Mystery leak

[dammad]

My 1999 996 Tip just developed a leak from appears on the left exhaust. It appears to be red/orange liquid (coolant) and it dripping on to the exhaust from the inners of the rear bumper. I've peered from the bottom and top and can't seem to find the source of the leak. Also I'm mystified because this point is further back (rearward) than the engine itself. Above and the right is the air filter, but I don't see any obvious signs of a coolant pipe nearby and it is too rearward to be something like the water pump (I had this fail 15000 miles ago).

Any ideas/pointers on where this might be coming from while I search from the workshop manuals for some hints?

Dammad

[Loren]

Sounds like a cracked coolant tank to me.

[dammad]

Sounds like a cracked coolant tank to me.

I thought that too, but the coolank tank was replaced $15k ago and I can't see any leaks from there. Any other pipes rearward of the engine that might be leaking?

Coolant in the expansion tank does not seem to have dropped in level (despite a 24" circle of liquid under the car). All other liquids look at the right level also.

???

[Loren]

The cap can leak (especially if it ends in 00) and the sensor at the bottom of the coolant tank is also a known problem.

There are other hoses but none that would leak onto the exhaust (that I recall).

[Chuck Jones]

Red orange liquid? Does it feel oily? If so, could it possibly be a leaking strut? Usually the oil from the strut is clear and oily. IIRC the OEM coolant is either pink or greenish.

[dammad]

Red orange liquid? Does it feel oily? If so, could it possibly be a leaking strut? Usually the oil from the strut is clear and oily. IIRC the OEM coolant is either pink or greenish.

My bottle of Porsche coolant is more orange than pink, but it's probably orangey-pink.

Struts got me to thinking and I dug around at the back of the car.. For the US version, the bumper seems to have two impact absorbers. Any idea if those are liquid/oil filled? Seems to be coming from around there.

Edited July 9, 2008 by dammad

[Loren]

If it smells sweet it is coolant.

[dammad]

If it smells sweet it is coolant.

Alas it does seem to be coolant. Overnight the coolant level slowly dropped a few mm. Looks like a leak from the coolant tank bottom.. I'll have to drain it and pull it out.

Thx.

[dammad]

Checked around some more in the morning and it was the sensor at the bottom of the coolant tank. I would have through that when they switched the tank 10k miles ago they would have changed the seal, but that's where its leaking.. I'll take it back to the place I had it before to see if they'll fix it for free.

Cheers.

[deanslist.us]

I have the exact same leak, anyone have any info on the part numbers for the seal or sensor?

[Loren]

The new switch/sensor is 997.641.503.00 -- US MSRP $21.95

It has its own sealing surface.

[RFM]

Strange, this kind of sensor is not in direct contact with the cooling water, correct me if i'm wrong.

[deanslist.us]

The new switch/sensor is 997.641.503.00 -- US MSRP $21.95

It has its own sealing surface.

Thanks once again Loren :renntech:

[slbates]

The coolant sensor on my 99 is a dry sensor and has no seal. I confirmed this via a pressure test before I installed the new tank without the sensor in place.

[PTEC]

RFM and slbates are correct. The sensor is dry, it doesn't actually sit in coolant. It sounds like you need a new tank.