Help 97 Blazer..Changed lower intake manifold gasket

I just finished replacing the lower intake gasket on my daughter's 97 blazer 4WD 4.3 engine. It seemed to go well. Lots of caked up old pink dex-cool
had the back 2 ports completely filled...like closed off with packed up crud.

I have 2 concerns No Heat/ possible overheating engine & P0340 code.

To test run it after the repair...I added back about a gallon of water..no coolant,which seemd to fill up the radiator...I started it up and it had had quite a bit of white exhaust. seemed to get better as it idled. took it for a drive and seemd to run good, and the white exhaust seemd to go away. It did throw a OBDII code of P0340 Cam shaft Position Sensor circuit. I noticed that I didn't have much heat..so I flushed & backlushed the heater core and it seemd like water was going through the heater. I had done this once before on this Blazer and it had heat like mad after that...until today

Took it for another drive and it didn't seem to get much warmer and the temp gauge looked like it was getting way to hot...getting into the red. Circled right back home and started looking for possible causes..I know I didn't have the entire coolant systme completely filled...maybe that caused the overheating/ I have pulled the thermo and I am going to flush from the lower radiator hose

I did have the distributor out to change the intake...but I'm sure that I'm dead on with it's position..and it's not missing or running rough or anything
I will check the wiring/hook-up.

Any ideas? what would you check Are there any common bone-head mistakes I may be making?

Spit
I did not change the thermostat..and I haven't backflushed or properly filled the engine/radiator yet and maybe that's the biggest problem

I found the P0340 problem ...I forgot to hook-up the electrical harness to the distributor. DUH!

I pulled the thermostat last night it looked sort of "dex-cool gummy" but not terrible. I'm going to back flush it today with the thermostat out and see what I can bust loose.

Do the heater cores ever plug up so bad that backflushing won't clean them up? I had heat until doing the manifold gasket... I didn't seem like either heater hose was getting particularly warm....but I'm sure I ddn't have the correct amount of coolant in the system. Do the heater hoses themselves ever get so plugged that they back-up...

Any ideas or comments welcome

Spit

On the code clear code and see if it comes back.
If so you will need a engine capable scanner to do the final set the dist camshaft retard setting position.

On the heater heat.
First make sure you bleed air out of system and get it full of coolant.
Then make sure engine comes up to running tempt 195-200 degrees.

On heater core sometimes you can flush or blow them out.
Blow threw it with a air hose and see if it has any air going threw it.
If so run a water hose threw it both ways to flush it.
And sometimes I have reversed the heater hoses and run for a few days to help flush them out.

Mt-2500
Thanks for the information. I spent a good part of this morning flushing the entire cooling system and now it's working great, I've got all the heat I would ever want.

Once I hooked up the wiring harness to the distributor that I forgot hook-up, I reset the OBD-II and it hasn't come back. I have high hopes that everything will be Okay.

thanks again for your ideas. you were right on the money.

Spit

You are welcome and thanks for posting back how it went.
Glad you got good heat.
Good Luck
MT