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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCoolant overflow due to hot weather?
Reported or suspected cause
old, dried-out coolant tank cap
Reported cause
No successful repair reported for this finding.
1
Identified cause
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Suspected cause
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Reported cause
The likely cause of this issue is an old, dried-out coolant tank cap.
Leading evidence: 'old, dried-out coolant tank cap' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'old, dried-out coolant tank cap' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check leaks' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Reported cause · Original poster
So I found where it was leaking, and of course, it was the reservoir tank...
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Reported cause
The issue was a temperature sensor that controls the rad fans.
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Performed · outcome unconfirmed · Original poster
I checked the reservoir tube that throws out coolant in case of an overfill and it had a drop of coolant so i assume that's what happened.
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Performed · outcome unconfirmed
I had them both replaced (though one is leaking again).
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31 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Hey guys!
Today was the hottest day here in MD since i owned my Porsche and i noticed that the reservoir tank expelled some coolant. I checked the reservoir tube that throws out coolant in case of an overfill and it had a drop of coolant so i assume that's what happened. Its been a good daily for the past 3 months, no complains and no leaks..This is the second time it happened recently but the first time was a couple of drops only. I did top off with water that first time the next morning..
Is this expected behaviour on these cars? I am positive the reservoir is not leaking and i added a UV additive to verify for leaks in the area just to be sure..
Keep an eye on your temps. About a quarter inch past 180 degrees when driven hard is about normal. If you can see coolant in the reservoir, I think that's OK. The high to low mark is only about a pint of coolant so I wouldn't be topping it off to the full mark as it will expand when hot and do the same things again. Lifting the pressure relieve and expelling unwanted liquid. You might want to clean some of the crap out from between the condensers and the radiators as a build up there can overheat the system. If you are a DIY man there are good video's on YouTube on how to do that job.
Do yourself and your car a favor and buy a new coolant tank cap. Latest one I think ends in P/N 04. I drive in Florida and it has been very hot lately, 90+, coolant temp. running about in the middle of the zero of 180. I never see a loss of coolant or drips from the expansion tank overflow drain pipe even on the hottest days.
The system shouldn't expel any coolant. The likely cause of this issue is an old, dried-out coolant tank cap. This is a common issue. Pelican and other Porsche sites carry the updated coolant tank cap. I had to replace the cap on both of my M96-powered cars, as the original (1999 and 2003) vintage caps both crapped out and allowed coolant to escape.
*edit* Dammit, didn't see that Joe posted the same info earlier. Oops.
MAX on the reservoir is for HOT engine with expanded coolant. MIN, or a little above, is for cold engine/coolant.
Refilling to MAX when cold will cause some, 1/2 - 1 cup?, to be expelled when fully warmed up.
UPDATE:
So I changed the coolant cap and that did not solve the problem. My next step is to replace the coolant tank but first I want to make sure that its bad.
Whats the maximum PSI that I should add to the cooling system to check for leaks?
Had the same problem and tried the quick fix of replacing the coolant cap......no luck. The issue was a temperature sensor that controls the rad fans. I can't recall how much the repair was exactly but sub $150 parts and labor.
Owner of EU Autowerks in Toronto (a favourite Rennlist Toronto shop) when I reported the problem said that the first place to look was fan operation if the cap was replaced.
Neto,
Are your radiator fans kicking on when the car is hot? (check both sides). Also, when you turn the A/C on, the fans should come on no matter the temp of the coolant.
The radiator fans operate on two different speeds, and the fan resistors that allow the two speed operation often fail causing the fan to cease working.
There are also relays in the relay panel next to the fuse block under the driver's side dash. The relays can go bad and cause one or both speeds to cease working.
If you need more info on this subject, just search the forum as there are several good threads about diagnosis and cure.
Bad news, I went to the garage of my workplace to get the car and I saw a lot of coolant on the floor. The reservoir has coolant but it is definately lower than the minimum mark. Now I am not sure If I should topoff and drive home... I will definately check on the radiator fans a bit later today before driving the car.
Since I recently replaced the coolant cap (last week), could this cause the reservoir to hold more pressure and by doing that it could crack the reservoir even more than it was? Thats why I have a lot of coolant in the floor? I think I might lost around a liter.
On the bright side, it should be a lot easier to track down the leak now that it's so obvious.
1L is not a lot. The whole system has ~23L. Not to say it's ok to drive it around since you don't know how FAST it leaks when driving the car.
Have you looked under the car?
When I got my 2003 the lower seals on the water pump housing were leaking. I had them both replaced (though one is leaking again).
the leak is coming fro the rear driver side above the muffler so I am almost positive is in the reservoir area. I made it home fine, and the car did not leak. I am noticing that it only leaks when it reaches the right part of the "0" in the 180 mark.
I assume there is more pressure in the reservoir while the car is hotter right?
My coolant tank had a leak in the same area after replacing the cap with a newer version, so I had to install a new tank. That was a few years ago and seemed to solve the problem for me.
I opted to NOT drive my care after I spotted leaks. Did not want to risk anything crapping out which might lead to overheating (and more expensive repairs). Mu guess is your tank is cracked on the backside....not visible unless off the car. Best of luck.
P.S. Would also be a good time to inspect/replace associated parts: lines/hoses, WP, t-stat, serp belt, etc.
This is what mine looked like. It started as a little antifreeze smell sometimes. I couldn't see any sign of a leak. Then about two months later I started to see a couple of drops on the "frame" under the tank.
Do all coolant tanks yellow with age regardless of the climate the car is stored in?
The coolant tank on my 2003 looks very white compared to the pics I see of leaky ones. I'm thinking a previous owner might have already had it replaced.
They get "cooked" by the heat rising from the left muffler. Interesting that the engine compartment cooling fan blows on that area.
Mine, 2003, looked white on top so I thought someone might have changed it. It was a little more yellow on bottom where the cracks formed.
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