Thermostat House /Lower Intake Manifold on 2000 Malibu 3.1L V6

I have been using the Haynes manuel to change the leaky intake manifold gaskets. Everything was going fine until I had to loosen the heater pipe fitting from the thermostat housing/lower intake manifold. In the illustrations, the manuel shows a nut that fastens the heater pipe to the thermostat housing. My problem and question is, the thermostat housing doesn't have that nut. The heater pipe just goes into the thermostat housing. Does this sound normal or did I receive a faulty vehicle when I purchased it? The thermostat has never been replaced. Again, I have a 2000 Malibu with a 3.1 Liter V6. The top of the intake manifold says 3100 SFI V6. Please help!

Jay

This is the same type of housing my son has on his 1999 4 cylinder Pontiac Grand Am. The heater pipe has a hump on it that causes it to snap into the thermostat housing. Problem is - you have to be Superman to make it fit. Once again - GM and their profit first engineers. I think I'll try Toyota.

The tube will pull right out of the lower intake manifold. It only has an o-ring on the tube. Don't even bother to attempt to disconnect the coupler. There is a bracket on the tube that is on a stud with a nut holding it in place. Take off the nut and when you life off the lower manifold the tube should pull right out with a little persuasion

Never seen one without the fitting in the t-stat housing. Should take 2 wrenches to separate. If the nut wants to turn with the tube you might have to heat the nut so you don't break the tube. When doing a set for int's , it doesn't hurt to do a t-stat, and oil pump drive o-ring at the same time to save in the future. Also, don't put the dexcool antifreeze back in, flush the system with water and replce with green coolant. Orange stuff is horrible and known to destroy aluminum and steel inside the engine. (I.e head gaskets etc. in the future...)

Take a look under the hood of my '98 Malibu and you'll see one without the fitting.