I am about to replace my tstat due to the housing leaking a little when it gets a but chilly at night. I bought one with a rubber seal and the guy at the part store said I won't need a gasket. Does anyone know if that's true or do I still need to run a gasket?

 

What year is your truck?
Iam not sure if it changed but on mine (08 3.7 2x4)
I did not need the gasket, since it came with one.
IF our refering to the original that the truck came off the lot with it serves the same purpose
The original has a slip on style gasket wich has the rubber on both sides and a slit in the circumfrence that goes around the outer edge of the thermostat itself
The aftermarket has a top sit gasket which only sits on the outside of the edge of the circumfrence

I tried to explain it the best i could, and i could be wrong.
I changed mine and havent had a problem when u change it if yoru certain u did it correctly and you still have leaks you may check iinto changing the actual thermostat housing itself. I got a chrome one for 26$

 

I guess I'll find out if there are any apparent cracks in the housing tomorrow. I just find it odd that it leaks whenever it gets close to the freezing temperatures at night here lately, but not during or after driving.

 

I just realized your location. I'm in Terrell, which is about 40 minutes south of Greenville. Ha small world

 

Well I cant really figure a reason, besides pressure that it would leak if that even makes sense
Are you sure its coolent thats actualy leaking?
Could be condensation coming from somthing else
But to be on the safeside 50 bucks for a thermostat and housing and u doing it yourself is free labor really really good idea if u ask me

and yea lol I got threw terrell all the time on my wave to kaufman and sometimes up to silver saloon or backroading home

I sent u a pm with my number so if u ever got any questions u can text me!

 

the rubber seal around the thermostat.. will shrink with age ...

over time it getting smaller and the cool/cold will make it just a little to small and leak past the housing.

same problem with the PT Cruiser. and all Chrysler Vans.

 

Yeah it's just a minor coolant leak at the bottom area of the thermostat housing. There was a freeze this past weekend and it didn't leak but whenever it gets around 30s at night it's been doin it a little bit again. I think the spill area looks a little bigger than what it first did so I'm gonna replace it today if the weather permits, because it looks like it might start getting progressive.

 

Mine did not have a gasket stock but I do use a gasket now. It is cheap insurance to help guard against leaks.