Question on high mileage motors

OK, my question to those with more experience with high mileage motors. I've got a 95 F150 XLT extended cab with factory tow package. 5.8L engine, AT, etc.. 201,900 miles on the odometer. No major work, just tune ups. Since I got my Miata a couple years ago I don't drive the truck much. I've also neglected it for a while also. Primarily use it for HD runs or local hauling. Once a year I do tow a camper to a hillclimb that I corner work at. The hillclimb is this weekend so I'm prepping the truck for the 1 hour drive with camper trailer and club supplies. Admittedly it's been too long since I changed the oil although not a lot of miles, like maybe 3000 - 4000 miles since last oil change, that equates to over 2 years. No problems before I changed the oil today. Now under medium to hard acceleration it sounds like valve clatter and I back off it. Oil pressure good, right amount of oil (6qt capacity), don't overheat, no leaks and runs normal under light load. Since I'll be hauling a trailer I am concerned about the valve clatter, I'm sure that the trailer load will load the engine and cause valve clatter. Will it decrease with more run time on the oil? Maybe just some sledge buildup in the motor? Is there anything I can do quickly to fix this? Some of you guys are more experienced with high mileage motor than I am. I've never kept a vehicle this long before. Didn't do this before I changed the oil. Maybe I should have left it alone.

First thing I'd do is check the oil pressure with a real gauge to see if the problem is actually tied to the oil. Or is it pre-ignition "ping"? Maybe it's getting crud buildup on the valves or something. Dump a can of BG 44K in the tank and run that through along with some higher octane fuel.

It should free it self up with some heat. Did you use a thicker oil this time? If my 96's get 10w-40 it ticks a little when cold but use 5w-30 or 5-20 it's fine. Got a way to pull out 1 quart? if so add some Risalone (yellow jug)

44

If your truck sits a lot there is likely a crap load of bad fuel. Run some fuel injection cleaner and maybe some premium fuel through the little piggy.

Windsors are known for carbon buildup as well.

last time i lost an engine due to changing the oil, it happened pretty quick, within five miles of driving after the oil change, and got progressively louder.

It started as a rattle (which i though was a valve issue at first, but within a minute it became that unmistakable rod knock. that was in a 78 firebird i bought cheap from the original owner with 100k on it, and later found out he NEVER changed the oil since new. 4 hours later it had a olds rocket 350 in it though, i had one left from my cutlass, so happy ending there, at least until i blew that one up...

its been my experience that poor maintenance engines will eat themselves pretty quick after tune ups, minutes , not hours, so if your truck is still going, your probably okay

fuel stabilizer in the gas tank (i use half the recommended dose for maintenance) will clean up the fuel system far more effectively than most fuel additives, and is less expensive. ive gotten far better results with that than techron or the other stuff available. Ive also gotten positive results from rislone in domestic engines, but i try and avoid oil additives, modern oil is so much more advanced that i doubt the effectiveness of additives except for as a short term bandaid on terminally ill motor..

924 hit on something.

Dating oil does not work anymore. There is so little that will separate in todays oil that you should just worry about length of service and quality of oil in the tank. Black oil is not bad, GRITTY black oil is bad. It takes rolling the oil in your fingers.

Make sure what you are hearing isn't an exhaust leak, too. They can make a racket that sounds just like bad engine noises and sometimes do it only under load. Barring that, I would have to agree with ddavidv.

Thanks guys, you helped again. When I first heard the sound I thought it was valve clatter but after sleeping on it I thought it might be detonation, heavy detonation. I used 10W-30 in it. Took it out for a drive tonite and it didn't clatter. Took your guys advice anyway and filled up one of the two tanks with premium fuel and added fuel system cleaner (Sea Foam) to the tank and drove it around some more. Couldn't find that BG 44K so used Sea Foam instead. Still a gas hog but runs smooth again. Got some Risolene just in case but haven't put it in yet. Looks like I will be able to tow a camper and haul the club supplies to Crow Mountain Hill Climb after all.

Great!