Coolant problems - is it safe to drive two hours to the garage?

Hi all, for some context my '01 C4 cabriolet (produced August 2000) has been sitting in the garage for three-ish months during a clutch job. It has 87,000 miles, and I've put 210 miles on the new clutch. Yesterday, I was seeing little wisps of steam emitting from the driver's side of the engine bay. I thought it was just too much coolant. But after a short drive and idle , a massive plume of steam billowed out of the engine bay and it poured about 1 1/2 gallons of coolant onto the concrete. Just before I shut the engine down, the temp gauge showed normal temp. Right now, oddly enough, it's holding distilled water and otherwise behaving; this morning I drove it 5 miles to school and so far, all is normal. I personally haven't had the car for very long so I'm not sure if the engine sounds different or if it's just paranoia. My fear is that the water pump disintegrated. The thing is the coolant/water in the reservoir changed colors from clear to orange, which makes me think the water pump is at least functional enough to circulate water through the car. I need to replace the somewhat leaky water pump; the problem is that my dad's garage is an hour and forty minutes away. Should I risk it and drive it there, checking the coolant level every 10 minutes or so? Do I even have anything to worry about, or is it just the old coolant cap? Is there perhaps some way I can check the oil temp to make sure the car isn't overheating? Thanks for the help. Sucks that I just got the car from my dad and it's already acting up, but I guess you come to expect this in a 20 year old car.

DO NOT DRIVE IT!!!! HAVE IT TOWED!!!

If your water pump is bad, you risk destroying your engine if the impeller breaks apart and spreads small pieces through the coolant passageways.

Coolant tanks are known to crack and the caps can leak as well. if the water pump is leaking you should be able to tell that pretty easily. Pull the oil cap and make sure you don't have a milkshake in there. I'm not going to fill your head with fears about a cracked cylinder or head pressurizing the coolant system causing the coolant blowout.....yet. Check the simple stuff first. And, NO, I wouldn't drive it until you know the cause.

I would tow it, but just to clarify: where was the steam coming from And where was the leak coming from. Right side of the engine could be the coolant tank (upper) or the WP (lower) or any one of the hoses. That would help you determine if it�s the water pump or some other component(s) that need to be replaced.

I had a similar problem just two weeks ago. Car ran fine, then when stopping to refuel on our desert trip, it dropped a lot of coolant at the gas station. Turned out I had a major air bubble in the system after a recent flush (I didn�t do the flush, garage did it), which brought the pressure up higher than the cap can handle. It�s been running good since. Had it checked by two different mechanics, car behaves normal.

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Most common problem with these car are cracks in the coolant expansion tanks. Over time, they will crack ... this is because they're under pressure and in constant exposure to chemical and heat. Replace ONLY with a genuine OEM Porsche expansion. Be ready for the Porsche tax, because they charge a lot more for the mk1 Porsche 996 than they do for the mk2 Porsche 996 expansion tank. Watch this if you want to try to install it yourself... You Tube Driving with a coolant problem is risky and if it's a crack on the tank, it will only get worse. Depends on the length of the drive too. If you try to drive it to the shop, you better keep a close eye on engine temps. Cheers!

In my opinion the cost of the tow will be peanuts compared to the cost of the repairs you will need. So either try to find the cause yourself, or tow it to the mechanic.

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The steam was coming clearly from the left side of the engine bay. Couldn�t tell where the massive spill was coming from but Which oil cap, the filler nozzle or the oil pan? Btw the left side of the engine has always had oil leaking, maybe it has something to do with it? Hopefully not. We just changed the oil 200 miles ago (had to inspect IMS) and it looked fine with no shavings or milkshake. I�ll take off the air box tonight and look at the pump.

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I agree. The thing is it�s holding (currently) distilled water, it isn�t losing coolant, and the temp gauge shows nothing unusual. There�s definitely a bit of pressure released when I take off the coolant cap, so I�ll try to inspect the expansion tank but I don�t think it is the problem. I�m not pushing it hard anymore until I get it solved but I don�t really have another car as of now. Any chance you know how to check the oil temperature?

