Mekanik Posted December 29, 2011 Share Posted December 29, 2011 I’m working on a 2003 F-Series with a 6.0L. The customer’s concern is lack of heat at idle (vent temp 90F). All you have to do is accelerate and the heat comes back (140f). My ECT and EOT pids are around 185f when it’s idling and not producing heat. The ECT and EOT really don’t change after the vehicle is accelerated. This vehicle originally came in when the HP oil pump plug fell out. During my testing of that I noticed a huge EOT/ECT split and I replaced the oil cooler. There was a lot of debris in the oil cooler. After that repair I replaced the thermostat, de-gas bottle cap and then another tech flushed the heater and replaced the water pump when I was on vacation. He said that he had good flow through the heater core and nothing came out of it. I know that the hose going to the core from the front cover wasn’t VERY hot, and the hose coming out of the heater core was luke warm at best. The customer was complaining about this before I did the HP oil pump and the oil cooler, and I vacuum tested the cooling system twice and it held perfect vacuum. The coolant level is full. I see a little bit of coolant stains on the coolant bottle, but it’s not like it’s low on coolant. Any help? Quote Link to comment Share on other sites More sharing options...
lmorris Posted December 29, 2011 Share Posted December 29, 2011 Back flush the heater core. It sounds like it is restricted. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted December 29, 2011 Share Posted December 29, 2011 Two things that I have run into that can cause this. One is a thermostat not operating as designed and the second is blown head gaskets. You have already replaced the thermostat so I would check it for combustion gasses in the cooling system. I like to install a clear piece of hose inline with the heater hose inlet and watch the flow. I bet you don't have much flow coming out of the front cover at idle. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 29, 2011 Share Posted December 29, 2011 Two things that I have run into that can cause this. One is a thermostat not operating as designed and the second is blown head gaskets. You have already replaced the thermostat so I would check it for combustion gasses in the cooling system. I like to install a clear piece of hose inline with the heater hose inlet and watch the flow. I bet you don't have much flow coming out of the front cover at idle.I agree about checking for flow to the heater core but suspect the front cover has cavitation damage. The other tech probably missed it... Quote Link to comment Share on other sites More sharing options...
ETS Posted December 29, 2011 Share Posted December 29, 2011 Sounds like heater core may be restricted I agree. Watch for debris & flow when you backflush. I did head gaskets last month on my personal truck for same problem. [06 F350] Fixed it. It was building excess pressure in degas bottle after a running under boost. No combustion gas was detected at idle doing block test. It also had a coolant usage issue 1/2 gallon a month. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 29, 2011 Share Posted December 29, 2011 Sounds like heater core may be restricted I agree. Watch for debris & flow when you backflush. I did head gaskets last month on my personal truck for same problem. [06 F350] Fixed it. It was building excess pressure in degas bottle after a running under boost. No combustion gas was detected at idle doing block test. It also had a coolant usage issue 1/2 gallon a month. The heater core HAS been flushed... Quote: After that repair I replaced the thermostat, de-gas bottle cap and then another tech flushed the heater and replaced the water pump when I was on vacation. He said that he had good flow through the heater core and nothing came out of it. I know that the hose going to the core from the front cover wasn’t VERY hot, and the hose coming out of the heater core was luke warm at best. Quote Link to comment Share on other sites More sharing options...
ETS Posted December 29, 2011 Share Posted December 29, 2011 Sorry missed it. Flat rate reading this morning. Also flat rate eating at the time. Looks like big ticket then. Quote Link to comment Share on other sites More sharing options...
Mekanik Posted December 30, 2011 Author Share Posted December 30, 2011 Front covr cavitation damage? So coolant is bypassing and not expelling 100% of the coolant to the heater core? How do I find this? Could it have been seen with the water pump off? Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 30, 2011 Share Posted December 30, 2011 Front covr cavitation damage? So coolant is bypassing and not expelling 100% of the coolant to the heater core? How do I find this? Could it have been seen with the water pump off? Yes. You would have to remove the pump to inspect. As mentioned above adapt a piece of clear hose so you can see if there is decent/any flow. You may well have a core that is plugged? Sometimes you can't flush the crap out... Quote Link to comment Share on other sites More sharing options...
