disapearing antifreeze-where does it go?

[wannafbody]

I have 2 Fbodies one with a V6 and an LS1. On my LS1 the overflow bottle was empty and the radiator was full. On the V6 the overflow bottle was empty and the radiator was a bit low. The V6 may have some small leak around a hose which might be an explanation. Both have a vented overflow which allows air in. Is it possible that the hot coolant in the overflow along with engine compartment heat could be allowing the water in the overflow to evaporate. This might also explain why the overflows get the gunk buildup over several year intervals.

Now, this is a pattern I've noticed with other vehicles as well. I had a New 94 Mustang that needed coolant added every year.

 

[Burt]

Everytime you run your car, some hot liquid goes into the overflow tank, so some evaporation is normal. Once a year is not abnormal. More than that could be intake manifold or head gasket. My guess is the new mustang had an intake manifold gasket leak. It happens.

 

[Bluestream]

Some may leak into the oil, some may get burned up, some may leak externally. My BMW has used about 1/2 liter pwe year since new

 

[Quattro Pete]

Originally Posted By: Bluestream
My BMW has used about 1/2 liter pwe year since new

Mine seems to be using about the same. No coolant found in engine oil.

 

[Carbon]

Could the pressure cap be leaking?

 

[Stu_Rock]

I used to lose coolant in my FWD 3800. Two things fixed it:

1. The Sundram-supplied radiator caps (marked "TVS") are [censored]. I used to lose coolant until I replaced it with a Stant. I never was able to observe that leak happening; it must have been smaller than pinhole-sized.

2. I also had a leak at the coolant temperature sensor. It backed itself right out of its threads. Re-torque it.

Of course, these are just two items on a long list of things to check.

 

[Carbuff]

It's possible that you have a small coolant leak that only occurs when the engine is warming up. Then, the coolant stops leaking and what is there dries up.

I've also seen poor quality clamps on the overflow tanks allow air to get sucked into the rad instead of air, during cooldown.

FWIW

 

[Stu_Rock]

Clamps on the overflow line--good thinking.

And my apologies for the censored word above. That's my first time being censored on here. It's not that bad of a word, but replace it with "junk."

 

[mechanicx]

I don't think you should evaporate much coolant and have to add. I don't know how long it has been since you added coolant but reservoirs shouldn't normally go dry. One place coolant can get lost and be hard to detect it out the waterpump weep hole. As was mentioned check your hoses, pressure cap, oil and look over the engine for any signs of coolant leaking.

 

[440Magnum]

Originally Posted By: wannafbody
I have 2 Fbodies one with a V6 and an LS1. On my LS1 the overflow bottle was empty and the radiator was full. On the V6 the overflow bottle was empty and the radiator was a bit low. The V6 may have some small leak around a hose which might be an explanation. Both have a vented overflow which allows air in. Is it possible that the hot coolant in the overflow along with engine compartment heat could be allowing the water in the overflow to evaporate. This might also explain why the overflows get the gunk buildup over several year intervals.

Now, this is a pattern I've noticed with other vehicles as well. I had a New 94 Mustang that needed coolant added every year.


The ONLY vehicle I ever owned that could go as long as a year without adding any coolant was my wife's 1993 Chrysler LH series. Not coincidentally, it was the only car I ever owned that had a pressurized overflow tank.

Cars with non-pressurized overflow tanks slowly lose water to evaporation. Its just physics, there's no way around it. Even a pressurized overflow tank will lose a little water should the cap ever have to vent any gas (which is virtually all water vapor, after all) for any reason.

The only thing a bit odd is that the reservoirs were empty... that seems a little on the excessive side

 

[ahoier]

My 08 Optima, when I bought it noticed the coolant in the clear/translucent overflow tank was below the Low line....so I had the dealer bring the jug out to the lot and he topped it off for me. It's been about 6 months now, and it's creeping back down, I got a UOA waiting to be sent in, see if there's any coolant detected in the oil, and depending on what the report says, I'll be taking it to the dealer for service (still under warranty til 80k) to see if they can figure out the problem. I suppose, the UOA isn't necessary, but it was more for curiosity-sake than anything...being my first UOA on a little over 4k of bulk Pennzoil 5-30. But I'm sure having the UOA in hand will let the dealer know there's a real problem and hand, and not just simple evaporation, etc....if there is a leak somewhere.

 

[Geo_Prizm]

I had to add half a liter to the coolant overflow reservoir last year.It is now lower than it was.Before I had not noticed any drop in the levelHowever last fall I had the timing belt and water pump replaced on my car.Could it be that they inappropriately fitted the water pump?

Also, I notice that when I let the car idle for a minute or two after freeway driving, the level is a little higher than when I do not idle the car and stop it right away.

Any comments?

 

[Gary Allan]

Originally Posted By: Carbon
Could the pressure cap be leaking?


Originally Posted By: Stu_Rock


1. The Sundram-supplied radiator caps (marked "TVS") are [censored]. I used to lose coolant until I replaced it with a Stant. I never was able to observe that leak happening; it must have been smaller than pinhole-sized.



I had two on my jeeps that drove me nuts. No visible leaks ..held pressure when hot.

It was only due to "what's left" that I changed the caps out (at different times). I would just find the coolant gone. Nothing showing.

The nearest I can figure is that it pushed it out as the pressure came up, but the thermostat wasn't opened yet. After the stat opened, the gasket swelled and it held pressure. The leak had to be small, but had to occur around the cap itself and not venting it to the tank. The same sorta thing can occur with hose connections, but you can usually see the puddle on the warm up and the cool down. It takes a bit for the hose to swell the leakage shut with heat. The pressure pushes it out before then.