1998 Bravada Oil pressure

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1998 Bravada Oil pressure

Postby red98dime » Sat Feb 25, 2012 7:46 pm

Hey guys. I have a question for you. I have a 1998 Bravada that I am working on for a guy. He wants me to change the motor and thats fine I know how to do all that. But the truck runs really good it only has 147,xxx miles. Now the problem is after running for 10-15mins the oil pressure drops from like 45 all the way back down to 0. There is no knock. The oil is very black. Now could this be a faulty gauge, or pressure switch, or oil pump. I just don't want to have to charge the guy for changing the motor if its something simple. thanks guys.


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Re: 1998 Bravada Oil pressure

Postby 88LT1Blazer » Sat Feb 25, 2012 7:53 pm

Put on a mechanical gauge to verify pressure. If the reading is true, a motor swap in a shop calls for 20 clock hours.
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Re: 1998 Bravada Oil pressure

Postby red98dime » Sat Feb 25, 2012 8:02 pm

Any body know where there is a fairly easy location to get a oil gauge on the motors in this bravada with out ripping a bunch of stuff off the motor. Thanks
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Re: 1998 Bravada Oil pressure

Postby Telco » Sat Feb 25, 2012 8:20 pm

If the oil is very black, how many miles are on the oil? If it's a fresh change, even if it isn't knocking the bearings are toasting. If it's not knocking, he can get away with a bearing change and perhaps a new oil pump. It isn't going to be long before it does start knocking.
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Re: 1998 Bravada Oil pressure

Postby sphere478 » Sat Feb 25, 2012 9:40 pm

he will bring it into the shop for low oil pressure requesting a new motor ..but he wont change the oil :roll:

agreed verify oil pressure by other means easiest way ive tried is to replace sender and monitor with volt meter or another gauge to eliminate possibility of faulty gauge and sender at same time

if pressure is accurate tear-down and check/replace lifters and bearings and or oil pump or replace motor
other areas to lose oil pressure cam bearings galerie plugs distribuitor etc..

i have a hard time believing that motor has no knock at 0 psi tho

change that oil asap!
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Re: 1998 Bravada Oil pressure

Postby red98dime » Sat Feb 25, 2012 11:20 pm

Ok well now that I have got to listen to it and see what it does. It will need a new motor probably due to lack of oil changes. :shock: Sitting at an idle it has 45 psi of oil pressure. under any kind of acceleration the pressure drops down to around 35 psi and a slight rod knock. The more acceleration you give it the louder the knock. That was when I shut it down and call him with the news. Now I get to change a motor in a 98 Bravada this will be fun. Thanks for the help.

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Re: 1998 Bravada Oil pressure

Postby sphere478 » Sat Feb 25, 2012 11:35 pm

Had a friend with a 4.3 vortec thats almost exactly what it did except he drove it around for a year like that after fixing the missing oil lol had two bad mains caused by a oil cooler line mishap caught too late fried his block

don't warranty that motor lol :) wander how many miles he had on that change.. check the sticker!
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Re: 1998 Bravada Oil pressure

Postby lowblazin94 » Sun Feb 26, 2012 2:25 am

Pull a valve cover and see how it looks. If there's been a lack of oil changes then you will for sure know that way.
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Re: 1998 Bravada Oil pressure

Postby 94S10V8 » Thu Mar 22, 2012 5:08 pm

Common issue with these motors once they get a lot of miles on them. If you are going to put a used motor into it, especially if the truck is a 4x4, I recommend replacing the rod bearings and at least inspecting the mains and always replace the oil pump. Just good insurance so that you don't end up doing the work again.
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Re: 1998 Bravada Oil pressure

Postby Rickracer » Fri Mar 23, 2012 11:30 am

If I had done bearings in my 4.3 a year or so ago, I probably STILL wouldn't have the V8 in it yet, :mrgreen: :mrgreen: :mrgreen:
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