Mekanik Posted December 30, 2011 Author Share Posted December 30, 2011 Originally Posted By: Mekanik Front covr cavitation damage? So coolant is bypassing and not expelling 100% of the coolant to the heater core? How do I find this? Could it have been seen with the water pump off? Yes. You would have to remove the pump to inspect. As mentioned above adapt a piece of clear hose so you can see if there is decent/any flow. You may well have a core that is plugged? Sometimes you can't flush the crap out... Okay, I see. Can you tell me where in the front cover the cavitation occurs and how it will effect the flow to the heater core? Quote Link to comment Share on other sites More sharing options...
lmorris Posted December 30, 2011 Share Posted December 30, 2011 Remove the waterpump, it is pretty evident once it is removed. Just because someone said they flushed the heater core doesn't always mean they backflushed it. Better to do it anyways just to cover your ass. Takes all of 15 minutes to do. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 30, 2011 Share Posted December 30, 2011 Remove the waterpump, it is pretty evident once it is removed. Just because someone said they flushed the heater core doesn't always mean they backflushed it. Better to do it anyways just to cover your ass. Takes all of 15 minutes to do. I agree with back-flushing it, yourself, before pulling the WP. I just wish the auto industry had/used a flow meter for testing flow like is used in hydraulics. http://www.hedland.com/ Watch the video at lower right of site. Quote Link to comment Share on other sites More sharing options...
Mekanik Posted December 30, 2011 Author Share Posted December 30, 2011 Remove the waterpump, it is pretty evident once it is removed. Just because someone said they flushed the heater core doesn't always mean they backflushed it. Better to do it anyways just to cover your ass. Takes all of 15 minutes to do. I agree, I was really disapointed to see someone else working on it when I came back to work. coolant flow through the heater core is something I would like to see for myself. How does the cavitation cause lack of flow? Quote Link to comment Share on other sites More sharing options...
ktmlew Posted January 8, 2012 Share Posted January 8, 2012 Here is a flow meter. Apparently Mopar thinks they are worth having? http://www.ebay.com/itm/Miller-Special-T...=item3a5ada06ec Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 8, 2012 Share Posted January 8, 2012 I'm almost certain that is a PS tester, not a cooling system tester. I've posted pics here before of the Hickok Ford cooling system flow tester, I'll look for it. It's from the 80's and obsolete now. Edit: Quote Link to comment Share on other sites More sharing options...
Mekanik Posted February 7, 2012 Author Share Posted February 7, 2012 The guy FINALLY brought the truck back in. I removed the hose going to the heater core and fired up the engine and found NO flow out of the hose at idle, but as soon as the engine is above idle it sprays out coolant like a fire hose. I need to take a look at the cold start drivability and then I'll remove the water pump to inspect the front cover. Thanks guys! Quote Link to comment Share on other sites More sharing options...
Mekanik Posted February 7, 2012 Author Share Posted February 7, 2012 No cavitation on the front cover. Does anyone have any ideas on this one? Quote Link to comment Share on other sites More sharing options...
mchan68 Posted February 7, 2012 Share Posted February 7, 2012 Does this truck have one of those coolant control valves by any chance? Is it functioning properly? Just throwing ideas out there. Quote Link to comment Share on other sites More sharing options...
Mekanik Posted February 7, 2012 Author Share Posted February 7, 2012 No it doesn't. I'm flushing out the cooling system as we speak. Quote Link to comment Share on other sites More sharing options...
ETS Posted February 8, 2012 Share Posted February 8, 2012 Truck was built before July 19, 04. Early style pump. Bumb question but.... Did someone change front cover to late model design? Is it the correct pump? I am not sure they will interchange haven't had very many early trucks apart. Maybe too much clearance inside cover? Belt tensioner OK? Belt slipping on pulley or pulley spinning on shaft? Just my for what it's worth. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted February 8, 2012 Share Posted February 8, 2012 Having trouble remembering, did you check the cooling system for combustion gasses? Quote Link to comment Share on other sites More sharing options...
Mekanik Posted February 15, 2012 Author Share Posted February 15, 2012 That's actually what was wrong with this truck. Initially I checked it and I had 12psi cooling system pressure on accel. It was kind of borderline, but this was in December when it first came in. My service writer really didn't want to 'go there' because we just sold the truck. I felt like the headgaskets were leaking a little bit, but it probably wasn't going to fix the truck. What I found strange is that ALL the headgasket jobs I've done on 6.0ls, I've never come across this complaint. But maybe nobody has ever noticed it, because when the truck is being driven it produces heat. Another thing I found strange is that the degas bottle really wasn't venting. But I it wasn't venting externally, the gas has to go somewhere!!! That's when it dawned on me. I overlooked the obvious. When I checked the colling system pressure last week it was 16 psi; much worse than when I first came in. There wasn't much left of the sealing surface of the headgaskets. I really felt humbled by this truck. There was something obviously wrong it, but I was convinced there was something else. This truck was a real lesson for me to not let my manager's feelings about what he wants me to do or not do affect my diagnostic process, and not overlook the obvious. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted February 15, 2012 Share Posted February 15, 2012 Quote Link to comment Share on other sites More sharing options...
ktmlew Posted February 15, 2012 Share Posted February 15, 2012 Yikes. Wasn't expecting that. Can you use a combustion leak detector on these? Sure would speed diag and help CYA... Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted February 16, 2012 Share Posted February 16, 2012 Yes you can, here is a picture of it being used on a 6.4l to find a bad horizontal egr cooler. Quote Link to comment Share on other sites More sharing options...
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