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Coolant Leak


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Foolishly let my '99s (~53k miles) coolant get an inch or so below the 'Min' level before topping up to full on Saturday. Historically I've had no problems with overheating or coolant loss, in fact no other work except clutch and tires...

Today while driving the red overheat warning light starts flashing, all the time the temperature remaining right at 180. (Outside temps have been 65 to 80 lately here in San Diego). Stop, check the reservoir and it's bone dry. Luckily carrying the extra coolant and water from Saturday so I fill as best able (~2 in below 'Min')and return home, less than a mile. Temp stays at 180, no flashing light.

Get into the driveway, stop and get under the right rear. Traced dripping coolant to just in front of the right rear tire, dropping off a low point about 2 inches inside the right edge from what appears to be a jacking point...

With engine off, 15 minutes later the resrvoir in empty again

Any thoughts? :(

Coolant looks 'fresh and clear' no other engine issues.

Thanks!

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I am in San Diego also, but I have only planned for this eventuality, I would suggest Scotts Porsche in National City to check it for you, Good guy's there, very fair.

I will probably do mine if it happens.

Ask for Ken.

(619) 474-5588

I will try to find the web site for you

Tell them the guy with the Red Boxster sent you...

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New revelation.... After removing the reservoir cover (looking for the bleeder valve) I found tons of antifreeze residue and a small overflow port which runs down through the center of the tank, also caked with moist residue. I suppose it's there to handle and oil or coolant spills while filling...

Is it possible that my pressure cap is shot? After pulling the carpet and closely inspecting the tank it looks in very good shape, no residue on the sensor or around the base. Also, there remains about 3 inches of coolant in the tank, below the view of the check window, but no evidence of further leakage since it cooled down 3 hours ago.

I know the easiest way to check would be to get a new cap, fill the reservoir and go throughout the bleed process... does this make sense though?

Would my topping off last Saturday make this failure more likely?

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A local Porsche shop recently put on a cooling system tech session. Porsche is on something like the 7th generation of the plastic tank. I have bought a special tool to remove the spring band clamps on the hoses when it is my time as I have been told they are a pain to get to.

Porsche has also come out with a new cap that seals better. The part number ends in 01. There is also a new procedure to check the cooling system for leaks and bleeding it. Wish you were in San Jose as this would be a nice DIY project.

tank8.jpg

1-17-04_rmg_tech_035.jpg

tank15a.jpg

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Cleaned filler cap area, refilled to capacity and brought to temperature with bleeder valve cover off. No sign of leaks around the cap or bleeder. The puddle on the ground says I still have a problem... Looks like a tank change is in my near future.

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  • 1 month later...

I have this problem now too!... and i'm in the Bay Area! anyone want to film this procedure? As a temp fix, is it possible to use JB weld where the leak is located? It isn't forming any lakes, but my cooland level has definately dropped and I see some wet spots on the floor of the trunk.

Thanks

Edited by dejavo0
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Openwater did replace the tank himself. And he did it from the top.

I have not done it but Peter said the hard part is getting to the spring band hose clamps due to lack of access, which you replace with normal worm gear clamps. That is why I bought this tool, just in case.

It is a project you can't film since you cannot get a camera into the engine compartment where the hoses and clamps are. If you have a place to work on your car I'll give you a hand.

hose_clamps.jpg

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Openwater did replace the tank himself.  And he did it from the top. 

I have not done it but Peter said the hard part is getting to the spring band hose clamps due to lack of access, which you replace with normal worm gear clamps.  That is why I bought this tool, just in case.

It is a project you can't film since you cannot get a camera into the engine compartment where the hoses and clamps are.  If you have a place to work on your car I'll give you a hand.

  hose_clamps.jpg

Thanks Tool Pants, I appreciate your offer. Perhaps we can do this during a work on cars day. In the meantime, I'll fill up the coolant again to be 100% sure its coming from an opening in the tank.

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hey update on my experimental fix.... it looked like it worked! The JB weld was actually able to stop the coolant leak. After i wiped off the residue and cleaned the outside of the tank. I just put globs of that stuff underneath the coolant tank. It completely stopped the leak, seems that stuff can handle temperatures up to 500 degrees :jump: BTW....i drove for a few days already with my ghetto fix, and its holding up well :drive:

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On my old tank there was a small failure along the seam between the black 'top half' and the translucent 'bottom half', the epoxy must have failed under the pressure and heat. The other areas were mid-tank, on the backside, unviewable from the trunk space without removal... The three weakened areas were dark brown, almost black, with noticeable spider vein cracks running throughout. The 1st and 2nd were at the junction of two of the 'lobes' of the tank you see on the outboard side. I assume the junctions we're not made thick enough to stand the pressure and heat either. The last defect (leaking) looked the same, but was in the middle of a flat area of the plastic... a little scary.

