Possible Blocked Heater Core?

[DGrant09]

With the colder temperatures and running the heater I have noticed that the engine temp wants to crawl upwards while I have the heater on. Basically everything in the cooling system is new except the heater core. The cap is 13psi, thermostat is 195, and she puts out good heat in the cab. I have not seen any signs of coolant leaking in the cab. Could I have a partially blocked heater core?? If so, should I just replace it or try to clean it out with something?? Or am I guessing wrong on this??
Thanks
Dan

[Thunderfoot]

The heater ON would help with the cooling of the engine so it would run cooler... With it off the valve is shut off to the heater core so the fluid doesn't flow through it, so it doesn't help with cooling of the engine then. Also, if you are getting good heat in the cab then your Heater core is not plugged, if it was you wouldn't be getting good flow (like the valve closed) and it wouldn't heat well...
The one shouldn't have anything to do with the other for the engine running warmer...
Just out of curiosity does the gauge change with the heater fan being on/off?

[DGrant09]

I have not tried to run with the heater on and the fan off to see if there is a difference. We ran the engine the last half of the summer, even pulling a trailer, and the temp would stay around mid-scale. Now it will move towards the hot side when I run the heater. Now that I think of it I see what you say by helping cool the coolant. The heater core is nothing more than a small radiator. Any possible ideas, maybe the thermostat is sticking??

[Thunderfoot]

Yeah, I would lead more to the thermostat going out/sticking... The thing I was thinking on the heater fan being on or off, was maybe it effecting the gauge reading, but if it was something like that it would effect the oil and fuel gauge readings as well... Thermostat is a good place to start.

[DGrant09]

That's a bummer for it is relatively new (June). I guess it would give me the chance to add more coolant for the colder temps coming..
I maybe able to get to it tomorrow. Still elbows deep in a new beetle! #&@^#&@^ foreign cars anyways! Everything is special and costs a fortune!
Thanks
Dan

[peanutman]

DG09, i was having a simular problem. At idle my factory heat gauge would rise and even more with the heater on which should lower your temp a little. I changed all the obvious with no help. Went to auto zone and bought me a $16.99 sunpro mech heat gauge and found out that i was running between 185-205 with a 195 thermo. that was in the texas heat at idle.
I don't trust these old gauges in our bumps.