Keith Browning Posted March 12, 2008 Share Posted March 12, 2008 I am pretty sure the tech is going to find a restricted heater core but I have to ask if anyone has run into a 6.0L SD that the heat gets cold when idling, say at a traffic light. Accelerate and the heat gets hot again. No other cooling system concerns or overheating. He did install an new thermostat and vacuum pump on prior repairs. I also recommended removing the water pump to inspect it's condition... Quote Link to comment Share on other sites More sharing options...
BrunoWilimek Posted March 12, 2008 Share Posted March 12, 2008 I have had no personal experience on this issue, however, have read numerous reports of this concern on Pro-tech. I searched it and the results are in as follows. Number 1 cause is head gaskets, followed by plugged oil and EGR coolers, and also plugged waterpump or cylinder head ports in the block. Good luck. Quote Link to comment Share on other sites More sharing options...
Shlep Posted March 12, 2008 Share Posted March 12, 2008 Bruno just about hit all the possible causes except one, I had a 6.0 doing exactly that and after doing all the above mentioned parts I decided to have a peek at the water pump, found the impeller had come apart. Quote Link to comment Share on other sites More sharing options...
Tony302600 Posted March 12, 2008 Share Posted March 12, 2008 Have been told that front cover's also cause this issue. Last few i worked on had low coolant due to degas bottle overflow. But we had one that a while back that had engineering scratching their heads....guy traded truck in. Quote Link to comment Share on other sites More sharing options...
DwayneGorniak Posted March 12, 2008 Share Posted March 12, 2008 Is the coolant at the proper level? If the level drops below the min line, the coolant will not flow properly to the heater core and as Bruno said: #1 cause is head gaskets or blown EGR cooler. Quote Link to comment Share on other sites More sharing options...
Tony302600 Posted March 13, 2008 Share Posted March 13, 2008 If those test pass, i've had radiator hoses that only leak when the truck is parked outside in the cold with the pressure gauge cause low coolant level. I've had good amount of trucks come through that WILL NOT show sign's of a leak, or leak when sitting in the warm shop with the coolant pressure tester on them overnight, but park them outside and u will find the leak overnight. That's my suggestion if the headgasket, and egr cooler test pass. Quote Link to comment Share on other sites More sharing options...
Mekanik Posted March 13, 2008 Share Posted March 13, 2008 If those test pass, i've had radiator hoses that only leak when the truck is parked outside in the cold with the pressure gauge cause low coolant level. I've had good amount of trucks come through that WILL NOT show sign's of a leak, or leak when sitting in the warm shop with the coolant pressure tester on them overnight, but park them outside and u will find the leak overnight. That's my suggestion if the headgasket, and egr cooler test pass. I totally agree. Even if I'm going to do headgaskets or coolers, I like to park the truck overnight with the pressure guage. It is amazing all the other small leaks that you won't notice when the engine is warm. How would the front cover cause a lack of heat at idle? restriction? Quote Link to comment Share on other sites More sharing options...
Tony302600 Posted March 13, 2008 Share Posted March 13, 2008 Yes, I can't remember the whole story since it was a year ago, something about lack of flow, or restriction, but they said that they will notify our dealership of a revised Front cover and waterpump Part# to cure this customers truck. The customer didn't end up buying it because he traded it in on a new 6.4L month before they were available. It was an early, early, early 03 truck, that's all i remember. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 13, 2008 Author Share Posted March 13, 2008 More on this. I dealt with the customer this morning. When we returned to the dealership I noticed a loud gurgling noise from the heater core after shutting the engine off. The customer also insists this started months ago after we replaced his EGR cooler. Hmmm. With no other symptoms, coolant usage, overheating, coolant loss or overflow we thought it hard to believe this is base engine related. We ran this by our FSE and some other people at Ford and they know of a few instances of air pockets forming in the heater cores. Remember the older Taurus? Uh huh. So, we checked the heater core for flow and found it to be free flowing. I suggested to the tech that he lay it on a bench, fill it with coolant and cap it before reinstalling it, fill the system until coolant comes out of the heater hoses before connecting them. He was still putting it together when I left for the night... I'll let you know if this fixes it. Yeah, I know. An air pocket? It's not far fetched. I just don't recall having this problem ever with a Super Duty. And just for the record, the water pump and front cover still have not been inspected despite my rcommendation. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted March 13, 2008 Share Posted March 13, 2008 There is never a bad time to use the air lift.... But... if we have had "good heat" followed by "no heat", we are not airlocked. A heater core can appear to have good flow when we hook it to a garden hose.... But water main pressure is going to be 50+ PSI. That kind of pressure drop is going to make almost any heater core look good. The engine water pump can't even hope to make that kind of pressure drop. Check the temp of the inlet hose and the outlet hose.... A restricted core is going to have a significant difference Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 13, 2008 Author Share Posted March 13, 2008 A heater core can appear to have good flow when we hook it to a garden hose.... Check the temp of the inlet hose and the outlet hose.... A restricted core is going to have a significant difference The hose nozzle is on it's last leg and it squirts like an old man peeing so we didn't have much pressure or volume. The water flowed freely. The hoses did in fact show a distinct difference until we raised the RPM's. It's the gurgling noise that has us and if it wasn't for that I would agree with you 100%. At this point I am not discounting anything though and this one will be one to remember regardless of what the outcome is. Good thing that core comes out fairly easily. /forums/images/%%GRAEMLIN_URL%%/wink.gif Quote Link to comment Share on other sites More sharing options...
Tony302600 Posted March 13, 2008 Share Posted March 13, 2008 I've never used anything but my airlift when refilling and vehicle after a cooling system repair. It's awesome because it will not hold vacuum if you have a tiny leak which is a time saver if you were to just fill it the old fashioned way. Then realize you have a leak, then drain the system and fix the repair. It's saved me a couple of times. No heat at idle is no flow (if cooling system is full and no degas bottle overflow). That's why i would lean to the front cover/waterpump. Keith, i've had 3 or 4 truck's exhibit no sign's of degas bottle overflow til the customer say's the magic fraze... "Happen's when Towing my 5th wheel" I've had some customer come back with their trailer so i can check with my gauge to see if it goes over 18psi... On Edit: What year is this truck? Any residue on the degas bottle from sign's of it ever overflowning? I'm assuming you guy's followed the tsb for degas bottle overflow? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.