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Why did my Mustang's oil pressure fail once it started being worked on?

1257 Views 7 Replies 8 Participants Last post by  pierre
I drive a 1996 Mustang v6 3.8. Back in July I took it to a mechanic for what I concluded was bad bearings, once he started working on it the oil pressure completely cut out. I've since had a different engine (only 40000 miles) put in from a 2001. I had some vibration in the engine since it was put in, and when I took it in Friday to have that resolved, the oil pressure cut out again once the mechanic started checking things out. I've already put in a new oil pump, and if it gets primed pressure gets restored, but the mechanic isn't sure if that'll be consistent or if it'll drop out again. Need an expert answer. Between the engine replacement and Friday I've had oil pressure every time, which makes this extremely frustrating. Thanx for the help.
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i would chek the oil pressure sending unit. sweet thing :)
As soon as your engine is turning, the oil pressure is self priming. If you loose oil pressure, there is only two things that can happen: 1) oil pump bad 2)blockage.

It sounds like you are being scammed as this problem happens on 2 different engines.... Beware of this mechanic!!!!!!

The problem is NOT you or the car, its the mechanic.

Be carefull as this engine may now have a problem in the future.

Good luck.
Hopefully you did not go to the same mechanic as he may be running a scam on customers.
I don't know what you mean about "If the pump get primed pressure gets restored. Once the pump is pumping it should always keep its prime. If the pressure drops it might be the bearings are worn.
are you sure it,s not the oil sending unit? if the motor is quiet when it,s running then it,s not the bearings. before you installed the oil pump did you pack the cavity hole with petroleum jelly so it won,t suck air the first time you started it?
I have no idea but u have one sick car dude
Best place to find "experts" is this site, for sure. LMAO.
Are you sure that you are actually losing oil pressure or is the sending unit for the gauge going bad? If the sending unit gets plugged up, or in anyway starts to fail, it can give you all kinds of crazy and inconsistent read outs when your engine is maintaining oil pressure just fine. It could also be a loose or bare wire that is causing the gauge to ground out and give you bad readings.

If you are losing pressure, its hard to say why. The oil pump being replaced may have been your problem and I would just keep an eye on that, if you no longer have an issue then problem solved. Since the oil pan should have been removed to replace the pump, I would assume it was cleaned well and any debris that may have been clogging the pump has been removed as well.
Thats the best advice I can give with the information provided. best of luck
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