Coolant leak - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Viper5 · 02-20-2009, 12:04 PM

Got a 2000 boxster S and a coolant leak to boot. I noticed that the level only gets low while the car is on. I removed the underneath and I used a pressure tester to simulate the car being on at 19psi, and sure enough I could spot the leak.

The odd thing is I still can't tell where it's coming from. I can only see the two spots that it's dripping. Would it make sense that the source could be from above (such as the pump) or not since the car isnt on when I use the tester? I'm worried that it won't be a simple fix and i'll have to replace that. The two spots I see the leak is out of the hose and out of the screw thats connected to some sort of bigger piece. The pump looks like it's wet around the belt, but I don't see why since I havent started the car in over a week. So maybe this is my source afterall. By the way, I just removed the clamp on the hose and it was leaking before that too. I'll attach a photo and hopefully someone can point me in the right direction.

mylamb · 02-20-2009, 02:32 PM

You should try and see a specialist/dealer about this. It's a quick diagnosis (maybe 1 hr?) and you don't want to wait/play with leaking coolant if you don't know exactly what's causing it.

Faulty reservoir cap?
Faulty coolant tank?
Hose?
Failing water pump?
Gasket - which could be a royal pain.

tommy986 · 02-20-2009, 02:49 PM

Looks like your water pump needs replacing to me.
That's where mine was leaking. Water pump replacement fixed it.

Tommy

Viper5 · 02-20-2009, 03:12 PM

Quote:

Originally Posted by tommy986

Looks like your water pump needs replacing to me.
That's where mine was leaking. Water pump replacement fixed it.

Tommy

Did you have someone tell you that or were you able to figure that out on your own? If so, then how? And how much did it cost?

How is it the water pump if I didn't turn the car on (not giving power to pump) and it's still leaking?

tommy986 · 02-20-2009, 04:09 PM

Quote:

Originally Posted by Viper5

Did you have someone tell you that or were you able to figure that out on your own? If so, then how? And how much did it cost?

How is it the water pump if I didn't turn the car on (not giving power to pump) and it's still leaking?

After reading in this forum and others about water pump failures, I figured it out on my own. I'm not a mechanic, I just play one on weekends. :-)
If I remember correctly, the failure mode is that the shaft wears, so it's seems possible that a system under pressure could still push water down the shaft without it spinning. The only other part in that area, dealing with water, is the thermostat, which is off to the side from where you took that picture. I replaced it at the same time since I was draining the system anyway.
If i were doing it again, I would get one of those 160 degree thermostats from Flat6innovations.

I sourced all my parts from Sunset Imports since they had the best prices and good service too.

Tommy

tboyer · 02-20-2009, 04:13 PM

Quote:

Originally Posted by Viper5

Did you have someone tell you that or were you able to figure that out on your own? If so, then how? And how much did it cost?

How is it the water pump if I didn't turn the car on (not giving power to pump) and it's still leaking?

Cost: $900.00

Could be leaking and catching residual on the surrounding brackets/hoses/etc....after the dealer replace my water pump (and sep belt), it appeared to still be leaking the next day with a fresh puddle under the car.

Turns out that coolant had found its way and pooled on other parts surrounding the pump. Problem solved after a day of driving.

Viper5 · 02-20-2009, 07:30 PM

After thinking about what is happening with the dripping of fluid, I have come to the conclusion that the hose is OK. The nut is OK. I strongly believe that the leak is actually above the point of drippage. I'm leaning towards a bad pump, but what other possible parts could it be if it's dripping from right above (which is right where the pump is located)? Basically, I want to know if any other possible part could be failing causing a leak at that spot. Or maybe due to a lesser expensive part such as an o-ring or gasket.

Also, if it is indeed the water pump, will I be able to tell if I take a look at it tomorrow by tearing the firewall down and looking at it from a top view?

Another question is, if I remove the water pump, can I determine if it is the causation of the leak and if so, how?

Thanks.

Viper5 · 02-22-2009, 02:19 PM

I removed the water pump and I'm not sure what to look for to see if it's bad, but it seems to look fine. I attached some pictures of it. When I turn it via the pulley, it does not turn freely, but at the same time there is some resistance. Is this normal?

cnavarro · 02-22-2009, 03:20 PM

Is it me, or does it look like there's a bit of silicon on that sealing surface and transfer onto the gasket? Looks like it might have been removed previously.

While holding the housing and trying to spin the pulley, it doesn't freely spin? That doesn't seem right - every pump I've handled spins freely without any resistance.

Viper5 · 02-22-2009, 05:21 PM

It turns freely in the sense that there is no sound of rattling from inside. But obviously there is some object inside causing friction to slow it down. Thats all I meant. When I grab the pulley and rotate, it will go for about 4 times around. I can't really see the impellers while they are spinning but it seems like about that many. Which picture are you referring to with the silicon? And what should it look like.

Blue-S · 02-22-2009, 07:12 PM

There should be a weep hole on the front of the pump casting, at the bottom of the bearing area. The weep hole is needed to vent coolant that will seep into the bearing if the shaft seal is failing. The problem is that the pulley hides the weep hole.

My 2000 S has a one-year-old genuine Porsche pump on it, and it's already weeping -- as is evidenced by a coolant smell in the garage after driving the car, and pinkish streaks all over the front of the pump casting. Looks like I will be swapping a new pump onto my car soon. I can't pursue a warranty replacement because the pump was installed before I owned the car.

Viper5 · 02-22-2009, 07:25 PM

I just can't tell if there is anything wrong with the one I have. I think I may just order another one with the gasket anyway since I don't see what else it could possibly be.

My current pump has a part number ending in '3,' but this one ends in 4. Blue-s, what does yours say? I'm gonna call tomorrow to see if it fits. When I click on info, it says it fits all models up to 2004 whether it be boxster or boxster s EXCEPT for the 2000 boxster s. This sounds like a mistake and I will call to confirm this. The Laso part number is the same and it says it is indeed compatible with the 2000 boxster s.

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1364385&parttype=2208&a=FRc1364385k1134011

Viper5 · 02-28-2009, 01:41 PM

After ordering my part from rockauto for less than 100 bucks, I was able to successfully fix the leak. I guess it was either my pump or gasket, but now it doesn't matter

. In the process I managed to shear a bolt but it was already tight so it doesnt leak there. I hope I don't have to do any work in there soon because I don't know how to get that sucker out. When I was testing my old water pump by removing it and reinstalling it right before I ordered the replacement, I managed to shear another bolt. I was able to get it out fortunately since it was on the bottom. Nothing vise grips won't fix. So a warning to those who do this, the bolts suck and WILLL shear if you make them too tight. When you start getting a little resistance, turn it 2 rotations max or it will shear. Thanks for all the help.