QuestionQUESTION: Hello, I have a problem car that only gets heat while sitting and running.I have flushed the core, and all related components. I check for smooth operation of blend door with the actuator removed it seems fine. when driving for a few minutes I loose the heat completely.So I left the actuator out and manually set the door to full hot then drove again. The same thing happened lost all heat. I then checked for codes and got 36 and 23, I can assume that 23 came up when I was operating system while actuator was removed but can't be 100 percent certin of that. The atc display seems to work fine,no blinking or fading in and out ect.The car is a 2000 concorde lxi...please help!!!! and Thanks
ANSWER: Hi Russ,
The next issue, setting aside the codes both of which might have been due to the disconnection of the actuator, is whether you may have air trapped in the cooling system such that you aren't getting good coolant flow through the heater core. Also how does the temp gauge read on the dash, at least 1/3 to 1/2 scale?
I would verify that the two hoses that flow from the engine compartment to the heater core feel about the same temperature rather than one noticeably cooler than the other.
Then if they don't I would try bleeding air from the syetem using the bleed valve located near the thermostat housing at the front of the engine. Tell me which engine you have if you can't find the valve.
Attach a 4' length of 1/4" hose to the nipple sufficient to go over the front of grille to a container to catch it for reuse (you don't want to let coolant get on the drive belts, thus the hose). You then open the bleed valve. Then you pinch close a different hose, the one that connects the two sides of the pressure bottle where fluid is added to the system. Then you add coolant in a small stream to the filler opening (so as to allow air to escape while you are pouring (or use a special funnel that is sectioned to be sure that air can escape, part no. 8195 Miller tool). You keep adding fluid to the bottle until fluid comes in a steady flow out the 4' hose. Then you close the bleeder valve. Then you keep adding fluid to the bottle until it is full on the section of the bottle that is in-board. Then you put the cap on the bottle and unpinch the hose that was previously pinched. Check that you only have coolant in the smaller in-board side of the filler bottle. If necessary drain the larger out-board side of the filler bottle by disconnecting the connecting hose and drain it from that larger side.
Let me know of anything unusual that you observe with regard to the questions I listed above.
Roland
PS Please 'rate' my answer. Thank you
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QUESTION: K I have checked for air in the system there seems to be none. I have a laser temp sensor and the temp on both heater hoses at the core is about the same. they both are around 165 or so. I have changed the thermostat as well. flow in and out of the core is good when checked with both heater hoses off. is it possible that the water pump loses flow at speed? I have also check for hydrocarbons with a gas analyzer at the tail pipe. they are within normal values. I also did a hydrocarbons test at the coolant bottle with a chemical dye test so I don't think its the head gaskets either. thanks Russ
ANSWER: Hi Russ,
I am impressed with your armamentarium of test tools! It is possible for the water pump impeller to get loose or perhaps have some loss of efficiency over long usage due to corrosion. But the fact that you measure only 165 temp on the heater hoses makes me wonder about whether your thermostat might be set to open at too low a temp so that your cooling system is running too cool. What was the temp calibration according to the box that came with the new thermostat? The coolant should really be well over 200 (do your fans ever come 'on' which typically happens at about 220?) so that if you could raise that value you might well get better heat in the cabin. You apparently have good flow through the core just too cool.
The cost of replacing the water pump would discourage me from recommending that as a possible fix.
Roland
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QUESTION: K so the stat is rated at 190 and the fans do come on when the temp gage in the car just passes half way...the car does not overheat at all and runs perfect. The only other thing I noticed was about a 30 or 40 degree temp diff between upper and lower rad hoses. thanks Russ
AnswerThat temp difference in the radiator hoses would be expected. But I wonder now that you mention the fans coming out at just over 1/2 scale whether your coolant temp sensor may be a bit pessimistic and is turning on the fans at too low a temp. What is the laser temp reading at the thermostat housing when the fans come on? If it is below 210 then the resistance of the temp sensor may be reading too low for the actual coolant temp.
Roland
PS Thanks for the rating and nomination, Russ. I wonder whether you still have the code 23 and 36 on the controller readout? And if the hoses are still only showing 165 then the engine is running too cool unless your temp reader shows the thermostat housing is indeed at 210+. I just can't see how the hoses to the core can be similar in temp but you get insufficient heat with the engine at normal temp unless the blend door is not in the correct position so that heater core is being by-passed and instead is flowing through the ac core (though not is use). When you took off the blend actuator and tried moving it to full hot are you sure you went in the direction of hot and was it locked in that position so it wouldn't drift back to an intermddiat or cold setting? Might their be a mechanical disconnect between the coupling and the door? Maybe couple of things have gone wrong.
Roland
PPS Another 3.5L LH-body owner wrote with the same issue as you. Here is an interesting item that he discovered, as well as something I found in the '04 factory manual. Please let me know what you learn:
QUESTION: Hi Roland,
Thanks once again for the information. It sure sounds like Russ and I are experiencing the same problem.
The air was bled from the system after replacing the thermostat and checked again after driving it a couple times.
I really feel the fundamental problem is coolant is somehow constantly flowing through the radiator. This would account for the slow warm up while idling and drop in temp when the vehicle is moving.
I may have stumbled upon something that may address the problem and wanted to run it past you. Thinking the thermostat purchased from the local parts store may be defective (it happens), I went looking for parts & prices online. That's when I came across this part: Gates #33676 - Thermostat Seal (ref: http://www.redline9.com/gates/gates_thermostat_seal/33676/i-344294.aspx). The vendor lists separate part numbers for this seal and a thermostat gasket.
Now, I'm wondering if this seal is needed to prevent coolant from getting around the thermostat or the metal gasket? If the original one broke down, that would also explain why the original thermostat wasn't stuck open as I expected it to be.
Any chance you can find out the odds of this having any bearing on the problem?
Thanks,
Chris
Answer: Hi Chris,
I didn't find a reference to a 'seal' in the shop manual but did find one interesting statement in the '04 manual:
"The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat carefully remove the bulged metal from the thermostat housing using a suitably hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing." The staking is apparently to attach the thermostat to the housing before assembly. Also I notice that they show the bleed hole to be at the 12 o'clock position.
I wonder if you may have some 'bulged metal' in the housing that needs to be removed. I too wonder what the Gates 'seal' might be.
I suspect you may be reopening the housing and if you do to either check the metal or use the seal please let me know how it works out.
Roland
PS Thanks very much for the rating and nomination. I will also share your finding with Russ.
