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Heater only Luke warm at best


GazM3

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Hey chaps. 

 

The heater is not very hot for some reason.  The coolant seems to be hot entering the heater valve and the return pipe is hot as well.  I've bled the cooling system with the radiator uphill.  

 

Ive removed the heater valve and it seems to function fine.  Disconnected the cable and manually altered the valve so it's in the fully open position and still Luke warm.   

 

Not sure.  I've got a warmer thermostat which I guess can be installed.  Other thing could be a partially blocked core.  Perhaps it needs more bleeding?  

 

Not sure.  Any advice is welcome. 

1974 2002 2.2stroker, DCOE45's, 300deg cam, 5 spd, 3.91 LSD // 1984 E24 M635csi, dogleg 5spd 3.23 LSD. // 1994 E34 540i, supercharged 16psi, 6spd E85 only, 3.15 LSD // 1997 E36 M3 Evo, low comp supercharged 18psi 6spd (under construction)

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What I'd check with the heater valve open:

 

1.  If the coolant level is just at the bottom level of the upper rad hose, you won't get much heat out of the heater.

2.  I'd burp the upper rad hose with the coolant near the top of the rad.  See if the coolant level drops.

3.  Drain the block at the plug under #4 exhaust port.  If there is sludge, you have a clue.

4.  Put a garden hose on the heater core input (hose in engine bay) and disconnect the core output hose to see what comes through.

5.  Worst of all... remove your heater core for re&re.

 

Your thermostat will cause engine overheating if it's not opening.  So...not likely the problem.

Edited by PaulTWinterton

73 Inka Tii #2762958

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Citric acid can be of value for a flush for CRUD (mixed with water, brought to FOT, then drained, fill and flush again 2x with water). Mercedes Benz sells a premixed bottle for use in some of their diesel engines, or you can buy food grade citric acid online, health food store etc. Ive used as much as 1/4 cup per gallon. Automatic dishwashing liquid is also an excellent cooling system flush, 3 oz per gallon. Caveat being that if you have near pinholes in solder joints or thin walls in the Cu (end tanks, cores etc) you may have more leaks when you are done than you bargained for. 

 

Another thing many people do not understand is you cannot mix coolant types freely. IF someone has ever, in the past, added say PINK coolant to GREEN, you can get silica coming out of solution (which is fine "sand" particles) that love to collect in the smallest of spaces.

 

JUNK can collect in the heater box, like leaves, dog hair, dirt, beer bottle labels, fingers, etc which will impede airflow over the core.  

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Thanks guys.  The flushing of the heater core sounds logical start point.  I may get some clear hose to connect to the exit to see what stuff comes out.  

 

Citric acid vid looks the go.  Let's hope i don't cause any issues with making the core leak.  

 

What about that CLR stuff?   

 

Also so when using water pressure to flush it is it best to reverse the direction ?  

 

Cheers

1974 2002 2.2stroker, DCOE45's, 300deg cam, 5 spd, 3.91 LSD // 1984 E24 M635csi, dogleg 5spd 3.23 LSD. // 1994 E34 540i, supercharged 16psi, 6spd E85 only, 3.15 LSD // 1997 E36 M3 Evo, low comp supercharged 18psi 6spd (under construction)

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If you are using a hose then reverse flush. There's a range of chemical flushing agents available (but good tips on the homemade stuff above!) followthe instructions on these and then have another session flushing your system with water. 

rtheriaque wrote:

Carbs: They're necessary and barely controlled fuel leaks that sometimes match the air passing through them.

My build blog:http://www.bmw2002faq.com/blog/163-simeons-blog/

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 I'd compare the temp diff between the heater input (valve side ) and heater output (carb side) looking for about a 10-20'f difference,  On the other hand your fresh air flap might be stuck open and diluting the heat the core is putting out.  

If everybody in the room is thinking the same thing, then someone is not thinking.

 

George S Patton 

Planning the Normandy Break out 1944

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The fresh air flap is a good point.  The coldest it gets here is about 0deg c so when the air flap is open it would mix with the 80deg coolant and produce 40deg air approx.  

 

went to start my 2002 and battery was flat.  Done a quick charge and it didn't turn over like it had a collapsed cell or something as battery was at 12.8v. 

 

Gawd with classic cars the is always something 

1974 2002 2.2stroker, DCOE45's, 300deg cam, 5 spd, 3.91 LSD // 1984 E24 M635csi, dogleg 5spd 3.23 LSD. // 1994 E34 540i, supercharged 16psi, 6spd E85 only, 3.15 LSD // 1997 E36 M3 Evo, low comp supercharged 18psi 6spd (under construction)

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UPDATE:

 

I finally got around to reverse flushing out the heater core.  Used some of that CLR stuff just soaked it for a few min and reverse flushing with clear hose removed some gunk initially and nice and clear flushing it for 10 min or so.  I delicately removed the heater valve and adjusted it properlay also, threading the cable back through the hole in the bolt was pretty tricky.  

 

I te-bled the cooling system parking the radiator up hill and burped all the pipes.  The heater works significantly better.  It's not super hot on full heat but I suspect the fresh air flap being open and the cool thermostat ((170) the culprit.  I have a 180 thermostat I can install if need be. 

 

 

Thanks for for your help with this.  

1974 2002 2.2stroker, DCOE45's, 300deg cam, 5 spd, 3.91 LSD // 1984 E24 M635csi, dogleg 5spd 3.23 LSD. // 1994 E34 540i, supercharged 16psi, 6spd E85 only, 3.15 LSD // 1997 E36 M3 Evo, low comp supercharged 18psi 6spd (under construction)

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Well done!

 

Mike S had suggested attaching the cable to the heater valve before bolting the valve back in place. 

 

... I need to plumb my core back in; I haven't done that after rebuilding and installing it...

 

Cheers,

Ray

Stop reading this! Don't you have anything better to do?? :P
Two running things. Two broken things.

 

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Yes I did put the cable on before but had to keep it inside the bracket.  Not much room in there to work. 

1974 2002 2.2stroker, DCOE45's, 300deg cam, 5 spd, 3.91 LSD // 1984 E24 M635csi, dogleg 5spd 3.23 LSD. // 1994 E34 540i, supercharged 16psi, 6spd E85 only, 3.15 LSD // 1997 E36 M3 Evo, low comp supercharged 18psi 6spd (under construction)

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