lower intake manifold leak
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lower intake manifold leak
I have a 98 4x4 with a 4.6 engine, the lower intake manifold is leaking, looks like its plastic, is this a big deal to change ? Also what else needs to be changed while doing the repair ? I'v heard of horror stories of hydro lock, the manifold is leaking but not much, when does the hazard of hydro lock come in to play ? Thank you in advance for your help.
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From: Fort Smith, Arkansas
What exactly is leaking at the lower intake?
The only thing that would leak from the lower intake is vacuum.
Or else there is something else wrong.
The path of air through the 4.6L engine starts in the throttle body, down into the lower intake (a.k.a. plenum), then back up into the upper intake, then into the heads.
Hydrolock can occur if the UPPER intake gasket or O-ring seal fails and coolant gets sucked into a cylinder.
This is usually preceded by a noticeable loss in coolant.
The only thing that would leak from the lower intake is vacuum.
Or else there is something else wrong.
The path of air through the 4.6L engine starts in the throttle body, down into the lower intake (a.k.a. plenum), then back up into the upper intake, then into the heads.
Hydrolock can occur if the UPPER intake gasket or O-ring seal fails and coolant gets sucked into a cylinder.
This is usually preceded by a noticeable loss in coolant.
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lower intake manifold leak
Hi Sam I Am, thanks for the reply, it looks like antifreeze laying under neath the lower intake, it also looks like black plastic pieces laying there as well, the engine seems to be running good and the radiator tank is staying full.
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From: Fort Smith, Arkansas
Just because there is coolant under it, that does not mean it is the lower that is leaking. It could be the coolant tube running under the intake leaking. Or it could be the upper intake leaking at the crossover, or even the thermostat housing.
There is no coolant at the gasket for the lower intake, but there is on the upper intake gaskets.
There is never a "good" leak, but if you do not notice a drastic drop in coolant level it doesn't sound severe yet. You should definitely identify where the leak actually is or else plan on replacing all the intake gaskets and the whole intake. Some of the replacement intakes are one piece, no upper & lower, just one piece.
There is no coolant at the gasket for the lower intake, but there is on the upper intake gaskets.
There is never a "good" leak, but if you do not notice a drastic drop in coolant level it doesn't sound severe yet. You should definitely identify where the leak actually is or else plan on replacing all the intake gaskets and the whole intake. Some of the replacement intakes are one piece, no upper & lower, just one piece.
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