2002 Cadillac DeVille with Anti-freeze leak, now all anti-freeze came out? while driving


If not on the radiator, then wherever it is - isn’t that where to hook up the pressure tester?


I do know the radiator was replaced.


Normally yes.

But since there isn’t a pressure cap on the radiator. you pressure test the cooling system at the coolant reservoir where that pressure cap sits.



What radiator cap? I fill the coolant through the overflow. That cap then? There is not a cap to fill the radiator on the top of the radiator.


See @Tester’s last reply.


This is my overflow where I add coolant. And the cap on it. Just took these pictures. It is dark and cold out. I will have to do better pictures tomorrow in the daylight. It is suppose to rain though.

Is this what you are referring to or are you referring to something that would be on the actual radiator? I know there is a drain plug at the bottom. Unsure about where any other caps would be on the radiator. Thank you.


The radiator doesn’t have a pressure cap. So don’t waste your time trying to find one.

If you were to pressure test the cooling system, that’s where the pressure tester would be connected.



So I can’t do it or do I get an adapter for that cap on the overflow?


I’ve got the adapter for my pressure tester because you never knew what kind of pressure cap GM was going install on the overflow.



So I can do the pressure test using that overflow cap area if I can get an adapter and borrow the tester from AutoZone? Or no, I can not do the pressure test because I can not connect to the radiator?



You insert the adapter into the overflow bottle, turn the handle on the adapter to make it expand the rubber seals to seal it to the overflow bottle, connect the pressure tester and apply pressure to the cooling system.



Great! Thank you. Does AutoZone sell the adapter or do I need to go to some place like NAPA? Did you see my picture of the dipstick and the reply with it?.


It doesn’t seem like a pressure test would be needed if it’s leaking bad enough to blow coolant everywhere. The leak should be fairly obvious at this point, if I read the original post correctly. I’d fill it up with with water, start the engine, and look for the wet spot(s).


Thank you. I was wondering about that earlier today. Since it was towed home I have not tried to add coolant or water. I guess I though it would leak out. I was concerned about starting the car and ruining the engine. I really wonder if it is that upper radiator hose. Mostly because I am not sure what else would be up in that area that coolant could spray out of.


Could be the hose. The radiators are bad to leak where the plastic end tanks join the aluminum radiator also. There’s a possibility it’s leaking elsewhere, and spraying coolant on that area that you see that’s wet. Most likely, though, the leak will be close to that wet area. You can fill it up with water, start it, drive it, whatever. As long as it doesn’t start to overheat (watch the temp gauge), you won’t damage the engine. I use water because it’s cheaper and I wouldn’t want to waste coolant knowing that I was about to take something off of the coolant system to repair a leak - and lose the coolant. If you do use water, be advised that you can damage the engine if you leave water in the cooling system overnight and it freezes. You need a 50/50 mix of water and coolant (or buy the premixed stuff) if your car will see freezing temps. It’s more costly, but if you think you might not be repairing it immediately after you find the leak, it might be safer to fill it with antifreeze when looking for the leak.


Thank you. I will try with 50/50 mix, that is what I have been putting in it. It did overheat before I had it towed. My Chilton manual does not show the hoses, very brief information on that area. I would like to know exactly how many hoses there are that could be leaking.


And that doesn’t include the radiator hoses.



Thank you. That is what I was afraid of. Tons of hoses!


That oil looks to me like the engine overheated due to lack of coolant. If you don’t have enough coolant, your temp gauge won’t go up because the sensor is no longer immersed in coolant. The time to fix a coolant leak is when it first appears.


Thank u. The “check coolant level” would come on and I would add about 1/2 gallon anti-freeze. Nothing else happened such as temp issue until the day it was towed. That oil had 335 miles on it. Seems dark. Over the last few years I asked several mechanics about why I would have to put 1/2 gallon anti-freeze in my car to where I probably put in 4? gallons before that day. Nobody had a clue as to why it would go through it if I never saw a leak or puddle under my car.