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I have a 94 t-bird, V-8, with a 4.6. It has 98,000 miles on it and has been serviced regularly, really treated like a baby. It has recently begun using oil at a high rate, about a quart a week. We cannot find any leaks, it isn't blowing black smoke out the tailpipe. Any ideas? Remember, I'm female and pretty challenged when it comes to cars, so explain any ideas like I am a child. I'd like some input before the mechanic attempts to take my next paycheck (have to find a new mechanic).

We have always used Mobile 1, synthetic in it. Thinking about changing to regular oil if this continues and we can't find the problem. Any thoughts about that?

Thanks - You guys always give me the best advice and save me a lot of $.

Melanie - Southern Maryland
 

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Some thoughts:

Check the coolant reservoir near the battery (when it's cooled off, of course), and make sure there's no oil and coolant mixed together in there. Another place to check would be the oil dipstick - make sure it's not discolored.

You mention it's not blowing black smoke, but do you notice bluish smoke if you accelerate after the car's idled for a period of time, such as a very extended red light, or a visit to an drive-up ATM? Oil burning would result in blue smoke.

Dye kits are available to aid in leak detection. See if some of the better parts shops may have them. You may have to do an oil change immediately afterwards, though.

I was reading up on "Excessive Oil Consumption" in the service manual, and found a reference to the PCV system (Positive Crankcase Ventilation):

(Excerpt is from the 1994 Service Manual)

5h. If the oil consumption rate determined is unacceptable, proceed to Step 6.
6. Check PCV system. Make sure system is not plugged.

It had me thinking that if the PCV system is clogged, you can start by replacing the PCV valve, especially if it's old and never been replaced (just a few dollars at a parts store or dealership). Here's a picture of where it's located on the RH side of the engine (it's the part indicated with the number 1):



A quick test for the PCV valve: remove it, and shake it. If it doesn't rattle, replace it.
 

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Sorry to post whore, but it sounds like my problem!

My PVC is good(well...it rattles), but it's coming from the intake on my car(Crown Vic). The PVC valve is in the passenger side valve cover and a hose for what, "I DON'T know" is on the driver side valve cover going into the air intake. I removed that hose, stuck my pinky into it and oil was all over my pinky. Then I thought about the trottle body, it's oil covered too. I just cleaned it. It was really bad when I swiped my finger on the back of the butterfly.

What gives?
And how can I fix this.
 

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When you say a quart a week, how many miles are you talking about?

I have found that finding leaks on the 4.6L can sometimes be "interesting" to say the least. My 4.6L leaked like a sieve and it took me forever to find the leak. Sometimes that area that is wet is nowhere near where the leak is. And I’ve noticed that often the oil won’t reach the ground and leave any tell tale puddles or spots.

A place to check that is notorious for leaking is the gasket between the oil filter mount and the block. Unlike most engines, the oil filter does not screw onto the block, but rather there is an “adapter” between the block and the oil filter. The problem is that usually when people change the filter (it’s a PITA) they spill oil all over that area and you never know you have a leak.

And I agree with IronChopz 100%.

Good luck and welcome to the boards! :thumbsup:
.
 

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95crwnvic54 , if you can temporarily remove that hose, I'd suggest doing so, and spraying the inside with a carb cleaner, or soaking it with Seafoam to help unclog it, if that is, in fact, where it's clogged...

I've never encountered a plugged PCV system, so this is a "home-made" remedy. If anything, it's less costly than the dealership's possible recommendation of replacing all the tubing...

This diagram shows typical PCV flow, and you can see how it may get plugged:



Item/Description
1 - Valve Cover
2 - To Air Cleaner Outlet Tube
3 - Crankcase Ventilation Tube
4 - Throttle Body
5 - Intake Manifold
6 - Positive Crankcase Ventilation Valve
 

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504 Bird said:
Even if the PCV itself is fine, there is a small screen that sits underneath it that maybe clogged. To get it out you have to remove the rubber grommet (that in my case crumbled from age) they only cost a few bucks and then replace/clean the screen. Better detailed info. can be found on this link
Does the 4.6L have that screen? That link is talking about the 5.0L. :2huh:
 

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Nice catch 94 Daily Driven, actually I don't know and didn't even pay attention that link was for a 5.0. When I replaced my pcv, my grommet fell apart, that is all I know. I saw that link and tried to help someone else out, I think I will delete it from this thread, since it seems to be useless here. Thanks for the notice!
 

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Don't delete it. Just edit it to say it's about the 5.0L. I didn't know about the screen... (but then again, I've never worked on a 5.0L except building the engine proper) :D

Still good information, just about a 5.0L, not the 4.6L. :thumbsup:
 

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Discussion Starter #10
I drive approximately 100 miles per week. The man says it used 1/2 quart (not a quart) after one week, which is still a lot.

After I find the problem (haven't looked yet but will this weekend), is it okay if I switch to regular oil? Have used Mobile 1 synthetic since day 1 with the car.
 

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1/2 quart per 100 miles has to be a leak somewhere!!! If you were burning that much through the engine, I would say you would be fouling plugs and killing mosquitoes! :beek:

Personally I would stay with synthetic just because it is such better oil. And remember that you really don't have to change the oil as often with synthetic. When I run synthetic, I change the filter every 3K miles (and top off the oil) and then change the filter and the oil every 6K miles. That has always worked for me. :thumbsup:

And I’ll bet you’re going to find a leak by the engine block and the oil filter adapter. That’s a lot of oil going somewhere. :beek:

Good luck!
 

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mjohnston said:
...After I find the problem (haven't looked yet but will this weekend), is it okay if I switch to regular oil? Have used Mobile 1 synthetic since day 1 with the car.
I'd say to stay with Mobil 1 if the problem is repaired. You could take a large piece of cardboard from an old box, place it under the car overnight, and see what you find in the morning. There's gotta be a leak somewhere! I had the same problem that 94 Daily Driven 4.6L described (with the gasket and mount) - and didn't notice it until the car was parked on a mild slope, and there was a neat puddle under it by lunchtime...

Check your PM when you get a minute.
 

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IronChopz

Hey, It was clogged up! Well, more like pinched.

The rubber hose off the plastic hose from the PCV was colapsing from the age and heat.

I replaced the 3" short section with a 3/8" tranny fluid rubber hose. The hose was much stronger and resistant to colapsing.

The car overall runs 10 times better. This must have been my problem for a long time. Goes to show why you need to replace the rubber under the hood :)

Thanks alot IronCopz.
 

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You're welcome, 95crwnvic54.

I've seen that happen on my car also...rubber hoses crumbling apart. I found out how easy it is to fabricate replacement stuff, as a result!

:thumbsup:
 
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