Using Synthetic in a 140k mile engine...

[Islandvic]

My '96 Crown Vic has 140k miles.

The 4.6 modular has had regular 3-5k mile OCI's its whole life with either 5-30 or 10-30 Quaker State or Pennzoil Conventional with the original owner.

I bought the car in 2000 w/ 65k. I shortened the OCI to 3-4k using Valvoline All-Climate for the first year, then switching to MaxLife Dino afterwards (1qt/1000 mile consumption). In 2004 I switched to Super Tech for 2 or 3 OCI's, but oil consumption went up (1qt/500-700 miles).

I then discovered Motorcraft Synthetic Blend 5w30 and Motorcraft filters. Last 3 OCI's I have used Motorcraft (1qt/700-850 miles comsumption).

With the recent PepBoys and AZ specials, I have a collection of Syn oil now.

I just changed the oil yesterday with a Bosch Premium filter (free) and ValMaxLife Synthetic 10-30.

I have an established baseline of oil consumption. The valve stem seats are worn and are the culprits.

I will use either Exxon High Mileage ($1) or Valvoline MaxLife Synthetic 5w30 as top offs for the consuption. I had used $0.89 Super Tech before as top offs.

The car has had a religious PM schedule. Also, I just replaced the PCV to see if it helps the consumption.

I know no oil is a magic cure, but will I see any benefit from MaxLife Syn?

Will there be any surprises?

If my motor consumes a quart every 700-1000 miles, what type of OCI should I use if I'm adding oil at every other gas fill up?

If I'm adding fresh oil all the time, can I extend the OCI?

Thanks...

 

[darkdan]

Hurts my feelings you go to other boards to ask advice on stuff. =(

Auto-RX your engine. Then switch to a real synthetic instead of those group IIIs.

You'll be running 6k to 10k OCI in no time.

 

[BlazerLT]

Do the standard 3k interval for the first synthetic oil change.

Then after that you can easily go 5-6k with no problems.

 

[ruking77]

Yes a couple of points. First is you really don't have a baseline as to how sludge up (if at all) your engine currently is. So if you do not wish to use RX then do the first synthetic oil change early to let its greater detergency do its work. Second synthetic will not erase the wear already done due to running conventional oil, but should slow down subsequent wear. You can measure existing wear and extrapolate from that but I am sensing that would be overkill for you.

I have been going 15,000 miles OCI's for so long that for me it is the new "normal". But even at that, given my driving and habits 15,000 mile OCI's is probably belt and suspenders thinking!

 

[Islandvic]

quote:

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Hurts my feelings you go to other boards to ask advice on stuff. =(

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I ask here because I know my man DarkDan and Ulver hangs around here too!

Yes, I know the Syn's I got from AZ are only group III and not true POA's.

The M1 I got from the B3G3 free coupons will go in my '00 Silverado and '01 GMLS.

The Group III synthetics I bought at the AZ discounted sale will go into the '96 Crown Vic because of its high oil consumption.

I may make the Auto-RX plunge this spring. I want to see how much consumption I have with the ValMaxLifeSyn first.

DarkDan, plus this spring I want to do the Valve Stem Seat service from "the other site". When I have the valve covers off, I want to use that as the baseline for sludge, then run the Auto-RX.

I may switch to the M1 after the full cleaning and rinse.

quote:

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I have been going 15,000 miles OCI's for so long that for me it is the new "normal". But even at that, given my driving and habits 15,000 mile OCI's is probably belt and suspenders thinking!

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Ruking, Do you run used oil analysis? What's your mileage and model?

 

[Dr. T]

Try a 5-40 or 5-50 to decrease consumption. Also, with these weights you should be able to do 7.5-10k OCI's eventually (once things are cleaned out).