Originally Posted by adam_
Macster- if he has owned it for 2-3 years and never topped it off, it is down 1/2"...is that a leak for sure?
I'm not going to disagree with the rest of the post, but just wonder if it might be excessive.
My wording was very poor. And you rightly called me on it.
Let me take another stab at it: If the level over time -- even if it is low -- remains constant that is not a leak.
Now this assumes by low the level is just at or slightly below the low level mark.
If the level is lower than this, almost certainly there is a leak. This assumes that at some point the level was correct and now it is not and is instead down by a significant amount. Coolant doesn't shrink with age, it (or the water in it) evaporates from a leak in the system, or sometimes just drips out of a hole, that is until the level drops below the hole and then water leaves as vapor and its leaving is slowed.
If the level drops any, even if is just under the low mark, any change in level could be a leak. I say could be I don't see how it could be anything but a leak.
If one can afford to wait and see adding fluid to bring the level up and carefully noting the new level and then watching the level, checking it over time to see if it remains constant or goes down again will answer the question of is there a leak or not.
Now I have to point out I got fooled just the other day. I "checked" the coolant level on my Turbo and it looked ok. That is there was some discoloration in the tank and while I could not distinctly see the fluid level the level looked ok, if a bit low. I even jostled the car (as best I could, the Turbo's back end is damn heavy and I'm not able to move it about like I can my Boxster's back end) and *thought* I detect movement of fluid that looked like while the level was low it wasn't that low, just a bit 1/2 inch or so under the low level mark.
I was wrong. I saw what I wanted to see not what really was there to see.
Today I checked more thoroughly and that low level was not just under the low level mark but nearly a half a gallon of distilled water below the low level mark.
What I thought to be coolant and what I thought I was seeing was just the natural or unnatural staining of the plastic coolant tank from the anti-freeze when the level was at the proper level.
Even though I jostled the car trying to see the fluid move a bit I fooled myself into thinking I saw it move when in fact I did not see it, could not have seen it move.
Oh, I think it clear the leak in the case of the Turbo is the coolant cap.
My advice is to be doubly sure where the level is. Physically take a "depth" reading. With engine cold stick a finger into the coolant tank hole and be sure you can touch coolant. If you can then carefully note and write down the level on a piece of paper.
If you can't touch fluid then this tells you the level's alot lower than just a fraction of an inch and that is a leak. Even if a bit low, there may be a leak but as I metioned above if one can take the time to confirm this by observing the fluid level over time he should do so.
Now another digression: My Boxster had been making a kind of funny groaning noise when I turned on the A/C. Now I know when the A/C is turned on the radiator fans come on. I wanted to hear then come on but I wanted to hear them come on from the coolant tempeature climbing to the point the Ecu turns on the fans.
I picked a rather mild day: Temps in the mid-70's. Drove the car around town in stop/go driiving. Nothing gruesome just driving the car around obeying all the traffic laws. Got the engine nice and hot. Of course I had the A/C off.
Drove home and parked the car and let the engine idle a while. I wanted to get the engine and the coolant hot enough that the radiator fans would come on.
Didnt' happen fast enough to I increased the engine's speed to 2K and held it there for maybe 15 seconds then let it drop down to idle for a while. Did this several times. I was observing the coolant temp using an Actron OBD code reader/data viewer/logger.
Sure enough at 212F I thought I heard the fans come on but the fan noise was not as loud as I remembered.
Got out and checked the driver's side fan. It was obviously running. Walked over to the passenger's side fan and found it was not running. Aha!
Then I noticed a trail of water that led from the right front corner of the car out into the parking lot. It looked like when I backed the car into its parking space the car left a trail of water.
I checked and it was not water, but coolant. Between my fingers the fluid had the oily feel of anti-freeze.
Walked towards rear of the car to check the coolant level when I noticed as I got closer coolant pouring down from the car to the ground just ahead of the passenger side rear wheel.
Long story short: The Boxster's coolant tank had finally let go. It had been leaking some time which was obvious when old tank removed. And I knew even before the tank removed cause I could smell anti-freeze around the rear of the car. Not strong, not as strong as the odor was with hot anti-freeze pouring out at my feet but anti-freeze nonetheless. But I had been ignoring it.
Now I know the smell of anti-freeze a pretty sure sign there's a coolant leak.
I screwed up and could have screwed up the car. Luckily the leak happened at home and not out on the road. There are many excuses I could make but I think the real reason what happened is I just didn't want to know. I have spent some money on the car recently and was just wanting to avoid spending any more for a while. I don't mind servicing my cars and I don't mind paying to have things fixed when they go wrong, but I just like these things that go wrong to be separated by lots and lots of time.
Anyhow, my major point I want to make is if one suspects a leak he can possibly do as I did and get the car nice and hot -- just by driving it around town for a while and then letting the engine idle and even running the engine at 2K rpms with the car stationary and of course the A/C off to the point the radiator fans are turned on. They are turned on low when the coolant temp reaches 212F (and are shut off when the coolant temp drops to 205F).
Now as soon as one hears the fans come on if he then turns off the engine the engine's heat load will tend to raise the coolant's temp a bit more and pressure will increase and if there's a leak one may by lucky enough to see it, hear it, even smell it.
And know there's a leak and get it taken care of before it turns into a gusher of a leak.