for first time.

Past 2 days wife’s been driving it: waiting on coolant maintenance parts to get here for her 4Runner; and if it hasn’t dropped more by morning it won’t have moved in 2 days of driving.

 

How much have you put it total between top off and initial fill? Is your heater blowing hot? Is your radiator low under the cap or just the overflow? Are you seeing leaking ?

 

Since initial fill, and what I thought was top off, 1/2-3/4 gallon about 1 cup at a time.
Radiator always been full, it was just pulling out of reservoir.
Heater, and everything works as it should.

I thought o-ring was leaking because seemed to be more dry antifreeze on the SAIS pump.

And just looked, and confirmed didn’t loose any today.

 

And how long ago was the I initial flush refill?

 

752 miles ago. 1.5 months ago.

The largest amount I added was right after running it so hard this past weekend. Which was maybe one and a half cups.

 

Doesn’t sounds unreasonable to think it’s still purging small amounts of air.

Keep an eye on it over the next few weeks. If it continues to drop then further investigation is needed.

 

1K including highway speeds and you are still having to add coolant? You have a leak. Either externally or internally. No way it takes that long to burp air. Maybe a day or two at most.

 

I didn’t think it should take that long

It’s not smoking. If it was internal loosing that much every 50-75 miles it should be smoking like an old freight train.

I’m just surprised it has at least slowed down significantly.

Couldn’t quite tell this morning if it was still at full or not. But Usually level has dropped at least 1” in reservoir after a drive.

Unless it has stopped It’s on my agenda to go through all hoses and gaskets under intake, on tundra, After I get radiator, water pump, all hoses etc replaced on wife’s 4runner which will hopefully be this weekend if all parts get here when they’re supposed to.

 

You need to do a pressure test on your cooling system. You could also scope your cylinders at the same time and look for coolant or piston wash which would indicate cooling loss.

 

Been a week, and no more loss.
Changing the water pump on the 4Runner today, got me wondering if it might have been the o-ring lube I used, and it finally cleared out.
I don’t know. Still perplexed.
It was permatex but seemed to be more of an oil type i would use on packing a hydraulic cylinder.
Cleaned it off o-ring on 4Runner just in case and used antifreeze instead.

 

When you drained your coolant for the work, did you do it by opening the drain valves on the engine block? If so, you may not have tightened them enough. That's what happened to @jpink when we worked on his.

 

I checked to see if they were leaking any. Couldn’t find any signs of it.

 

Snug em up with a wrench. I don't remember how obvious it was for him. It definitely sounds like you have a leak though. Unless you just didn't add enough to start.