Hey Guys. Something strange happened to me today. I filled up the coolant level back in the begining of July because the warning light appeared on the dash. I filled it up and everything seemed fine until today. Anyway, I had to go to work and I started the car for the first time of the day at about 2:30pm. The coolant level warning message made its grand appearance once again today and I thought it was odd because I had only topped it off in the begining of July. (I realize that it's hot out and the coolant drains much quicker). I filled it up, the light went off, and the car drove perfectly to work. After my shift was over (7 hours) I moved the car to see if anything had leaked and there wasn't a drop of anything. I went home and was about to pull in the driveway when I realized there was a huge stain in the driveway. I don't understand what happened because if there was a leak or the radiator was going south, I thought there would be fluid on the ground when I had checked the car after work. I briefly checked the radiator and I didn't see any leaks or any broken hoses. I also did not see any coolant splattered around the engine bay. (The engine bay in my car stays hot for about 3 hours after I turn the car off. Is this normal? The car is a 1994 530iA. I know that my mom's Infiniti Qx4 stays like this for about 4 hours but I don't know if that has anything to do with my car) Any idea what happened??? Any info. would be greatly appreciated. Thank You.

By the way, anyone know how to get coolant off of a brick driveway??? My parents are about to kill me. :)

Hmm...how's it shifting? I don't know about your car, but with mine, and probably yours, the transmission fluid passes through the radiator, cooling it from 500 degrees to 300, or so I was told. Anyway, if a certain part of the radiator is broken, the coolant and the transmission fluid will mix...so it might, in theory, ave been used as tranny fluid...well, some of it.

Do you use BMW coolant? BMW coolant has the uncanny ability to seal minor leaks leaving a white/blue residue. It's possible it leaked the night before and then upon cooling, sealed itself.

Are you sure the leak on the driveway was coolant?

Get some simple green and start spraying.

Do you use BMW coolant? BMW coolant has the uncanny ability to seal minor leaks leaving a white/blue residue. It's possible it leaked the night before and then upon cooling, sealed itself.

Are you sure the leak on the driveway was coolant?

Get some simple green and start spraying.

I'm not sure what was in the tank when I originally filled it up (in July.) But for the past two times, I have used prestone. Your theory sounded pretty good, but now I went to look under the car this morning and there was a 6 inch spot under the car. I filled it up pretty good yesterday, so I don't know if it was just overflow or not. I'm sure it was coolant because it had that maple-syrup smell, if you know what I mean.

Another question, since I practically filled up the whole tank yesterday, I'm just wondering if I should do the "pressure procedure" it says in the manual. Is it really necessay to use a compressor to equalize the pressure? Could this be causing the leak? Thanks for the info.

It's pretty well established that you are loosing coolant. The question now is where. A careful visual examination may reveal evidence of a leak in the form of discoloration or residue. If that's negative the next thing to try is to examine the car with it fully up to temp and running. You may then see coolant leaking. Note that in both of these it may be nessary to examine from the underside of the car, which means a lift or having the car on jack stands. Particular places to examine include all hoses and the waterpump. As a last resort pressuring the coolant system and checking for leaks and/or leakdown may be necessary.

On the "darker side" you could have a leaking headgasket that's overpressurizing the system and causing coolant to be vented via the overflow. That may only happen when the car has been driven at highway speeds. The overpressure may only cause venting at speed (if you are unlucky) or only occasionally when the vehicle is parked. Checking for that condition can be done by test strips that reveal combustion gasses in the coolant or by pressurizing each cylinder with 150-180psi for a few minutes while monitoring coolant system pressure (on a cold and hot engine).

I'd say the check carefully for evidence of a leak and if you can't find one take the car to a shop and have it professionally diagnosed.

My radiator's been leaking, but it's pretty obvious when you open the hood. At the top of the radiator, where the water hose goes in, there's a plastic neck that the hose attaches to. On mine the plastic is old and brittle, and it leaks from there down the radiator. Could be the same story on yours. If nothing else, fill it up and let it run while looking for drips out the bottom. I'm guessing you're going to find it's the plastic on the radiator that's gone south, especially if it's original to the car.

Hope you figure it out.

When I top off the coolant in the Ferrari and go drive it, the car regulates the coolant level to what it likes by spitting out whatever overfilled coolant it does not want. It scares me sometimes when I forget that I just topped it off.

My radiator's been leaking, but it's pretty obvious when you open the hood. At the top of the radiator, where the water hose goes in, there's a plastic neck that the hose attaches to. On mine the plastic is old and brittle, and it leaks from there down the radiator.
You need to replace that radiator ASAP. At some point in the near future that neck is going to break off completely and dump all of the coolant in seconds. That sort of catastrophic failure can result in engine damage, depending where it happens and what the car is doing at the time.

You need to replace that radiator ASAP.

Doing that today. :D