Do not recall what my Boxster's new cap looks like...

Have been very slowly leaking coolant on my '01 base, trusted indy mechanic found nothing with pressure test, but did find coolant at the triangular point where the exhaust manifold meets the exhaust system (does this sound right?), is not sure what it is although he suspects this could indicate a very serious problem. Any thoughts?

Thanks.

2001 Base, purchased in 2004, replaced engine at 130K+, RIP 2017

I have a slow coolant leak on my '01 base and it's from the coolant reservoir tank.
Pull back the felt covering in the trunk, passenger side, and you can check for dampness yourself.
I seem to be adding about 1 gallon of coolant/distilled water mixture per month.

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boxsterd
I have a slow coolant leak on my '01 base and it's from the coolant reservoir tank.
Pull back the felt covering in the trunk, passenger side, and you can check for dampness yourself.
I seem to be adding about 1 gallon of coolant/distilled water mixture per month.

Based on my experience with my Boxster that could very well be a coolant cap leak.

With no signs of any leaks the low coolant level light came on. I added nearly a gallon of distilled water and brought the level up to where it should be.

I checked as best I could and found no signs of a leaking coolant tank. I removed the cap and cleaned it in the sink under hot water and then cleaned the tank threads to which the cap threads onto.

In around a month of almost daily use the light came on again. Still no leak sign but I kind of remember seeing some water condensation on the underside of the trunk lid or maybe on the rubber seal that circles the fluid service bay.

On a hunch I used aluminum foil to tent the bay with the engine up to temperature and in a few minutes there were drops of water on the foil. On another hunch I bought a new cap. Leak solved.

The coolant tenk did eventually leak but in my car's case it never leaked enough to drop the level enough to cause the low level warning light to come on.

The only real sign I got of a coolant tank leak was an odor of anti-freeze once in a while when the engine was up to temperature.

I kind of found the coolant tank leak by accident. A test to confirm both radiators were running when the coolant got too hot turned into a "hot" coolant pressure test which after just a few moments after shutting off the hot engine when the fans were running had hot coolant gushing out of what proved to be the bottom of the coolant tank.

To show you how the lack of heat and pressure can have the tank leak heal itself, I let the car cool down over night then the next morning using distilled water brought the coolant level back up to where it should be. Seeing no signs of leaks under the car I started the engine and drove it a couple of miles to the dealer. At no time did the coolant leak and at the dealer even after I parked the car no leak sign appeared.

In the case of your car regardless of the leak source you need to find it and fix it. The inability of the system to hold pressure can result in localized overheatring which can cause collateral damage to the engine. A seemingly live with it leak can be an engine killer if the leak results in a cracked head. Wtih these older cars a few thousand dollar repair bill can be the last straw and results in the car being lost.

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MarcW


Based on my experience with my Boxster that could very well be a coolant cap leak.

[i198.photobucket.com]

Old on left, new design on right.



Edited 1 time(s). Last edit at 12/04/2016 11:02AM by Harvey in FL. (view changes)

My car's old cap I believe looks like the old cap in the picture.

The old cap had a part # ending in "00" IIRC. The newer caps either have a part # ending in "02" or "04". My info is there is no "03" (or for that matter an "01") cap.

Whichever new cap is used it is important the threads on the tank are clean of of any dried anti-freeze residue. The same goes for the top of the tank where the cap seals. And the cap must be tightened down all the way. This last part can be tricky if someone is not familiar with how much force it can take to screw that sucker down all the way. 'course, one doesn't want to over do it either and ruin the cap or the tank threads.

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MarcW
The newer caps either have a part # ending in "02" or "04". My info is there is no "03" (or for that matter an "01") cap.

Well, that's not odd.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

and dripping on it. Known leak points are water pumps, reservoirs, and, of coruse, loose clamps.

Grant

gee-lenahan-at-gee-mail-dot-com

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JackintheBoxster
Have been very slowly leaking coolant on my '01 base, trusted indy mechanic found nothing with pressure test, but did find coolant at the triangular point where the exhaust manifold meets the exhaust system (does this sound right?), is not sure what it is although he suspects this could indicate a very serious problem. Any thoughts?

Thanks.

Like Grant suggested you have to look at what's above the place where the coolant is found.

That the pressure test found no leak sign has me favoring the coolant tank. My experience is these can be cooant tight cold or even warm but leak when the coolant is hot.

You can check the tank yourself. With the cold coolant level in the coolant tank at the best level -- you can use distilled water to bring the level up but don't over fill the tank -- start the engine and drive it around the neighborhood. Turn off the A/C. Drive the car around until the engine is fully up to temperature. Ideally enough up to temperature you can hear the radiator fans come on. Back at home then raise RPMs to 1K or thereabouts and hold until the radiator fans come on. Turn off the engine.

As the heat load of the hot engine raises the coolant temperature and subsequently its pressure. Thus if there is a leak it will almost certainly make itself known. Avoid putting any part of your body too close to the car. When I did the above described test the coolant tank quite unexpectedly gushed its contents of hot coolant out a split along its bottom to the ground just ahead of the rear wheel. Just before it did this there were some signs of a leak and had I gotten down to try to peer up to see what was going on could have gotten a face full of hot coolant splash.

I think the coolant probably dripped there to that point on the exhaust manifold. Take Grant/Marc's advice on checking if the coolant is escaping from water pump, loose hose/clamp, or under reservoir (which dumps coolant in front of pass rear wheel).