This is on the 455 Olds in my 54 GMC 2.5 ton and dropping the pan is easy as pie, nothing in the way at all. I was going to pop some dents out of the pan and clean the clogged pickup screen. While I had the pan off and the valve covers off I wanted to know if pressure washing the oil drainback holes in the heads will push water in the wrong places? Or will the water just shoot straight down and onto the ground? I can let things dry out a few weeks too as the truck is currently being restored, it's not going anywhere anytime soon.

 

Personally I would avoid water, as IF it gets into bearings, rust and seizures could quickly result.
Is it possible to use another method of cleaning like solvents or even long pipe-cleaner things?
I have never had an Olds engine opened so others would be able to give more certain answers.

 

I would think that would be OK, providing you throughly dry everything and spray some kind of rust preventative on the internal parts.

 

First, I would use a water based solvent. NAPA sells one such solvent that surprised me in how well it worked. Second, definitely have compressed air to blow the water out. Third, starting the motor as soon as possible after cleaning (yeah, I know you have to put the pan back on) will boil out any remaining water. There's always moisture in the oil pan from condensation. It just gets evaporated as soon as the engine gets up to temperature.

 

I like the idea of the water-based solvent, but don't like the idea of "water under pressure" w/ bearings "anywhere" around. True, Joe, that there is moisture in the engine, as water is one of the bi-products of an engine, but never would I apply water under that type of pressure to an engine, especially internally. There are chemicals that you can add to your oil after physically-by hand cleaning out the return passages in the heads. I'd be worried about possibly blowing water deep into a tight space (bearing). Pressure washing, w/ water, anything on the inside of an engine doesn't even sound good to me.

 

Bearings hate water, even more so than cats.......
I accidentally got some water into the clutch of my Ford when I cleaned the engine (tear in fork boot) and now the pilot bearing makes an nasty howl when the clutch pedal is depressed any. After 1000 miles, it has not gotten better.
After this mishap, I would prefer to keep water out of mechanical stuff unless it is torn down and can be dried well immediately afterwards and doused with a petroleum product.

 

The reality is that by the time the water could even get to the bearings, there would be virtually no pressure left and little way for it to displace the oil film on the journals. The bigger problem is that the oil drain holes angle into the lifter valley and any crust that gets dislodged will be blown into the lifters and onto the cam lobes. Here's a better idea. Since these are straight-drilled holes, use a small wire brush and solvent from the valve cover side of the head into the lifter valley. Use lots of paper towels in the lifter valley. A gun-cleaning kit works very well. Once the crust is removed, use the gun cleaning pads to wipe out the inside of the drain holes. If the holes are badly plugged, a small drill bit gets you started. I've actually had this problem on an abused Olds motor. The plugged drainback holes were causing oil to pool under the valve covers and run down the valves (as well as under the valve cover gasket). Of course, in the end I did a valve job.

 

When I came across engines with gummed up oilways I used the following method;
Pour a pint of diesel fuel into the oil filler, run the engine at fast idle for 30 minutes.
Drain the oil and fit a new filter, refill with a high detergent diesel oil.
After 500 miles drain the oil, replace the filter again and refill with the recommended oil - job done.
This worked on an engine with the oil so gummed up when I undid the drain plug black goo trickled out, the customer asked me to look at it because the oil light stayed on when he started the engine - he hadn't changed the oil in 8 years!.

 

Joe,
I like your method of cleaning the drain-back passages w/ the bore brush and pads, and also catching the chips/crud like you said. I used to buy pick-ups from a big company that wouldn't make major repairs after 10 years, they'd just sell the truck cheap. Got one f/ $200.00 that smoked like heck, w/ nice body and big overhead rack. Got it home and noticed alot of oil coming out of the passenger side valve cover (through the gasket). I knew right away it was the drain-back passage clogged. Pulled the valve cover and saw that whoever changed the valve cover gasket last, had left big pieces inside which got caught in the rear passage and stopped it up. I took a screw driver and picked the old gasket material out of the passage and when I started it up, the smoke cleared and the engine ran great. I drove the truck f/ 8 years w/o any problems, and when I sold the truck, it was starting to give a puff of smoke out the tail pipe when I'd first start it in the morning when it needed an oil change. Talk about a smoking engine. LOL!!! Sold the overhead rack, first thing, f/ $250.00, and sold the truck f/ $500.00. I sold it due to getting an '83 G20 Chevy van, in great shape, needed bottom end bearings, f/ $100.00 from my neighbor. Have had the van f/ about 6 years and it still runs great. I love the old work vehicles.

 

I appreciate the replies guys, I think I'll 86 the pressure wash idea. I'm going to go ahead and pull the heads so I can thoroughly clean them out. I need to do valve seals anyway and just for good measure I'll replace the head gaskets since it's very likely this engine has seen some very hot days with a neglected cooling system. Once on the road I think i'll try the ATF method to get it cleaned up inside. It's a good running engine so I don't plan on doing anything more to it unless it really needs it.

Here's what I was greeted with when I popped the valve covers! Not an Olds V8 but you get the idea....

http://www.renault4.co.uk/technical/oil-sludge.jpg

 

My 2 cents worth.
Try using Reslone instead of the ATF fluid. I've used it for years on all types of gas & diesel engines. Add a qt. at each oil change till your oil stays clean, then once in a while after.
Stetzie