996TT coolant consumption

[laalves]

Yesterday the computer display warned me to check coolant level. Temperature was nomal: 80ºC.

I stopped and checked the level and indeed low it was. Went to the closest gas station, temperature stable @80ºC, bought the fluid and replenished. Took two and a half litres to become halfway between MIN and MAX.

I drove this car for about 7000km since I bought it, from a Porsche Zentrum, fresh out of the major check @83700km.

Is this consumption normal? My tailpipes look normal, I don't get any smoke clouds behind me and I also don't get any puddles on the ground.

What are your experiences regarding coolant? Note that temperatures have been in the high twenties (ºC) lately.

[Loren]

No that consumption is not normal. You either have an external leak or an internal leak.

Check the obvious first - look for leaks under the car, check the tank cap and coolant tank itself (for cracks). 996TT is also know to blow a hose off - but if that happened you would have lost most all of your coolant.

[PTEC]

A small amount of consumption is normal. All water cooled cars will "use" some coolant. Its possible the coolant wasn't topped off at the last service. Top off the reservoir when the car is cold and keep an eye on it.

Edited July 6, 2008 by PTEC

[laalves]

Mmmmmm.... Two different opinions. I guess I'll have to keep an eye on it. I have no external leaks, that's for sure.

If I had internal consumption, I would expect foamy oil and/or exhaust stains in the tailpipes and/or exhaust smoke. None of those signs exist. Obviously the foamy oil is not easy to spot, what I did was to remove the oil cap with the engine hot and check for foam. Again, if the hose is too tall, I may have foam and not notice it.

I have rechecked the level today and what is missing from the coolant can I bought, and it actually topped out with 2 litres.

I'm going to watch this closely now.

[Loren]

2 - 2.5 liters is quite a bit more than normal consumption IMHO.

[White987S]

I agree with Loren, that's a ton of fluid.

I hope you added a compatible fluid. Could be something as simple as the coolant cap or they did not properly fill the system at the last service.

[RFM]

Don't forget to check the piping under the oil filter area on top of the engine for cooling water residues too. The cooling water drips on the flat top side of the hot engine and evaporate, there are no drips on the floor in this case.

[Chuck Jones]

If it was the cap with that amount of fluid loss, you'd defiitely see the white encrusted residue around the lip of the top as well as the telltale white crustation down the side....he doesn't indicate he sees any indication of a point of origin for the loss....so perhaps the he should look up towards the front radiators? Porshe likes those dogone clamps they use kuz they can be assembles so quickly....and whenever I run into them on a project, I replace them with the screw type stainless ones.

As Loren said, the 996 TT has had more than its share of blown radiator hoses....mine blew on the passenger's side...and that side seems to see more blown hoses than the driver's side. What seems strange to me is that with the amount of fluid you say youre losing....that you cant' see an exit point. Two litres is a LOT of fluid to come up as MIA.

[laalves]

Well, I am worried. There are no residues/incrustations around the cap, nor anywhere visible.

Also, no fluid on the ground anywhere in my garage, front or back.

Can only hope it wasn't topped up for long, including in the last service, 7000km ago.

We'll keep you guys posted.

[laalves]

Went downstairs, had the car running for a while and checked again. No residues, no steam, nothing.

Took a note of the P/Ns of the tank and cap:

Cap: 996.106.447.00

Tank: 996.106.057.01

Any known glitches?

Edit: a bit of searching here and Googling elsewhere has convinced me I may need a new coolant cap, 996.106.447.01 or later. Going to try that.

Edited July 6, 2008 by laalves

[White987S]

Did they do a coolant service at the last major service?

[laalves]

Did they do a coolant service at the last major service?

They ticked it in the checklist....

[Loren]

The cap should end in part number -01 or 02. Caps with part number -00 are known to leak.

Caps are under $15.

[laalves]

The cap should end in part number -01 or 02. Caps with part number -00 are known to leak.

