2004 possible coolant leak

Joined
Oct 29, 2018
Thunderbird Year
2004
My 2004 ran running hot today on my way to work. Been having a coolant loss without a noticeable cause for some time now. After it had a chance to cool down I decided to add coolant directly into the coolant fill pipe on the thermostat housing. I ran the car for a while for a visible drop once the Tstat opened. As I'm intermittently adding water I notice what looks like water coming right out from just below the threads of this fill cap opening. Now without the cap on there tight the water flowed out with ease but when I put the cap back on securely it "appeared" to have stopped. Having never removed this Tstat housing before can anyone tell me does this appear to be a normal aspect of the housings design? Because this is a hot region of the engine it would explain my coolant loss without the evidence of a puddle since it would be evaporating as it leaked out.
 
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Joined
Aug 27, 2019
Thunderbird Year
2004
My 04 ran running hot today on my way to work. Been having a coolant loss without a noticeable cause for some time now. After it had a chance to cool down I decided to add coolant directly into the coolant fill pipe on the thermostat housing. I ran the car for a while for a visible drop once the Tstat opened. As I'm intermittently adding water I notice what looks like water coming right out from just below the threads of this fill cap opening. Now without the cap on there tight the water flowed out with ease but when I put the cap back on securely it "appeared" to have stopped. Having never removed this Tstat housing before can anyone tell me does this appear to be a normal aspect of the housings design? Because this is a hot region of the engine it would explain my coolant loss without the evidence of a puddle since it would be evaporating as it leaked out.
Yes these are cheap crap you will need to replace the water neck too and might as well change out the water pump radiator hoses and fan belt since you are going to have all stuff off of the front of the engine
There is a few tricky things you will need to do for the water neck but it's doable if you are mechanically inclined
 
Joined
Aug 9, 2012
Thunderbird Year
2004
My 2004 ran running hot today on my way to work. Been having a coolant loss without a noticeable cause for some time now. After it had a chance to cool down I decided to add coolant directly into the coolant fill pipe on the thermostat housing. I ran the car for a while for a visible drop once the Tstat opened. As I'm intermittently adding water I notice what looks like water coming right out from just below the threads of this fill cap opening. Now without the cap on there tight the water flowed out with ease but when I put the cap back on securely it "appeared" to have stopped. Having never removed this Tstat housing before can anyone tell me does this appear to be a normal aspect of the housings design? Because this is a hot region of the engine it would explain my coolant loss without the evidence of a puddle since it would be evaporating as it leaked out.
I had a lot of overheating issues with my 04 Bird. There are 3 very small screws that hold the Tstat housing on. It is a cheap plastic part, so no wonder it wears out prematurely. If you buy the part, make sure you order the gasket, as it does not come with it. Duh? Also, check your water bottle, I had a very fine crack in it (another plastic part) and it leaked water very finely, i had to top off with a gallon of water every week until this was discovered. I also replaced the radiator, and had every o-ring and gasket under the main intake replaced until it finally stopped overheating.
I still have a 1962 TBird, but have to admit, i traded my 2004 in, as at 114k miles, it was wore slam out.
 
Joined
Oct 29, 2018
Thunderbird Year
2004
Yes these are cheap crap you will need to replace the water neck too and might as well change out the water pump radiator hoses and fan belt since you are going to have all stuff off of the front of the engine
There is a few tricky things you will need to do for the water neck but it's doable if you are mechanically inclined
Thank you for the information. I'm really surprised but not that they opted to make a constantly expanding and contracting part out of plastic. I have replaced many of the parts for cooling with no improvement including multiple head gasket integrity checks. As I saw the water coming out I thought it was an optical illusion or maybe its designed that way on purpose. By the way my delay in replying to you was the result of the admin sending me a msg that my post didn't meet subject criteria so I thought he deleted it.
 
Joined
Oct 29, 2018
Thunderbird Year
2004
I had a lot of overheating issues with my 04 Bird. There are 3 very small screws that hold the Tstat housing on. It is a cheap plastic part, so no wonder it wears out prematurely. If you buy the part, make sure you order the gasket, as it does not come with it. Duh? Also, check your water bottle, I had a very fine crack in it (another plastic part) and it leaked water very finely, i had to top off with a gallon of water every week until this was discovered. I also replaced the radiator, and had every o-ring and gasket under the main intake replaced until it finally stopped overheating.
I still have a 1962 TBird, but have to admit, i traded my 2004 in, as at 114k miles, it was wore slam out.
Wow! that is a lot of potential leak points. I will follow your advice to the T. I bought the car for my wife and I want to keep it running as good as I can. She loves it but hasn't wanted to drive it much because of the coolant mystery. She had it repainted vintage green and it looks incredible but what fun is a car you can't drive? Personally I would like a 1962 too!
 
Joined
Aug 9, 2005
Thunderbird Year
2003
cars have a LOT of parts made of plastic that crack and leak especially with 15 year old cars.
I have replace the coolant recovery (plastic) tank 4 times. replaced the thermostat manifold 2 times and the rubber O ring gaskets for that housing that they charge $10 a piece for 4 times. the water pump twice, the radiator once.
now I have to replace the Dual Coolant Control Valve for the heater because it allows hot coolant to flow all the time to the heater.

Funny all the coolant hoses are original.
 
Joined
Aug 9, 2012
Thunderbird Year
2004
cars have a LOT of parts made of plastic that crack and leak especially with 15 year old cars.
I have replace the coolant recovery (plastic) tank 4 times. replaced the thermostat manifold 2 times and the rubber O ring gaskets for that housing that they charge $10 a piece for 4 times. the water pump twice, the radiator once.
now I have to replace the Dual Coolant Control Valve for the heater because it allows hot coolant to flow all the time to the heater.

Funny all the coolant hoses are original.
you got me beat, but not by much Flash :).
 
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