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Mystery of the Vanishing Coolant

Discussion in '"Stock" Alpine' started by Alpine 1789, Apr 9, 2011.

  1. RootesRacer

    RootesRacer Donation Time

    Not exactly, but I get what you are saying.
    The top tank (in the case of SIII to SV) has some volume that the coolant can expand into. Its not much but the thermal expansion of the liquid is not huge.
    Ideally the cooling system would have no room for expansion so that it pushes out a little coolant as it gets hot and sucks it back in after it cools.
    These cars were not actually designed for closed cooling, though you can make them work.

    Any and all coolant pushed out was intended to be lost and at some point the engine would find a pressure equilibrium where in the course of a startup cycle, no coolant is lost.

    The earlier cars (SI/II) have an expansion tank which provides about 1/4 liter of expansion which makes them not as good for making a closed cooling system.
  2. agmason54

    agmason54 Donation Time

    Maybe this will help

    I was on a long haul home last summer and while driving in my sleep at night my generator tried to jump off the engine.The bottom generator bracket bolts backed off and all that was holding the generator was the bolt on the water pump that holds the generator bracket.I thought it fell off but it snapped off instead.I tightened the bottom generator bracket bolts and ran without the top bracket and the water pump/generator bolt.I never put 2&2 together but that is when I started loosing coolant.I could drive a few hundred miles then my temp would come up slowly. I would pull over and top off the coolant with what was caught in my overflow bottle which is nothing more than a plastic quart oil jug.
    My final guess is that I would loose enough antifreeze to make it hot enough to push out the antifreeze into my overflow jug. I was convinced I had a slight head gasket leak.
    I then parked the beast and put a piece of card board under it to catch the usual leaks and that is when I noticed the antifreeze on my cardboard after a few weeks.That little green stain saved me pulling the head.While driving I could never catch it leaking.
    Meanwhile I have removed the water pump,drilled out the broken bolt and managed to snap off an EZ Out inthe drilled out bolt down inside the engine. Damit MAN!!!etc...
    Meanwhile I found an outfit that sells a tool that cuts and drills HARD steel bolt extractors.Go to Youtube and checkout Rescue Bit. It is my last chance to save my threads in my block.
    Anywho thats my story about vanishing coolant.
  3. Nickodell

    Nickodell Donation Time

    I had trouble with the same bolt three years ago (wrote about it on the forum). I began the usual process of drilling a pilot hole in the broken bolt stub and using an E-Z Out, but couldn't shift it. With the prospect of a busted E-Z, instead I drilled out the bolt stub and then slightly oversize, so as to eliminate the old threads. Then I tapped new (coarse) threads and used a larger diameter bolt. To do this you have to use three taps: First a pilot tap (aka Taper Tap), then a transition tap (aka Plug Tap - less taper) and finally a Bottoming Tap (no taper) in order to tap to the bottom of the hole.
  4. agmason54

    agmason54 Donation Time

    I think we are off the subject talking about tapping holes.My point was that my broken bolt holding the generator allowed me to loose antifreeze.
    I know about tapping holes and the different taps but I am trying to save my original threads.I would go to a Heli coil rather than an oversized course thread bolt.That's why I mentioned the Rescue bit as a last resort to save my threads,to mount my generator,to stop my leak to drive my car.
    Meanwhile were is Jim's coolant going?......
  5. Nickodell

    Nickodell Donation Time

    In my case the bolt hole was blind, so there was no leak. I'm not sure where you were losing it from, unless from the water pump gasket due to the bolt no longer cinching that side down. Not everyone knows about the different taps. When I posted about this three years ago I had several replies or PMs saying this was news to them.

    Now I know that this will be heresy to some, but in Jim's position I would try a jar of Bar's Leaks. I have used this on several cars over the decades, and never had a problem with it clogging radiators or heater cores. Some 25 years ago I had a small leak in Matilda's radiator, and Bar's fixed it for 18 years until I finally replaced the rad. when a larger one developed at the top tank joint. Few people know that this product was once used to fix a leak on the nuclear sub Nautilus:

  6. RootesRacer

    RootesRacer Donation Time

    Not to detract from your post but here was my solution to a weeping rad cap on my SII header tank.
    I fabricated and aluminum brazed an aftermarket filler cap onto a base which I bolted in place of the stock filler cap (which used non standard length caps which are more or less unavailable now and often incorrect when bought new).
    There is a tube below the flange which preserves the factory notion of a gas expansion zone.

    The cap is a 9psi chevy cap that has a seal on the top to allow proper function of the recover system (like most newer style caps). The old caps (like ours) dont have a rubber seal on the top of the cap since they werent intended to hold a vacuum for coolant recovery.
    The "stock" cap bought new from S.S. weeped coolant out the overflow above 4.5psi and wouldnt suck coolant back when the tank pressure dropped.

