steve r

I know this isnt a mustang but I figured someone might know the answer. My girlfriend has an 08 altima 2.5 and I changed the oil 2 days ago. Then later in the night I checked the oil and the level was perfect. Then I noticed the coolant reservoir was low so I added coolant up to the max line. Then the next day I smell coolant so i open the hood and coolant is everywhere. It looks like its coming out of the radiator hose. The funny thing is, is that the coolant level in the reservoir is at the same spot as when I checked it the first time and it looked low.. any ideas?? thank you

petrock

That makes sense if its got a normal radiator cap with the reservoir connected at the radiator cap. If it does, then the reason its doing that is the radiator cap is cold. So its sealed off the engine coolant from the coolant in the reservoir. When the coolant/motor gets hot, the pressure in the coolant system increases and compresses the radiator cap spring and allows the excess fluid to flow into the reservoir. As the motor cools off, a vacuum occurs when the pressure decreases and sucks the fluid from the reservoir back into the motor. See http://auto.howstuffworks.com/cooling-system7.htm

To figure out where the leak is coming from, go to your local auto parts store and rent a radiator pressure tester, hood it up where the radiator cap goes and pump it up to the PSI listed on the radiator cap. At which point, listen for hissing and look for leaks or squirting fluid. Should be fairly easy to find the leak judging the amount of fluid you're loosing.

Good luck...

mb3000

If the coolant system in the car utilizes a conventional "overflow" than you really should add coolant to the actual radiator cap & burp the system.

If you KNOW you have a leak, you can take the hose that connects the overflow to the water neck & stick a compressor blow gun into the hose, adjust your regulator to just below the pressure rating of the radiator cap that is installed on the car (you should be fine with 10psi, don't know for sure though) and watch for the leak.

petrock

Ummm... How would that work? The coolant overflow hose is upstream of the radiator cap. The radiator cap seals off the coolant in the coolant system from the overflow and its hose. The radiator cap only opens when enough pressure builds up in the cooling system. So sticking a compressed air hose on the overflow hose won't do anything because the radiator cap will be closed not allowing the pressure to go into the cooling system...

Even if it did work, it would be pretty hard to do because even 10lbs of pressure is a decent amount to hold against a small overflow hose. Would be pretty challenging to keep the pressure on the hose. On top of that, you would need a second person to hunt around for any leaks while you hold the pressure on the hose....

Use a radiator pressure tester instead. It makes it into a one person job and is extremely simple to use.

mb3000

Just a way to save some money instead of buying the tester. The reason I said "if you KNOW you have a leak" is because when you shoot 10psi into the hose, it's going to shoot coolant out of whatever leak(s) you have. The system won't be pressurized to 10psi because of said leaks, even though you will release some pressure when you loosen up the radiator cap.

Again, this might not be the case for said vehicle's coolant system.