Been trying to get my coolant flushed and filled all week and finally went at it this morning. When I went to do it the other day, I found a small leak between the thermostat housing and the engine, so I ordered a gasket and picked it up yesterday. Got everything drained out and removed the housing only to find no gasket there and no sign that one had EVER been there. Not only that, the bolts barely took any pressure to get loose. According to the service manual, a gasket should be there. WTF????

My truck has been good to me but sometimes I wonder if it wasn't built using whatever parts they could scrape up from the previous model year. I never could get my Superchips to work because it kept saying the settings were not stock for its year, even though they had never been changed. Now I find parts that should be there just missing altogether.

 

Was there any RTV there, or just absolutely nothing?

 

Nothing, nada, zilch. Just metal to metal with 2 bolts holding the housing on. I'm surprised it held the coolant as well as it did all this time. My first thought was that the gasket just got eaten away over time. But I find it hard to believe that happened to the point that there is not even a sign that one was ever there.

 

So is the leak gone now?

 

Yep, think so. I just went back out and checked it after letting it cool down and my coolant level is right where I want it to be and no signs of any leaks.

 

Well that's good! I wonder if it came from the factory that way.

 

Not everyone uses a gasket.. some just lay a bead of rtv on it and call it a day.. the rtv, especially if black, could have been blasted out with the leak..

 

they dont use a flat gasket on the 5.7 or 4.7 . they ues a rubber ring around the thermostst. it might leak if the bolts were not tight. i have seen a flat gesket sold, but the ones i have worked on have never used it.

 

I guess I feel a little better about that but it's odd that the service manual shows a gasket and the gasket exists and looks exactly like the one pictured in the diagram in the manual.

I had a very small, slow dripping leak and it couldn't have been happening long because very little coolant leaked out of the system. I don't think there was enough pressure to wipe out any sign of gasket or rtv.

The rubber ring around the thermostat was there and it looked in good shape, and the bolts were not loose, they just weren't very tight, if that makes any sense. They were probably loose enough to cause the leak given that there wasn't any kind of gasket in there.

Oh well, it's fixed now and nothing got broken.

 

^^^^^^^^^^^^^^^^
What he said.