  7. agmason54

    agmason54 Donation Time

    vanishing coolant

    I dig that.Nice job.I got away with bending the ears on the cap and adding an extra rubber washer.My theory is my water pump gasket weeps because of the broken bolt still unremoved. I'm too disgusted to mess with with it until I can wear shorts and work under a tree and watch my buddie get HIS busted tap out of my engine....
    Have you checked out the Rescue bit on Youtube?
  8. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    I have been traveling the last few weeks and haven't had much time to chase this down. I did have some time last weekend and today to work and drive and do have an update. First, the good news: the missing coolant is no longer just vanishing. It is now all over the inside of the engine and engine compartment. Whatever was slowly seeping out is now a full-fledged leak. That should make things easier to see, but I still can't find it. I took a short highway drive on Sunday, then put the car up on ramps so I could find the leak. Coolant was everywhere, but it appeared to be most prominent on the left (driver's) side of the engine. One thing I did notice while under the car (with the engine running and coolant still dripping) was that the radiator drain plug seemed to be leaking. Further examination revealed that rubber gasket had deteriorated and was basically gone. Even if this wasn't the whole problem, I figured I ought to take care of that before proceeding further. I let the car cool down, installed a new rubber gasket, then went out for another drive. Lo and behold, there was no leak! I even put the car back up on the ramps and let it idle for about 30 minutes. Dry as a bone. Could it have been that easy? Nope.

    Today was a nice day so I drove the car to work. It is only a 15 minute drive, mostly highway and basically the same drive as I had done on Sunday after replacing the gasket. Once again, I arrived here to find a completely wet engine compartment. So, the mystery remains, albeit changed. The coolant is no longer vanishing, but I still can't find the leak. I am about to replace all of the hoses and probably the radiator (I will start by testing my spares and use one - at least for now - if it tests out ok). But, I hate to do that if the problem is elsewhere. Before I start randomly replacing stuff, does anyone have any ideas? Why can't I find the frigging leak when water is dripping down and spraying everywhere at highway speeds? Does the fact that it is intermittent suggest anything to anyone?

  9. tony perrett

    tony perrett Gold Level Sponsor

    Why not try my earlier suggestion and add a water-based fabric dye to the coolant? Not expensive and it should show where the leak is.
  10. RootesRooter

    RootesRooter Platinum Level Sponsor

    Have you tried popping the hood and revving up the hot engine while standing over it and just watching for a few minutes? If it's spraying all over the engine compartment after just a 15-minute drive, the leak shouldn't be that tough to spot!
  11. George Farrell

    George Farrell Donation Time

    My guess would be the water pump seal. The coolant could get past the seal and be sprayed around by the pulley. That doesn't explain why the left side would be worse does it?

  12. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    I suppose that is an option, but the coolant is pretty easy to see. Its already dyed green. (Someone suggested trying a black light. I picked up a "party bulb" at Home Depot, which is what they apparently call them now, but it didn't put out enough light to do anything.)

    I did. That is part of what is so strange about this. And I did that after a drive similar to today's, and got nothing. I reved the engine with a bright flashlight at every possible junction point, but couldn't see a thing.

    That could certainly be the problem and part of the reason why I am hesitant to start replacing parts without first knowing the cause. But, I checked the inside of the pulley in response to an earlier suggestion and it was dry. I looked at it again this morning and, despite the water everywhere else, it was still dry.

  13. tony perrett

    tony perrett Gold Level Sponsor

    The advantage of using a dye is that you can make a really concentrated solution rather than relying on the pale colouration that coolants usually have. I am convinced that this method is worth a try.
  14. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    Just to add to the mystery, I just drove home and, everything was dry when I arrived. Same route, only difference is that the outside temperature was around 50 on the way there and 70 on the way home. I topped off the radiator before leaving (although I hadn't lost all that much coolant; the level was less than 1/2 inch lower than when I left), so that was probably pretty constant, too.
  15. RootesRooter

    RootesRooter Platinum Level Sponsor

    Jeez! What a conundrum!

    One final, awful, grasping-at-straws possibility: a cracked block. The crack would likely be next to, and in a horizontal line with, the bolt holes for the alternator bracket. Tight when cold, porous when hot under load?
  16. thomson

    thomson Donation Time


    Just a guess but you should not fill the tank above 3/4 full water is uncompressorable so you need some air which is to allow for the expansion of the water with heat.
  17. RootesRacer

    RootesRacer Donation Time

    Before you succumb to ill thoughts, if you over pressure the rad and your rad cap has no top seal (not sure if later rad caps have this seal, earlier ones DO NOT), the fluid will come out the cap even with an overflow.
    So dont assume that just becuase you have an overflow that it cant still come from the cap.
  18. Nickodell

    Nickodell Donation Time

    As the pulley rotates counterclockwise as seen from the driver's seat, it would be likely to fling more to the left side of the engine bay.
  19. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    I am afraid I have thought of that too, and that is the spot I was afraid of. I can't see anything there, but the only way to be sure would be to pull the alternator, which I may get to.

    I am not sure what 3/4 full is, but I always heard to fill to about 1" of the filler neck. Is this not correct? Note: I have installed an overflow tank, but no fluid is going into it.

    I certainly like this thought and have thought about the cap for a while. The SV caps - or at least the cap I am using - does not have a rubber ring the way modern ones do, but it does have a thin metal (maybe copper, but I am not near it at the moment) ring there. I wonder if I could make some kind of thin gasket to better seal it off as a test?
  20. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    I thought I'd post a quick update. I decided to go ahead and do the easy part first and replaced the radiator, cap, the upper and lower hoses, and the bypass hose - all bought from SS. I filled the radiator with water, started it up and let it warm up. No leaks, so I went out for a quick drive around the neighborhood. Still no leaks, but I let it cool down, then checked everything again and went out for a longer drive, about 30 minutes on the highway, plus a little local driving. So far, so good; everything is dry. It is cold and wet today, so I didn't stress the cooling system, but I am optimistic. Forecast for tomorrow is worse, and then I will be out of town for a few days, so it will be late next week before I can really test things. Of course, then I'll have to deal with the head gasket, but one thing at a time.

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