Hard to find Coolant leak.. - Team Camaro Tech
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post #1 of 10 (permalink) Old Oct 24th, 19, 03:39 PM Thread Starter
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Hard to find Coolant leak..

Found a few teaspoons of fresh coolant under car. Looks just like it came out of a new jug. It is landing under the starter. There is only 1 drop showing on bottom of starter. Heater hose at fire wall is not leaking. With engine cold I got a coolant pressure test kit from loan a tool program. Holding 15 PSI but I did get 1 drop to land on the tray under car.

Not finding any "trail" coming down motor. Under the head, PS rear of motor, there is "grime" (read oil and road dirt) but can't distinguish it as coolant and the coolant that is on ground is like new.

Maybe the freeze plug behind starter??

Would I need to have the T stat open (engine at operating temp) to include the "block/motor" in this test?

No sign of coolant in oil or oil in coolant/Radiator

Can't see any "moisture" beading at head/block seam. Nothing around intake

Thoughts?
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post #2 of 10 (permalink) Old Oct 24th, 19, 05:01 PM
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Re: Hard to find Coolant leak..

My first thought was heater core/tube or hose. If your certain its not the head' there isn't much more over there than the block or freeze plug. Does it leak when hot or only after it is cool and been sitting? Expansion rate under heat/cold of the freeze plugs could mean they shrink a bit more when cold causing leak??? Hopefully some engine builders will chime in with their experiences. If you jack up the nose maybe you can get in there deep enough to see the freeze plug? Maybe start by ensuring the area is CLEAN and dry. You might be able to zone in on it then.

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post #3 of 10 (permalink) Old Oct 24th, 19, 05:03 PM
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Re: Hard to find Coolant leak..

freeze plug or heater core.

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post #4 of 10 (permalink) Old Oct 24th, 19, 05:39 PM
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Re: Hard to find Coolant leak..

Black light. if the coolant doesn't glow on it's own under a black light you can get an additive. It will light up the trail.

Jeff
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post #5 of 10 (permalink) Old Oct 24th, 19, 05:50 PM Thread Starter
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Re: Hard to find Coolant leak..

Thanks guys, does the T stat need to be open (engine warmed up) so the pressture test tool is inserting pressure in intake/heads/block?

Wiped head/block area and pumped back to 15 PSI and that seam is dry....one drop on floor pan and a drop on bottom of starter.

PSI bleeds down to about 6-8 after 15 min. IDK if the "seal" the tool is making is 100%. Its the cone "universal" compression fit
fitting in this kit as there is no dedicated, out of at least 20 caps, one that fits the old 2 slot radiator neck

The area behind starter (against block) is "moist" (oil/road grime but moist compared to rest of motor) which is where the rear freeze plug is. I will pull starter to get a clear visual.

My initial thought was the heater hose connection, or core, but (even after tighting the clamps some) that joint is bobe dry

IDK, but assume, it "weeps" during driving but there is a teaspoon or so (drops) from parking it on the pan I put under the car

This is the 327 original to the car, according to #'s, but at some point was rebuilt in its life. The forward freeze plug looks good...the rear one behind starter has crud built up in it. Will know more when I pull starter

should it be the plug, what size freeze plug for 327?
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post #6 of 10 (permalink) Old Oct 24th, 19, 06:46 PM
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Re: Hard to find Coolant leak..

Roger, There's a pipe plug just above the oil pan rail in about the middle of the engine.
If it's seeping coolant could follow the block and find its way to the starter. I don't think
you'll see it from the top side. You'll have to get underneath the car. Worth a look anyway.

Al

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post #7 of 10 (permalink) Old Oct 24th, 19, 08:24 PM Thread Starter
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Re: Hard to find Coolant leak..

Thanks Al, I see the plug on each side and didn't know they were water jacket plugs.. Not leaking from there

Car is on stands and I will pull starter to see the rear PS freeze plug..
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post #8 of 10 (permalink) Old Oct 25th, 19, 02:24 PM Thread Starter
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Re: Hard to find Coolant leak..

Quote:
Originally Posted by SoCal805 View Post
Maybe the freeze plug behind starter??
^^^^^, it was the freeze plug behind the starter. It had been weeping for some time given the crud that was built up behind starter. Just cleaning the plug with screwdriver....pushed a hole through it. It was not a brass freeze plug.

Put some shellac around a new plug and pounded it in and all good now. The front ones, behind MM, have been replaced with brass at some point
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post #9 of 10 (permalink) Old Oct 25th, 19, 02:38 PM
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Re: Hard to find Coolant leak..

Wow, you caught that just in time.

Al

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post #10 of 10 (permalink) Old Oct 25th, 19, 02:54 PM
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Hopefully the ones behind the flywheel have been changed with brass too. Brass is all I use. Not that much more money, but will last forever.

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