Coolant Leak... strange but true

[Macfluke]

My old girl (89 C1500 5.7) has developed a iffy coolant leak which hasn't been found. Sometimes you can smell coolant outside after driving it but no leak is found, it's not much of a leak but I have had to add coolant to the reservoir after a period of time. No coolant smell on the inside and the windshield is not fogging. The system has been pressure tested and nothing found. I'm thinking whatever is leaking must be hitting the hot engine and evaporating. Guessing this is a developing situation...


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[c1500deathtrap]

If you are loosing coolant and can't find a leak, look at the oil and plugs.

 

[Macfluke]

If you are loosing coolant and can't find a leak, look at the oil and plugs.

thanks, but...
oil is clean and no white smoke from the tailpipe


Sent from my Commodore 64 using 300 Baud Modem.

 

[skylark]

Look really closely at the radiator. Check the tanks but more importantly check the fins. I'm betting you'll find a small pinhole leak in the fins.

 

[Oldblue98]

Oil does not have to be milky for it to be intake gaskets seeping, mine was seeping as you describe and I could smell it but what little it dripped down the back the exhaust was burning off and I had to add coolant. It will continually get a little worse if it is intake, I crawled under mine and you could see hints of where it had run down the back. And there was a little on the starter. But the crazy part was it never showed on garage floor ! Upper and lower intake gaskets cured my problem. I was lucky mine was not leaking where it went in the oil, but when you change them you need to do a oil change and filter run it some and then change it again. When the intake is pulled you will get some that may go down in the engine.
"If this is your problem" Just throwing it out there.
I did not want to be bothered with doing it and found a reputable garage that did it for 350.00. I had got a GMC dealer price to do it and Jessie James wanted a grand to do it

 

[Oldblue98]

Look really closely at the radiator. Check the tanks but more importantly check the fins. I'm betting you'll find a small pinhole leak in the fins.

Yes I had that along with intake gaskets, tank on driver side was seeping ever so slightly, it was the original radiator so I got my quarters worth out of it.

 

[Macfluke]

Look really closely at the radiator. Check the tanks but more importantly check the fins. I'm betting you'll find a small pinhole leak in the fins.

I didn't take a hard look at the radiator, but I will now... thanks

Oil does not have to be milky for it to be intake gaskets seeping, mine was seeping as you describe and I could smell it but what little it dripped down the back the exhaust was burning off and I had to add coolant. It will continually get a little worse if it is intake, I crawled under mine and you could see hints of where it had run down the back. And there was a little on the starter. But the crazy part was it never showed on garage floor ! Upper and lower intake gaskets cured my problem. I was lucky mine was not leaking where it went in the oil, but when you change them you need to do a oil change and filter run it some and then change it again. When the intake is pulled you will get some that may go down in the engine.
"If this is your problem" Just throwing it out there.
I did not want to be bothered with doing it and found a reputable garage that did it for 350.00. I had got a GMC dealer price to do it and Jessie James wanted a grand to do it

I'm going to keep checking it and see if anything develops and if it turns out to be the intake it will go to the shop, years ago I would have pulled it in a heartbeat but not anymore I have become selective on what I do now... thanks

 

[Oldblue98]

I didn't take a hard look at the radiator, but I will now... thanks


I'm going to keep checking it and see if anything develops and if it turns out to be the intake it will go to the shop, years ago I would have pulled it in a heartbeat but not anymore I have become selective on what I do now... thanks

Yes sir I know what you are saying that is where I am now, what use to be fun is not fun anymore ! I know how to do most things but it no longer amuse's me =)

 

[smdk2500]

I had the same problem on my 95. I could smell coolant but could never find where it was leaking. it finally got bad enough and was starting to puddle up on the intake right by the throttle body. I dont know why it was puddling up there since there isn't a coolant passage there but thats where I found it.

 

[alpinecrick]

My old girl (89 C1500 5.7) has developed a iffy coolant leak which hasn't been found. Sometimes you can smell coolant outside after driving it but no leak is found, it's not much of a leak but I have had to add coolant to the reservoir after a period of time. No coolant smell on the inside and the windshield is not fogging. The system has been pressure tested and nothing found. I'm thinking whatever is leaking must be hitting the hot engine and evaporating. Guessing this is a developing situation...


Sent from my Commodore 64 using 300 Baud Modem.

Most likely the intake is leaking--the TBI's and 1st Gen Vortecs are notorious for it. And often when you shutdown and get out of the truck is when you'll smell it.

Usually the leak is in one of the rear corners of the intake. Sometimes it leaks to the outside, sometimes to the inside. Check your oil for coolant. It may not be leaking enough to show up in the oil, but it ain't good for the motor.........