Crankcase Gunk Removal Idea

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The vehicle: 1990 K1500 with 5.7L TBI 190K miles. I'd like to drain the oil in my old truck this weekend. It's been 2 years since I've drained it....about 20k miles. It burns about a quart every 600 miles. I change the oil filter (Napa Gold) every 5k miles. When I top off the oil (with at least a quart), it gets either new oil (usually Maxlife NextGen) or old oil that I drained from my Honda and/or Subaru (high end synthetic with about 5k miles on it....so plenty of life left in this used oil). Truck has a sludge issue when I purchased it 3 years ago. My idea, to help get rid of any more gunk, crusty, sludge, etc. is to drain the oil after a nice hard highway run, leaving the filter intact. Fill crankcase with 5-6 quarts of either A.) Kerosene or B.) 50/50 mix of Kerosene and Mineral spirits. Unhook wire from coil to distributor and crank truck over for several 15-20 second intervals in an attempt to circulate the solvent. Let solvent sit in pan for 30 minutes or so, and then drain. Install new filter and fresh oil. You guys see any problems with this type of "flush"? It's an old, tired, beat up, abused engine. If it dies tomorrow, I won't be surprised. But do you see this "flush" doing any damage? And no, I'm not real worried about the solvent breaking loose tons of crud and clogging up my oil pickup. I've run a few gallons of MMO through her for the past 30k miles.
 
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Before you do that try this. Get 2 gallons of this.. http://www.amazon.com/Gunk-CC3K-Carburetor-Cleaner-Basket/dp/B000ABGA4E Walmart and parts stores have it cheaper. Run a can of Berrymans Chemtool in the oil for 20 min at idle then drop the oil and reinstall the plug. http://shop.advanceautoparts.com/p/berry...-0116/7040112-P Pour 5 qts into the pan through the oil dipstick tube. Let it sit a day or two, over the weekend is best. Then.. Remove the valve covers and use the 3 qts left over with a parts cleaning brush to clean the heads. Rinse with Kerosene from a cup or spray bottle and drop the oil plug. Run cheap dino for 1K then back to normal. The engine will be well cleaned.
 
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Leave it alone - just run 10W-40 Maxlife to reduce consumption and continue with your used oil top offs. 2yr-20k OCI with that amount of top off sounds about right. It's not broken yet, resist the urge to try breaking it.
 

Phishin

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Originally Posted By: Bud_One
MMO (Marvel Mystery Oil) hide
I've run GALLONS of MMO through my crankcase for 20K miles. Anywhere from 20-40% MMO. I'm looking for something a bit more HARSH. Even something that might dissolve any crud that might be stuck on the oil pickup screen as well. I'm sure there is some crud stuck on there. And no, I'm not willing to drop the pan. I'm not really willing to do anything to this old motor. except keep it alive.
 

Phishin

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Originally Posted By: Trav
Pour 5 qts into the pan through the oil dipstick tube. Let it sit a day or two, over the weekend is best. Then... Remove the valve covers and use the 3 qts left over with a parts cleaning brush to clean the heads.
Trav....why pour through the dipstick tube? Why not down the oil filler cap in the valve cover? I thought it would give at least one oil return port a good cleaning.... And I've already pulled the VC's before and scrubbed the snot out of them. But I still find flakes of crusty black stuff on the rocker arms that I can touch through the oil filler cap hole.
 

Phishin

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Originally Posted By: Phishin
Originally Posted By: Trav
Pour 5 qts into the pan through the oil dipstick tube. Let it sit a day or two, over the weekend is best. Then... Remove the valve covers and use the 3 qts left over with a parts cleaning brush to clean the heads.
Trav....why pour through the dipstick tube? Why not down the oil filler cap in the valve cover? I thought it would give at least one oil return port a good cleaning.... And I've already pulled the VC's before and scrubbed the snot out of them. But I still find flakes of crusty black stuff on the rocker arms that I can touch through the oil filler cap hole.
Originally Posted By: SteveSRT8
^^^He wants Kreen by Kano Labs!
She's already seen 2 different full quart doses of Kreen when I first got her. Would it be too dangerous to just pour 5-6 quarts of mineral spirits or toluene into the crankcase and let the truck turn over for 20-30 seconds with the ignition disabled? Will these solvent ignite due to compression and vapors?
 
