Steaming! EEK!

So, topped up the oil today, noticed the coolant (or whatever - on the left hand side) was below the min mark, so topped that up with water. Took her for a spin, all was well, until I stopped at home, and noticed steam coming out of the engine cover. Opened the boot, and as far as i can tell it was coming from the coolant thing, and there was water all over the engine near it. This has never happened before, so should i have filled it with something other than water? I'm somewhat panacking as ive heard about the header tank not being covered under warranty, and a pricey fix... it seemed fine... but i'm looking for some reassurance! [ ]

Check the coolant tank cap. I seem to remember reading something similar to this problem before, where the relief mechanism integral to the cap had lifted allowing coolant to escape. Have a look at the cap, there is a metal 'spring clip thing' which I think is part of the relief valve mechanism - check it is seated. Hope this helps.

Happened to me once - all it was in my case was that I hadn't screwed the cap on properly!!! Needed about 2 litres of water by the time it had stopped blowing it all out and was fine afterwards. Which was just as well as I was in Germany on business at the time.

Also worth checking the header tank cap. If the part number ends in 00 then it's the old type, and these have a tendancy to leak. Some coolant often gets blown off after a feisty blast but usually this goes into the catch tray by the cap/down the overflow tube. The part no. for the newer version of the cap ends 01. If there is a crack in the tank (and it's likely to be difficult or even impossible to spot) - and very possibly the problem manifests itself only when the coolant temp gets higher than normal - then it's going to be a new tank. It's not such a huge job and you should be able to get it down by a specialist for somewhere between 200 and 300 notes (the tank alone costs about 120). Or, of course, it could have been that you didn't tighten the cap down (as mentioned already).

Thanks guys, Well its a '98 R C2, I just went back down now it had a chance to cool somewhat (still around the 80 mark). Didnt see the part number thing beforehand, but i couldnt see a spring, there was a mesh inside a blue cap if that helps? The level was back down to minimum, i tried the cap on tight and it looked okay - no obvious leakage there. I guess I just need to wait and see if it happens again, then its either a new cap, or worse, a tank!

Seems the odds are that most likely you've got one of the older caps anyway so trying a new one is worth a go. If the problem persists you are most likely looking at a new tank. The tanks do deteriorate (stands to reason: plastic construction, lots of hot-cold-hot, etc.) so it's probably bound to happen sooner or later. I lived with the problem for a while; it only ever lost coolant when I'd been doing a lot of stop-start driving (London was lethal!). So, in the end, I bit on the bullet and got a new tank. No probs since.

Well, the level was a few mm over the min, so i made sure the cap was tight and went for a 'gentle' drive. All was well. Then I had some fun, and it was still fine. So either I was a numpty and didnt secure the cap, or the crack is higher up... so ill fill it up tomorrow and try again..

My theory is that when things get hot any "crack" (and it could be as small as a pin hole) opens up and so allows coolant to be lost. But it is just a theory.

That makes sense - which is why i took her for a spin as well... Anyway, im going to top it back up now and see what happens!

Good luck - you'll find out sooner or later (tried-and-trusted trial-and-error method)!

Okay, topped up this morning, took her for a good long enthusiastic run and all is fine, not some much as a sniff! So it was either the spring in the cap (did have a fiddle) or more likely, numpty here didnt tighten it enough!

Bear in mind with all this topping up with water your coolant mix is going to be heavily diluted.....if u were to go by the book, u would have to take the car to Porsche to have that dilution addressed with Porsche coolant......or at least u should be using some kind of coolant and not water......Porsche may reneg on some claims if they see u topped up your tank with water.

Good comment/observation.

ah? okay. Should I take it to Porsche then? Or could i buy some specific coolant from Halfords etc?

I'd say it would need to be a 'Porsche approved' product but I don't have a list. Pop into your OPC and ask just to be on the safe side.

