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Guest Message by DevFuse

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What is the direction of flow at heater core?

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6 replies to this topic

#1 PonchoCatalina


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Posted 19 February 2007 - 03:16 PM

I'm not getting a lot of heat out of my '91 Loyale and I'm pretty sure from reading other posts that my heater core is "congested." When the engine is warmed up and I turn on the heat I get a quick, warm blast initially followed by steady cool air. I would like to try flushing the core as my first step, but I want to make sure I backflush first to avoid driving gunk deeper into the core. So, my question is: which way does the coolant flow at the core? Which port is the inlet and which is the outlet? Thanks!

#2 Turbone


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Posted 19 February 2007 - 10:51 PM

The one on the left/bottom is the inlet.

#3 GeneralDisorder


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Posted 19 February 2007 - 10:56 PM

It doesn't actually matter - the core is symetrical with respect to flow. Hook it up however the hoses fit best for you. So you could reverse the lines after you flush it just to help it out.

*note* - this is NOT the case for EA81's. Only EA82's.


#4 Gloyale


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Posted 20 February 2007 - 07:00 PM

The one on the left/bottom is the inlet.

I think to clarify it should be said that the outermost hose, the one that gos straight under the manifold to water pump is the inlet into heater. The one closest to the center of the car, coming from the intake body is the inlet. They can be reversed as GD said, but then the two hoses would cross over eachother, and the water is still going in the same direction through the hoses, just backwards through the heater. This is good to do when you run a cleaner through before your flush. Switch the hoses, run the cleaner and do your flush. Then switch them back(or not) and refill system.

I've also flushed just the heater core with a garden hose cut and clamped on to the outlet.

As a side note, poor coolant circulation can cause the same effect on the heater function. How sure are you that you've got good pump circulation? If you've run just water for a while, and you've got an aftermarket waterpump, the impeller may have rusted away. You would likely be overheating or running hot sometimes as well. If you've got good antifreeze with no rust in it this is probably not the case. Just thought I'd pose the question.

#5 baccaruda



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Posted 21 February 2007 - 02:38 PM

also, I would advise that if you flush your heater core, that you completely disconnect it from your engine and water pump because you don't want whatever's flushed to go into your engine :dead:

#6 Spiffy


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Posted 21 February 2007 - 11:53 PM

on mine I just disconnected the hoses from the engine end (keeping them attached to the heater core end so I had some hose to work with) and put the garden hose up to one end... I didn't have the pressure up very high, and when I started to get a lot of resistance I'd back off and switch to the other hose and do it again... it didn't really move the first few times... but after going back and forth from inlet to outlet more and more gunk started coming out... once I was getting good water flow I could hold the garden hose right up to the heater hose for more pressure and pushing erosion action...

and not to hijack the thread... GD, what is wrong with doing it on an ea81? is there something like a 1-way valve in there? bad for the flow control flapper thing?


#7 psylosyfer


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Posted 18 March 2007 - 02:21 AM

running the car with the heater on the cooler hose (under spare tire) is the outlet, blowing it out with the garden hose works great!

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