Internal engine cleaners?? Which one

hey i got a 4.3, 1990 and its very sludgey under the valve covers, also the oil barley makes it to 2400 miles before it looks grity, changed the pcv valve, air cleaner, is there a good engine cleaner that wont ruin anything out there.
one friend said use the wrong stuff and you might wind up cleaning out something that will then cause a knock or worse.

Something safe would be to use cheap oil that meets spec, and change it at say, 1000 miles until it's clean. Have you read about different oil filters? I did. I won't use a Fram any more. Not that it caused trouble, but my used oil is noticably cleaner with a better filter.
I use "Rislone" in my Saturn. I add about a half litre 1000 km before a change. But the engines pretty clean. I'm not a fan of additives, but the Saturns' have been know for rings sticking.
hopefully others will post too

hey i got a 4.3, 1990 and its very sludgey under the valve covers, also the oil barley makes it to 2400 miles before it looks grity, changed the pcv valve, air cleaner, is there a good engine cleaner that wont ruin anything out there.
one friend said use the wrong stuff and you might wind up cleaning out something that will then cause a knock or worse.

You are better off to leave it alone and just change the oil and filter a little more often.
If you put anything in it even a different brand of oil and it breaks the sludge all lose it will drop down in the oil pan and stop up the oiling system.:grinyes: :lol:
If you have the valve covers off just clean out the drain back holes on the ends of the head.
MT

The best cleaner you can use is polyalphaolefin, bar none. Just keep using it until the engine is clean, and you can extend the oil change intervals to 6-10,000 miles. You may want to change filters and top off the sump at the normal intervals, however.

hey i got a 4.3, 1990 and its very sludgey under the valve covers, also the oil barley makes it to 2400 miles before it looks grity, changed the pcv valve, air cleaner, is there a good engine cleaner that wont ruin anything out there.
one friend said use the wrong stuff and you might wind up cleaning out something that will then cause a knock or worse.

Try using Lucas oil system treatment. I've used it my 1993 GMC truck for years. The engine has 340,000 kilometers (over 200,000 miles) Put one litre of lucas and 4 liters of oil. Use it every time you change your oil and use a good quality oil.

Welcome to the forum, enjoy it, ... however, this thread is over a year and a half old, please don't post in old threads.