Took the LC for an oil change and the dealership suggested using motor oil 10/30w "high mileage" for high mileage vehicles. My 94 has 186+k miles. The oil cost about a dollar plus per quart more. Any opinion/s on this? Thanks..
I am just shy of 159K on my 1991 and I use the high mileage in my rig..since I run the mighty 3FE I use 10w40 but I have noticed a marked improvement in consumption and fewer leaks and ticks out of the engine since moving to the high mileage formula.
I have been running this for about 6 oil changes now as an FYI...I saw improvements at about the 4th change.
I feel there is merit to additives and conditioners for the seals in these oils. I am sure the oil gurus (Cary, etc) will have more to say and there is that http://www.bobistheoilguy.com site for more info...but my experience has been positive.
Consumption with 10w40 non-high mileage was ~3/4 quart per 3K. Now I am at less than 1/4 quart per 3K. I have also noticed my rear main leak has stopped producing as much in the last 2K or so of driving...not sure if this is due to changes in weather or environment or if the additives fattened up the seal for me?
Absolutely not worth the extra money. If your rig uses 1 qt. or less per 3k mile oil change you are not outside "spec". My '93 with 265k uses about 1.5 qt. per 3k mile oil change. I'm within "spec".
FWIW, I tried the high-mileage oil for a while and noticed no difference. I got tired of paying extra for no perceived benefit. I went back to my old stand by, Valvoline 10w30 (I use NAPA 10w30, made by Valvoline, cheaper).
I bought my 91' two months ago with 161K. I talked to the Po who had no preference for oil usually, but stayed with a 10-40w and according to him "never" went over 5k between LOF's. I'm running Delo400 Chevron 15w-40 which is one of the best imo, for running a non-synthetic oil. I understand why you are concerned about switching to a syn oil now...
Maybe, i need to see what Bob the oil guy thinks about my choice.?
You can switch back and forth with synthetic with no concerns. The Delo 15w-40 is probably the best Mineral oil right now, and several UOA's have shown it to give wear numbers in line with good synthetics. As long as the temps don't go bellow about 30F where you are, it is a good choice.
I run high mileage oil in my old Montero which have very common problem with worn out valve seals with only 80-100K miles. It reduce the oil consumtion quite a bit when new but after 1k miles it loses its seal swelling and the consumption goes back to normal. Mind you this vehicle was using 1 quart every 1 k miles and it uses 1 quart of high mileage oil every 2.5K miles which is very good improvement.
In my case they do not help much since the valve seal are pretty worn already. The seal conditioner expired after about 0.5-1K miles which is very good since you do not want to overswell all seals.
I think they are worth if you have little oil leak or if you want to prevent seal hardening use it every other oil change.
Rotella has a semi syn oil Shell ROTELLA® T Synthetic-Blend http://www.shell-lubricants.com/products/pdf/ROTELLA T SYNTHETIC BLEND.PDF
I am still thinking of semi syn or maybe full syn Rotella T 5w40 as I am due for a oil change and the weather should get cold the next two months.
I added a qt of Chevron 10w30 and its 1/2 qt low now with 2600 ni on oil change.
I do have a leaking oil pan.