Coolant Leak from Where?

[Yarls24]

I got home after a 35 mile drive, and when I put her in the garage, about 1 minute later I had about 8 oz. of coolant on the floor. I checked all the hoses, nothing coming from them. I was thinking it could be the water pump, although after running the car up to temp twice, it never leaked again. My friend looked at it, (he is a Chevy Fanatic) he said probably the water pump. I am puzzled, you would think if it was the water pump, it would have leaked again after the test. But it did not. The car is not leaking anymore, I will do some running around town later in the week, and see if I can duplicate this problem. We could guess from where the leak was, but couldn't pin point it. The water pump looked ok. The resevoir bottle was fine, thr radiator was fine also. Let me know your take on it.

 

[c4cruiser]

See if you can rent a cooling system pressure tester from a local auto parts store or rental shop. Bring the system up to 15-17 pounds and leave it there. If there is a leak you should be able to find it. Whee was the coolant on the floor sitting in relation to the motor?? Front, back, either side??

 

[Yarls24]

Coolant on the passenger side of the car. Very hard to determine where it was coming from. A pressure test will tell the where the leak will be for sure. I had the intake gasket, thermostat changed about a year ago.

 

[Yarls24]

Looked like the front of the motor if I had to guess, definitely not the side or back.

 

[c4cruiser]

If it's not the water pump, it could be the thermostat housing, the hose connections to either side of the throttle body, or the heater hoses where they attach to the motor. Could even be a weak hose clamp if you still have the spring clamp style.

Water leaks are sooo much fun!!

 

[Yarls24]

Checked all of these too. Everything looks clean

 

[Yarls24]

Checked all clamps. I have one spring type clamp left on the big hose going in to the motor. No residue at all on it. Hoses were all dry too. Very freaky incident I must say.

 

[taegdh]

I hate to ask this, but: " DID YOU RUN YOUR AIR-CONDITIONING WHILE YOU WERE OUT?"


I too have gone off the deep end looking for a "phantom" leak, only to find that it is condensate on the cold return line from the A/C unit. Moisture from the atmosphere condensates on it and flows onto the surface once you stop. This occurs very often in warm moist summer times... It doesn't need to be going full blast for this to happen either. Just having it on......

Check that out before you start pulling water pump, and as previously stated, invest or rent a pressure tester, pump it up to 15 to 18 PSI, and if there is a leak somewhere, it'll show. There is also special dyes which can be used with "black" lights to indicate water/coolant leaks. Less than $25 if memory serves correctly.

The one thing about the waterpump is that if it is weeping out the shaft, you would have a stream of it hurled all over in the same vertical plane off of the pulley, and not puddling.

 

[vetteboy86]

From what I picked up, the leak was under the front passenger side of the car. It was however in the front. On my 86 the overflow is in the general location, I dont know where it is on yours but just thought I would take a stab at it.


Craig

 

[Yarls24]

Thanks guys for all the advice. I did not run the air, had the top off on this day. I will go over the car with a fine tooth comb, before I pull the water pump. I am bound and determined to find out where the anti-freeze came from. There was no sign of leaks from the overflow area. We jacked the car up, and crawled underneath, and still couldn't find it. There is an air pump located in the area by the leak, but can't exactly see where that leak may hve come from. The big hose is right there, and maybe that old clamp may have gave a little, but no sign of leaks from it. I don't know guys, looks like the pressure test will have to occur after one more time out. I will keep you informed, and I do appreciate all your help.

 

[Moonunit 451]

I had a similar leak. I was only able to find it with a pressure tester. There was no way to track it down visually cause you can't really even see that there is a hose there. In the photo below, look in almost dead center through the A/C bracket. There is a y hose there. The factory one was molded and no longer available. I got this one from the dealership, and it was SOOO much fun to replace

 

[Yarls24]

Thanks Moon. Great picture. I will look tonight. Will rent a pressure tester later on this week, when I have time. I will check where the overflow tube might be running to also. Thanks again for the advice.

 

[Yarls24]

I found the leak

Its the waterpump. Took it out for about 5 minutes, then it started leaking. Got her home real fast, opened the hood, there she was. Leak coming from the bottom of the water pump for sure. I am relieved I found it without having to do a pressure test. I am not sure why it didn't leak while just at idle yesterday. But I will tell you as fast as it starts leaking, it stops. Pulled it in to the garage, no leaking. What will an AC Delco waterpump go for? How much do you think a shop might charge to do this? What else should I replace when doing a waterpump? I hear everyone say the opti-spark, but cash is a little thin these days. I am thinking that the hoses need to be replaced as well. Let me know guys.

 

[c4cruiser]

You should at least replace the upper and lower radiator hoses. Of course do a coolant flush and replace with a 50-50 mix of ethlyene glycol (green) coolant and distilled water (grocery store about $1.00/gallon) You'll need 2 gallons of antifreeze and 2 gallons of distilled water.

Your '88 does not have the Opti-spark distributor. Only the LT1 and LT4 motors from 92 on had the distributor at the front of the motor under the water pump. You should remove both knock sensors at the bottom center of the block to drain all of the coolant.

Inspect the front of the radiator for garbage and dirt and use a garden hose from the fan side to push any debris and dirt out from the between the tubes. Junk in front of the radiator is a common problem with C4 hot coolant temps.

 

[Yarls24]

Thanks, car runs fine right now. I will take your suggestions.

 

[captbane]

hi all ! was heading into work this morning and had to either get on it hard or get rearended by a truck speeding down the hill behind me ! made the turn off a 1/4 mile down the road and my temp gauge was climbing like all get gone! kicked on the heater and defroster and limped into work a mile away at about 300 degrees! when i opened the hood i had steam comming from what looked like down low on the pass. side of the rear of the block! couldnt tell where the leak was because of the steam in my eyes. oil looks ok. i was hopeing that it was the intake manifold as im told they are prone to go on 89s with 80k or so on them but i just cant see the leak, there are alot of cables at that point on the l-98. my corvette repair guy said to fill it up with collent and nurse it home, stopping to add water if needed. so i did and in 10 miles the temp never went over 180.but it was leaking when i poped the hood, it dropps on the cat or pre -cat and makes it hard to see whats happening! still no clolding of the oil. hehe, please tell me there is some kind of hose,drain plug or something back there and that i dont have a blown head gasket!! because if i do, there is not much sence to only doing one side when ya have to tear the moter down that far to replace the gasket! can anyone say zz383/425 crate moter? lol, i was going to wait a year or so to do that but........ive 94k on this vette. has anyone priced the zz383/425? any input i will be grateful for! cya on the road......well pretty soon i hope!! Doug Castner . captbane@yahoo.com

 

[taegdh]

I had a similar thing happen a couple years ago at 4 in the AM on the eastern shore of Maryland. I couldn't find any leak but it was steaming like hell out the overflow. I waited a couple of hours, pulled the thermostat and drove it the rest of the way to my destination in North Carolina, then back to New Jersey the next day. I figured that the waterpump probably cavitated enough air in the coolant and the air pocket ended up on the manifold side of the thermostat.

There is a brand of thermostat called "Fail Safe", that if it fails, it automatically stays in the open position. I got a 180 degree in mine and no overheating problems any more.

BUT with that, I would also look in the front of the radiator and make certain that you didn't gobble up a plastic bag, or some other kind of flotsam or jetsam and effectively blocked the radiator. No air over the fins of the radiator and you can't cool down the engine.....