Apart from going to Porsche, and getting stung for the nice black plastic Porsche bottle, the only one I know of with Porsche approval is Havoline AFC. Rumour has it that this is what Porsche re-bottle. http://www.arteco-coolants.com/approvals.htm

The problem is you can't know how diluted your coolant is, unless u know precisely how much you've lost, and how much water u put in (not necessarily the same)...so how are u going to know how much coolant to drain and replace? (assuming u know how to) In the manual it states 'If in an emergency pure water has been added, the mix ratio must be corrected at an OPC' To go by the book, you'll probably need to drain the entire system (not easy - maybe get a pro to do it) and start again using some Havoline AFC as Richard mentions. Remember this is all 'by the book' advice.....I'm sure your engine will run fine as is....you could always hazard a guess as to how much water u put in, work out the current concentration, drain out some of your existing coolant mix and add some undiluted approved coolant to bring the 'mix' back up to 'approved' levels. That's what I'd do anyway. Phew![:-]

Hi Fidgits, I've had overflow problems on one of my previous cars (not a 911). Although in your case it could have been the filler cap it is definitely a no-no to fill up with water only and not a 50:50 water antifreeze mix. The antifreeze doesn't only lower the freezing point it also raises the boiling point. If you are driving in a spirited fashion (or sitting static in traffic, climbing a long hill) with a diluted mix you could have had local boiling and a rapid increase in coolant pressure hence the overflow. If you correct the mix and get a new filler cap and it happens again then the most likely cause could be a small leak in a cylinder head gasket or cylinder liner. If it was a big leak you would notice a change in the coolant colour (to white you may also get an oily residue floating on the coolant) and possibly a build up in yellow emulsion on the oil filler (though this is common on 911's) and white smoke under engine breaking from an/the exhaust/s. A small leak just builds up the presssure in the coolant system over a period of time while running leading to a burp out of the filler but can lead to a big failure. My advice is to keep an eye on the temperature gauge for a few longish varied runs until you are sure the problem has gone. It may be nothing but keep an eye on it and only top up with water in an absolute emergency. Google engine overheating to learn more if it continues to be a problem Cheers, Hilbert

By filling with water only, you will also be reducing the corrosion inhibiting properties of the coolant. Arteco suggest at least 33% HFC to give protection down to -20°C, and 50:50 down to -40°C, so you should be OK for now provided you haven't used more than a couple of litres of neat water to top up. The system capacity is 22.5 litres, so I'll leave it to you to work out what your dilution rate is likely to be! You still need to get it corrected though.

right... i'll call my local indy tomorrow and see if he can drain/refil the coolant for me. Thanks for all the replies guys!

Just called my local indy. He 'stated' that the coolant needs 11 litres of the coolant with a small amount of water, and an hours labour.. So his price for draining and refilling the coolant was 128.66 !!! I was expecting 50-60 quid max... can anyone comment on the above price - is this right?

Okay, nothing like a big number to put your brain into action. I added somewhere in the region of 1 litre of water, so if the capacity is 22.5 litres, I wont have diluted it that much, and i can simply 'top it up'. I'm loathe to pay that much money just incase the tank does have a crack, and then get a 400 quid bill, plus the 128 again to fill..

By my reckoning: Optimal mixture: 11.25l water/11.25l Coolant Your mixture: 11.75l water/10.75l coolant ( u lost 1l coolant mix, u added 1l water) Removing 1l of your mix you get: 11.25water/10.25l coolant(not exactly.Near enough) Adding 1l of coolant u get: 11.25l water/11.25 coolant. So u need to remove 1 litre of your current mixture, and then add 1 litre of 'pure' coolant to get your 'mix' back to 50:50. Assuming you have 22.5 litres capacity and u added/lost 1 litre of water/coolant. No need to spend £128.66 [ ]

I was hoping to infer in my previous post that you are unlikely to have diluted it sufficiently to be worth worrying about. If I were you, I'd just get a litre of coolant, and use it neat for top-ups. Edit: Beat me to it Rodney!

Great minds Richard![ ]

re-bottle? re-bottle? What? Porsche? Oh come on now Richard, what on earth are you trying to say? [&:] [ ]

yeah, thanks guys, thats the way i was heading on this... seems silly to get the system flushed for the sake of 1 litre of coolant..

I am gonna stop reading these posts. On the way home tonight - blinking temp gauge, temp rising and on reaching home steam issuing from the front PU - Now I am thinking rad or a hose. With a 128 quid for a coolant drain and refill anyone got an idea on the cost of the rad being replaced. Could have done without this the day before I leave on business to Texas - Now I have to rely on the Mrs to sort!!! God help me I will probably come back to a Vectra siting on the drive!

You could suggest that while you are in George Dubbya's home state that your wife swaps your Water Porsche for an Air Porsche so that the problem does not recur. I'll bet that she sees the sense in this.[8|]