Foo - Overfilled my coolant a little

My vehicles coolant was very low, so I bought a gallon of premixed stuff rated for 150k miles. The manual said to keep the coolant level right at the Maximum mark, this was barely above minimum. Anyways, I added a little too much. When I remove the cap, coolant isn't spewing out or anything. But the level is about .375" above the MAX mark on the main reservoir. Is this going to be a problem?

Nope its fine
its just going to spill out to the max line an if it goes low again .. you might have a problem?? i would pressure test the cooling system an see if u have a leak some where
henri

It's all good.

Your car's going to explode!

Well, I don't think there is a leak anywhere. I have not noticed any oil or coolant on the floor, and hte previous owner said he has not touched the coolant in a few years. Thanks :).

Shouldn't be. .375 is nohing, dont worry about it?

Now was the car hot when you checked? The reservoir is fuller when the fluid iis hot and if it ok cold it could be overflowing when warmed up.

Well, I don't think there is a leak anywhere. I have not noticed any oil or coolant on the floor, and hte previous owner said he has not touched the coolant in a few years. Thanks :).

If its been a few years, you might want to get the cooling system flushed and refilled. The antifreeze becomes acidic over time and will rust out the metal parts of the cooling system. I think the recommendation is every 2 years, but could be wrong on that.

Shouldn't be. .375 is nohing, dont worry about it?

Now was the car hot when you checked? The reservoir is fuller when the fluid iis hot and if it ok cold it could be overflowing when warmed up.
The car has not been run for 2 days. I think since I added basically 1/2 of a gallon of coolant, that it will be alright in terms of functionality.

The car has not been run for 2 days. I think since I added basically 1/2 of a gallon of coolant, that it will be alright in terms of functionality.

Functionality always - the worse thing could be to drip some coolant.

The real danger is not filling it up enough. Such a small amount more isn't going to a be a problem as long as the coolant reservoir isn't so tiny it can't handle a bit more fluid as it heats up and starts flowing in and out of the engine.

Should't be a problem at all. Usually, there is a reservoir tank situated next to the radiator that holds over flow coolant that comes out of the radiator when the engine gets hot (coolant expands), and when the engine get cooler again, theoretically its supposed to suck the coolant back down. Don't hold me to this, but I think I've read in a few owners manuals that you should keep that reservoir about half filled.

The over flow coolant is able to escape the system because the radiator cap is designed to let coolant out at a certain pressure. Ifyou look on the cap you can see the rating.

No prob. after a really long run observe it,if the level bugs ya,soak a bit-up with a rag,the worst it'll do is spill-over and stink,only reason to be concerned enough to get rid of a little excess.

dont worry about it. worry about under filling it.

when the car is cold. COLD. take off the radiator cap. The level should be right up to the cap and then anything in the bottle is extra and dont worry about it. (keep it like half filled). If you take off the cap and it is low fill it up directly in the radiator.

Also dont do it when it is hot. If you take the cap off when it is hot (and pressurized) when the pressure drops from whatever the cap is rated at to atmospheric pressure the coolant will instantly boil and blow up in your face.