Hey all, just joined and this is my first time posting to the forum, so be forgiving if this is in the wrong location..
Picked up my first Challenger last Saturday and almost have it on the road again, but I've got a little bit of a head scratcher. my 318 is overheating (starts to overpressurize/boil after just a few minutes of running), I'll give as much info as I can, so it'll be a long post.
I started working on the cooling system Thursday night after work (an automotive repair shop in Oregon). The PO had straight water in it, so I changed it, and at the same time put a new water pump, hoses, thermostat, radiator cap, and flushed out the radiator. The heater hose port on the w-pump was completely clogged with crusty coolant, so that wasn't a good sign.. took it for a test drive to find out it's overheating. Heater core is leaking too, but that's a separate issue. Got home, bypassed the heater core and pulled up the intake to check the passages. No blockage, so put it back down. Tried another thermostat (180*) with a hole drilled in it and used a vacuum filler to check for further leaks/fill it. None found, so filled it with 50/50. Test drive again, still boiling. Tested cap, good, and thermostat is opening. Placed a rag in front of the radiator and it stuck so I have good air flow through the fins. Water pump is pumping, and heat is being pulled out of the radiator. Used a temp gun to measure temp at various spots and found that it'll start to boil when the t-stat housing only reads about 130*. Checked #1 and #2 cylinder temps at the front of the heads, #1 approx 177*, #2 approx 235*.
its acting like I've got air stuck in the block somewhere, based on the early boiling temp. My main question is: since the coolant was so nasty, and still looks pretty bad after changing it twice, does it sound like I've got a bunch of sediment buildup around #2 cylinder walls causing a hot spot? I'd really rather not pull the heads, but if it comes down to it, whatever.. any other ideas would be greatly appreciated, thanks!