996 3.4 Coolant Eruption
Discussion
2 weeks ago the low coolant light came on and I topped it up with about 1l of distilled. I put too much in; it was dark and I put in probably 0.5l too much. All was fine, I drove about another 200 miles. Fine.
On Saturday I drove to my godson's in Westerham from Abingdon, where I live. I drove the last 5 miles from the M25 junction rather spiritedly on the fast country roads. 2nd and third gear, most of the revs in 2nd. I pulled up outside their house and made a quick call with the engine running. 3 minutes or so. I pulled into the drive and noticed a lot of steam coming from the back. No odd noises, though. I foolishly did not look at the engine temp light before I turned off. I look at it all the time in general though and would have noticed if it had overheated. I don't think it had. Going round the back coolant was pouring out onto the ground. It then stopped doing so quite promptly. There was no obvious leak under the car, but it was coming from the left hand side. I did not open the lid when it was pouring out. When Indid there was coolant around the top of the tank around the cap. The coolant is pink and you can taste it in the air! I did not want this to spoil my day so just left the car.
Next day I opened the lid and the car took 4.5l of distilled. I'm the sort of man that has this on hand. I turned it on. All was well. No noises, no obvious spurtings. I drove back to Abingdon gently, stopping at the new services on the M25. The coolant seemed lowish, but not really low and the light had not come on. Back in Abingdon this morning, I looked at the level and I put in circa 0.5l of distilled as it seemed low ( stone cold now). Spoke to Hartech and Tobias was out and they'll call me back. The car's in good condition and was serviced at Hartech in August. It has a low temp thermostat and is a veteran of a lengthy Alpine tour over the summer. It needs no oil, usually very little coolant (1l per 8000 miles), and the rads are fine, I understand, and have been replaced at points over the car's life.
At length, is this just coolant expanding and not having much air to compress as the tank was overfilled? Pressure is released as the coolant is very hot after a spirited drive and then a complete halt. As pressure is released coolant boils and rockets out of the cap holding valve open... I hope so, otherwise I will need some new plumbing.
Any thoughts gents?
On Saturday I drove to my godson's in Westerham from Abingdon, where I live. I drove the last 5 miles from the M25 junction rather spiritedly on the fast country roads. 2nd and third gear, most of the revs in 2nd. I pulled up outside their house and made a quick call with the engine running. 3 minutes or so. I pulled into the drive and noticed a lot of steam coming from the back. No odd noises, though. I foolishly did not look at the engine temp light before I turned off. I look at it all the time in general though and would have noticed if it had overheated. I don't think it had. Going round the back coolant was pouring out onto the ground. It then stopped doing so quite promptly. There was no obvious leak under the car, but it was coming from the left hand side. I did not open the lid when it was pouring out. When Indid there was coolant around the top of the tank around the cap. The coolant is pink and you can taste it in the air! I did not want this to spoil my day so just left the car.
Next day I opened the lid and the car took 4.5l of distilled. I'm the sort of man that has this on hand. I turned it on. All was well. No noises, no obvious spurtings. I drove back to Abingdon gently, stopping at the new services on the M25. The coolant seemed lowish, but not really low and the light had not come on. Back in Abingdon this morning, I looked at the level and I put in circa 0.5l of distilled as it seemed low ( stone cold now). Spoke to Hartech and Tobias was out and they'll call me back. The car's in good condition and was serviced at Hartech in August. It has a low temp thermostat and is a veteran of a lengthy Alpine tour over the summer. It needs no oil, usually very little coolant (1l per 8000 miles), and the rads are fine, I understand, and have been replaced at points over the car's life.
At length, is this just coolant expanding and not having much air to compress as the tank was overfilled? Pressure is released as the coolant is very hot after a spirited drive and then a complete halt. As pressure is released coolant boils and rockets out of the cap holding valve open... I hope so, otherwise I will need some new plumbing.
Any thoughts gents?
Coolant system is sealed so won't lose a drop unless there is a leak. Often only sign of leak is when engine running and up to temp or just turned off, as will only escape when pressurised, and leaks during running will just boil off as touches hot engine parts.
Your first low coolant warning indicated a leak, but obviously you need to find the source! Least expensive is a too loose hose clip (has any work been done requiring coolant hose removal recently?), most expensive is radiator leak or even water pump. Your driving style won't have precipitated leak - the cooling system will hold a steady temp once operating temp reached.
The simplest way of finding leak is to pressurise system when cold using coolant pressure test kit, which replaces lid of expansion tank. No risk of overheating and you can feel all round hoses etc without 3rd degree burns! Also look carefully under car after it's stood for any patch which can give you clue about leak location.
Your first low coolant warning indicated a leak, but obviously you need to find the source! Least expensive is a too loose hose clip (has any work been done requiring coolant hose removal recently?), most expensive is radiator leak or even water pump. Your driving style won't have precipitated leak - the cooling system will hold a steady temp once operating temp reached.
The simplest way of finding leak is to pressurise system when cold using coolant pressure test kit, which replaces lid of expansion tank. No risk of overheating and you can feel all round hoses etc without 3rd degree burns! Also look carefully under car after it's stood for any patch which can give you clue about leak location.
Edited by stratfordshark on Monday 21st October 18:39
Edited by stratfordshark on Monday 21st October 18:41
Thanks, I will of course look for leaks. It is quite normal to use half a litre of coolant in 8,000 miles. It is not a sealed system exactly as it has a pressure release valve in the cap. If over filled that cap is activated as expanding liquid with nowhere to go creates sufficient pressure. I have had two 996s and driven 60,000 miles in them, and had 4 rads and 2 header tanks and two header caps replaced.
My situation was an eruption of coolant seemingly from the cap. Followed by a 100 mile drive with little to no loss of coolant. This occasion cannot have done the car any good but there is a reason for the pressure cap...
My situation was an eruption of coolant seemingly from the cap. Followed by a 100 mile drive with little to no loss of coolant. This occasion cannot have done the car any good but there is a reason for the pressure cap...
i had a leak on my front rad, which you have not got as you have checked there! But if the filler cap has leaked (as everyone knows this is common fault & cheap to fix!) or you have just used a bit of coolant over time, perhaps when you over filled it something has air locked! I know that my mechanic, when he changed rad & refilled system says there is quite a lenghty procedure to "burb" the system! You have to put on ramp at angle & run at certain revs to get rid of air lock! Could be it?
let us know ?
cheers Ian
let us know ?
cheers Ian
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