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Help! Coolant leak from the BACK of the engine somewhere!

Old 02-12-2007, 10:19 AM
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Default Help! Coolant leak from the BACK of the engine somewhere!

I have a bad coolant leak that's dripping down to the oil filter. It appears to be coming from the back of the block somewhere.

Just rebuilt the entire engine. Did I forget to install something? Help!
Old 02-12-2007, 10:22 AM
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Did you check the crossover tube fittings on the back of each head? There's a little o-ring that need to be under each fitting.
Old 02-12-2007, 10:32 AM
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but there isn't a crossover tube on the back right? Just the front?
Old 02-12-2007, 10:41 AM
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You have to block off the 2 fittings on the back of the heads or it will leak bad. The hole look just like the holes on the front of the heads where the crossover is used.
Old 02-12-2007, 11:37 AM
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I'll check it over tonight. If that's the case, would it make sense that the leak gets worse after driving it?

Also, if that's NOT the case, what else could it be? Surely it wouldn't be a cracked block/head? I guess it could be a blown head gasket, but I JUST rebuilt the engine and replaced EVERY seal/gasket in it.....
Old 02-12-2007, 12:09 PM
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I'd bet on the coolant vent plugs in the back. The reason it gets worse after driving is because the thermostat opens up and fluid starts to flow.

If it's not that, it may be a head gasket, but it would have to be installed wrong in a big way lol.
Old 02-12-2007, 12:10 PM
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I also say it's the gasket that goes in the block offs located at the rear of the block.
Old 02-12-2007, 12:26 PM
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Does it look like this? MS paint rocks! haha

Old 02-12-2007, 01:28 PM
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ttt!!
Old 02-12-2007, 03:44 PM
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ttt!! Just looking for more ideas! Thanks!
Old 02-12-2007, 05:38 PM
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UPDATE - The leak appears to be coming from the area directly above the oil filter... Wonder if it could be a freeze plug
Old 02-12-2007, 05:39 PM
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JL calm down bro. Send me a pic to jmws6@hotmail.com Ill look at it. Either you forgot to put the block off on the back of the head or the plug in the side of the block.
Old 02-12-2007, 07:00 PM
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Originally Posted by JLSain
Does it look like this? MS paint rocks! haha

Yes, the gasket is supposed to fit through that nipple (hehe).
Old 02-12-2007, 07:03 PM
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Originally Posted by JMBLOWNWS6
JL calm down bro. Send me a pic to jmws6@hotmail.com Ill look at it. Either you forgot to put the block off on the back of the head or the plug in the side of the block.
Get on aim sometime bro. I'll PM you my aim name incase you deleted it. It'd be nice to talk to ya.

It's gotta be the plug in the side of the block.

Weird thing is, the leak wasn't there for the first 20 minutes of run time. Once we started putting the transmission in, we noticed the leak. It was very small at first. After driving the car for 15 miles, the leak is now a smal, steady stream.
Old 02-12-2007, 07:38 PM
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I called no answer dork!
Old 02-13-2007, 12:05 AM
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830 number? LMAO. I thought it was a bill collector!! LMAO
Old 02-13-2007, 01:50 PM
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Anyone know what the GM part number is for a freeze plug?


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