4.5L 88 Eldorado External Coolant Leak

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Other Cadillac Engines Discussion, 4.5L 88 Eldorado External Coolant Leak in Cadillac Engine Discussion; Vehicle description : 1988 Cadillac Eldorado, 4.5L, 134,000 miles, Cylinder head gaskets replaced once prior to 85,000 miles several years ...
  1. #1
    88_Eldo is offline Cadillac Owners Member
    Automobile(s): 1988 eldorado
    Join Date
    May 2009

    4.5L 88 Eldorado External Coolant Leak

    Vehicle description: 1988 Cadillac Eldorado, 4.5L, 134,000 miles, Cylinder head gaskets replaced once prior to 85,000 miles several years ago.

    About two years ago, the upper radiator hose blew out. The car did not overheat, most likely since it happened in the middle of another cold Ohio winter (never even threw a temp light, and the engine temp never exceeded around 200-210 degrees).

    About a year ago, the engine started spitting antifreeze out in the worst spot imagineable: Between the cylinder head (the one closest to the front of the car) and the block. The car had to sit in the winter time since there was no way I could rip it apart in the cold. Now that I have some time, I'm digging in.

    1) No white smoke
    2) No coolant in the oil
    3) No coolant leaking anywhere else.
    4) Flush with stop leak didn't do a thing.

    The first suspect I thought was the coolant hose that runs parallel to the block. However, upon closer inspection I saw the water was dripping from that spot between the block and the head, and not shooting out of the hose.

    So, that left me with two possibilities.

    1) Is it the intake manifold gasket?


    2) Is it the head gasket?


    3) Is it both! (Yikes).

    I'm waiting on the gaskets and a metric distro wrench to arrive via FedEx, so I have some time before I take off the intake. Obviously, I don't want to change the head gaskets unless I have to since the exhaust manifolds are a pain to remove. My instinct tells me it's the intake since the lower ports sit underneath the head anyways, and normally I thought head gasket leaks present themselves more internally than externally.

    I'm wondering if I should just do the head gaskets anyways since everything's been dismantled already.

    I looked all over these threads and couldn't find anything - most apologies if there's something out there already.


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  3. #2
    88_Eldo is offline Cadillac Owners Member
    Automobile(s): 1988 eldorado
    Join Date
    May 2009
    Thread Starter

    Re: 4.5L 88 Eldorado External Coolant Leak

    This is fixed now. I ended up doing the water pump hose that's spliced by the head area and the head gasket. She runs like a champ now. The toughest part of this job I believe was the distributor hold down bolt. I spent hours trying to get that darn thing in and out properly. I ordered a 15 MM distributor wrench from JC Whitney and still had a heck of a time getting that bolt to tighten down. I recommend taping and marking all wires/hoses etc. Some interesting things I found while working on this as tips in case anyone needs them:

    1) When I put the car back together, the transmission started to shift from 2nd to 1st gear kind of hard. It ended up being a bad vacuum line connection from the trans vacuum modulator to the throttle body. I put new line on and it shifted smooth as silk.

    2) Power steering lines should be fitted prior to tightening down the pump to the bracket on the engine.

    3) I also found the power steering was leaking from underneath the car by the front of the radiator. The Power steering return line was leaking where the rubber part is pressed into the metal part. I did not want to replace the entire line, so here is what I did as a workaround. I cut the line where it was leaking. I then went to Home Depot and bought a male adapter = 3/4" outlet on one end, and 3/8" on the other. I spliced the rubber to Power steering pump end to the 3/8" side, and 3/4" heater host from the metal tube to the adapter. No leaks, power steering works like a charm. Just make sure the threads on the brass adapter are sealed with teflon tape. I have driven the car for several miles without any issue - should be fine until I can get the bread together for a new return line assembly.

  4. #3
    steelybill is offline Cadillac Owners Enthusiast
    Automobile(s): '85 Fleetwood FWD
    Join Date
    Mar 2009

    Re: 4.5L 88 Eldorado External Coolant Leak

    It's good to hear that you have it under control

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