Oil seeping from thermostat housing
#1
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Car: 1991 Firebird
Transmission: T5
Axle/Gears: 3.42 w/auburn racers diff
Oil seeping from thermostat housing
I have had oil seeping from one part of my thermostat housing, i immidietly thought blown head gasket, but there is no coolant in the oil, and i drained the radiator today, and there was no sighn of oil in the coolant. I noticed the small leak after turning on the heater one night, i bought the car over the summer, and had never turned on the heater, after a few minutes there was a lound buzzing sound coming from behind the dash. I shut the air off right after hearing the noise. the next day, i popped my hood and there was the leak. I have not turned on the heater since then and the leak has seemed to stop. Any Ideas would be really appreciated.
#2
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Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Ok im not sure if its just me but that really confused me...
Thermostat housing has nothing to do with the heater loop, which should in no way enable a oil leak.
I cannot see any way oil will come out of a thermostat housing and not get mixed in with the coolant.
Got any pictures of whats leaking?
Thermostat housing has nothing to do with the heater loop, which should in no way enable a oil leak.
I cannot see any way oil will come out of a thermostat housing and not get mixed in with the coolant.
Got any pictures of whats leaking?
#3
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Car: Z28
Engine: Sb2.2 406
Transmission: Jerico 4 speed
Axle/Gears: Ford 9" 3.60
Few problems here:
The thermostat housing is no where near a oil passage, sealed by something that could leak, and in the event of a leak, you would see it (oil) prominantly in the coolant. The closest thing that has oil, is the lifter valley, which is an intake thickness, through the coolant crossover, away. No way you are leaking oil from the thermostat housing. Seeping coolant, possibly. Engine gets dirty, grimey, whatever, then the coolant seeps and moistens it all and yes, it could take the appearance of an oil leak.
Buzzing behind the dash could be fan motor operation.
The thermostat housing is no where near a oil passage, sealed by something that could leak, and in the event of a leak, you would see it (oil) prominantly in the coolant. The closest thing that has oil, is the lifter valley, which is an intake thickness, through the coolant crossover, away. No way you are leaking oil from the thermostat housing. Seeping coolant, possibly. Engine gets dirty, grimey, whatever, then the coolant seeps and moistens it all and yes, it could take the appearance of an oil leak.
Buzzing behind the dash could be fan motor operation.
#4
TGO Supporter
i'd clean it up and watch for where whatever it is might be coming from. like was said there's no way it's an internal oil leak getting out around the t-stat unless you filled your radiator with oil.
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Car: 1985 Trans Am
Engine: 383 Stroker
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Could be coming from where the intake meets the block in front of and just below the thermostat housing but it would happen all the time, not just when the heater is turned on. Tricky problem.
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#8
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Car: 1991 Firebird
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Thanks for all the replies, after replacing the coolant, and driving the car the past couple days the leak has seemed to stop, i plan on pulling the intake after putting her away for the winter, then maybe i'll figure out exactly what it was.
#9
COTM Editor (Retired)
Re: Oil seeping from thermostat housing
i am having the exact same issue, but i'm not sure if heater use has been a factor. no apparent oil in the coolant, no coolant in the oil, no loss of oil level, and no loss of oil pressure - just a small amount of oil seeping from the thermostat housing gasket. wierd.
#10
Re: Oil seeping from thermostat housing
I think when you disconnected the evap system harness you switched hoses by mistake. Try removing the evap hoses from it's connector (on top of the engine) and simply switch them and reinsert. Run the engine for about 10 minutes to chase the gas fumes from the oil cap and you should be fine if this is the issue.
I have had oil seeping from one part of my thermostat housing, i immidietly thought blown head gasket, but there is no coolant in the oil, and i drained the radiator today, and there was no sighn of oil in the coolant. I noticed the small leak after turning on the heater one night, i bought the car over the summer, and had never turned on the heater, after a few minutes there was a lound buzzing sound coming from behind the dash. I shut the air off right after hearing the noise. the next day, i popped my hood and there was the leak. I have not turned on the heater since then and the leak has seemed to stop. Any Ideas would be really appreciated.
#12
Re: Oil seeping from thermostat housing
UMMM... Wrong post. But I'll leave it in case it helps someone.
I think when you disconnected the evap system harness you switched hoses by mistake. Try removing the evap hoses from it's connector (on top of the engine) and simply switch them and reinsert. Run the engine for about 10 minutes to chase the gas fumes from the oil cap and you should be fine if this is the issue.
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