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Coolant recovery container overfill

Discussion in 'Neon' started by AllanC, Feb 17, 2016.

  1. AllanC

    AllanC Well-Known Member

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    Vehicle is a 2003 Dodge Neon with 2.0 liter 4 cylinder engine and 40TE 4 speed automatic transaxle. Current odometer reading is 282,350 miles.

    Problem is the coolant recovery container mounted next to the firewall is being overfilled by coolant from the cooling system. When the engine is cold, you add the proper coolant thru the radiator cap until the system is full. Then you make sure the recovery container has coolant at the ADD mark.

    You drive the car for 1 hour at highway speeds and then stop. After letting the vehicle sit for several hours and cool down, the level in the coolant recovery container is almost at the top and ready to spill out the overflow. You remove the radiator cap and the coolant in the system is low.

    This has been a ongoing issue for several years with this vehicle. This is the link on this forum where I discussed in year 2013.

    Coolant filling up radiator overflow bottle

    I have replaced the radiator cap several times and the last new cap installed one month ago was a Mopar unit. Cap made no difference; coolant still being pushed into the recovery container. Engine does not overheat. Ample heat from heat at all times. Engine temperature gauge is steady and normal at highway speeds and when idling.

    One repair shop I recently had inspect the car said the heater core was leaking. This was bleeding off the pressure such that when the engine cooled vacuum in the cooling system is being lost and will not return coolant from the recovery container to the system.

    Sounds plausible but there are no drips under the car from a leaky heater core. And there is no sharp, sweet smell in the ventilation system which I would tend to expect if a heater core is leaking.

    So I decided to disconnect the inlet and outlet to the heater core and install a length of 5/8 inch heater hose and completely bypass the heater circuit. I filled the cooling system through the radiator cap and adjusted the coolant in the recovery container to the ADD mark. I drove the car at highway speeds for 60 miles and let it sit. Recovery container filled to the top.

    I used a suction gun and drained the coolant from the recovery container and filled the cooling system. System full; recovery container fluid level at the ADD mark. Drove car again at highway speeds for 60 miles and same results. Recovery container filled to the top and cooling system low on fluid.

    So bypassing the heater circuit disproved the theory that a leaky heater core is causing vacuum problems in the cooling system. I am not having much luck finding a repair facility that can go beyond guess work. At this point my guess is that the engine does have a minor head gasket leak. I would like to have some definitive proof that the head gasket is leaking.

    Would a test where an adapter is placed in spark plug hole, cylinder placed at top dead center so valves are closed and cylinder pressurized to 150 psi pinpoint a leaky head gasket? Would a head gasket leak only when engine hot and not when engine cold?
     
  2. valiant67

    valiant67 Rich Corinthian Leather
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    I suspect the shop may have been right about a leak, just wrong about it being the heater core.
    First thing I'd try is to rent or borrow a plain old cooling system pressure tester. You might find something like a weak hose clamp breaking down the vacuum/pressure the system needs to operate.
    I believe you can also use the same tester to look for higher pressures due to a head gasket problem though I've never had to.
     
  3. ImperialCrown

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    By pressurizing a cylinder with compressed air in the spark plug hole one at a time with the cap off, look for bubbles in the coolant after a few moments. This would indicate a likely head gasket leak.
    There are also chemical testers that test for the presence of CO2 in the coolant. CO2 would be a combustion by-product that is also a good indicator of a combustion-to-water jacket leak.
    The combustion leak will gradually push the coolant into the reservoir bottle.
    The heads themselves usually hold up well, but may need light resurfacing with a 3M Roloc disc to prepare the surface for sealing with the new MLS (multi-layer steel) head gasket. Fiber head gaskets offered by Fel-Pro, etc. are obsolete and will leak again.
     
  4. AllanC

    AllanC Well-Known Member

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    I finally found a pressure tester that had the proper connecting cap for the cooling system filler. I attached and pressurized the system to 16 psi. I timed the drop off in pressure. It took 3.5 minutes for the pressure to decrease from 16 psi to 15 psi. Is this slight drop off normal or should it hold the pressure indefinitely? I looked and felt hose connections and did not feel any wet areas.

