I picked up a 71 F-100 a few weeks ago and it had an oil leak so I pulled the intake manifold off to fix it and man I was shocked. The inside valley and bottom side of the intake were just covered in buildup. I also popped the valve covers off and the same thing...all over the rockers and pushrods.

I wish I had more time, money and space and I'd just redo the engine but I don't. However it's hard to put it all back together knowing it's in such dirty shape.

My main concern in the oil pressure may be affected by the pump screen being clogged up with sludge. I've thought about running some Engine Oil cleaner through it (Gunk makes something) but I'm not sure if I'd be doing more harm than good.

Would it be possible to get the engine pan off so clean it out and the screen without pulling the engine?

Any tips would be appriciated.

 

I've heard of guys running a quart of trans fluind in with an oil change. ATF is high detergent.

 

most of the oil change shops have a chemical engine flush available that is used with the engine running for about a half hour then new oil and filter. ive used them a few times with decent results.

 

da_jokker, Welcome to FTE The best truck show on the net.

DO NOTHING! The ol motor is probably well worn, and if you try to clean it up now, you can cause all kinds of problems. You probably can run it for a while like it is.

Leave it alone, and start saving for a rebuild down the road.

My 2

John

 

if you start messing with that sludge you will end up looking for an engine sooner than later.

 

My thoughts as well, when I get an engine like that all I'll do is clean the gunk from the underside of the valve covers, but that's it, leave the engine itself alone.
If it ain't broke...etc, etc....

 

I agree. Don't touch it. That gunk also may be clogging all sorts of seals that would otherwise be leaking. Running detergents can cause them all to open up. Then you've got a real mess.

I'd suggest driving it a lot and changing the oil frequently over 500-1000 miles or so. This should safely wash out some of the excess gunk.

 

Thanks guys...I guess I'll do just that..nothing.

My only concern is that the oil pump screen may be partially plugged. I think what I'll do is check the oil pressure with an actual tool (the gauge seems to register low) and see what I get. If the pressure is fine, then I won't worry.

If it's low, then maybe I'll pour some flush in, but NOT run the engine. Just let it sit in the pan and hopefully it will loosen up anything on the bottom of the screen. Then I can just drain it, pour some cheap oil in..drain it again..and so on until it all comes out of the pan.

 

Running the engine cooler has a habit of helping that sludge acrue, so I would make sure a thermostat is installed. Lots of people remove the thermostat so the engine runs cooler, but this is a side effect of that.

So if I were you, I would scrape all the obvious gunk that I could get to easily while the intake was off, but I would agree those most recent posts above, to not run motor flush through it afterwards. You'll loosen all that crap and then who knows what all will get clogged.

You might want to use a thinner grade of oil, and change your oil filter often.

 

run a diesel rated oil for the high cleaning abilities it will not break it all up at once but instead over 5k or so. run 15w40 and a good filter.

 

It's not that bad, you must lift the motor and drop the pan on the crossmember to get the oil pickup off. This can get interesting if your not good with your fingers, especially getting it back on(You have to work through a 2" opening). But If your exhaust gaskets havent been touched, you may break the studs when unbolting them.
Ultimately, I am with the rest of these guys. Until you are ready to invest in a rebuild or swap I would run synthetic oils and watch additives as some of these tend to do more harm than good. I use BG products only as most others add to the sludge. Try ENGINE PURGE!!

 

If your worried about oil leaks then i would rebuild the motor, otherwise thow her back together, run it till you cant stand it. If you have more time than money i would pull the motor, buy a gasket set, and dissasembly and clean everything, and put it back together, assembly lube, fresh oil, hunky dory. No need for new parts, reuse them all (unless their shot). so a $70 gasket set, plus $50 or more for misc BS and your running again with a motor that doesnt leak and has no sludge. If you cant pull the motor, pull the pan, rockers pushrods, intake and lifters, spray her down with degreaser, and clean her that way. After the water, blow with compressed air and douche it with WD40. New gaskets, some oil in each cyl, and your good to go. We do it all the time in the heavy equipment repair. It may not be the right way to do it, but it gets you by.

 

da_jokker, The engine got to be in the shape that it is in now over time, and if the screen is partially plugged, while not ok to use in a newer engine, should be left alone.

Speaking from experence, when you take a gummed up engine and start cleaning it on the inside you could create a new imbalance and may find the rebuild schedule moved up.

Best to drive it, save up your coins, don't rush it along.

John

 

I would replace your valve cover, oil filter and oil pan/pickup gaskets. Its not a bad idea to see what is in the pan, I am glad I did. My motor is all original, never been touched minus regular maintanance. I have some sludge of course but would have never known about the piston skirt that was knocked off(it was laying in the pan along with some pieces of rings)by the arm. There were also ring pieces in the pickup I cleaned out.So I may need another motor, a good thing to know ahead of time. I replaced all these gaskets and cleaned the pickup, and my oil pressure is optimal. The reason I started investigating the problem of lost oil pressure. But once again all in all I would touch this as least as possible until you are ready bro.

 

When my tired ol 390 with 180K started losing oil pressure the last few yrs, I decided it was time. Finally located a virgin 390 block and crank, hauled it to the machine shop and let them do what they had to do. Wasnt in a hurry, so was able to collect the rest of the add ons when I had the money.i had to drive the truck everyday, so this worked for me. Kept it basically stock, except for warmer cam, better rings, rods, valve train, upgraded gaskets, etc. then when it came swap time (2 mo later), it was an easy day for getting that done. bolt on stuff was manifold, headers ,carb, fuel pump, starter, alt, plug wires, etc. Already had the better ignition setup, and misc. Also installed new clutch assembly, and eventually drive line. This all came before power steering install, so we're getting there. this summer it got new paint, aluminum radiator with elect fans. It never stops, I've driven this truck for 16 yrs, so maybe it will run for another 16 yrs. been kicking an idea around with doing it again, but taking my time and building a thumper motor for it. then I would have to deal with that darn smog test every yr. Rats!