'02 SC thermostate replacement

[Brad303]

Hey guys,

My daughter's '02 X needs a new thermostat. The service manual recommends fully draining the coolant. Is that completely necessary? I'm hoping to get this done this afternoon, and would rather avoid the drain/refill if I can.

Other than that, it looks pretty straightforward. Remove air cleaner/duct, take off water hose from inlet housing, remove housing & replace the tstat.

Anything I'm missing, or need to be aware of?

 

[Muadeeb]

It looks like the thermostat will be pretty hard to get to without removing a few other things, namely tensioner brackets. All of that is easier to do with the radiator out of the way. It's easy to do, pretty quick, so might as well do it, get a couple gallons of fresh coolant in there, and make your life easier in the front end.

 

[Brad303]

So, It turns out it's relatively easy to get to the t-stat. I just had to remove the hose and bracket going into it, then I had pretty clear access.

It's harder, however, to get a recommendation on the proper liquid gasket from the local auto parts store. We sprung a leak after running for about 10 mins, and the truck was still overheating just like before. It wasn't a dripping leak, but it was steaming pretty heavy when the engine warmed up.

What's worse, another local shop recommended a real gasket in place of RTV, but it was leaking after install. When wrenching on the t-stat housing bolts, I stripped the threads in the engine mating surface.

What now? I'm shy about tapping it at that angle and limited accessibility. Is the engine mating surface part of the engine block itself, or can that be replaced? Couldn't see it well in the dark and how it's recessed, but it could be either.

 

[Muadeeb]

The thermostat housing is a separate part from the block, so deal with that separately if needed. Block to housing there's a paper gasket used, it has a rectangular hole with two mounting screws. For the housing to hose fitting, you use a liquid gasket. Permatex 51813/51817 is the Nissan recommended, which you can get from amazon pretty reasonably.

Or your local Oreilly's may have the tiny tube in stock (51817).

If you don't have the FSM from Nissan, grab them from NicoClub while it looks like they still have them up: http://www.nicoclub.com/FSM/Xterra/2002_Xterra/

 

[Brad303]

Okay, I'm looking at EM-76 and can see the tstat housing, although that diagram also has the water inlet. The manual is showing liquid gasket for all 3 connections (back, bottom & water inlet). Would you recommend paper for both of the block to housing connections?

I haven't had a chance to test the old t-stat, so I don't know that it was the problem. The system was *really* dry, so I'm guessing that even if it was working, there wasn't enough coolant in the system to circulate.

The radiator was recently replaced by a friend, so it's possible there wasn't enough coolant added at that point, or there could be a leak.

What are the chances that it's the water pump? I really don't want to have to replace it, but I'd probably do the timing belt at the same time. Never done one, but doesn't look $2500-hard (i.e. the cost of having it done at a shop).