White smoke from intake tubes
10-04-2014, 12:01 AM
#16
Rennlist Member
If the oil looks good then what Mrmerlin said. Let's get the cooling system figured out first. I honestly had no idea that the HCV and hose could cause the intake to "smoke"...
10-04-2014, 09:46 AM
#18
Team Owner
FWIW the HCV and short hose are the weakest points of the cooling system on a 928.
for good reason they are also at the top of the system so when they fail the least amount of coolant will be lost.
Its most common for the HCV and short hose to fail and then coolant to leak onto the hot manifold ,
then the smoke will rise up through the intake manifold and air cleaner housing,
if the top of the aircleaner isnt on properly ( usually unseated at the rear of the assembly as its the hardest part to see)
( housing could also contain the famous KnN filter) then the smoke will also come out the inlet tubes
for good reason they are also at the top of the system so when they fail the least amount of coolant will be lost.
Its most common for the HCV and short hose to fail and then coolant to leak onto the hot manifold ,
then the smoke will rise up through the intake manifold and air cleaner housing,
if the top of the aircleaner isnt on properly ( usually unseated at the rear of the assembly as its the hardest part to see)
( housing could also contain the famous KnN filter) then the smoke will also come out the inlet tubes
10-04-2014, 10:48 AM
#19
Nordschleife Master
I was thinking that if coolant was running down the front of the engine it'd be vented through the belt covers into the intake ducts. Maybe the thermostat housing is leaking? Hopefully not a leak from the head gaskets in that area.
I'd suspect a bad thermostat installation. Thermostat in wrong, no seal at rear or bad thermostat.
To your questions:
1) Yes. If the water pump is bad the engine will overheat totally. The overflow bucket isn't in the flow path. It's a dead-end.
2) No. I'm not really suspecting the radiator. Any sign of stop-leak gunk being put into the engine? It's a lot of money to throw a new radiator at the problem.
3) Give that smoke a good whiff. Easy to confirm that it's coolant.
4) If the radiator is leaking it'll do it while the car is hot and idling. Hoses, with loose clamps, can leak, too. The overflow tank is in the back corner and the AC condenser is in the middle-rear if the spots are there.
I'd suspect a bad thermostat installation. Thermostat in wrong, no seal at rear or bad thermostat.
To your questions:
1) Yes. If the water pump is bad the engine will overheat totally. The overflow bucket isn't in the flow path. It's a dead-end.
2) No. I'm not really suspecting the radiator. Any sign of stop-leak gunk being put into the engine? It's a lot of money to throw a new radiator at the problem.
3) Give that smoke a good whiff. Easy to confirm that it's coolant.
4) If the radiator is leaking it'll do it while the car is hot and idling. Hoses, with loose clamps, can leak, too. The overflow tank is in the back corner and the AC condenser is in the middle-rear if the spots are there.
Last edited by GlenL; 10-06-2014 at 01:04 PM. Reason: Hominym
10-06-2014, 12:25 PM
#20
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I just had this same problem on another car. (Not a 928)
The head gasket had blown in such a way that water was getting into the cylinders and the exhaust gasses were getting pushed back into the coolant system but the water was not mixing with the oil. I have pictures of the failure too. Hoping it isn't this but it sounds exactly like it. But that radiator did get hot.
How long will it run before overheating?
The head gasket had blown in such a way that water was getting into the cylinders and the exhaust gasses were getting pushed back into the coolant system but the water was not mixing with the oil. I have pictures of the failure too. Hoping it isn't this but it sounds exactly like it. But that radiator did get hot.
How long will it run before overheating?