I have an old 1995 Cadillac Deville with the 4.9 engine in it It leaks coolant when parked?

I have a 95 Cadillac Deville with the 4.9 engine that has started to leak coolant

It is not from the water pump ( from what I. Can tell)

And is not from the upper or lower hose and is not from the thermostat housing

It does not leak while driving ( I look under it sometimes when stopped at a stop light ) but it has a good drip after I park it and does not stop dripping

Now here’s the weird thing if I notice the drip once I park I can get back In The car and rev the engine or drive it a few feet (quickly hitting he has) it will stop leaking and not leak anymore

What could this be I’m stumped

I know quite a bit about the car as I’ve had it at least 10 years and I have changed a few water pumps among other things on it through the years but I just can’t find this leak it’s coming from behind the ac compressor( it is not he compressor it’s hot coolant)

12 Answers

  • Anonymous
    7 months ago
    Best Answer

    Okay so you know your way around a wrench. Good to know(for me). First, you know pretty well WHERE it is coming from (hopefully) and that it is coolant.

    So, you do realize that the AC works only when the engine is hot and hot coolant flows through the A/C unit. Which means there are coolant hoses and clamps there. Hoses shrink in thickness over time....kind of like when you go on a diet. At some point the belt around your waist can be cinched up another notch tighter...or your pants fall off. The hoses(all coolant hoses have belts(clamps) on them and they were tight when FIRST installed. Over time they get cooked out and shrink & harden. It is what rubber does.

    . So those clamp ends maybe can be tightened a wee bit more (or the hose as to be replaced because it has partly dissolved from the inside out to make a pinhole crack that only leaks when the engine is hot and coolant pressure is at it's highest. Sometimes you JUST REPLACE THE HOSES with new ones and be done with it. 25 years is a long run for a rubber hose.(considering 7 years is the guaranteed life of a hose).

    I am not going to dig up diagram specs on the Caddy...but also look at the heater hoses that lead to the GATE. That is the shut off valve for the flow of coolant to the A/C unit and there is a GATE for the heater core. which is activated by the Heat/no heat lever inside the car on the dash. It is a steel wire that pulls or pushes the gate open and closed. When gate is closed - no coolant flows. The gates wear out and maybe leaking. Replace the gate with new one is the repair. You can wrap your gate in a plastic bag and tie off both ends so any leaking water remains in the plastic wrap IF IT IS LEAKING and will not steam out or leak out. Always test first to see if that is the problem...if coolant is in the plastic then you got a drip. Give it a couple of days and then open up the plastic wrap and see if it is dry inside or drops of coolant exist. Wrap it in such a way that lever function is not impeded. I know it is fiddly, but why replace something THAT MAY NOT BE THE ISSUE?

    . The heater core or A/C core generally do not leak but the hose connections to them at the clamps could. If the carpet underlay is soaking wet, and tastes sweet, there is your leak and the underpadding has been soaking up the moisture like a sponge. Get you hand between the carpet and the underpad and feel if the underpad is wet. It could be leaking inside and you have never known it.

    It is a bit by bit analysis to figure it out. You do know how to tell if a water pump is leaking....on the bottom of the waterpump there is a small WEEP hole. When you see coolant(I use the blue stuff as that hangs around and is easy to see) at the WEEP hole...when nothing should be there, then the water pump seal is starting to leak. You just replace the pump.

    Many people do not think about the gates but the gates do move and with repetitive movement comes WEAR....WEAR=eventual leaking.

    You mention upper and lower hose. That is 4 clamps. Now look for the other 15 or so clamps on smaller hoses. Also inspect your overflow tanks for leakage and run your finger along the underside of it and see if finger is wet. Wet means leak.

    Realize this all has to be done on a dry day and a day you do not go to the car wash. Give yourself a "fighting chance"

    I did not opt for A/C so am only speculating on it having 2 Gates. It may only have one.

    . Having a repair manual to look into is WAY better than just guessing. I always got the books from the PUBLIC LIBRARY in Auto Maintenance section. As there are different publishers thumb through them quickly in the library before taking out what you deem to be the best in describing it. I like "Haynes Publishing" as they give a wiring diagram for the electrical(not that you need electrical) but the others do not. So somebody is looking harder. Lots of pictures and diagrams and a good explanation helps too. Many mechanics have various books for various cars because they all are not the same. So getting to borrow a book for 2 or 3 weeks is more than enough time to find your problem.

    You are missing something. If you only have plain water as coolant, lose it. Water, when it dries up leaves no TELLTALE sign it was leaking as water leaves no trail. Use the Blue stuff. It is easier to see when the leak happens and that it is coolant.(and AntiFreeze is also AntiOverheat and a lubricant for the waterpump and also a rubber hose conditioner. Much more than just plain water. And get the 50/50 stuff (50coolant +50water)

    If coolant was leaking from waterpump seal, the weephole will show a blue stain if not a blue wet droplet hanging out the weephole.

    Thermostat will never leak as you had a thermostat gasket and you assembled that schit correctly, RIGHT?

    The back and forward movement of the car just means you forced the drip to take another route to get to the ground...maybe much longer and it evaporates before it can drip onto the ground. If you lay under the car you can see several different routes.

    The only way I can tell if it is hot coolant is by the color.(and by the taste test) Touch the tip of your tongue on antifreeze and right away you can tell if it is sweet. Then spit out the spit a few times and you do not think about it anymore. It is not enough to make you sick. Taste my wife's cooking and you know this poison tastes way better. Besides the sweetness taste buds are on the end of the tongue, so no need to swallow.

    Seems to me that the liquid could be water humidity from the A/C unit dripping down. You did not say how you know the difference.

    Maybe you are worrying for nothing.?

    40+ year mechanic.

    • Anon
      Lv 5
      7 months agoReport

      BS " hot coolant" . Warm Refrigerant exits evaporator, cooled in condensor, even cooler on entrance to evaporator by means of expansion valve. No "clamps" only welds/epoxy joints and screw flare fittings.

  • 7 months ago

    I would listen to a mechanic.

  • Anonymous
    7 months ago

    Leaks can be difficult to pinpoint. Get that tracer stuff from a parts jobber and a UV light. It might be dripping from a hose and then running back to where you notice it. Tighten all hose clamps.

    I have a bad oil leak, it blows back to tailpipe and burns. It is from bottom of engine, but, Where? I also need D/M to pinpoint.

  • Anonymous
    7 months ago

    I just farted

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  • 7 months ago

    Any GM Dealer or trusted private mechanic can pressurize the cooling system at the location of the cooling system pressure cap and watch for the leak on the ground or on a lift.

  • 7 months ago

    It's condensation from the A/C!

    • Emilio N7 months agoReport

      Read my post I said it is definitely not condensation and is hot to the touch

  • 7 months ago

    rnaybe you should take it to a rnechanic and have thern check it out

  • 7 months ago

    Get a mechanic to pressure test your cooling system. That will usually reveal leaks which are otherwise difficult to pinpoint.

  • Dze
    Lv 7
    7 months ago

    well, theres heater lines to, did you check those .. and also the heater core is back behind the firewall ..

    • Emilio N7 months agoReport

      No I have not it’s not behind the firewall but from bottom side of engine by compressor I just can’t see it’s origin from the top or bottom but My heater is. It blowing hot

  • Fuhr
    Lv 6
    7 months ago

    You might have a crack in the radiator.

    • Emilio N7 months agoReport

      It’s not near the radiator it’s from under the passenger side under engine I just can’t see it from top or bottom

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