OP - If you want to try to detect the issue yourself, you want to pressurize the cooling system, without running the motor, to find leak points. If you can’t find the issue, do not drive the car. Even a $300 tow is massively less expensive than a multi-thousand dollar repair/replace of an M96.

Only Durametric will show you the oil temperature. Hope you find your leak.

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Obviously, the coolant tank is on the driver side so that's the likely culprit. The coolant tank cap is a known issue, and on my car at least it has to be tightened past where I'm comfortable to get it not to leak. When I don't really tighten it, it leaks and makes white steam.Did you recently check the coolant level and then not tighten the cap enough? That happened to me last week. The indicator that this is not a major issue is that the coolant loss didn't seem to come from the car overheating. Meaning the steam was likely caused by an issue in the cooling system, not an issue with the engine getting too hot. All that said, don't drive it until you figure out why and where its leaking. Overheating your engine even temporarily can cause permanent damage.

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When you get a hairline crack in a pressurized tank, it will still retain pressure, but overtime it will spew lots of coolant out. Don't be fooled. More than likely, it's the plastic tank. Also, don't be fooled into purchasing an aftermarket tank, buy it from Porsche. Also, the steam is more than likely from the expansion tank spraying coolant/water onto the exhaust which of course is extremely hot and will create the steam you describe. Personally, I wouldn't drive the car in this condition, but as I said before, if you make the trip, keep a close eye on the temps. Overheating these engines is very bad. That's why it's better to err on the side of caution and protect your car.

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thank you for the help. How can I ensure the temp gauge is accurate? Is there any chance the water pump can fail entirely, not circulating water, thus overheating the engine while seeming normal?

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What you're talking about is the failure of two systems at the same time, the water pump and the monitoring system. Also the failure of the monitoring system is such that it is sending incorrect temperatures, not no temperatures. I suppose its possible, but is really highly unlikely. And look, the cooling system on these cars is fragile. The coolant tank cracks (my car is on its second), the coolant cap seals fail (third or fourth), and there's a coolant hose connector on the front of the engine that will murder everyone you care about if you touch it (not really, but it does break easily). I'm surprised that the radiators being so far away from the engine doesn't cause more issues, frankly. In all probability, you've got a coolant leak, like a lot of us have had. Its possible the water pump is leaking but from where the steam is coming from, its probably the tank or the cap. Have it towed to this shop and they'll figure it out.

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Yes, the impeller can come loose from the shaft, the pulley can also come loose from the shaft, and the shaft can break.

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Yes, but then the car would overheat and his temp gauge is showing normal.

get AAA and get it towed.

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Yes, this is exactly my fear. My question is if the water isn't circulating, is there any way to know? Because if it's not circulating, perhaps it is possible that the coolant temp sensor is not sensing water coming from the heads, but instead the water which is just sitting where it is, heated up by radiant heat. For example, if the pump isn't working and there is no circulation of the water in the system, is it possible that the temp gauge is just reading the non-moving water where it sits? Or is there some safeguard against this, such as an oil temp sensor or maybe a temp sensor somewhere in the engine, that would perhaps throw a check engine light? Surely Porsche wouldn't put the faith of protecting the engine from overheating into one coolant sensor... And one more thing - is it possible that the problem was just a loose cap? Or rather, could a loose cap cause about a gallon and a half of coolant to spill out and steam to billow like in the movies? This happened after a short, warm drive to a drive thru and sitting at idle, about 2 or 3 miles.

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Possible. Check around beneath the cap and look for dried water residue on top of the tank in that area. These caps need to be installed tight. Read that as TIGHT!

