Coolant Leak But From Where?

buckyAugust 2, 2005

I have an 88 Chevy Sportsvan with a 350 engine. I noticed the coolant level in the reservoir tank was low last week so filled it to the full cool level as the engine was cold. After a long trip I noticed coolant leaking under the vehicle. Checked hoses, rad, water pump but couldn't find source of leak. Overflow outlet on reservoir was dry. Reservoir level returned to the same level it was before I filled it. Engine runs cool with no over heating. Does not spill coolant when I run it with reservoir practically empty just when it is topped up to the full cold mark. Whats happening here and where would the coolant be escaping from? Thanks

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You can visually check the 'weep hole' under the water pump, the hoses, thermostat housing, freeze plugs, and the radiator. With the radiator full and the cap off, you can start the engine and look for air bubbles. A steady, regular streem of bubbles can be an indication of a head gasket problem. The heater core is another place it can leak but usually the windows fog up, there's a smell, or the carpet on the passenger side gets wet when that happens. Beyond that, you'll have to get a pressure tester to check the cap and cooling system.

    Bookmark   August 2, 2005 at 7:56AM
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The use of the pressure tester is the way to go.
With a 17 year old vehicle ALL of the hoses should be new - unless the the original quality was extraordinary.
Check the engine oil for the presence of coolant/moisture (brown mayonaise)...
Gary has nailed things down well.

    Bookmark   August 2, 2005 at 12:18PM
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There might be a crack in the reservior which is allowing coolant to leak out of it--I had this problem with my car, it was leaking where it bolted to the radiator fan shroud and whenever the coolant got above that level, it'd start leaking slowly.

    Bookmark   August 2, 2005 at 12:21PM
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Another thing to check is the carpet on the passenger side up under the dash. And see if it is wet. Could be heater core.

    Bookmark   August 3, 2005 at 9:48AM
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So where was the leak, Bucky ??

    Bookmark   August 4, 2005 at 12:18PM
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Thanks for the replies fellas. Haven't found a leak yet. Hoses are all good, heater core is not leaking, no coolant in the oil, water pump is not weeping or leaking. The only thing I can figure is that when the engine is at operating temp the coolant expands and escapes through the reservoirs overflow. I've put a small plastic bottle on the overflow to see if thats whats occurring. My Dad had an 87 Caprice that used to do that. Once the coolant found its level it ran fine and cool and didn't lose any more coolant. He ran it that way for years. Hopefully this is the same thing. If not, I'll keep on a lookin. Bucky

    Bookmark   August 5, 2005 at 2:30AM
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Radiator cap ?

Fell underneath it after a drive to see whether its wet.

    Bookmark   August 9, 2005 at 4:49AM
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I found the problem fellas. Spring on the rad cap must have weakened over time. Installed a new one and it illiminated problem. Thanks a lot for the feed-back to my inquiry. Bucky

    Bookmark   August 12, 2005 at 12:35PM
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John , you beat me to the punch and hit the nail on the head..The radiator cap is something that I forgot about - they are that well built...but after 17 years .....And there is a test for these caps...

    Bookmark   August 13, 2005 at 12:31AM
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I have a coolant leak on my 94 Chevy Berretta. 2 weeks ago I noticed the meter on the dashboard said low. I filled it up with new coolant and everything was ok, but only for a couple days and it was back to low. I igonored it for about a week, now today I see lots of green coolant leaking out the bottom of my car. As it turns out Im going to be selling this car soon in a matter of weeks anyway... What should I do?

    Bookmark   September 3, 2006 at 9:07PM
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I have an 1988 Pontiac Sunbird SE and i got a coolant leak from under the alternator. COuld it be the gasket from the motor?

    Bookmark   May 8, 2011 at 11:34PM
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i have a 97 SHO new water pump housings have been new ,welded even in possible weak spots,in the from the intake manifolds also re-done but i am still getting a stream of water from the backside of the motor that is hitting the ground by the oil pan area.could it be a heater hose or something back there?

    Bookmark   August 21, 2011 at 2:33AM
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