Losing motor oil - 1 quart every 1000 miles

[LordHalbert]

I notice that I seem to be losing 1 quart of motor oil every 1000 miles (roughly).

I have a 94 GT (Coupe) with 104,000 miles.

I use Mobil 1 10W-30 with a Motorcraft oil filter.

My timing is set to about 10* and I always use 91 Octane.
My PCV valve has been replaced multiple times and recently (last month).
I do not see any oil pooiling on the ground after the car has been there all night.
I also do not see any other obvious leaks. I asked a car mechanic to
find the leak and he could not find it.

Why am I losing 1 quart every 1000 miles?
Is this normal for my car?
If this is abnormal, how can I stop the oil loss?

 

[Badlilstang]

With that many miles id be running 10-40 and probably look into running some high milage oil that will recondition seals. Does the car smoke at all? look inside throttle body and see if you can see any oil puddling up in the intake. High milage motors end up with blow by and that causes oil to push past the pcv valve and also past seals like the rear main and front main seal. Its not normal to burn 1 qt every 1000 miles.

 

[LordHalbert]

My stang does not smoke.

I haven't checked the throttle body yet but externally, I see no leak.

May be my Stang isn't leaking but is burning the oil instead - I don't know.

Will using a Mobil 1 10W-40 effect my performance any?

I don't really mind tossing in a quart every 1000 miles, it's only like $5 a quart or so. It's a free oil change every 5000 miles !!!!! Seriously, it's mildly irritating, I just wanted to know what's causing it.

 

[mto502]

If you have an aftermarket intake chances are it's sucking it up into the intake through the PCV valve.

 

[LordHalbert]

Nope, my 94GT is mostly stock.

Here are my mods - I should have listed them earlier:

* 3.55 Gears
* K&N Air filter
* Pulleys
* Dynomax cat back

That's is, the rest is bone stock.

 

[mto502]

Nope, my 94GT is mostly stock.

Here are my mods - I should have listed them earlier:

* 3.55 Gears
* K&N Air filter
* Pulleys
* Dynomax cat back

That's is, the rest is bone stock.

How long has the car been using this much oil? You may want to take it in for a quick compression test.

 

[LordHalbert]

It's been doing this for years.

So a "compresion test" is a standard test that most mechanics can perform?

 

[mto502]

It's been doing this for years.

So a "compresion test" is a standard test that most mechanics can perform?

Yes. They simply remove your spark plugs and hook up a gauge in the spark plug holes. Then they'll have you turn the motor over 3 or 4 times. The psi on the guage should be no less than 130 psi. Even at 130 psi you should keep an eye on it. This usually indicates whether your rings are shot or not. If the compression is low the next step is to do a leak down test to find out exactly why and where the compression is being lost.
I just did a compression test and all cylinders read between 155 and 170 psi. Those numbers are good so I didn't need to do a leak down test. I have 54 cc heads so the compression on mine may have been a bit higher.

 

[Badlilstang]

10-40 wont effect performance at all. I agree with what the guy said above.. aftermarket intakes are VERY bad about sucking oil through PCV valve. A stock motor like yours should not have that problem tho. If its burning oil you may need to start running a can of restore with every oil change. 104K miles is a lot of miles but ive seen mustangs with 200K miles on them and still running great with no oil consumption. If its burning oil usually you will see smoke but if its burning a small amount you may not notice it. Check your spark plugs and see if they have oil on them. If you find the problem make sure to post what the problem was.

 

[95YellowGTbeasT]

Go down a hill let off the gas when u get near the bottom of the hill FLOOR IT and if any smoke comes out you have bad valve stem seals, i had the same problem hopefully my H/C/I will solve it


Nick

 

[mto502]

Go down a hill let off the gas when u get near the bottom of the hill FLOOR IT and if any smoke comes out you have bad valve stem seals, i had the same problem hopefully my H/C/I will solve it


Nick

That should have taken care of it since you have new valves. Did you do a compression test ?

 

[VIPERn94Five-0]

try some high mileage oil...use one less quart of oil and 1 quart of Lucas....that stuff is amazing.....



Anthony

 

[LordHalbert]

No, I haven't done a compression test yet.

I just purchased some Mobil high milage oil (sythetic blend).

I was thinking about adding this additive that supposed to stop leaks but I decided not to use it - you never know what those can do !!

 

[Joes95GT]

If there are no spots on the ground, that means oil is getting burned. It is either getting past the rings or through the valve guides.

Joe

 

[5LiterFever]

i used to have an 89 GT that burned oil. no smoke or anything, i would just check the oil periodically and notice it getting low. also it never left spots on the ground or anything. the problem was solved when i changed my oil and put in valvoline maxlife oil for high mileage engines. it seemed to run smoother after that, stopped burning oil, and picked up 2mpg. i would highly reccomend it.