The tank I put in (Apr '05) was the 9th version (.09) porsche has introduced. Nine tanks in 7 years!

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Sometimes I wish I still had my 2 Fiat X1/9s I had in school. My first was a carb version with a metal tank - never a problem. The second was a fuel injected version and for some reason Fiat switched to plastic when fuel injection came out. A seam on the plastic tank would fail over time - went through 3 of them. Then I got smart. Went to the wrecking yard and got a metal tank to replace the plastic. Real easy to replace the tank on that car, and that was the end of the problem.

Maybe Fiat makes the Boxster tank. With the mid-engine Fiat the tank was in the hot engine compartment. On the box it is in the trunk. Strange that Porsche could not get it right the 1st or at least the 2nd time. 996 also has a plastic tank like ours and they have the same problem, but it does not seem to be as common.

I bet you will have to replace the tank sooner or later. Maybe the 10th version will be out by then.

post-24-1087752253_thumb.jpg

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Sometimes I wish I still had my 2 Fiat X1/9s I had in school.  My first was a carb version with a metal tank - never a problem.  The second was a fuel injected version and for some reason Fiat switched to plastic when fuel injection came out.  A seam on the plastic tank would fail over time - went through 3 of them.  Then I got smart.  Went to the wrecking yard and got a metal tank to replace the plastic.  Real easy to replace the tank on that car, and that was the end of the problem.

Maybe Fiat makes the Boxster tank.  With the mid-engine Fiat the tank was in the hot engine compartment.  On the box it is in the trunk.  Strange that Porsche could not get it right the 1st or at least the 2nd time.  996 also has a plastic tank like ours and they have the same problem, but it does not seem to be as common.

I bet you will have to replace the tank sooner or later.  Maybe the 10th version will be out by then.

LOL! Fiat = Fix It Again Tony.

What is up with these coolant leaks??? I just got my introduction to it last night in my not-often-driven '99 Boxster. Just some background on my car. I drive it maybe once a week and sometimes only once every couple of weeks but this week I drove it 3 times. It has 51K miles on it and I live in a very hot climate. Temps have been just a bit over 100 for a few weeks straight and no temp warning light has come on during this time. I do have the older cap with the PN that ends in "0".

I took a nighttime mountain drive last night. It was about 85 degrees out. I drove up to about 2000 feet and all seemed fine, no temp warning light. I parked for about 15 minutes with the engine off. Started it back up to continue and noticed the red temp warning light blinking. Oh crap. I was up in the mountains, pitch dark, nothing around, including water. I had no choice but to limp home which luckily wasn't that far. I took it easy getting back down the hill and home. That was about 15 miles. (I know, I know but there was nothing between where I was and my home.) The temp gauge read just over the 180 mark by about 4 mm.

The radiators were clear and I checked my coolant and it is way low; well below the minimum mark. I removed some of the carpet in the area of the resevoir and noted no pooled coolant. In fact there wasn't even a film. The carpet did have a darker gray stain that feels slightly sticky but that could be oil or whatever. There is some coolant near the cap. Coolant is visible in between the raised lettering on the top of the resevoir. (Note: I don't remember exactly when the last time I check that area but I'm pretty sure that when I did there was no coolant present.) I do not have any coolant pooled on my garage floor and have not noticed any drops. As I said, the car sits for long periods of time so it would have time for coolant to pool over time. A look underneath right now does not reveal any drips or obvious signs of leakage.

First, what is happening to my coolant? It is disappearing somewhere and probably kind of quickly. I say that because I don't drive the car often and have never had the temp light go on. It was only last night it came on. Presumably if it had been leaking out slowly it would have gone past the minimum level sensor before last night and the light would have gone on earlier. The coolant level is about an inch or so below minimum.

Second, what to do? My dealer is about 5 miles away. The manual advises that plain water can be used in an emergency so that is what I think I will do and get it to the dealer. What can I expect the dealer to do to troubleshoot this?

Third, what is the worst case scenario? (Dare I ask.) If it turns out to be the worst case scenario what should I do about the car?

Thanks for your feedback and patience with this long post.

