996 Coolant disapearing and reappearing
04-18-2015, 09:47 PM
#31
Race Director
Thank you for your response.
In California, the Porsche mechanic replaced the water pump, spark plug, coolant. He tested the car 70 miles. Apparently the car was working fine. When I picked up the car in Bellingham (it was towed), it was smoking ( like in some of the You Tube video), but we only let it run for 1 mn. The first Porsche mechanic in Canada replaced the AOS and the coolant tank (was told it was fixed). Picked up the car, but then within 10 miles, 4 gallon of coolant disappeared. Returned car to first mechanic. Was told me the motor was toast (coolant in the exhaust). Towed the car to a second known Porsche mechanic. They replaced front radiator hose, refill coolant, checked for leak run engine and bleed air, but he told me that exhaust gasses are super-pressurizing cooling system and suspect major motor repair work or replacement. (however, no coolant in exhaust)
I drove the car the next day and have been driving a few miles almost every day and trying to burp the coolant in case. (I start my day on a hill trying to burp any air from the coolant reservoir)
Many people on this site keep thinking like me. The motor run nice, start no problem, run smooth. But I keep smelling coolant on the back left of car.
and, the coolant tank pressure remains overnight. When I drive there is no increase in temperature past the 0 of 180. No loss of coolant, but level below minimum when I drive. Also oil pressure just below 1 after 30 mn drive at idle (start the day at 5, pressure normal when I accelerate). Level going up to normal level after I open the lid of the coolant reservoir the next day (after a hiss sound)..
I like the idea to throw water from a bucket to check if it could remove smell.
I think these are my options:
1) if smell =a) leak b) coolant around motor outside reservoir
2) if pressure remains in the coolant tank overnight = a) air pocket, b) bad tank c)broken hose d) cylinder heads and/or cylinder sleeves.
Note: re. the engine light mentioned in previous post: The sensor was P1130 oxygen adaptation, idle range 2 - Above limit Suspect mass air Flow metre is starting to fail. As mentioned so far the engine light has not come back yet.
If it is bad tank, could it damage the motor or just keep pressure in the tank and then leak coolant?
Now, I am not a mechanic, but I would think that a simple pressure test should eliminate all problems other than 2 d) Am I right?
In California, the Porsche mechanic replaced the water pump, spark plug, coolant. He tested the car 70 miles. Apparently the car was working fine. When I picked up the car in Bellingham (it was towed), it was smoking ( like in some of the You Tube video), but we only let it run for 1 mn. The first Porsche mechanic in Canada replaced the AOS and the coolant tank (was told it was fixed). Picked up the car, but then within 10 miles, 4 gallon of coolant disappeared. Returned car to first mechanic. Was told me the motor was toast (coolant in the exhaust). Towed the car to a second known Porsche mechanic. They replaced front radiator hose, refill coolant, checked for leak run engine and bleed air, but he told me that exhaust gasses are super-pressurizing cooling system and suspect major motor repair work or replacement. (however, no coolant in exhaust)
I drove the car the next day and have been driving a few miles almost every day and trying to burp the coolant in case. (I start my day on a hill trying to burp any air from the coolant reservoir)
Many people on this site keep thinking like me. The motor run nice, start no problem, run smooth. But I keep smelling coolant on the back left of car.
and, the coolant tank pressure remains overnight. When I drive there is no increase in temperature past the 0 of 180. No loss of coolant, but level below minimum when I drive. Also oil pressure just below 1 after 30 mn drive at idle (start the day at 5, pressure normal when I accelerate). Level going up to normal level after I open the lid of the coolant reservoir the next day (after a hiss sound)..
I like the idea to throw water from a bucket to check if it could remove smell.
I think these are my options:
1) if smell =a) leak b) coolant around motor outside reservoir
2) if pressure remains in the coolant tank overnight = a) air pocket, b) bad tank c)broken hose d) cylinder heads and/or cylinder sleeves.
Note: re. the engine light mentioned in previous post: The sensor was P1130 oxygen adaptation, idle range 2 - Above limit Suspect mass air Flow metre is starting to fail. As mentioned so far the engine light has not come back yet.
If it is bad tank, could it damage the motor or just keep pressure in the tank and then leak coolant?
Now, I am not a mechanic, but I would think that a simple pressure test should eliminate all problems other than 2 d) Am I right?
If the problem is a simple coolant leak a pressure test most of the time finds the leak. In this case the leak might not be so simple. It might be a crack or something that is allowing combustion chamber gases into the cooling system.
Let the tech advise you but I would think checking the oil for any presence of water/anti-freeze would be a step. It might be of value to send a properly obtained sample out for analysis which among other things looks for anti-freeze compounds on the oil. Also, the water content is checked.
Plugs should be pulled and they should all look the same. Often if any coolant is getting into the engine though a cylinder the plug from that cylinder is clean.
But a particularly nasty looking plug is also a sign something's wrong with that cylinder. No misfires though and no CEL so I suspect the plugs will prove to be 'ok'. But let the tech tell you this.
As I think Jake R. mentioned water in the exhaust is also a smoking gun (paraphrasing what he said).
The car is not of any use to you the way it is now. I do not think you can do anything to address the behavior. While the problem may not be serious you risk more serious engine trouble, damage even, if the cooling system is compromised.
So spend some time and research and find a good Porsche repair shop in your area. One that comes highly recommended by other Porsche owners and recently too. Often a good shop can have good techs for a while then the techs leave for greener pastures and the shop is resting on the laurels earned by techs no longer there.
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03-01-2023, 08:15 PM
#34
Rennlist Member
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98-996 (03-01-2023)
