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willism
Advanced Member
United States
250 Posts |
 Posted - 02/22/2011 : 12:07:46 PM
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Hello all got a 2003 E350 with a 7.3L I'm getting very little heat out of. What Ive done so far 2 thermostats checked the 3 air blendors they work the electric blendor that works. Changed the potentiometer for the heat control removed the electric blendor motor and checked that the movement was good and nothing was stuck or any pens or junk was in it. Replaced water pump and fan hub flushed the whole cooling system cleaned radiator and checked the fan shroud all good. Bought a coolant funnel that helps get the air out of the system when you refill just in case I was getting air in the system. Was pretty warm about 50 degrees out when I backed it out of the shop temp took a long time to read normal on the gauge. Went and drove it and as soon as you get to a light and hit a idle no heat did what the driver said worked and dropped it in a lower gear and worked the hell out of it you could get pretty good heat but not like it should... any ideas cause were fresh out
** also did a test to check for exhaust in the coolant and it was fine** |
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tigger2
Advanced Member
USA
470 Posts |
Posted - 02/24/2011 : 06:04:22 AM
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| It sound as though your heater plumbing is putting a loop in the cooling system that bypasses the thermostats, make sure the outlets are past the thermostat and inlets are below the water pump. We received a batch of fs65's with the heater hoses both on the pressure side of the motor cooling system. |
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willism
Advanced Member
United States
250 Posts |
Posted - 02/24/2011 : 07:21:01 AM
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| Thanks for reply tigger but on my 2nd or 3rd trip in the shop I looked into that and everything flows correctly.Had some fs65's with mercedes that had the same problem with a few yrs back. Also when I flushed the system I flushed with hot water both ways thinking maybe there was a flap of rubber restricting flow when it warmed up was a long shot but didn't take any time but didn't find anything there.... |
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BJ Henderson
Advanced Member
USA
280 Posts |
Posted - 02/24/2011 : 07:22:50 AM
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If engine temps get normal, I would check the door inside that is the temp selector door. It is where the little electric motor shaft slides into it. They break inside. I had to put one in 2 weeks ago.
Hope this helps...let us know! |
CMTT,CMAT,CMBT |
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willism
Advanced Member
United States
250 Posts |
Posted - 02/24/2011 : 09:04:39 AM
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| Checked that when i put a new motor on looked good and there was not anything blocking and you can here it when you change the temp switch closes better than it did with the old motor on it. |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 02/24/2011 : 09:59:53 AM
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| Check the hose that runs from the surge tank to the engine for kinks. I had several where the tank was removed and re-installed with the hose kinked. |
“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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BJ Henderson
Advanced Member
USA
280 Posts |
Posted - 02/24/2011 : 4:07:38 PM
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If you have one of those infrared non contact heat guns, I would check the hoses in and out of the heater core. That is the first thing I grab when someone tells me about a heater or AC problem.
They are very handy! They cost a lot less now, too. |
CMTT,CMAT,CMBT |
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wrenchmen
Senior Member
USA
115 Posts |
Posted - 02/25/2011 : 09:29:37 AM
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Is the engine reaching operating temp?. Determine this first.
No need to check blend doors, etc. if engine is not reaching operating temp.
If coolant is hot than feel the heater hoses, they should be hot, if there is a blockage to flow than you should be able to feel where
the temp changes and help you to locate the problem. I have seen Chevy Express vans with partialy blocked heater cores.
They would have very poor heat at idle, but decent heat while driving. A bore scope inserted into the heater core revealed the
crud blocking the coolant flow. |
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7.3L Heat Issue
