My needle gets to just a bit under half on the stock water gauge, never really likes to idle under 1100-1200 and the heat is luke warm... if I hold the revs at 4000-5000rpm going down the road the heat will immediately get scoulding hot, probably time for a new thermostat? Or maybe my car had a 160 or something installed?

BTW it's 10f outside :P

 

Sounds more like a WP problem, or a blockage or air pocket in the cooling system, because:

1. if the heater IMMEDIATELY gets hot, the water had to be hot already, and all you've done is make it circulate better with the higher revs
2. if it were a thermostat problem, most likely the water and heater wouldn't get hot even at higher revs, since the load on the engine is no higher than at lower revs

However, it could be that the thermostat is stuck partially open, and I am not fully understanding your symptoms.

Dave

 

Do you hear a gurgling or 'rushing' sound from the heater core (right side footwell area) when you rev? I'm tending to agree with Dave....

 

hmm i'm thinking it's stuck partially open, what i'm saying is it doesn't appear to run warm enough... i thought the gauge was supposed to sit @ dead on 9 o'clock, and when i load the engine harder while driving i can get the heat to increase (i usually drive at 2000-2500rpm, if i take it to 4000-5000 i get some hotter heat following for a few seconds)... i.e. the water pump is functioning perfectly or it'd be too hot and possibly be cooling down with more rpm

 

The stock gauge is crap. It will sit just under 9 oclock right up until it starts moving and then it usually goes for the red. MOst osf us run an aftermarket temp gauge that actually gives you a reading. These cars should have a 180 degree F. thermostat (not even sure you can find a 160 for it) and that would be too cold for it to operate properly. The heater (my car anyway) puts out better heat on floor/defrost, more so than through the dash vents, which I belive to be typical of these cars (owners manual confirms this) not sure why it would fuctuate that much temp wise in the heater core unless like said begore your getting poor circulation or perhaps air in the system.

 

It's quite common for older tstats to stick partially open and be obvious in our climate here in michigan, very common for cars with tired tstats to run 40-50f too cold