Bad heater core?
 

Hello all, I am having a problem with my 96 Chevy S-10. Its a single cab, 4.3l v6, 4x4, 5 speed manual.

My problem is this: I have NO heat whatsoever! Even after achieving full temperature on the guage, the heater will blow nothing but cold air.

This is after replacing the (stuck) old thermostat, flushing the system with a Prestone product, and refilling with the 60/40 antifreeze/water solution (Prestone 'safe for all engines' type).

At first, the temp guage would work up to 210 or so, then drop back to the normal operating temp (160 or so?). A friend said this was normal, that the system would stabilize after purging the air bubbles.

This condition hasn't gone away, though it does subside quite a bit after a bit of driving. Still, it is occuring after approx. 250 miles of driving with the new coolant.

I would HATE to have to deal with a new heater core or other complex job. I am quite handy, but stuff is no fun when its 15 degrees outside!

Can anyone diagnose a potential problem here? Where should I start looking for the most simple solutions? I have access to a good set of tools, and have several new-model junk yards available to me (cost is always an issue!).

Thank you in advance for any help. I look forward to being a member of your forum here.

RE: Bad heater core?
 

feel ther hoses going into the core with a hot engine..both should be hot,,,if 1 is cool and 1 hot,its plugged.
you may try to remove the hoses and blast air thru the core

RE: Bad heater core?
 

For those searching this topic, I will follow up with the end result of this problem.

On the advice ofa friend who mentioned 'air in the pipes' as the potential culprit, I ran the truck for nearly an hour with the radiator cap off to encourage the air to purge itself.

The result: Success! I now have full heat, and the cycling of the temperature gauge is settled down to the normal range.

Thanks for the reads and the forum.

RE: Bad heater core?
 

That can happen. I had to ride with someone who hadjust had their coolant changed (air locked heater) with no heatfrom Fargo, ND to Watertown, SD in -20 degree F weather. Although, that was years ago in a full size Oldsmobile.