1996 Cadillac Deville leak down test ; procedure.

LRAC55

MEMBER
1996 CADILLAC DEVILLE

Engine problem
1996 Cadillac Deville V8 Front Wheel Drive Automatic

how do you do a leak down test pulled plugs, put air in cyl. Hear air leaking into plenum and escaping from other plug holes engine runs not out of time. At idle temp stays at 196* but in drive. Foot on brake, part. Throttle temp goes to 200* plus and cooling system pressure goes to 30 psi+ is this a blown headgasket or a crackedhead? Thanks lrac55

3 Replies

BMRFIXIT

MECHANIC
19,053 POSTS

1st thing 1st
you have to make sure that the cylinder that is being test is at top in compression stroke and valve are closed then you introduce regulated air to the
cylinder and listen for the air escaping
there is a test kit you can buy for checking head gasket
and if I to pull heads out definite send them to the machine shop for checking

did you check the water pump

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Monday, January 7th, 2008 AT 6:29 PM

LRAC55

MEMBER
4 POSTS

1st thing 1st
you have to make sure that the cylinder that is beingest is at top in compression stroke and valve tare closed then you introduce regulated air to the
cylinder and listen for the air escaping
there is a test kit you can buy for checking head gasket
and if I to pull heads out definite send them to the machine shop for checking

did you check the water pump[/quote:5436150fc9]
Yes the water pump has been replaced. The engine runs at 190 degrees and 8 to 12 psi at idle. When the engine is loaded and the throttle increased coolannt pressure goes immediatley to 30 psi. Cant seem to figure out the problem!

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Monday, January 7th, 2008 AT 7:03 PM

BMRFIXIT

MECHANIC
19,053 POSTS

1st thing 1st
you have to make sure that the cylinder that is beingest is at top in compression stroke and valve tare closed then you introduce regulated air to the
cylinder and listen for the air escaping
there is a test kit you can buy for checking head gasket
and if I to pull heads out definite send them to the machine shop for checking

did you check the water pump[/quote:edf0e97fd0]
Yes the water pump has been replaced. The engine runs at 190 degrees and 8 to 12 psi at idle. When the engine is loaded and the throttle increased coolannt pressure goes immediatley to 30 psi. Cant seem to figure out the problem![/Quote:edf0e97fd0]

did you try to run it with out the thermostat
it sound like its poor circulation
or blown head gasket
they sell a kit that you can use to check the head gasket
let me know

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Monday, January 7th, 2008 AT 8:04 PM