hose from water pump to thermostat

[Iconic]

I am about to replace the short hose from the water pump to the thermostat.
I can't see any way to do it without removing the thermostat housing.
Is that correct?
Also, I believe just two nuts hold the housing on. What torque do I use when reinstalling it?
Thanks for your help.
Mark

[Naj ✝︎]

Hi, Mark,

The new hoses are a bit shorter and I think can be changed without removing the t/stat housing if there is no a/c equipment in the way. On mine the head was off so it was easy.
You will need a new gasket (housing to cyl head) if you unbolt the the housing. Its 10mm studs but I don't think a torque is specified. On mine, the nut hex is smaller, taking a 12mm wrench instead of the normanl 13mm.

naj

[JimVillers]

Be aware that the hose is not a straight hose but a hose with a molded curve (121 203 00 82).  I believe that you can replace the hose without removing the thermostat but the clearances are tight.

[Iconic]

Thanks Naj and Jim.
I've got the correct hose with the curve or kink in it.
I did notice it was shorter, but I am having a very difficult time getting it in. I do not have A/C so it sounds like I should be able to do it.
So, I tried to remove the t/stat housing.
I removed the two nuts off the studs (mine are 12 mm hex nuts also).
The t/stat housing is stuck on (just like my distributor was stuck, really stuck).
I've got the gasket ready to go too.
I soaked the area where the housing meets the head and also soaked the stud ends with a good penetrating oil, so maybe that will help.
But, before I try to force it off, I wanted to make sure that only the two nuts hold it on. I did not want to do something I would regret later.
I will try once again to get the hose on without removing the t/stat housing.
I push it all the way on one side, then I can almost get it on the other side. Are there any tricks beyond that?
Thanks guys.
Mark

[Naj ✝︎]

Try dish washing liquid for lub.
Works for me!

naj

[Larry & Norma]

And mabye dropping it very hot water to soften it a bit!

[DavidBrough]

Hi Mark,

You may have to cut the old hose off especially if its gone a bit hard and its then much easier to remove the thermostat housing. I found that the housing will only come off with the hose if the studs are also removed and these can often seize in the head. I would just cut the old hose off and then freeing the thermostat housing for its new gasket is much easier.

Good luck

[Iconic]

Naj, I already tried the dish washer soap. At least I know I'm on the right track. I'll use more soap this time.
Gnuface, Hot water to soften it up is a great idea. It certainly should handle the heat.  The new one is definitely softer than the old, of course, but I will give this a try if my next attempt fails.
David, had the old hose off already. It was definitely stiff, maybe even a little crunchy. My t/stat housing did not come off with the hose removed. I'm sure it has never been off in 40 years.

I don't need to remove the thermostat from the housing to remove the housing from the head, do I?
In the mean time, I'm going to attempt again tonight getting that hose on without removing the t/stat housing.
I have a tendency to be very gentle until I get the confidence from you guys to go at it.
The same thing happened with my stuck distributor. It just needed more force (torque in that case).

Now I have more confidence. Thank you.
I'll keep you posted.
Mark

[DavidBrough]

Hi Mark,

You don't need to remove the thermostat prior to removing the housing but it does seem that yours needs quite a shock to get it to come off. I found quite a lot of corrosion on the studs with mine but I did manage to remove it by just hitting it with a hammer, thankfully I didn't have to hit it too hard as you only end up knowing the limit when something breaks. If your sure that the gasket seal is OK for the thermostat why not try removing the water pump to fit the hose if you can't get it on any other way.

[Iconic]

I never got the thermostat housing off, but I did get the hose installed.
I'm not proud of the fact that I trimmed approximately 3 mm off of it to get it in. I really didn't want to disassemble more (like the water pump) since I really want to drive it this weekend.
I'll know in a few days if it worked OK. I'll be surprised if I have a problem. It should be fine.
I did use lots of soap !
Thanks to all for your help.
Mark

[Iconic]

Update: I had no problems on my trip (540 miles total !! (870 km)).
It was over 90 degrees F (33C - 35C), and I had some stop and go traffic, so the fluid got good and hot and it was a good test of the system.
Thanks again for your help.

[Benz Dr.]

Since you already have the hose off this won't matter but removal of the thermostat housing is only possible using heat if it's really stuck on. The combination of aluminium, steel and a bit of antifreeze can almost weld everything together.
I use more heat on the metal parts such as exposed screws or nuts than I use on aluminium parts. You can use a certain amount of heat on aluminium but you can also damage it so you need to be careful. At some point it will start to smoke around the threaded studs ( they always do ) and that's when you stop. Let it cool a bit and then use pentrant. When the parts are cool enough it won't go up in smoke and will stay on the parts. If you use anything before you use heat it will catch on fire or simply burn away however, the pentrant will work much better on hot parts so use it again once it cools.
If it doesn't come off heat it again but not as much - the pentrant will burn a bit. Keep doing this while trying to move it off the long studs that go into the head. It will come off eventually.

I blast parts like this clean and make sure all the drilled holes and threaded holes are perfectly clean. Use lots of anti seize on the screws and on the studs during assembly.

The cooling system should be drained and ordinary water run  through for a short cleaning. I've had coolant pop back at me due to fumes or something in the coolant. Best to play it safe.

[Iconic]

Dan,
I got lucky this time and didn't need to remove the thermostat housing.
But, the info you gave will pay off the next time I need to use heat.
I haven't used heat that much and the points you made answered some/all of my questions and I would feel more confident next time I need heat.
Don't worry, I'll have a fire extinguisher handy. 
Mark