need help pinpointing possible source of coolant leak

[BIG_1088]

hello friends

today after getting my truck inspected i discovered a coolant leak coming from somewhere in the passenger side right by the transmission, there is a picture below of where i found coolant at

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there also seems to be some coolant residue on those two hoses in the foreground which makes me think that has something to do with it, but i am still new to working on vehicles so i have no idea if they're the cause

if anyone has any ideas or clues please tell me, feel free to ask for more pictures or details if needed

thanks

-big

 

[someotherguy]

Taking a wild guess since you didn't say what year/engine/etc. but it looks like a TBI small block, several possible sources for a coolant leak that would drip down to that area. I'll list them in order of probability (IMO):

1. Heater hose quick-connect at the passenger rear of intake manifold. If it's the original one the metal goes bad and they leak. If you so much as look at it hard it will snap off, and the fitting can leave pieces inside the intake making it a chore to replace. Lots of posts all around the 'net on dealing with the issue.

2. Intake gasket leaking and running down the back of the heads/block. Somewhat common on high-mileage TBI engines. A hand-held inspection mirror and bright flashlight may help find it. Not a difficult replacement but also not exactly simple, especially if you're new to working on stuff. I did a write-up on it with pictures but it still is a bit involved.

3. Expansion plug (aka "freeze plug") between engine and transmission, big PITA to replace, and unless the cooling system hasn't been looked after it probably isn't the source.

Richard

 

[Vanishing Point]

You might want to inspect and check the entire length of hoses that feel either too soft and mushy or too hard and brittle and trace these two hoses coming from the (firewall bulkhead) passenger side as you have stated, from its connection from passenger compartment heater core to the engine block and if all is dry, then it might be a freeze out core plug usually (brass or steel in color) on the passenger side of engine. Also if I might suggest please give us more information regarding VIN# mileage, year, make, model and size of engine that helps a lot when trying to diagnose these concerns. And if you still can't find the leak, and its within your budget a coolant pressure tester from Stant #12270 30 pound cooling system pressure tester at amazon for around $70.00 bucks would be money well spent on your vehicle.

 

[someotherguy]

I think the hoses he's talking about are the transmission cooling lines in the picture, since there's coolant drops on them. But your point is valid. And sometimes you can score used cooling system testers a bit cheaper. I've still got a Snap-On test set I bought years ago for a fraction of the new price. Wonder if I can get adapters for it to fit my '06's...

Richard

 

[BIG_1088]

Taking a wild guess since you didn't say what year/engine/etc.

oof, i apologize as i was in a hurry typing this up

it is a 350 like you said and the truck was manufactured in 1997

1. Heater hose quick-connect at the passenger rear of intake manifold. If it's the original one the metal goes bad and they leak. If you so much as look at it hard it will snap off, and the fitting can leave pieces inside the intake making it a chore to replace. Lots of posts all around the 'net on dealing with the issue.

2. Intake gasket leaking and running down the back of the heads/block. Somewhat common on high-mileage TBI engines. A hand-held inspection mirror and bright flashlight may help find it. Not a difficult replacement but also not exactly simple, especially if you're new to working on stuff. I did a write-up on it with pictures but it still is a bit involved.

3. Expansion plug (aka "freeze plug") between engine and transmission, big PITA to replace, and unless the cooling system hasn't been looked after it probably isn't the source.

Richard

i'll have to check those, i honestly hope it isn't something like the plug because i am in no way equipped to pull the transmission and i can't afford it

thank you though

 

[someotherguy]

OK, 1997 of course is Vortec not TBI; the heater hose quick connect is at the front of the intake on yours and is still fragile but not likely the source of your leak since it's at the back. Intake gasket failure on the Vortec small block is SUPER common and in fact happens on almost all of them once they are near 100K miles or so, varies; also can happen if they were repaired back in the day before the improved gaskets were available.

Watch your oil very closely for any signs of coolant contamination as the Vortec small block intake gasket failure can often leak coolant into the oil which will wipe out your bearings in a hurry.

Richard

 

[mckee1710]

I found coolant leaking at a similar spot on my 97 K1500, traced it up to the intake manifolds (very common gasket failure as others have mentioned.) check the back of the lower intake manifolds, on either side of the distributor.

 

[east302]

Adding to the pressure tester recommendation, a lot of parts stores will rent you the kit. You essentially buy it and then get all of your money back when you return it.

The caveat is that they lead rough lives being rentals, so take a look at it before you walk out. Make sure the gauge reads zero, for example.

 

[BIG_1088]

OK, 1997 of course is Vortec not TBI; the heater hose quick connect is at the front of the intake on yours and is still fragile but not likely the source of your leak since it's at the back.

i've actually pinpointed the leak coming from the quick connect, it seems to have been running from the connection down between the valve cover and intake manifold and off the rear of the engine block, and thank god it's that too because it just made my life 100000% easier

Watch your oil very closely for any signs of coolant contamination as the Vortec small block intake gasket failure can often leak coolant into the oil which will wipe out your bearings in a hurry.

Richard

i've already changed the oil and found no contamination, and looking back on my trucks history it had it's intake gaskets replaced, now my life is much easier

the worst thing i'll have to do on this truck is replace the starter now because the coolant somehow managed to screw it up i am pretty sure, but that's a project for another day (or next week)

anyways, thanks everyone for your help, i really appreciate it

 

[HotWheelsBurban]

I think the hoses he's talking about are the transmission cooling lines in the picture, since there's coolant drops on them. But your point is valid. And sometimes you can score used cooling system testers a bit cheaper. I've still got a Snap-On test set I bought years ago for a fraction of the new price. Wonder if I can get adapters for it to fit my '06's...

Richard