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Thread: Not this $#!* again! (Coolant leak at rear of engine)

  1. #1
    Stupid Newbie DaraSue's Avatar
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    Not this $#!* again! (Coolant leak at rear of engine)

    So the other night I'm pulling into the garage after work and I see a puddle of antifreeze near where the front of the car is when it's parked. (I noticed this as I was coming in, so I'm not sure when the leak actually occurred.) I wipe it up and the next morning there doesn't appear to be substantial new leakage, but maybe a few more drips so I put the pressure tester on.

    It immediately gets worse from here.

    I pumped the tester to about 10-11 PSI and then there's a pretty good stream of liquid coming down the back of the engine. I can't tell exactly where it's coming from but it looks like there are streams running down either side of the lower pulley, and antifreeze pooling on the flat part between the pulleys.

    leak.jpg

    The big hoses aren't noticeably wet by the clamps and the weeper hole under the water pump feels dry, too. I tried tightening the hose clamps and used the tester again this morning (only up to about 7 this time) and it still leaks.

    The weird thing is, I checked where I'd parked the last couple days at work and didn't see any antifreeze on the ground there, either. So it's like the radiator leaked one time in my garage and then I broke something using the tester.

    Has anybody else had this happen and not had to take the intake manifold off to fix it?

    (I never did manage to replicate the leak from the front. I tightened the clamp on the driver's side of the radiator, though.)

  2. #2
    EFI'd dn010's Avatar
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    My guess would be a leak that has filled up your "valley" and it's running down the timing cover. If you can't find any of the main, large & accessible hoses hoses leaking then it looks like you'll be removing the intake manifold to inspect the hoses on either side of the water pump and the ones at the back of the pump.
    Last edited by dn010; 11-21-2017 at 02:59 PM.
    -----Dan B.

  3. #3
    Stupid Newbie DaraSue's Avatar
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    Quote Originally Posted by dn010 View Post
    My guess would be a leak that has filled up your "valley" and it's running down the timing cover. If you can't find any of the main, large & accessible hoses hoses leaking then it looks like you'll be removing the intake manifold to inspect the hoses on either side of the water pump and the ones at the back of the pump.
    Arrrgh, that's what I was afraid of.

    I found this guide: http://dmctalk.org/attachment.php?at...1&d=1484494853

    Are the copper washers for the fuel lines something I need to order from DMC or is there an off-the-shelf replacement?

  4. #4
    EFI'd dn010's Avatar
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    Actually, while that appears to be a very thorough write-up, you don't actually need to remove all the lines from the fuel distributor (FD) or the FD from the car. You can unbolt the fuel distributor from the mixture control unit using the three flat head screws and just the one fuel line on the top center of the FD needs to be removed (I can't recall where it goes since I don't have K-Jet anymore) so that you can access the third screw that holds the FD in place. When you're lifting it off the control unit, be careful not to drop the plunger (you'll dump a lot of fuel and risk injuring the plunger). You can slide your hand under and hold the plunger in and once you clear the FD from the control unit, wrap something around it so the plunger stays in the FD. I used to tie wrap around the whole FD so that the plunger stays in and then tie wrap the FD to the bar on the back wall so it stayed out of the way. You'll also need to unbolt the cold start valve using the two hex bolts so that you can keep that line attached as well.

    If you do choose to make things more complicated by removing every line on the FD, you can get the copper washers from a parts house. Since this is your first attempt at this, take pictures along the way of how the vacuum lines attach, and how the connectors are connected so you have something to go back and look at should you forget. Otherwise, post here and we'll walk you through.

    EDIT: You should also be able to peek around with a flashlight to verify if indeed your VOD has been filled with coolant. Either that, or run a long screwdriver down a gap and see if it comes up with coolant on it.
    Last edited by dn010; 11-21-2017 at 03:53 PM.
    -----Dan B.

  5. #5
    Stupid Newbie DaraSue's Avatar
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    I just tried sticking a Q-tip on a stick down behind the water pump and it came back wet so I guess that's where the problem is. If I have time tonight I might try to get started just in case there's anything I need to go buy tomorrow.

  6. #6
    Senior Member Chris 16409's Avatar
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    You should be able to lift the mixture control unit out of the way enough to remove the intake manifold. That way you don't have to disturb any of the fuel lines. Maybe the leak is coming from the two hoses coming off the back of the water pump? I'd recommend Silicone hoses for the back of the pump. Once you tighten them down, they don't require additional adjustment unlike conventional rubber hoses may require.
    Chris Miles

    For Better or Worse I own a DeLorean!
    1983 Grey Manual, VIN #16409, Fresno, California

  7. #7
    EFI'd dn010's Avatar
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    While a hose is the likely culprit, other causes could be a pinhole from rust in the water return line or, like what happened to me once, a cracked flange on the side of the head that you clamp the water pump hose onto!


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    -----Dan B.

  8. #8
    TGTF (Too Greek to Function) AugustneverEnds's Avatar
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    I dealt with a leak that looks like yours for close to a year. It would drip when the engine was cold and dissipate when everything warmed up. I replaced the hoses with silicone, tightened the clamps several times and still had a leak. Turned out to be the gasket between the water pump and its back plate, and the back plate had a few gouges that prevented a perfect seal. I bought a new back plate from DeLorean Europe and cut my own gasket out of cork type material and have been dry for over a year now.
    Nick A.
    Νικος Αυγουστινατου

    1988 BMW 325iS
    1982 DeLorean DMC-12

  9. #9
    Stupid Newbie DaraSue's Avatar
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    Well, I got as far as trying to take the W pipe off but it won't come loose (all 5 bolts are out). Any ideas?

    (I realize "put it back together and take it to somebody who at least theoretically knows what they're doing" is probably the best one but everybody's going to be closed for the holiday. Arrrgh!)

    Another potential issue: when I was taking the idle speed motor off, the pipe it was attached to on the back side was really loose and it just slid out. It looks like it has some electrical tape wrapped around the long end. Is this normal? I'm not 100% sure where it actually came out of so I hope I can get it back in.20171121_171659.jpg

  10. #10
    Delorean Guru
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    Quote Originally Posted by DaraSue View Post
    Well, I got as far as trying to take the W pipe off but it won't come loose (all 5 bolts are out). Any ideas?

    (I realize "put it back together and take it to somebody who at least theoretically knows what they're doing" is probably the best one but everybody's going to be closed for the holiday. Arrrgh!)

    Another potential issue: when I was taking the idle speed motor off, the pipe it was attached to on the back side was really loose and it just slid out. It looks like it has some electrical tape wrapped around the long end. Is this normal? I'm not 100% sure where it actually came out of so I hope I can get it back in.20171121_171659.jpg
    If you removed all of the bolts just tap it and it should come loose. Tape on the pipe is not supposed to be there, someone tried to seal the pipe and did not know there is supposed to be an "O" ring that seals the pipe in the mixture unit. Often when you disassemble things you find all kinds of unusual things that have been done. Part of a job like this is to undo all of the stuff done incorrectly. Once you get the intake manifold off, pressurize the cooling system and the source of the leak should be obvious. In any case you will be doing the whole job anyway. Call your favorite vendor and order the "Master Water Pump kit". It should include all of the seals, gaskets, hoses, belts, and water pump to replace everything.
    David Teitelbaum

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