    I am wondering about the seal on the water pump shaft. I guess it is possible it could leak slightly and allow a pressure drop? Since the water pump is driven by the timing belt it is not easily viewed. I have no telltale trace of coolant leaking in the area of the water pump.

    With the system pressurized through the tester, I started the engine and suddenly accelerated the engine rpm quickly in several attempts. The pressure on the gauge held stead at 15 psi and did not spike. So would that tend to indicate NO head gasket leak????
     
  5. AllanC

    AllanC Well-Known Member

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    After lots of different tests with cooling system testers, I finally got confirmation with usage of a chemical test that there is a head gasket leak. But it is very minute as it takes the engine running at highway speeds for 1 hour to push any significant amount of coolant into the recovery reservoir.

    IC: you say the heads hold up well on these engines. Can that mean that the head gasket fails but the head is not warped????
    I know that the only way to be certain is to remove the head and have a machine shop use precision instruments to check for head warp. If it was just a gasket fail, I could replace just the gasket and head bolts and do a repair relatively inexpensively (If I do my own labor).
     
  6. ImperialCrown

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    I have found that the heads rarely crack or warp on the 2.0L and it is generally a routine head gasket replacement.
    Coolant seeps into the steel/aluminum sealing area of the head-to-gasket surfaces and corrosion begins. This will cause pitting in the aluminum head surface and a compression leak into the water jacket begins. It can be a very small leak at first.
    A warp check with a straight edge (steel ruler) and feeler gauges can be done per the service manual. You shouldn't have to send the head out for service. Usually if no major overheating has occurred, you are OK.
    Multi-Layer Steel (MLS) Head Gasket Installation Procedures for Chrysler 2.0L and 2.4L Engines - Engine Builder Magazine
     
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  7. AllanC

    AllanC Well-Known Member

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    Thanks IC for the explanation. When I remove the head I will know the area to inspect.

    What is the cause for the corrosion? Dissimilar metal i.e. steel on aluminum???
     
  8. dana44

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    There is that, and the other is liquid and combustion gas contamination with the heat, air and heat combined will eventually cause corrosion and pitting. Gaskets do wear out, the newer designed MLS (multi layered steel) gaskets are very good at sealing. As IC said, warping is very rare, especially with no noted overheating.
     
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  9. AllanC

    AllanC Well-Known Member

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    I took the vehicle to a known repair facility and had the engine head removed. The head was inspected by a machinist with experience in engine rebuilding. After checking with a straight edge no warp was found. So a new head gasket was installed and the engine is back in service and I am driving the vehicle. While disassembled I had the shop replace the timing belt, belt tensioner pulley and the water pump.
    Short trip driving indicates no cooling system problems though the real test will be an extended drive at highway speeds.

    I retrieved the original head gasket that was on the engine. It has 4 steel layers and it appears there is some fibrous, black sealing material around the cylinder openings and coolant passages that is on both sides of each layer. On the sides that faced the head and block there are no obvious signs to me of erosion. So maybe the erosion that allowed combustion pressure to enter the coolant passages is in the inner layers sandwiched together? I will admit this is the first time I have seen a layered steel head gasket so I am a novice with these types of gaskets. Previous experience has only been with fibrous, single layer head gaskets.

    I appreciate all of the good advice given on this issue.

    The shop charged $1206 to remove and install a new head gasket. Included was a timing belt, belt tensioner pulley, water pump.
    Labor: $696 Parts $440. $70 Hazmat, supplies, tax. This is NE Oklahoma. I wonder how this cost compares with other areas of the USA?
     
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  10. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Yup. You can figure about $1200 for a head gasket replacement in MA. 6-8 hours, depending on car.
     
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  11. John Wood

    John Wood Well-Known Member

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    I think you did good on the price considering that included the timing belt, water pump, and tensioner. I would have guessed about $1500 to $1600 for that work.
     
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