How hard is it to do a heater core on a late 90's S10?

[AJMBLAZER]

My buddy's dad has a late 90's 2wd S10. His little beater DD truck. Dunno if it has AC or which engine.

He replaced the thermostat a while back with some generic parts store brand. Hadn't been working for a while so it was a cold winter for him. Now the gauge only gets part of the way warm and he never gets much for heat. I'm wondering if it's the thermostat or the heater core?

Going to try the heater core first and then if not that then the heater core. How much of a PITA are these to get to? I did mine with a friend in October and holy **** I never want to do that again.

 

[R3MiX]

I know this topic is a few days old, but nobody has answered it yet... So I'll give it a shot...

It would seem to me, that if the thermostat is opening too early, that would cause the fluid going through the heater core to not be warm enough, and also cause his gauge inside to not be 'where it used to be'. My best guess would be to swap out the thermostat for one of a higher temperature, which should force hotter fluid to the heater core. It should also make the gauge inside rise to the desired location.

 

[AJMBLAZER]

I'm going to definitely swap the thermostat out first. Get him a proper ACDelco one.


It's a 4-cyl truck too btw.

 

[onelow1ton]

the square body s10s are easer to do than the square body fullsize but not much there is just a lot of small screws/bolts

 

[AJMBLAZER]

His is a late 90's so round body style.

 

[USSkoval]

You have to pull the dash to do it. You also have to reach through a small opening on the firewall box (underhood) and undo a couple bolts. You can't do that part if you have fat hands/arms. The one I did had AC and the core was leaking, which is why it was replaced.

Now, these cores have a tendency of clogging, but they can be cleared easy. Unhook both heater hoses. Ball up a rag in front of one outlet (to catch the flying crap). Hit the other outlet with a few short blasts of compressed air to blow the gunk out. A blow gun with a rubber tip works well for this. It's easy and works very well if the core is clogged.

 

[AJMBLAZER]

We haven't touched it yet. I moved two weekends ago and the garage is a mess still.

Think we're going to try a t-stat first and then monkey with the heater core. Thinking the el cheapo stat he got isn't working.