Where is this fluid coming from!

[blackboxster]

Drove my 2000 2.7 boxster 2 weeks ago (very hot outside that day 109 degrees) parked it untill the other day and saw a 4 inch puddle of fluid on the garage floor leaking down inside of right back wheel, could not tell the color because it was mixed with dirt from under car. Looked under the car and the inside of the back right wheel has covered with this fluid, but only could see the fluid was kinda clear looking. Pulled tire off and noticed the entire control arm and part of the brake lines and brake pad indicator lines where moist and the bottom part of the shock and wheel bearing assembly was coated with moist dirt. I checked that rear brake line and master cylinder everything looked good. It didn't look like any place oil could be coming from, so I thought it might be from the shock, but it was alot of fluid and the suspension and shock seems to still work like it should. So I talked to a local Porsche mechanic he told me he saw something like that before on another boxster and was coolant. I checked my coolant and was a little low about 1/2 inch below min in reservoir tank, but I can't find where it could be coming from unless it is spraying from somewhere. I ran the car today with a/c on for awhile could not find any coolant leak under car or under reserve tank, could all this fluid be coming from the shock up at the top and spraying/leaking down when I drive and still have enough in it right now to still have a decent ride? Could not get any decent pics of this.

[wvicary]

It sounds like it's purging from the the coolant overflow. What is the part number on your coolant cap?

[blackboxster]

Can't remember right now but I did replace it with the newer one it's not the original. I can't find any sign of coolant from around the tank top, bottom, or cap. I pulled the carpet back and felt all around underneath the tank and it is very clean on bottom and top.

[ericinboca]

Can't remember right now but I did replace it with the newer one it's not the original. I can't find any sign of coolant from around the tank top, bottom, or cap. I pulled the carpet back and felt all around underneath the tank and it is very clean on bottom and top.

Right rear on the boxster is where you find the hose for coolant overflow. I agree with wvicary - coolant.

If the cap was off recently and not put back on squarely, it will vomit on you like that.

Air in the system usually results in overheating, but just to be sure, I think I would top off (just distilled water), be sure cap is on right, open the breather valve and drive around a few days keeping an eye on the level. Top off more if needed. If it all goes find, close breather valve and no worries.

[blackboxster]

When I took the coolant cap off today it had a good seal on it but I can't find where the overflow hose is.

and this may seem stupid but what do you mean by breather valve?- hose to AOS?

Edited August 17, 2011 by blackboxster

[ericinboca]

When I took the coolant cap off today it had a good seal on it but I can't find where the overflow hose is.

and this may seem stupid but what do you mean by breather valve?

Some things are going to look different as my 04 986S is a race car and it has some different parts and some stuff is missing, but the basics are the same.

First image is of the right rear with the tire off. You can see the rubber hose circled in red. This is the overflow hose. I had a coolant dump one time and it got everything wet as you described.

Second image is of the breather valve circled in red. With the little wire thing upright, as it is in the picture, the valve is open, allowing air to escape. With it down, it is closed. I drive around with it open all the time on the track as do the super cup cars. If it burps out some air, you may need to top off.

[blackboxster]

Thank You ericinboca, I saw the wire on the that cap today and was wondering about it but never did see that overflow hose with all the looking around I did underneath the car. Will top off and try this!

[crwarren11]

I've been there too...sounds like a coolant purge to me which I have had happen on very hot days (used to live in AZ). You don't need to remove the wheel to see the coolant overflow hose; it is visible from underneath the car and kind of jumps out at you because it's a hose with nothing attached to it (at least on the end you can see). The venting of the coolant can be caused by a blown heater valve (928-574-573-03) that runs ~$18 on Pelican. Reasonably easy to access and replace if you need to. But as ericinboca suggested, I'd just top it off and keep an eye on it for a few days to make sure nothing more is leaking. The only problem with that method is that it can sometimes vent when you don't realize it, then you're running around with no coolant, so keep an eye on the low-coolant light and your temperature. It always seemed to happen to me after I stopped and parked somewhere, though. If you're running hotter than usual then it may not be an isolated event and something that will require a fix.

After a few of these events, I ended up replacing the entire reservoir tank, and never had that particular problem again.

[blackboxster]

Just checked my coolant cap and 5 years ago I replaced an 00 cap with an 01 cap, now I hear there is an even newer one? Should I try it or am I wasting my time with it? It doesn't appear to be leaking from near the cap but didn't know if that would cause overflow from the hose too.

[Loren]

Just checked my coolant cap and 5 years ago I replaced an 00 cap with an 01 cap, now I hear there is an even newer one? Should I try it or am I wasting my time with it? It doesn't appear to be leaking from near the cap but didn't know if that would cause overflow from the hose too.

Usually you will see a leak or at least the crust of the coolant. If so - then have the cap tested and replace it if it leaks.

[blackboxster]

How do you test the cap?

And nobody thinks this could be the shock, or is it too much fluid for a shock?

Edited August 19, 2011 by blackboxster

[kbrandsma]

How do you test the cap?

And nobody thinks this could be the shock, or is it too much fluid for a shock?

Maybe cheaper just to update your cap to the 04 version. Cost $25 plus shipping. You can have your cap tested at any radiator shop.

Edited August 19, 2011 by kbrandsma

[Loren]

Most shops have a radiator cap tester - works the same.

As kbrandsma said might be easier to replace it if you suspect leaking.

[JFP in PA]

Loren and kbrandsma are spot on; we pressure test caps and entire systems just about everyday, you pay by the amount of diagnostic time required. The cap costs less than the time it takes to properly test it.....

[ericinboca]

And nobody thinks this could be the shock, or is it too much fluid for a shock?

I suppose it could be the shock, but it doesn't sound like it, at least in my limited experience with a leaky shock. I've not experienced a leaky shock on a Porsche, but have with an Elise. In that situation, you could actually tell something was wrong with that corner (it was right rear) when you drove it. It just didn't behave the same as the other corners.

And when parked, it dripped off the bottom of the damper. To have a lot of fluid on the control arm and other places, I think you would have to have a severe leak in the shock that would be noticeable. Shock fluid is an oil too, so not sure if the fluid you experienced seemed like an oil.

[blackboxster]

Ok so I drove the car today around 93 degrees today ran the a/c, and drove fast pushed hard couple times and all the while had the breather valve open. The temp never did get above 210 degrees and did not see any coolant come out of overflow hose on ground or on car. When I went to close the breather valve it did not want to close (guessing because it was still warm?) after it cooled off the valve closed just fine and easy. Anymore suggestions on things to try or was this just a unusual thing that might never occur again?

[ericinboca]

Ok so I drove the car today around 93 degrees today ran the a/c, and drove fast pushed hard couple times and all the while had the breather valve open. The temp never did get above 210 degrees and did not see any coolant come out of overflow hose on ground or on car. When I went to close the breather valve it did not want to close (guessing because it was still warm?) after it cooled off the valve closed just fine and easy. Anymore suggestions on things to try or was this just a unusual thing that might never occur again?

I think you are OK. Be vigilant on the temp, the coolant level, and the overflow hose for a few more days. If no other strangeness, chalk it up as an anomaly.