Caps are under $15.

Yes, thanks. I have just sent an email order to my dealer. The PET doesn't even list the -00 any longer, only the -01.

[porha]

hello

maybe,if the car had leaks before you bought it,and there was some changing(hose,radiators),maybe there was some air left in the system,and after those miles just went out. watch the coolant level every day if the leaks go bigger

sorry for my english

[PTEC]

Definitely update the cap. I didn't mean to imply that using 2.5L liters of coolant in 7k km was normal. What I meant that its possible that the coolant wasn't at the max level when the car was bought, even if it had a major check. As someone mentioned too it is possible there was air in the system from a previous repair and it worked itself out and the level dropped that way. If its not puking out on the ground the only way he can really do is to put the level to max himself and just drive it regularly and see what happens.

[JeTexas]

If it was me, I'd pull the oil drain plug to see if the oil looks like chocolate milk. If you drain it into a clean container, and the oil is clean, you can always pour it back in.

[Loren]

Oil/coolant mix would be very unusual on a 996TT.

[Chuck Jones]

I agree with Loren....very unusual to get the intermix on a TT.....however I'm beginning to like the scenario that perhaps a hose or something let loose before he bought it and the dealership replaced the errant part and refilled the system without letting it burp out the air. I know in my 99 996 when I replaced the cracked coolant tank....it seemed like it took almost ten days of coolant levels dropping down before it finally burped the air out of the lines and the coolant level stabilized. Up until that time I was going crazy trying to figure out where the coolant was going....it wasn't going anywhere....it was just the level stabilizing.

Once you get it filled it should stabilze out.....if it doesn't, then with that amount of coolant being lost, there has to be a major leak somewhere, but my bet is that it wasn't filled correctly to begin with.

I'm more concerned over your comment that you went to the auto store and bought "a can" of some replacement coolant....what did you buy that you put in there? Did you buy the Porsche coolant? Some of those other coolants don't mix well with the Porsche brands.

[laalves]

Right, so I went to the local Porsche Centre, talked with the chief mechanic and bought a new model cap. Interestingly, the label of the plastic wrap said "-01" and inside came a "-02" cap. Blue in colour, "Blau" in brand.

The plugging bit is quite different from my also blue, also "Blau" old "-00" cap.

So, the chief mechanic also told me it would be very unusual to have oil/coolant mix in a TT, he couldn't remember seeing such a thing. He obviously told me to keep an eye on the level, if it goes down I have a leak. He referred that, if I have damage to one of the radiators, due to sidewalk climbing or something, it may not leak while stopped due to having little to no pressure there but, while driving, it may leak. Given the symptoms, he believes that if the level goes down again, that is likely to be the cause.

Checking the looks of all the hoses I could have an eye on, they look quite new, not quite coherent with a 6 year old car. A lot of the pipes and fuel lines around also look much nicer than one would think of a 6 year old. Further, I also actually had some incrustation of water residue arounf the cap and in the cap itself.

Well, I will keep a watchful eye on this.

Thanks to all and this great forum!

[White987S]

Had the car been involved in an accident (frontal) prior to your ownership?

[laalves]

Well, it has the full Porsche Gebrauchtwagen warranty, so it cannot have had one. That's one of the conditions for being qualifiable for a second hand factory warranty here in Europe. Assuming the people involved were honest, I would say no. Hopefully.

[White987S]

I only suggested this (frontal accident) because you stated the hoses and fuel lines looked very new for a 6 year old car.

[laalves]

I only suggested this (frontal accident) because you stated the hoses and fuel lines looked very new for a 6 year old car.

Ah, ok. Actually I meant the engine compartment stuff. I figure they replaced a bunch of stuff for factory warranty requirements compliance.

Cheers, Luis

[White987S]

Luis, have a nice glass of vintage port, and don't worry about the coolant anymore! Just keep your eye on the fluid levels every couple weeks. :)