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I just had to put a quart of the good ole 5w30(mobil 1) in my 98GT. This comes only a month after the last time I had to put a quart in the car(do in fact it was low). The underside of the car is dry and shows no sign of leaks or bad gaskets. There is no oil in my radiator resivoir. When on the dyno absolutely no smoke of any color came out of my tail pipes. I change my oil every 1 1/2 months 2 max. I put 32,000 on it last year. Can somebody give me some insight? Is this normal. The car get excellent gas milage(not sure if that matters or not in the instance?)

Thanks,

Jayson
 

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Welcome to the club. This is the reason that I started searching for Mustang sites in the first place. Posted the problem, and got a lot of "well, mine doesn't use oil" or "it must be blowing through the rings or valve seals". Like you said, no blue smoke, no leaks. Uses about 2 qts every 5K miles. I do know that the 4.6 is known to use oil, and I've seen a lot of older ones that obviously burn it through the combustion chamber; blue smoke. All I can figure is that the catalysts are efficient enough (there's two on each side, you know) to burn it off for a while, but sooner or later they'll get loaded and quit working. I've got 60K on mine now and so far no smoke that I can detect. I tried a little experiment this time. I went from 5w30 to 10w30 to see if the oil consumption would go down. Too early to tell so far.
 

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Same thing here. It used just under a quart for 3000 miles. That's really not bad. My car has 53K on it. No leaks, no smoke. I had a 88GT that used 2 quarts between changes. Never a leak or smoke either.
 

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Same here. I burn about 1.5 - 2 quarts every 3000 miles. I have been using Mobil 1 5w30 since I bought the car at 25,000 miles. I now have 57,000 miles. No smoke, no leaks...what gives???
 

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Hmmmmmm...all '98 GT's. Is there a pattern here?:confused:
 

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I'm not sure about the 98s, but recently Ford was having problems at their casting plant. Apparently, some of the internal engine components had a high porosity (dead space) and they absorb oil over time.

Just a thought.
 

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i have a 96 gt and i use 5w30 mobil 1, i go through about a quart or more between oil changes. i started using it at 60k i have 69k now. i think it got worse with synthetic than regular oil. my oil pressure is low sometimes. the needle is on the N and sometimes on the R. this just recently started happning. I don't really care any more if it goes ill geta new one
 

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98MODMTR said:
Can somebody give me some insight? Is this normal.
My Panoz has the '98 Cobra drivetrain and it does not burn or leak oil. I use Mobil 1 5-30 tri synthetic and change once per year 'cuz I only put about 3,000 per year on the car. Every time I drive the car it's at an autocross or "spirited" driving on the canyon roads near my home. I use the entire range of RPM and throttle and it always puts a big grin on my face.

However, if the car did consume a quart or two every 3,000 miles I wouldn't worry about it as long as it maintained full compression and didn't show any symptoms. As my doctor once said, "treat the patient, not the lab results". No symptoms, no worries.
 

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Same thing. Engine is so clean, the Virgin Mary would be proud to sit down to Thanksgiving diner inside the "lifter" valley. Still uses 1.5-2 qts per change. Was thinkin on switching back to regular oil, as I use Mobil 1 now. I've had problems with Mobile 1 in my 96 Miata, so maybe there's problems with it in the Mustang?

:confused:
 

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No Control said:
Same thing. Engine is so clean, the Virgin Mary would be proud to sit down to Thanksgiving diner inside the "lifter" valley. Still uses 1.5-2 qts per change. Was thinkin on switching back to regular oil, as I use Mobil 1 now. I've had problems with Mobile 1 in my 96 Miata, so maybe there's problems with it in the Mustang?

:confused:
Been there, done that. no diff with dino oil. It's not the Mobil 1 that's the problem. Like I said up top, I'm trying a heavier weight oil this change to see if that makes a difference.
 

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bierbelly said:

I'm trying a heavier weight oil this change to see if that makes a difference.
Just be careful not to use too heavy a weight. Heavier weight oil generates more oil pressure, which can be good, but at a lower flow rate, which can be bad. A little heavier is probably OK but don't go overboard with a 20w-50 !
 

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Only went from 5w30 to 10w30. Didn't I read that the Cobra R uses Mobil 1 15w50? If I use 15w50, will my car run like a Cobra R?;)
 

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my 95 eats about 1-2 qts between changes. Have had it to ford and they thought it was the PCV valve being clogged. so they changed that, didnt work. I have the same problem, no leaks that I saw, and no colored smoke. Had it in the shop getting my trans worked on and they found out that the gasket around the oul pan was going. had it replaced and have not had the problem since. They found this out by putting a dye in when I had the oil changed and they were able to see where the leaks were coming from.
 

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bierbelly said:
Only went from 5w30 to 10w30. Didn't I read that the Cobra R uses Mobil 1 15w50? If I use 15w50, will my car run like a Cobra R?;)
Isn't a 10w-30 the same as a 5w-30 at operating temperature? Both should be 30 weight when hot, which would be around 10-12 cSt. A 40 weight oil when hot is around 13-17 cSt and the 50 weight should be anything over 17 cSt, most are in the low to mid 20s.

Those numbers might be a little off, but I think they're in the right ballpark.
 

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Michael Clements said:


Isn't a 10w-30 the same as a 5w-30 at operating temperature? Both should be 30 weight when hot, which would be around 10-12 cSt. A 40 weight oil when hot is around 13-17 cSt and the 50 weight should be anything over 17 cSt, most are in the low to mid 20s.

Those numbers might be a little off, but I think they're in the right ballpark.
Yeah, I think you're right, it's the 30 weight that counts at operating temps. I don't expect to see a difference, but 10w30 was the only Mobil 1 grade higher than 5w30, without stepping up to the 15w50. don't know if I want to go that high without a more in depth research of the consequences. I believe that the newer specs, 5w20, are really only for CAFE gas mileage savings, as compared to the 5w30 recommended for the '98s, but I've also heard, FWIW, that the tighter tolerances in the mod engine require a lighter oil than older engines. So if I go to a heavier weight oil, am I taking a chance? Don't know. (My gut feeling is it should not really be a problem. And you know, it's ususally recommended to go to a heavier oil as an engine ages).
 

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bierbelly said:
but 10w30 was the only Mobil 1 grade higher than 5w30, without stepping up to the 15w50.
I would guess that since 30w is a range from about 10 to 12 cSt, that the 5w-30 is near 10 where the 10w-30 is near 12. That would be a 20% difference, which may be significant. Worth a try anyway.
 

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Bierbelly let us know results of your expirement.
Seems like my baby likes oil as well, especially when taken to the track often.
BTW why it's bier and not a BEER. ;)
 

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Andrew WOT said:
Bierbelly let us know results of your expirement.
Seems like my baby likes oil as well, especially when taken to the track often.
BTW why it's bier and not a BEER. ;)
Yeah, I'll let you know. It's 'bier' since when I was on another site, 'beerbelly' was taken, and 'bier' is the german spelling. And we know that German bier is much better than any other beer.;)
 
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