Can a cooling system be too full? I have a leak in my radiator of my buick. I went to pull the radiator cap the coolant just overflows. It's on a completely full system. Would a leak cause this? Turns out it's leaking at a seam on the side tank where it meets the aluminum finned area.
Can a cooling system be too full?
- Thread starter E150GT
- Start date
- Status
Are you checking while engine is hot or cold?
Originally Posted by Ursatdx
Are you checking while engine is hot or cold?
Cold. Sitting overnight
Are you checking while engine is hot or cold?
Cold. Sitting overnight
Originally Posted by eljefino
The cap might not be the highest point in the system. Any bleeders on the water outlet?
The reservoir might be a tad higher. Seems like a pretty bad design to have coolant just flow out like that. There is a bleeder on the thermostat housing and it spits water when opened
The cap might not be the highest point in the system. Any bleeders on the water outlet?
The reservoir might be a tad higher. Seems like a pretty bad design to have coolant just flow out like that. There is a bleeder on the thermostat housing and it spits water when opened
Last edited:
I remember when I first brought my Passat home from the dealer who sold it (used) the coolant was too full. It was close to the top of the reservoir. The full line was in the middle of the reservoir or close to it. It didn't cause any problems but that might be because I caught it before it could cause a problem. I just hope that the ninny who overfilled it didn't use some incompatible coolant when they did that.
Originally Posted by Chuckh
I remember when I first brought my Passat home from the dealer who sold it (used) the coolant was too full. It was close to the top of the reservoir. The full line was in the middle of the reservoir or close to it. It didn't cause any problems but that might be because I caught it before it could cause a problem. I just hope that the ninny who overfilled it didn't use some incompatible coolant when they did that.
Well that ninny was me. When I bought the car I replaced the coolant elbows and thermostat and coolant. I'm not talking about overfilling the reservoir. When I take the radiator cap off the coolant comes overflowing out and doesn't stop until I put the cap back on. The coolant reservoir was filled to the cold line.
I remember when I first brought my Passat home from the dealer who sold it (used) the coolant was too full. It was close to the top of the reservoir. The full line was in the middle of the reservoir or close to it. It didn't cause any problems but that might be because I caught it before it could cause a problem. I just hope that the ninny who overfilled it didn't use some incompatible coolant when they did that.
Well that ninny was me. When I bought the car I replaced the coolant elbows and thermostat and coolant. I'm not talking about overfilling the reservoir. When I take the radiator cap off the coolant comes overflowing out and doesn't stop until I put the cap back on. The coolant reservoir was filled to the cold line.
Look - the reservoir sits higher than the radiator cap. This is a GOOD design because it allows all the air to remain purged and the cooling system to work efficiently. If the radiator cap was the highest point, then the reservoir would not be nearly as effective in keeping air out. The whole point of a reservoir external to the radiator is to keep the radiator completely full during normal coolant expansion/contraction.
Originally Posted by Chuckh
I remember when I first brought my Passat home from the dealer who sold it (used) the coolant was too full. It was close to the top of the reservoir. The full line was in the middle of the reservoir or close to it. It didn't cause any problems but that might be because I caught it before it could cause a problem. I just hope that the ninny who overfilled it didn't use some incompatible coolant when they did that.
The only possible thing is that the cap for the coolant recovery tank might vent coolant but that can ruin the seal on the vent sealing and you'll need a new cap. This is why the markings for the correct level is on the recovery tank itself.
I remember when I first brought my Passat home from the dealer who sold it (used) the coolant was too full. It was close to the top of the reservoir. The full line was in the middle of the reservoir or close to it. It didn't cause any problems but that might be because I caught it before it could cause a problem. I just hope that the ninny who overfilled it didn't use some incompatible coolant when they did that.
The only possible thing is that the cap for the coolant recovery tank might vent coolant but that can ruin the seal on the vent sealing and you'll need a new cap. This is why the markings for the correct level is on the recovery tank itself.
Is it a pinhole leak...seeing steam come out? General Motors cars use Dexcool which eats through plastic. On the Suburban it cost $750 to replace. If you do replace the radiator then get the system filled with Peak Global Life which doesnt contain the plasticizer chemical.
My Suburban had 3 radiators until I figured out what happened.
This is an old link but problems still happen today with Dexcool.
https://www.consumeraffairs.com/news04/2006/08/gm_dexcool.html
My Suburban had 3 radiators until I figured out what happened.
This is an old link but problems still happen today with Dexcool.
https://www.consumeraffairs.com/news04/2006/08/gm_dexcool.html
If the block and radiator are 100% full , it is a good thing . No air in the system . As everything warms up , the excess coolant will be diverted to the expansion tank . If the expansion tank gets too full , it will overflow on the ground / pavement .
With the engine off and everything cooling down , coolant will be pulled back into the radiator & the block . And all is well .
With the engine off and everything cooling down , coolant will be pulled back into the radiator & the block . And all is well .
Modern vehicles are designed to self-purge, meaning they will push out air and pull in coolant from the recovery tank. This results in a cooling system that is filled all the way to the radiator cap, no air. Older systems without recovery tanks will have an airspace below the radiator cap, when cold. Check for bulging radiator and heater hoses. If your radiator cap is over 6 years old, it might need replacing... maybe, maybe not.
The reason I ask is because I have never come across a radiator that pukes out coolant when you open the cap unless it's hot.
The radiator is leaking where the metal and plastic tank meet. I have a new radiator waiting to be installed this weekend.
The radiator is leaking where the metal and plastic tank meet. I have a new radiator waiting to be installed this weekend.
Originally Posted by E150GT
Turns out it's leaking at a seam on the side tank where it meets the aluminum finned area.
there's your answer
Turns out it's leaking at a seam on the side tank where it meets the aluminum finned area.
there's your answer
Nothing to worry about. In an ideal world, the block and rad are completely chuck full when cold. Once warmed up (actually long before), the pressure in the system begins to rise and at the pressure point of the cap, will begin to push coolant into the overflow. After shutdown and as the coolant cools, a vacuum forms and draws the required amount back to maintain equilibrium.
Puking coolant when cold and removing the cap could be as simple as a trapped air bubble trying to come out and/or a difference in barometric pressure on the day you filled vs the days you've checked. In other words you could have sealed in high baro and cracked it open at a lower baro. If the cap is good, it'll maintain that seal in spite of the pressure difference.
Puking coolant when cold and removing the cap could be as simple as a trapped air bubble trying to come out and/or a difference in barometric pressure on the day you filled vs the days you've checked. In other words you could have sealed in high baro and cracked it open at a lower baro. If the cap is good, it'll maintain that seal in spite of the pressure difference.
- Status
Similar threads
