I installed the new thermostat housing this evening and had a lot of trouble pushing the neck of the housing into the pipe that leads over to the water pump. As I was jiggling and pushing the neck into place and fastening that little metal clip, coolant started to leak from the water pump side of the car.

I'm thinking I pushed too hard and somehow disconnected or broke something down at the other end.

Please don't tell me I have to take everything apart again! What a pain in the *** this car is to work on.

Is there an easy way to access the pipe that leads to the water pump without taking everything else out again?

 

I suppose you didn't put a new pipe in?

If it's the old pipe, it probably broke where it is inserted in the block. It would start leaking there anyways... I suggest taking the intake off. Get something to make sure there is no debris in the water pump hole (inspection camera or so). And when inserting the thermostat into the pipe: the thermostat is keyed. You may need to rotate the pipe so that it lines up with the key on the thermostat.

And get some silicone grease. Makes the o-ring slide in much easier.

 

When you replace the thermostat housing, you need to replace the water pipe too. As mentioned above, take off the intake manifold (only 5-6 10mm bolts and one or two from below), pull out the water pipe and replace. I cut the useless tabs off the new pipe. Put some grease (I use dielectric grease) on both ends to ease installation. Take your time and do not push too hard as the plastic edges can chip easily. Purchase an OEM unit as less expensive units (reported here) have questionable quality, like burrs on contact points. Take a look at the contact points on all new parts anyway nowadays.

 

Yes, I had to replace the pipe that leads to the water pump. It was cracked and broken--must have been pretty brittle for it to crack like it did.

 

If you replaced the pipe - did you push it deep enough into the block? The black fins should be inside the hole and not sticking out by much.

On one occasion I had the o-ring slip off the pipe when I pushed the pipe in. Also had to rip out everything again - and bought silicone grease right away. I was able to see that with an inspection camera.

In general, if the pipe is seated properly in the block and it is rotated so that the thermostat key fits, and you put some grease on the thermostat o-ring and a thin film inside the tube, it should just flush in without much force.

The reason that you had some issues getting it in sounds like there was trouble in the first place.

 

It is pretty common. If you replace the thermostat, the cross-over pipe is likely to break or likely the seal on the water-pump side of the pipe. You will need a new pipe and seal.