Overheating & RUFF Idle

I have had a problem with my 1996 Blazer over heating and idling ruff (HIGH) since I changed the heater core. I have replaced the following;
- Heater Core
- Thermostat
- Water Pump
- Spark Plugs

I can not fully trouble shoot the idle issue because I am over heating. Please Help Somebody...

if you haven't already, replace your rad cap with a Stant brand cap. The ACDelcos have known defects.

is your coolant circulating? is the stat opening? does your upper rad hose get hot? is the coolant making it through the radiator?

after changing the heater core, did you refill with the correct amt of coolant?

did u replace your drive belt? does belt tension seem to be okay?

is the overflow reservoir system working properly? can u hear it chuggin' ?

if the rought idle only appeared after the heater core replacement, then go back and retrace your steps. Check all vacuum lines and connects esp in the area where u were working.



I have had a problem with my 1996 Blazer over heating and idling ruff (HIGH) since I changed the heater core. I have replaced the following;
- Heater Core
- Thermostat
- Water Pump
- Spark Plugs

I can not fully trouble shoot the idle issue because I am over heating. Please Help Somebody...

When the engine is completely cold in the morning, go out and remove the rad cap and see if the coolant is right up to the top of the rad.

Also check to see if there is any coolant in the overflow resevoir.

Replace the rad cap ASAP. And use anything other than an AC Delco.

Definitely change the rad cap asap! I changed mine and right away I noticed the temp staying a constant level. The AC delco one was leaking like a siv and not holding the pressure!