Here's the deal. I have a 89 honda accord. not original owner. Has 273,xxx miles+. I have been maintaining it to the best of my capabilities and with tried the least costly way(not really). ive done two tune ups in the past 12,000 miles and used high grade components. added new minor things : radiator hoses, fuel filter, spark plug wires, o2 sensors, anchor bushing, blah blah blah. Kept up with oil changes every 3,000 miles. Oil i use: 3qts of Castro gtx High Mileage formula 5-30w, with an "engine restorer & lubricant" additive by Automotive Products. Also use engine flush each oil change.

Now my question is: is there a better way i could be maintaining my car along with better use of Additives. My main concern is the oil i use. Ive been reading about other high mileage oils and i want to know which is best for me.

Some say synthetic you cant go wrong with. but i also heard that its more likely it'll leak if i switch to full synthetic since my engine has very high mileage.
so looking on to the many high mileage formulas out there. i cant figure which is the best: Valvoline Maxlife, Citgo Ultralife, O'Reily's, AMSOIL synthetic. I cant decide!

And does the grade matter 5-30, 10-30, 10-40w etc. I was recommended 5-30w but would it be better if i change to a diff grade?

Also, about cleaning. I've read about Auto-rx. what are your takes. I doubt seafoaming will do good to my car since it might clean too much.

Let me know anything you can think of to better maintain. Thanks!

If you've done several flushes, there's no reason to continue doing them every oil change. Perhaps every 4th or 5th might be better. You risk diluting your oil and causing seal and bearing damage by continuous use of flushes.

I would use Valvoline Maxlife in either 10W-30 or 5W-30 depending on your climate, as we are approaching winter. In the south, the 10W is fine, but if there will be truly cold weather, a 5W would be advisable. Maxlife has given many people good results and is readily available. I see no reason why a 5,000 mile interval wouldn't work. More expensive oils are intended for extended intervals, which are not advisable until a used oil analysis has been performed to gauge the fitness of your engine. The seal conditioners and additive sets that make an oil 'High Mileage' will basically perform the same tasks regardless of name brand or price.

There are many people who will advise using this or that additive. In certain cases there are problems that can be solved by the use of these, but I see no problem in your post that indicates the need for any fix.

The idea that a high mileage car has a need for additives due to it's mileage is a common misconception, and a difficult one to resist. After this many flushes, I have no doubt that your engine is pretty clean inside. With occasional use, as mentioned above, and in conjunction with a good HM oil such as Maxlife they will continue to serve you well.

It seems like you are doing fine, I would 2nd everything greenaccord02 has said here.

We've had a '89 Accord LX (automatic)in the family since new. You are ahead of us by 100,000 miles so my advise might not be all that helpful.

We have no oil consumption issues so continue using 5W-30 as recommended by Honda.

Be sure to replace the timing belt, transmission fluid, etc., at reasonable intervals.

If the valves haven't been adjusted lately you might want to bring them into factory spec's.

Engine oil seals are made of hard plastic resins with added plasticizers (usually diesters) to make them flexible. These diesters are very similar (in some cases the same) as those used as cosolvents in older synthetic engine oil formulations. Since these plasticizers are oil soluble, they will leach out over time. This causes the seal to harden, shrink and form gaps.

Modern high-mileage oils have a pinch of diester that helps replace that which has leached out to keep the seals flexible.

I have a '90 Mazda Miata I bought used at about ~140,000 miles that tends to only come out on good convertible days. Early on, it would smoke a little on start-up if it had been sitting more than a couple of weeks. I switched to a high-mileage oil and now I don't observe any smoke, regardless of how long it sat.

Unless you have solid evidence of deposit problems, I'd avoid engine flushes and just go with a good-quality high-mileage oil.

How long (miles or time) did it take before you started noticing an improvement?

I saw an improvement within the first oil change. This is not a miracle cure, as those things don't exist. This was just a little puff that indicated very mild wear and/or hardening. If a seal has degraded significantly, it has to be replaced. If you blew out your rear main seal by overfilling the crankcase, the seal has to be replaced.

The reason anyone is ever looking for a miracle automotive cure is because they ignored something while hoping it would go away on its own. Turning up the radio doesn't really make that noise go away.

I've been thinking of using a high mileage oil now that I have 125,000 miles on the engine.

here are the useful short list for your car:
* use generic silicone spray to lubricate your door seals. but dont spray it near to your intake system because silicone poisons oxygen sensor.
* for more mpg, get a wheel alignment, try the fresh spark plugs, air filter and properly inflated tires. you can use synthetic lubricants.