Kevin

Edited by Kevin369
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From my experience, the fact you haven't noticed coolant on your garage floor isn't surprising. When the tank fails, the coolant loss is immediate and dramatic. By the time I got my '99 home (less than 5 miles) there was barely a trickle coming from the bottom of the car.

This is what I did and it seemed to help pinpoint the problem..

- Remove your engine cover

- Remove all carpet (and the black styrofoam liner underneath) from the trunk.

- Refill your tank to spec with the coolant and water @ 50/50

- Install the new (.01) cap. You'll want it anyway

- Start you car and park it on a level surface

- Bring the car to temperature

- Run it for at least 20 minutes to build pressure

Look for either; coolant dripping from the bottom side of the tank, or escaping from a compromised hose in the engine compartment.

When coolant gets on the trunk floor it drains down through a small hole and ends up dripping off the right rear jacking point. If the leak had been small for some time, you may not have noticed a few drips in front of the tire and the styrofoam insert prevents it from staining the carpet. Coolant usually takes some time to evaporate, but if temperatures have been as high as you say, and your don't spend much time on the passenger side, you probably wouldn't have noticed. When the coolant dried next to my car, there was almost no residue.

Tank replacement is difficult, not impossible. The local shops in San Diego wanted around $750, I did my own for about a third of that.

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Thanks openwater. I'll be heading over to the dealer to pick up a new cap and some coolant. They have seven of the newer caps in stock. Does that mean they need stock for common replacements??? I'm going to do as you suggested and refill the coolant and watch it.

I did pull up the carpet and the black foam in that corner of the trunk and it looked coolant free so at this point I don't think it's a leaky resevoir. I shall see though and post my findings.

Thanks again.

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One other thing to check... If the cap failed there should be some residue under the black plastic insert that covers the cooling system bleeder valve. Remove the coolant and oil filler caps, pull it up and see if there's any evidence. My '99 had some residue in the opening of the overflow outlet which is in the middle of the tank, below the cover...

Also, not sure how far below the 'Min' mark requires the bleeding of the system. If you need to do so this link has instructions.

http://www.dietersmotorsports.com/tech/tech9-03-2003.htm

I had to bleed my system twice to get a stable reading.

Steve

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We had a cooling tech session in January at an independent shop. This shop has put on several tech sessions for us over the years. They do work on cars that are out of warranty. The owner said they have been replacing the 00 caps with the newer 01 caps. They even test the 01 cap before they put it in just to make sure. I have a January 1997 so I do not even have a 00 cap. My cap has the VW/Audi logo and part number on it like the early cars.

Any decent radiator shop can pressure test the cooling system and cap if you do not want to pay Porsche dealer prices. Just tell them it is really a VW. Peace of mind if you want to rule out a cooling system leak.

You would not need to bleed unless the coolant level has fallen below the height of the motor or something else is going on

post-24-1087936061_thumb.jpg

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Update:

Got the new version of the coolant cap ($19). It's interesting in that it has a sort of sleeve on the underside and there is some play between it and the rest of the cap and it looks like there is a hard plastic gasket up inside the cap as well. The old one is solid. I refilled the coolant 50/50 Porsche coolant ($10/liter) and distilled water. Incidentally, before I did this I removed the plastic piece that has the raised writing on it. I did notice some coolant and condensation below where that plastic piece was. There wasn't much but there was enough to see and wipe up. I also removed enough of the carpet and foam to watch for a resevoir leak.

After I filled and capped, I ran the car for about 20 minutes and watched for leaks. Nothing. Nada. Zippo. There was nothing around the resevoir, trunk, no drips from underneath, and nothing seemed to be coming from the underside of the engine. (I slid underneath and watched.)

When I shut it off, I waited a couple of minutes and then open the coolant cap. Whoosh! There was a pronounced release of pressure. I then reinstalled the old cap and started it back up. I let it idle for a little while before shutting it off and removing the old cap. Pssst. There was just a little rush of air but it was barely noticeable. I realize that not quite as much pressure may have been built up the second time because I didn't run it quite as long but I am thinking that my problem is tied to the old cap. At least that is my hope as opposed to coolant leaking into the engine. Bad, bad, bad. (There was a Boxster and a 996 at the dealer for new engines for this exact problem.) I think that if the old cap was bad and while the car was running, there was enough opportunity for coolant to escape/evaporate. I am told that once that happens it happens fairly quickly.

For now I am going to run the car and just monitor the coolant level. Wish me luck.

Edited by Kevin369
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