replaced thermostat housing today!!

[blackbeauty]

yup, i thought it would be a water pump, gasket, intake man. gasket or t-stat...nope. twas the housing in which the t-stat sit on. it had a hairline crack and leak bad. ford wanted 340 bucks..... turned around went to the junk yard pulled a brand new one in 5 degree cold in 20 min.....$5.00!!!! so the problem is my radiator cap is cold all the time, even if i drive for 20-30 min. fluid is topped off. i got good heat. new t-stat and water pump. upper hose is warm/hot. lower feels cool but that may be cause its freezing in new york right now . any ideas. 98 sport sohc 4x4. thanks.

 

[Bern]

In very cold weather, there may be so little coolant flowing through the radiator that it's hard to tell. If the gauge shows normal temps, and the heater works good, I would not worry about it.

 

[Cobraguy]

It's possible it's cold enough the thermostat doesn't open much...if at all. The coolant is simply recirculated through the bypass. As long as your temp gauge is fine, you should be fine

 

[rmelo99]

I just did the upper half of mine...but found due to screw threading issues I have to pull the upper and lower. How much of a PITA was it if that's what you had to do?

 

[blackbeauty]

i didnt remove the plenium as it wasnt nessassary once we found the root of the problem being the t-stat huousing. i wouldnt want to do it again but it wasnt hard. took about 3hrs w/ and experience mechanic, in a shop w/ a lift and air, was free though.

 

[gsbarry]

Not sure what to do...

I have a similar problem but can't decide if the lower housing needs replacement. I've pulled the lower housing already and don't see any cracks in it. When pulling the housing it did not appear to be leaking from the the thermostat gasket (where the upper and lower housing mate). Both sensors and the hose to/from the heater core were really gunked up, so I couldn't really tell if any of those were the culprits. There was also coolant pooling on top of the block behind the lower housing. Upper rad hose was fine. I'm not sure if it was leaking from the lower gasket to the manifold, but the gasket looks pretty good. It was basically a huge mess of coolant everywhere.

I do have two suspicions though. One of the bushings that mounts the lower housing was much more gunked up than the other two... maybe there is an internal crack I can't see? The other thing... the brown sensor will not thread all the way into the housing, literally half of the threads are still showing and that SOB is tight... has anyone else seen that? Maybe someone replaced it with the wrong sensor?

I guess I'll replace the gaskets at least, not sure if it would be a good idea to put some sealant on all the bolt and sensor threads...

Help pls..

 

[blackbeauty]

alot of the parts are some sort of plastic. once they get hot they expand then leak...if theres a crack. mine was easy to trace as there was coolant/white powder right at the crack so... id keep lookin, its there somewhere. btw ford wanted wayyyyy to much for the t-stat housing so id do the junkyard thing.

 

[BIGHVM]

Yeah this is always why I use a gaskit seal in a tube when I do these---They can tend too leak, I hate plastic stuff in engine bays, just dont seem right to use that at all!