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2004 Sebring 2.7 overheating.

Discussion in '200, Avenger/Sebring, Cirrus/Stratus/Breeze' started by ironman187, Jul 15, 2017.

  1. ironman187

    ironman187 Active Member

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    I just bought a 2004 Sebring base model with a 2.7 that is overheating. The owner was told by a shop that it needed a head gasket. I've done a compression test, and a block test (the one that tests for exhuast fluid in the coolant), there was no loss of compression between cylinders, and no exhaust gas present in the cooling system. I did a pressure test and saw a 3psi drop in 20 minutes. I also bled it. What should I look at next?
     
  2. ironman187

    ironman187 Active Member

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    Hmm, It seems I can't edit my post? Anyway, Forgot to mention the radiator fans do kick on as well. It doesn't overheat while idling, but I kick it up to 1500-2000 rpm and the needle climbs slowly.
     
  3. AllanC

    AllanC Well-Known Member

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    I think you can only edit a post you have made within a 10 minute time frame after you make the post. Others can correct me if I am wrong.

    Does the upper radiator hose get warm / hot to the touch? If it does not then it is possible that the thermostat is stuck closed and not allowing the coolant to circulate through the radiator.
     
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  4. ironman187

    ironman187 Active Member

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    The upper rad hose gets hot, and I get heat coming out of the vents in the car as well, there is no water in the oil that I can tell either, so I guess that rules out a bad water pump?
     
  5. ImperialCrown

    Level III Supporter

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    I have seen plugging radiator cores cause this. If they are hard deposits, then a flush usually won't work.
    Head gaskets usually held up well on these engines and by 2004 the water pump issue was much better.
    Moisture in the crankcase was usually from a seeping water pump. Once mayonnaise formed on the dipstick or under the oil filler cap, it was too late.
    Still at 13 years old, it could be a few things.
     
  6. ironman187

    ironman187 Active Member

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    How does one diagnose a clogged radiator? Also, It may be worth noting that when bleeding the system, I opened the bleeder screw, filled up the reservoir, and burped the upper radiator hose. Only a spatter of air and coolant came out of the bleeder. I couldn't seem to get a steady stream to come out no matter what I did. I just bought a new radiator cap, the old one was showing a very very slow pressure drop which could have been the rental tool I was using, but 6 bucks was cheaper than spending hours trying to chase ghosts if the cap did end up being the issue.
     
  7. ironman187

    ironman187 Active Member

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    Hmm, I may have found the issue. I noticed at higher RPMs, a little coolant bubbles out of the bleeder screw. I can't seem to get it tight enough to stop this from happening. Time for a new housing???
     
  8. ImperialCrown

    Level III Supporter

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    Leaks were common at this point. It is the metal 'nut' insert into the plastic manifold that leaks. Tightening the bleeder screw won't help.
    The thermostat is where the lower radiator hose mounts to the front cover. Many times I have seen this thermostat removed in order to try and fix an overheating issue. It is wishful thinking and doesn't fix anything. Make sure that the thermostat is there. It is there for needed flow regulation. If it is missing, flow through the radiator can be too fast and the coolant won't give up its heat.
    Checking the radiator internal passages for hard scale and deposits is difficult because you can't see inside. You may be able to detect 'cool spots' on the radiator fin surface by hand or by a handheld IR thermometer. Cool spots may indicate blocked tubes. At 13 years-old and an unknown past history, it's possible.

    The bubbles aren't right. After the air is purged from the system, you should have straight coolant. I realize that you already had a coolant sample tested for CO2, but if it is recently changed coolant, it may not have absorbed sufficient CO2 yet to give a positive reading. Have another coolant sample tested for the presence of CO2 gases after it has now been driven awhile.

    Automotive radiator overheating causes and cures (at http://dannysengineportal.com/automotive-radiator-overheating-causes-and-cures/ )
     
  9. ironman187

    ironman187 Active Member

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    Unfortunately I am unable to drive it due to the overheating issue. it jumps up within the first 10 minutes or so. it seems to slowly rise to the line above the halfway point, then jump suddenly from line to line from that point. I'll change out the plastic manifold, check the thermostat, and hope that fixes the issue.
     
  10. Doug D

    Doug D Virginia Gentleman

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    If it overheats at speed (or runs hotter than normal) and seems normal at idle, those are symptoms of a scaled or partially blocked radiator. I had a '92 Acclaim where the temperature gauge started to run at 3/4 mark when at highway speeds (normally would be at about the 1/3 mark) and would drop to normal when idling. Replaced the radiator and all went back to normal.

    Basically the radiator has lost the ability to effectively remove the heat from the system.
     
  11. ironman187

    ironman187 Active Member

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    Wouldn't a clogged radiator present as a cold upper hose though?
     
  12. ironman187

    ironman187 Active Member

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    So I got the new coolant manifold on, and found it was leaking around the threads on both the bleeder screw, and the temperature sensor. So I wrapped both in teflon tape. With the system bled, it took almost half an hour for the car to reach the midway mark on the coolant gauge, it stayed there for a few minutes, then started jumping again. I found the upper heater hose was leaking, so I put a new hose clamp on it, and that stopped the leak. I noted that the heat in the car blows hot, the upper radiator hose gets hot, and it gets very firm, also, the coolant reservoir seems to fill up completely. I also was digging through the glovebox and found the paperwork for the autoshop that looked at the car. It says that they found "300ppm HC" in the "radiator", so I ran the car 'til it reached operating temp and ran the block test again. The fluid remained blue. I'm at a loss. Is it the headgasket and my test kit just sucks, or did the shop get a false positive?
     
  13. ImperialCrown

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    If this is a slow head gasket leak, it may take awhile for CO2 gas to build up enough concentration in the fresh coolant. Does the repair order really call it HC (hydrocarbon)? HC isn't really a gas, more of an unburned (raw) fuel residue that could be from coolant contamination.
    It may take a couple of days of running to build up a detectable amount of CO2 in the coolant.
    A quick head gasket test I did in the shop was to apply shop air pressure into the spark plug hole with the valves closed. The tool was a short compression gauge hose with a threaded end and an air hose coupling end:
    MT26J200.jpg
    After applying pressure, the coolant level should rise in the reservoir and eventually you may see a stream of air bubbles. Do this with each cylinder to confirm a combustion chamber-to-water jacket leak. Note that a cracked head in the combustion chamber area could cause the same test symptoms, but 2.7L heads are fairly robust castings.
    If it takes a long time to warm up, that may be from a missing thermostat. Have you confirmed the presence of the thermostat? People love to remove thermostats in an attempt to fix an overheating problem and it doesn't.
    The threads on the bleeder screw shouldn't leak with the screw snugged (not too tight as the manifold is plastic with a splined brass bleeder screw insert). The coolant leak is usually from between the splines and the plastic.
     
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  14. ironman187

    ironman187 Active Member

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    I have not confirmed the thermostat exists yet, but that is the next order of business. I'll have to give the air pressure test a go as well. The repair order states "...after test shows 300 HC at Radiator will need new head gasket", then on the next page it says "Head gaskets have failed found over 300PPM H.C."

    Thanks for the help so far guys, I'm working on two of these cars at the same time, both with different issues, it's a bit frustrating.
     

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