Okay I'm stumped

[79BIG10]

I had been noticing that the coolant level in the radiator goes down to the same level after a few days of driving. I've added and added but again it goes back down well below where it should be (less than 3/4 full). I've replaced the heater core and still doing it. No leaks since the replacement and also have ran the engine to let the thermostat open up to get all the air out of the engine. It doesn't overheat at all just loses alot of coolant. I've checked the exhaust and nothing smelling sweet or any clouds of smoke. No water in the oil pan either.

Now I think that it's overflowing into the overflow bottle and not draining back into the radiator. Isn't it supposed to? I've changed the radiator cap and it's on 16lbs. rating. I see a couple drips from where I park and come out and it's leaking at the bottle but I check and it's right at the perfect level. Is there something I'm missing??

[PHOENIX]

Have you checked the radiator hoses really well?
The heater hoses really well?
Some of them hoses can leak just a little bit and almost impossible to see, but you'll notice the levels dropping.

You may have to get underneath to noticed the hose leaks, if its them.
Sometimes the fluid sits in the little valley under the engine and never gets to the ground. You would be surprised how much fluid can be held there .
Also the heater hoses can leak at the firewall, when this happens the fluid often travels down the firewall and onto the frame at which point it continues down the frame and might leak onto the ground.

If it only leaks when the system is pressured (which sounds like your problem) then the fluid could be dripping when you drive but not when you are sitting. Bu

So your overflow bottle is leaking?
Does the hose from the cap to the bottle go into the bottle all the way?

Check your water pump weep hole. Its located directly behind the pulley on the bottom. Its just a little hole. When the seal goes bad inside the pump water will leak from here. a lot of the time it only leaks from here when cold and you will notice it on the ground. When teh seal gets heated up it swells and sometimes stops leaking. But will leak again when its cold.

Not your problem, but if you notice a coolant puddle under your truck after sitting all night then its probably your water pump weep hole.

[79BIG10]

Originally Posted by PHOENIX

Have you checked the radiator hoses really well?
The heater hoses really well?
Some of them hoses can leak just a little bit and almost impossible to see, but you'll notice the levels dropping.

You may have to get underneath to noticed the hose leaks, if its them.
Sometimes the fluid sits in the little valley under the engine and never gets to the ground. You would be surprised how much fluid can be held there .
Also the heater hoses can leak at the firewall, when this happens the fluid often travels down the firewall and onto the frame at which point it continues down the frame and might leak onto the ground.

I'll check the hoses again. The upper and lower are not leaking. Only thing that might be are the ones going to the core itself at the wall.

Originally Posted by PHOENIX

If it only leaks when the system is pressured (which sounds like your problem) then the fluid could be dripping when you drive but not when you are sitting.

I've ran it sitting with the thermostat opened to make sure that the air is out of the engine and still does the same thing. Is there a way to unpressure it to where it won't leak?

Originally Posted by PHOENIX

So your overflow bottle is leaking?
Does the hose from the cap to the bottle go into the bottle all the way?

It looks like that's the only place where it's leaking. I think it gets hot and the coolant overfills the bottle thus it creates a tiny spot where it leaks out.

Originally Posted by PHOENIX

Check your water pump weep hole. Its located directly behind the pulley on the bottom. Its just a little hole. When the seal goes bad inside the pump water will leak from here. a lot of the time it only leaks from here when cold and you will notice it on the ground. When teh seal gets heated up it swells and sometimes stops leaking. But will leak again when its cold.

Not your problem, but if you notice a coolant puddle under your truck after sitting all night then its probably your water pump weep hole.

You're right in that it's not leaking at the weep hole but definately some good info for others.

[Slonaker]

I have a similar problem. My radiator overflows into the coolant recovery tank, but is not drawn back in as it cools off. I have had the truck almost 4 years, and it has never pulled it back in. I have replaced the waterpump, thermostat and housing (2X), radiator hoses (2X), heater hoses (2X), radiator, and radiator cap (2X). The heater core was replaced right before I bought it (I have the receipt provided by the previous owner).

I can't find any leaks anywhere. The system pressurizes like it is supposed to, but won't pull the antifreeze back into the radiator when it cools off. I'm baffled...

Slonaker

[NeCrOmAnCeR]

Originally Posted by Slonaker

I can't find any leaks anywhere. The system pressurizes like it is supposed to, but won't pull the antifreeze back into the radiator when it cools off. I'm baffled...

Slonaker

Have you replaced the overflow hose itself? Have seen them get soft and collapse rather than draw coolant back to the radiator. Have also seen the radiator neck designed wrong to where there is not a good seal with the outer sealing ring. So when the cap opens to purge pressure the coolant that comes out manages to flow down the hose to the overflow, but when the system cools the imperfect seal pulls air instead of coolant.


79BIG10

May also want to look at the core plugs on your block. May have a pin hole which opens when the system is under pressure, causing your coolant level to drop like you describe.

[Slonaker]

Originally Posted by NeCrOmAnCeR

Have you replaced the overflow hose itself? Have seen them get soft and collapse rather than draw coolant back to the radiator. Have also seen the radiator neck designed wrong to where there is not a good seal with the outer sealing ring. So when the cap opens to purge pressure the coolant that comes out manages to flow down the hose to the overflow, but when the system cools the imperfect seal pulls air instead of coolant.

I haven't. I bought a new one after the last round of head scratching, but lost it in my messy garage. I need to try it.

Slonaker

[79BIG10]

I think I might have the same problem as Slonaker now. I've still got the same old rubber factory line on the overflow. I"ll stop by and get a new one at the store and a clamp to make sure it's on tight.

[MSL]

How low is it getting? The radiators are not supposed to be filled to the top if you look on the side on the radiator there is a fill line its on the passenger side of rad that is where you fill it when cool. This could be something to think about unless you have a aftermarket setup.

[79BIG10]

Originally Posted by MSL

How low is it getting? The radiators are not supposed to be filled to the top if you look on the side on the radiator there is a fill line its on the passenger side of rad that is where you fill it when cool. This could be something to think about unless you have a aftermarket setup.

I've always filled it up all the way. The radiator is a OEM style replacement. I'll look for that level as well.