Sludge will be in the heads causing damage to the valve train.

 

No pulling the intake yet. I'm thinking this may be good enough to get a fair amount of that old gunk out. I saw someone else mention pumping air back to the oil pickup screen via the oil filter. Plug the center hole, then make something to cover that area and pump air back through. I'm going to make something out of 2.5" schedule 40 PVC pipe, cap, and an old filter gasket, fits it perfectly. Then let it bubble away in the kerosene.

Do you know how much fluid is enough to cover the oil pickup screen sufficiently? I was thinking about 2 quarts. I don't want to put too much and have it affect something else.

 

You could probably go as much as three quarts, before the fluid touched anything else above the oil pan.

I don't think you will be able to force air effectively past the oil pump, unless the pump clearances are getting bad anyway...... Not to mention that would also have the effect of pushing all the oil back into the pan, leaving the pump empty. So, on your next restart, the pump will not only have to prime itself, but, everything up to the filter again.....

 

agreed. Don't blow out the oil passages.

Pulling the valve covers would be another option, pour the cleaner down the pushrods/pushrod openings to clean out the lifters and lifter valley. Then let all that accumulate down below.

 

Simply pouring the stuff isn't going to dissolve the crud.... maybe what soaks in it in the oil pan, but nothing above that. You need to run the engine with it for that.

 

Or circulate the solvent......

 

Doesn't the oil drain back from the pump to the oil pan when the vehicle is off anyways?

At any rate it seemed to work fine at 25psi, could hear it bubbling away in there. I put 2 quarts of kerosene in. A lot of flakes of junk came out when I drained it, probably just what was loose anyways. I flushed it a few more times with kerosene and then poured some oil in there to get out the rest. I cranked with coil wire and fuel pump relay removed for about 20 seconds to prime the pump, and when I started the engine the pressure jumped up almost immediately.

Oil pressure seems a little better now but I also changed to GTX high mileage. If it keeps acting up I'll do the big job and clean the pan and replace the pump, pickup and rear seal, was just trying something simple first.

 

About 40 years ago, (1978) I worked for Napa. Went to a meeting where they brought in various vendors and their products. There was a rep from Valvoline. He was ask about sludge in an engine....... His opinion was, do not use any flushes to clean it out. He suggested changing the oil often, and the detergents in the oil would break down the sludge, suspend it in the oil, and then be drained out.

 

He just wanted to flash flush as much junk out ASAP then use a slower method.

Pulling the valve covers would have been more beneficial but not his choice.

 

I just had them off when I did the valve seals. You're right, didn't feel like taking them off again, especially the drivers side. I did clean the valve covers and that entire area around the springs out when I had them off.

I'm guessing that valley/hole in between the push rods is the oil drain that goes straight back into the pan?