Oil Pressure Gauge Fluctuating - Ford Mustang Forum
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post #1 of 7 (permalink) Old 02-22-2012 Thread Starter
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Oil Pressure Gauge Fluctuating

I have a 2000 Mustang GT 5-spd with about 152,000 miles. Just yesterday I noticed the oil pressure gauge was fluctuating when at idle or my clutch was in. It would go from normal (little more than half way) back to 0. Once I start to drive it goes back up to normal. I noticed this only happens when my car is cold and not warmed up yet. I also haven't changed my oil in 8,000 miles. I know, I'm a terrible person!!! I just haven't had but like $60 to my name on a good day. I'm a student so I'm not Mr. Moneybags yet. I have read in different threads that this could be the oil sender unit, or even just crappy Ford manufacturing and there's nothing I can do about it. Any ideas will help, and I plan on getting my oil changed in the next few days.

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post #2 of 7 (permalink) Old 02-22-2012
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Just take it to a shop or someone you know who has a good oil pressure gauge and see what it is then. The stock ones are pretty much on/off so anything can throw them off.

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post #3 of 7 (permalink) Old 02-22-2012
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Not going into the whole Dad thing, but you are going to have a lot less than $60 in your pocket when you are paying for buss tokens. Get’r changed.

When the oil is weak (dirty), or low on oil, or a plugged oil filter, this will cause the pressure to drop at a low idle, and then go up when you increase the RPM. Your oil pump is working overtime. Change the oil and filter and then see if you are still having the same problem. And before you do the oil change check the oil level right now and see if you are low.

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post #4 of 7 (permalink) Old 02-22-2012
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Get yourself an oil filter cutter and check the oil filter for metal shavings. If there any, check the timing chain tensioners for wear through.

The motor in my 2000 GT gave way at 145k. The plastic on the timing chain tensioners wore completely through allowing metal to metal.

When the metal wore through, the timing chains went slack and broke the plastic guides. The broken plactic pieces clogged the oil pick up thus starving the motor for oil.

The oil pressure went to zero and the motor seized up.

If the problem had been discovered before the guides broke, the motor could have been repaired with a new timing set. Instead, of needing a whole new motor.

I now inspect the oil filter after every change.

Now, it's possible that the problem is a bad oil pressure sender. It's a $6 part so it's cheap enough to change just to rule it out.

Don't ignore the low oil pressure.

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post #5 of 7 (permalink) Old 02-23-2012
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Burns... did the metal on metal make any crazy noises? How did that go unnoticed?
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post #6 of 7 (permalink) Old 02-25-2012
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It could be the oil pressure sending unit. They are about $30-40 and easy to replace. With 152,000 miles on the car, those simple parts stop working correctly.


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post #7 of 7 (permalink) Old 02-26-2012
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Originally Posted by sillyrabbit0420 View Post
Burns... did the metal on metal make any crazy noises? How did that go unnoticed?
Hey Rabbit,

Honestly I don't know because the prior owner actually turned the motor into a boat anchor. I bought the car as a "project" car knowing the motor was likely ruined.

I did the post mortem on the motor and discovered what caused the failure. From the amount of metal to metal wear, there is no way there wasn't metal in oil. The oil pick up was also obstructed with ground up plastic from the the timing chain adjusters.

The prior owner swore that the motor made no strange noise before the oil pressure went to zero. The motor stop cold before the prior owner could turn it off. During the post mortem, I found that the motor stopped because a large piece of plastic wedged between the crank and timing gear.

However, it did not matter because the motor was already hurt. The cam towers showed evidence of oil starvation. Metal galling/transfer had already happened between the cam towers and the cams.

The only salvageable part of the motor was the block and rotating assembly. Which I sold to someone to use as a "core' to rebuild their car. Both heads were beyond repair.

Once I determined the extent of the damage, I bought a salvage motor from a 2004 Crown Vic and did the Windsor to Romeo swap.

2003 GT Convertible (sold & missed)
2000 GT coupe (Craigslist project. Fixed. Now my DD). Windsor to Romeo swap.
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