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coolant leak

alz

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alz Enthusiast

alz

Posted
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I have a 99 Suburban, 5.7 4x4. It has a coolant leak coming from somewhere below the distributor. It only leak when running. There's so many emissions and hoses I can't pin point it. Can someone point me in the right direction? Is there something common there that causes leaks?

454ss Enthusiast

454ss

Posted
Posted

if i remember right a heater hose connects to the rear of the intake on the 350 vortecs and the coupling that it plugs into is probably leaking, common problem for them to go bad, your dealer should have them in stock.

alz Enthusiast

alz

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It looks like it is pooling up around the knock sensor and then flowing down the back of the block around the trans. After reading a few other posts, is this a tell tale intake manifold gasket leak?

454ss Enthusiast

454ss

Posted
Posted

could very well be the intake gaskets, i had to do mine twice in 140,000 miles. the coupler that i mentioned before started leaking first though.

alz Enthusiast

alz

Posted
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There is no leak at the coupler you speak of. This Suburban only has 65,*** miles on it. I got myself an inspection mirror and will take a look at it tomorrow. I have a feeling it's the intake gasket. When they talk about upper and lower intake, do they mean throttle body as upper and intake manifold as lower?

alz Enthusiast

alz

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I put a bottle of Bar's Leak in a few days ago and today I don't see it leaking. I know this is only temporary, but I hope it holds until spring or summer when it's a little warmer for intake manifold gasket.

96Z71asskicker Enthusiast

96Z71asskicker

Posted
Posted

by upper and lower intake you'll see the lower intake gasket (most prone to failure) is the one that meets up with the heads. check the croners of the intake manifold towards the back you will usually see it leaking out there. The factory gaskets they sold are crap, but gm did redesign them so when you replace them get the gm ones not flo pro's.

PaulQ Enthusiast

PaulQ

Posted
Posted

If I remember correctly my intake gasket on my 94 Blazer went out with about the same amount of miles....I would definitely check into that coupler though before you tear it down. Also try to minimize that chemical crap in your motor it usually tends to do more harm than good in the long run.

 

Paul Q.

  • 2 weeks later...
FivePointSevenLiters Enthusiast

FivePointSevenLiters

Posted
Posted

In some cases, an intake gasket leak will create a distinct whistle under certain failure conditions, decreasing intensity under throttle. Do you notice any sounds? A head gasket failure (in the location between a water jacket and the outer engine surface) will not create any symptoms of a head gasket failure (water in oil, white smoke, decreased compression) however will create a coolant leak during operation (or when system has pressurized coolant). For a few bucks, I'd invest in a nice extension mirror (throwing out my girls compact on stick) and see if you can pin point the leaks location. Peace.

  • 2 weeks later...
awdco56 Enthusiast

awdco56

Posted
Posted

Just finished replacing the lower intake gaskets on my Savana van. It's a "98" but only has 49,000 miles on it. When I removed the gaskets I couldn't believe the condition they were in. Between cracks and distortion it's no wonder they were leaking. I replaced with the GM gaskets. They're reinforced at the bolt holes to protect against over torque.

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