Cooling System

[James-Australia]

Hi to all, well it had to happen to me. Did a good deed by taking an older citizen out for lunch and while leaving and reversing to drop him of, I reversed slightly into a footpath divider. Well, got out more like jumped out to check and saw liquid gushing out and first thought turn of engine :blush: . For a minute thought is was petrol and my friend the old codger in my car was about to turn into barbecue bill. Relized quickly was water pouring from the the disconected coolent hose. Got towed on a tilt truck (flat bed) with more water out as tilted on an angle.

Ok sorry to bore you all :huh: my question and advice needed is >>>>>

now that i have lost water/coolant but having replaced the coolant hose with a new one from the dealer,

'can i just top up with coolant and distilled water' or,

do I need to get a coolant system flush/refill at a dealer?

Does a mear disconnection of a small coolant hose and loss of fluid require a total coolant service?

Much appreciated

Edited October 17, 2012 by James-Australia

[Loren]

It is always best to do a vacuum coolant fill mixed to factory specs.

Just consider it "early preventative maintenance".

[EleCTriCT]

some info on pressure test and filling adapters

http://www.renntech.org/forums/topic/40994-cooling-system-pressure-tester-adapters-available/

cheers.

[James-Australia]

Hello and thank you for the 2 replies. The question I still have is if I can top up the water and drive it to my nearest service centre or advisable not start it up at all so as not to cause damage on start up. You see when you contact your service centre they put the fear in you to a point where you have to relly on forrums to get an open opinion. So some feedback would be helpful.

Thanks

[Ahsai]

Since your car was tilted and you don't know how much coolant was lost, I think it would be safer to tow it to the dealer. If you just refill without a vacuum tool, you risk air pocket and hot spots created inside the engine when you drive it.

[white out]

What's wrong with burping the coolant system the "old fashion" way?

Edited October 18, 2012 by white out

[fpb111]

James,

This first three sound like a Boxster filler in the rear trunk.

Here are steps given in the service manual for bleeding the air from the coolant system:

1. Consider covering the trunk with plastic in case of a coolant overflow.

2. Remove the radiator cap, oil filler cap, and dipstick.

3. Pop the cover trim plate off the filler access area. This reveals the bleeder valve. If you remove the little screw above the trim plate to do this, be extremely careful to not drop the screw into any of the filler necks.

4. Flip the bleeder valve locking clip up to release it.

5. If you have an automatic transmission, remove fuse B1 (the ATF cooler valve).

6. Fill with coolant up to the bottom edge of the filler neck.

7. With the engine idling, occasionally revving the engine, fill up with coolant until there's no more room when the engine is revved. (Revving may raise the level a bit.)

8. Replace radiator cap.

9. Warm up engine until you are sure the thermostat is open. 10 minutes at 2500 RPM should do it, and you should hear the radiator fans come on.

10. Run 5 more minutes at 2500 RPM, revving to 5000 RPM every 30 seconds.

11. Carefully open the radiator cap, and top up the coolant.

12. Replace the radiator cap.

13. Run 5 more minutes at 2500 RPM, revving to 5000 RPM every 30 seconds.

14. Idle until the radiator fans cycle on and off once.

15. Carefully open the radiator cap, and top up the coolant.

16. Put everything back the way it was.

Edited October 18, 2012 by fpb111

[Loren]

What's wrong with burping the coolant system the "old fashion" way?

You will never get the air out.

In these new alloy engine the wall thickness is much less (reduced weight and increased strength) than old engine designs. Problem is that it is easier to get "hot spots" that can damage the engine very quickly.

I would not bet $21,000 plus replacement engine on "hoping" I have enough coolant or no other damage was done.

[white out]

I understand that the 996 has weak cylinder walls, but the engine shouldn't get hot enough burping the system to score or crack a cylinder.

The coolant tank is the highest part of the coolant system, how wouldn't air get out after properly burping the system?

Edited October 18, 2012 by white out

[Loren]

Air rises and gets trapped in parts of the casting - when the engine heats these "spots" get hotter as there is no coolant flowing by them.

From the 996 tech book...

"The principle of cross-flow cooling with fully integrated cooling water channeling was implemented to ensure that the cooling water is distributed evenly to all of the cylinders. A temperature drop between the individual cylinders is thus prevented. The cooling fluid is supplied through integrated lines. As already described in the casting techniques under Oil circulation, all of the cooling channels in the engine are produced in the casting process. Additional lines or hoses in

the engine are no longer required which, in turn, results in high reliability and low servicing requirements.

In the case of vehicles with manual transmission, 2 cooling modules (4) are used for cooling. These modules are mounted in the fenders in front of the front wheels. In the case of vehicles with Tiptronic transmission, a third module (14) is mounted in the front end of the vehicle. As a result, the ATF can be cooled using an additional oil-to-water heat exchanger in a common water circuit.

To prevent ice from forming in the oil separator at low temperatures, the oil separator is surrounded with coolant. The implementation of a special coolant means that the coolant does not have to be changed. It must be ensured that only the coolant prescribed by Porsche is used. The coolant capacity IS 22.5 liters."

[white out]

None of the information you just posted suggests that the system cannot be burped the traditional way. The coolant fill tank/expansion tank is the highest point of the coolant system. Under pressure air goes up, in the 996 it will end up in the coolant fill tank/expansion tank. The pressure created by the cooling system bleeds the cooling system of air.

Basic physics is generally impossible to change.

[James-Australia]

^{Hey guys and gals Ive created some healthy debate with my query. Please dont argue everyone has there own opinion. Well I've booked the vehicle in for a cooling system service and $500.00 later I hope my baby works well. Call me an idiot but the fear is already in me and its like my girlfriend sais 'i know everywhere you go and see everything you do' so better play it safe :P . All in all I still dont understand why the Germans would design a sports car and place a 100ml rubber coolent house at the very base of the engine at such a vulnerable position. The coolent 'pipe' could have continued right through. Maybe time for a 997. Thank you for your coments. All the best.}

Edited October 19, 2012 by James-Australia

[DBJoe996]

So glad to hear you got things fixed up right. There are all sorts of sensitive vulnerable things under there! Would suggest NOT backing over any more footpath dividers. Since the car is lower than most, it requires careful attention in parking lots...those concrete parking curbs can do some real damage. You did learn a little bit about your car and now have some valuable experience..and the car turned out okay...so smile and drive!

[JFP in PA]

None of the information you just posted suggests that the system cannot be burped the traditional way. The coolant fill tank/expansion tank is the highest point of the coolant system. Under pressure air goes up, in the 996 it will end up in the coolant fill tank/expansion tank. The pressure created by the cooling system bleeds the cooling system of air.

Basic physics is generally impossible to change.

Unfortuantely, Lorem is correct; there are other "high points" in the cooling system, such as the oil cooler, that are traps for air. Even with multiple manual "burpings", it is not unusual to find air trapped in system, which does not dislodge under pressure. Vacuum filling totally eliminates any trapped air, and any chance for hot spots to form and potentially cause damage.

Edited October 19, 2012 by JFP in PA