NEVER flush an engine.
Wish we knew how many miles are on your Bird's engine.
Years back had a number of Birds with 390 and 428 engines. They all got about 9 mpg. They all went through valve cover gaskets from time-to-time. They all started using a lot of oil at around 80,000 miles from worn valve guides and perished valve seals........the bottom end of the engines were bulletproof. If you were keeping this car for a long time, it would be nice to have the heads redone: new guides, seals, hardened valve seats.
NO - I wouldn't flush it at this point - you'd just stir-up trouble.....just change oil regularly as you are doing. Remember that it wasn't designed for todays lightweight oils (like 5-30). Back in the day we ran 10-40 if the engine was great shape......20-50 when it had high miles. If you're changing the oil at 3000 miles (which I still do on all my cars - even the new ones) synthetic oil would be a waste. It sure wouldn't hurt to drop the oil pan and clean it out (I'd probably pop-in a new oil pump while I'm in there): whether or not you want to do that might depend on how much sludge you see in the valve covers....if its clean there, the oil pan should be OK, too.
"Back in the day" we used to de-sludge engines by adding a can of "Rislone" which was basically kerosene, running the engine for a while, then draining. You are dealing with a 50 year old engine: I would not be in a hurry to loosen-up any deposits and send them circulating around inside the engine!!
I don't know what "detergents" are used in modern oils. I know that the best way to clean the innards is to change oil frequently......that "detergent" oils came into use along with hydraulic valve lifters, but didn't so much clean anything as suspend contaminants in the oil so they would be flushed away when the oil was drained rather than forming sludge.
Nice Car - Enjoy it. I had a '61,62,65,66,67,68,70. The unit-body '61-66 were a lot more solid than the later body-on-frame. I personally liked the '62 the best, but those '64-66 interiors were unreal -- -- now we don't even get any colors to chose from.
don't. if it drips oil a flush will not do a thing. find the leak and fix it. those old engines are very easy to work on. if you think you may have sludge. drop the pan clean the pan and oil pump screen, do not touch any other part even if there is a bit of sludge. seal it up fill it with oil. do another one at like 1500km and another after that at 1500 and it should get rid of some of the sludge. do not under any circumstance clean anyother part except for the oil pump screen and oil pan, if you dislodge a big enough piece of sludge and forget about it and it gets sucked up say good by to that engine.
Today's engine oil is light-years better than it was in 1964. Full synthetic Mobil1 has very strong detergent properties to keep the inside of the engine clean. Mobil1 now makes high mileage oil which will stop small oil leaks.
The engine on my 1964 Thunderbird drops a little oil, but it isn't bad. I usually add an extra liter periodically, and I completely change the oil about once every 3,000 miles. I read that on some cars, I should flush the engine every 30,000 miles, but on other cars it's counterproductive. Should I flush my engine or not, and if so, how often? My oil is a little dark, but not extremely dark.
I also periodically rotate my tires, get my brakes checked, and I get the fuel and air filters replaced--is there anything else I should be doing for general maintenance? I'm definitely not any kind of car expert, so please give me a detailed answer.
