I start my new-to-me '27 Tudor up w/o the radiator cap on and in less than a minute it starts to boil over / bubble up / steam? bubbles out.
What's are the symptoms of a bad headgasket?
I thought it was overheating b/c with the radiator cap on it I could drive around the block before it boiled coolant over. So I drained coolant, added detergent + TSP + water (first stage in flushing), ran it to circulate, and then I noticed how quickly it 'boiled'. Biggest tip-off, IR thermometer only shows engine & radiator temp of 150F.
Its also gotten harder to start (but that can be a zillion other things).
If it's a head(?)gasket, best to buy a 'complete' a gasket kit?
(Thanks to all prior posters herein on how best to replace a headgasket.)
Did you confirm the mixture and the timing? Overheating can be caused by running too lean on your carburetor mixture and or by not enough advance on the spark.
A blown head gasket blown into the water jacket would cause bubbles to come out the filler neck. It would also cause oil to get into the coolant from the oil film on the cylinder walls, especially true if the car is an oil burner. The temperature of 150 is not high enough to cause boiling, but overfilling could cause the coolant to flow out as it expands. The T is not a pressurized system and as the coolant expands it will run over the overflow. Try running the coolant level about one inch above the radiator core. It should not spill over at that level and when you drive the car it will spill over until it reaches that level anyway. If it still runs over at that level it would indicate your radiator is plugged and the heat rising to the top tank does not flow down into the core to be cooled.
With combustion pressure and cylinder oil in the coolant from a leaking headgasket the coolant gets a milky white color. The same with the crank case oil if coolant gets in there - but then it's likely a worse problem than a leaky headgasket..
Take a compression test. It might tell you something. Check the oil for contamination also. Spark lever position as mentioned (but it's happening awfully fast for that). With what you've said here so far I think there's a head pulling job in your future but make some checks first.
Sounds like too much coolant, it should just cover the top plate in the radiator. Since it shows 150 degrees, also remove the waterpump if it has one and check to see if you have one of the three row radiators that were common in 26 and 27.
Sounds like too much coolant, it should just cover the top plate in the radiator. Since it shows 150 degrees, also remove the water pump if it has one and check to see if you have one of the three row radiators that were common in 26 and 27.