I'm dealing with a similar problem. I'm 90% sure it's the coolant tank (it's yellow). Twice in the last few weeks It leaked coolant out below the driver's side muffler after being parked for a while. No steam, not a lot of coolant and engine temps were normal. It acts like it's only leaking when the tank gets pressurized after stopping the engine. The second time I stopped driving it and now I'm waiting for Pelican to send me a new tank. Mine's a '99 and I'm hoping I can do it without lowering the engine.

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My tank started leaking so slowly nothing was even hitting the ground. After driving in hot weather and parking in the garage I could smell antifreeze, but nothing was visible. After some time I started to see dampness on exhaust parts and finally a drip on the floor. When the tank came off it was cracked down the back and the crack exhibited dried water deposits. After changing the tank the smell went away.

Mine only does it when I park it and walk away. Apparently she's shy about wetting her pants.

DO NOT DRIVE THE CAR, HAVE IT TOWED!!!

This seems a bit of a �right of passage� with these cars. My story happened on my drive home (Charlotte) after picking up my new to me 2003 C4S from Denver. I had made it to the Tail of the Dragon and pulled over to enjoy the view. I looked in my rear view and saw steam rising from the engine bay. Now I had just sold my 964 so steam was a new phenomenon as this was my first water cooled Porsche. Luckily my insurance cover 200 miles of towing and had it towed to the nearest Porsche dealer. They found that there was air in the system so the air bubbles rose to the top during my spirited driving at the TOD. In addition, there was a slight crack in the expansion tank. I suggest you tow the vehicle to your nearest dealer and have them check out the coolant system and do not try and drive it there. Why risk it? Good luck!

Where are you located? Maybe one of us is near you.

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100% - get AAA Plus Membership for $150. You can use them 24h after payment. You will get four 100 miles tows / year and additional services. You could use them later if you have a flat if you dont trust a 20 yo spare. It is key when you have an older car. I am not affiliated to AAA.

Thanks for all of the advice, right now the car is behaving normally. I believe it was a loose coolant cap or a cracked coolant expansion tank because it hasn�t *yet* lost its fluids again. I don�t plan on driving it much until I replace the water pump but it seems safe enough for the drive as the temp gauge doesn�t show that it�s overheating. Once I get it to the garage I�ll get all of its cooling maintenance done; I�ll update if something else goes wrong. Soon enough I�ll have a lift and do all of the maintenance it needs. P.S.: I�m located near St. Louis.

sauregurke, if my experience with the dashboard temperature gauge dissuades you from driving the car, I will be gratified. I'm on my way to meet the family for lunch on a May afternoon when all of a sudden the temperature gauge light starts flashing. Luckily, the restaurant was just past the next light, so I pull in and pop the trunk, coolant reservoir looks low so I go in and have lunch and when I come out I pour in almost two 2 liter bottles of water that I always carry in the front trunk. l get home uneventfully and the next morning check the coolant reservoir and its full of intermix!!! Mind you, the temperature gauge never went past the 0 on the 180. Normally, the needle on the temperature gauge meanders between the start of the 8 and the end of the 0 depending on ambient temperature and traffic conditions. The point is, although the temperature gauge was within the normal range, the damage was done, cracked head and all that that entails. The culprit was a pinhole crack in the coolant reservoir and, but for the flashing light, the temperature gauge was reading within its normal range and I would have done a lot more damage than I did. I never saw a leak, or saw steam, or smelled coolant. I strongly recommend that car not be driven until the cooling system is 100%, but its your car to do with as you wish. Best of luck.

I tapped the front left corner of the car on a high curb. Did not see any coolant leak, temp seemed fine, so I drove ONE BLOCK to my home, backed into the driveway and saw the pink trail of coolant. Replaced radiator and refilled system, did not use vacuum system. Went maybe 20 miles before head cracked fully and coolant intermix, rebuild. Pretty sure it was that one block drive that initiated the crack, maybe the refill was not perfect. These heads crack really easily. You asked for advice, looks like you are ignoring a lot of good advice to TOW THE CAR. $150 vs. $20K?

Yeah, I had mine towed 5 miles, rather than risk injuring it further.