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Originally Posted By: Phishin
why pour through the dipstick tube? Why not down the oil filler cap in the valve cover?
You want to keep the contact time with gaskets and seals as short as possible. It is very aggressive on sludge and will liquefy anything that may be in the pan so you can drain it out. This is a good thing if the pan is not easily removable or you just don't want to bother. It also liquefies any crud on the pick up tube screen and that comes out with out.
 
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Originally Posted By: CT8
Pull the pan.
+1 First things first, manually clean what you can, and where it's easily reachable. Then rely on whatever solvent of choice to remove the remaining smaller proportion of the gunk.
 
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Interesting-20k since any draining and up to 40% MMO-and the engine still lives. I've done a few 'interesting' degunk operations, but you've got me beat I think. If the pan is staying on, try the 'nasty stuff' and see what happens-good luck!
 
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Also, the Amazon buyers didn't rate the Gunk carb cleaner as effective on carbs and one fella mentions a clorinated version that did much better- seems to be gone now, They still offer both kinds with brake cleaner however.
 

Phishin

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Originally Posted By: Lapham3
Interesting-20k since any draining and up to 40% MMO-and the engine still lives. I've done a few 'interesting' degunk operations, but you've got me beat I think. If the pan is staying on, try the 'nasty stuff' and see what happens-good luck!
Yeah Lapham3....I see no reason to change the oil!! I mean, in 6k miles, I've added 10 quarts to the 5 quart sump!!! I just change the filter every 5k miles. Although when I first bough the truck, I changed the oil every 1000 miles and the filter too. I've ran 40% MMO for as long as 3k miles before. Until I stopped dosing her and "naturally" let her consume it all and just started adding pure oil again. I love the fact that all my old PU from my Honda mixed with the M1 TDT or GC in my Subie goes into my old truck. I change my oil in those cars twice a year, so I get approx 18 quarts of decent used oil for the truck for "free" every year.
 
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Originally Posted By: CT8
Pull the pan.
+++++++++++1 Some years back, a buddy of mine did basically what you are wanting to do to an old Lincoln Town Car. I begged him not to do it. He did anyway. That was on a Friday. Friday of the next week, (seven days later), his motor locked up tight as a drum. Food for thought - if you don't care about the motor, why then are you trying to clean it out? If it were me and it was mine, I'd keep adding the used motor oil. I think your truck and the soon to be famous "Luv" machine (my 1986 Chevy Astro Van), might be a match made in heaven.
 
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Everyone suggesting drop the pan. This is a 1990 with almost 200K on it. This could turn into a royal PITA real quick. I came up with this to eliminate this fiasco or even engine removal in some cases. Four Wheel Drive Models Disconnect battery ground cable, then raise and support vehicle. Drain oil from engine, then remove front shield and front skid plate. Remove front axle from mounting brackets. Rotate front axle downward. Remove strut rods at inspection cover, then disconnect exhaust crossover pipe Remove starter, then the flywheel/torque converter inspection cover. Remove oil cooler line bracket, then the oil filter and adapter. Remove oil pan attaching bolts, nuts and reinforcements. Remove oil pan and gasket. Reverse procedure to install.
 
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If its running ok, why do anything? You said it: Its a 20 year old truck- I mean, most of us on here would love to hear what happens, but we are thinking this is a lab test. If it ain't broke don't fix it.
 
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I had a '94 C1500 350 TBI Suburban that burned oil faster than yours-I switched it to MaxLife, 20W50 at first & then NG ML 10W40 when I got it cheap enough & lowered my consumption to 1 quart every 1K. No sludge in mine, though. Still ran great with fairly lousy hot idle oil pressure when I sold it with 223K on the clock. If it is really as bad as you say, I would keep doing what you're doing now, no sense in risking blowing it up-although new crate motors from GM aren't really high, if you really like the truck.
 
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