Oil recommendation?

[RF Overlord]

A colleague just obtained a '98 Crown Vic (4.6L) that had originally been his father's company car. As such, his father said that all maintenance was performed "by the book". The car now has approx 90k mostly highway miles on it. My friend's wife will be the primary user, and she travels about 50/50 highway/local driving. What would be a good oil and OCI for this car? They're not necessarily interested in hugely extended OCIs, but would like to go more than the "usual" 3,000... BTW, as near as he can tell only having had the car about a month, it doesn't leak or burn any unusual amount... Thanks...

 

[Chris]

I sure like the Motorcraft 10-30. May need 5-30 by the book but may be OK with the miles on the car. 4000 should be easy, 5K with analysis to be sure.

 

[unDummy]

Use Mobil1 5w30 or Castrol syntec 0w30 year round with 7.5k changes or at least once a year.

 

[therion]

quote:

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Originally posted by unDummy: Use Mobil1 5w30 or Castrol syntec 0w30 year round with 7.5k changes or at least once a year.

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You recommend him switching to synthetic despite the high mileage??

 

[RF Overlord]

quote:

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Originally posted by therion: You recommend him switching to synthetic despite the high mileage??

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THAT was going to be my next question...

 

[Pantdino]

I'm a newbie here, so I'm not going to say much. But two thoughts: 1) "By the book" has always meant "inadequate" if it meant 7500 miles on dino oil, etc. 2) How long do they intend to keep the car? If they only expect to have it for a couple of years, it probably doesn't make much difference. If they plan to own it until it drops dead, it makes sense to go to synthetics, as it still has 100,000 miles in it if cared for.

 

[Amkeer]

I would use M1 10-30 and change it twice a year regardless of mileage.

 

[pscholte]

quote:

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Originally posted by RF Overlord:

quote:

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Originally posted by therion: You recommend him switching to synthetic despite the high mileage??

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THAT was going to be my next question...

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I have yet to see proof that you cannot switch a high mileage vehicle to synthetic. I have run synthetics in multiple vehicles to over 100,000 miles and I switched another bought used at about 49,000 miles and if I remember correctly another one at 90,000 plus. If it doesn't work in the aggragate someone is going to have to prove it to me.

 

[97tbird]

about switsching from dino to syn. at high mileage: since I also have the 4.6L sohc(1997) in my t-bird, I thought I'd drop a line...or a few. I bought my car when it had 72k miles, and the owner had always run Pennzoil dino. I ran Motorcraft and pennz.HM on this car for about 10k after I bought ir, and didn't consume a single drop in 3k changes. Those days I was not very educated and I switched to Pennz. synthetic 10/30 without doing ANY cleaning at 85k miles, and this triggered a consumption of 1/2 qt per 3k miles. since then I've learned a lot, and I switched to dino again, and did an Arx treatment, which brought down the consumption to almost zero again. This time, after Arx, I made the switch again, with GC 0/30 and hope the results are not like the last time I switched(the car has only 600 miles so far since this 2nd switch to syn.oil; I hope the Arx has helped, and that this time there'll be no consumption with the GC. I think it depends a lot on what condition the motor is in(sludge? worn out seals etc) when switching to syn.oil. The experience I had of course doesn't mean that all 4.6L sohc's with high mileage are going to start consume oil when switched from dino to syn. oil, BUT it probably gives you some peace of mind if you do someting like Arx cleaning first.

 

[KW]

Your favorite brand of 5 or 10W30 will do just fine in the car. I have had very good luck with Castrol 10W30 for years. If I had to chose I would get the Castrol GTX 10W30 and change it every 4 or 5K.

 

[williar]

I agree with KW, use a good-quality dino, but I'd recommend a flush with AutoRx first. I don't think a synthetic is necessary or advised in this application.

 

[RF Overlord]

quote:

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Originally posted by williar: I don't think a synthetic is necessary or advised in this application.

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I have some Pennzoil 5W-30 Synth Blend leftover from another project...would this be OK? I was thinking of a 6k OCI...

 

[KW]

The Pennzoil will work great.