forcefed1

well it's getting cold. I noticed a few days ago that my heat wasn't working.
after troubleshooting the mechanical things, I determined teh heater core was clogged up.
I took off the two rubber hoses. the one at the back of the engine, the one near the lower radiator hose connection. I hooked my garden hose to one end and attempted to flush out the gunk. after the normal green stuff came out the water ran very well and very clear.... so the heater core is not plugged up.

well I put everything back together and heat cycled the engine to get the air back out of the cooling system. I removed teh lower cover on teh heater core. when the engine gets up to temp, the heater core is not even warm to the touch. after 20 min of driving I finally get a little warm water flowing in it.

WHY IS THIS?
is there an internal valve maybe near the block that is not working?
It looks to me like there is no flow control at all on our cars.
does anyone know why the water would not be flowing through the heater core.
the engine gets up to temp just fine and holds a steady temp just fine.

RonKMiller

New OEM thermostat from Malloy should do the trick.
Don't even THINK of an aftermarket unit.

bajaman

I used to have a nuclear-heater-of-death in my car, it really got hot! Then....I did the block sealer to fix my 'O' ring leak and I think I must have plugged up my heater core.
I too was wondering about the flow control, obviously there has to be SOMETHING that shuts off the water flow to the core. I guess I need to get out the factory service manual and see what the schematic of the whole system is like.

RonKMiller

Before you assume you've done in the heater core with Block Weld change the thermostat. It's cheap and easy.

However you are correct when assuming you may have sealed up the heater core as well as your hopefully small O ring leak.

Since it reacts with air in the system, and the heater core is the highest point, guess where the highest concentration of Block Weld is located... where you really don't need it.

You can toss is a new heater core pretty easily, but pulling the dash is time consuming. Lots of stuff to break.

Bottom line, there is no free (hot) lunch.

darkside7

iTrader: (12)

do you have to pull the dash to get to the heater core??? sounds like a pain in the ***.

bajaman

Yeah....sigh....you really do have to take the damned car half apart to change the heater core.
I may have robbed Peter to pay Paul in my case, but hey...I've gotten several thousand trouble free, leak free miles from my engine since I BlockWelded it......
This weekend I am going to try and flush everything and put some antifreeze back in. It has been dipping down into the twenties here lately, I've been keeping the FD in a nice warm garage.

ttrx74me

Where would you reccommend getting a new thermostat at? And how dfficult would it be to change?

forcefed1

well seeing how I can't come up with any other reason. I called malloy, looks like ill be replacing the thermostat this weekend. I hope it solves my problem.
In the cold my car seems to warm up just fine but takes a hell of a long tome to make any heat in the heater core.
seems easy enough so ill give it a try.

LAracer

I'm currently having the same problem in my Honda. I replaced the thermostat since it was cheap and easy, but it didn't help. After reading this thread, I'm thinking maybe I have air in the core.

Let us know how it turns out.

pomanferrari

iTrader: (1)

I used to have great heat until I block welded my previous reman.

Now, it's lukewarm air coming out so I think the block weld coated the surface of the metals or somethiing and no heat transfer.

I know it's not clogged up as during the engine rebuild, I could flush water thru the core.

donny

your thermostat is stuck open, bottom line.

RX-007

If the thermostat is stuck open wouldnt the temp gauge get really low?