LT1 sludge, suggestions?
LT1 sludge, suggestions? So, I bought a '95 Z28 to use as my DD while I "slowly" redo my '92. The Z28 was only getting 13MPG so I figured I would try cleaning it up some. I put a can of seafoam in the fuel tank, poured half of another can into the crank case and tried to suck the rest of the second can through the brake booster vacuum line, but the engine simply would not run with the line disconnected, so I used a smaller vacuum line (going to the emissions recall thing) I drove it for about 200 miles and then changed the oil. There had already been an oil leak but after running the seafoam I lost almost a quart in a week, I found the source of the leak to be the rear of the manifold. My buddy came over on our day off and we pulled it apart. The 4 bolts/studs on the backside of the manifold weren't tight at all, and the manifold was easily removed by hand once unbolted (my haynes manual states that a prybar will likely be necessary to remove it) once it was off we were in disbelief by what we saw inside. The valley was full of sludge and the underside of the manifold was caked in it, I couldn't believe the car would even run it was so bad. After hours of scraping and using a shop vac to suck it out, we put it back together and immediately changed the oil (again) I think for now my plan is going to be to run a premium oil through it and change it every 2-3 weeks until it eventually comes out clean. Let me know what you guys suggest.
This is the underside of the intake manifold:
I got a quart of sludge from here alone:
This is the underside of the intake manifold:
I got a quart of sludge from here alone:
holy ****. if you really want to flush it out take it to sears or somewhere that offers an engine flush. we offer a flush that is really very effective. if you want to stick to oils that will get sludge out Pennzoil Ultra or some Mobil One will flush it out good.
Rockstar
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From: I'm on a boat! in Shreveport, La
Dude, that ain't right. That's absolutely horrifying.
My best guess as to why it's like that is the previous owner dumped(or even replaced the oil with) that "stop leak" stuff in there. It's a thickening agent and in mass quantities isn't good for an engine.
You see happy sem's valley? That's how it should look.
Here's mine after 250K miles, granted it's drained of oil, but there's no sludge.
I'm curious as to exactly what caused that if you ever find out.
My best guess as to why it's like that is the previous owner dumped(or even replaced the oil with) that "stop leak" stuff in there. It's a thickening agent and in mass quantities isn't good for an engine.
You see happy sem's valley? That's how it should look.
Here's mine after 250K miles, granted it's drained of oil, but there's no sludge.
I'm curious as to exactly what caused that if you ever find out.
It has about 135k on it. Previous owner also "fixed" a tear in the intake elbow with silicone caulking compound- also encapsulated one end of a power steering line with caulk. Found at least 4 pigtails that had the locks snapped right off- guess he muscled them apart rather than lifting the tab 
On the brighter side, the manifold has been back on for about a week and at my last fill- up the mileage was up to 16 from 13, and my oil pressure seems ok (no more leak)
So, what kind of a risk do I run paying a shop to flush it (as in sludge clogging up passageways)? Would that be a better option than doing frequent oil changes with an additive like autorx or something stronger like seafoam?
On the brighter side, the manifold has been back on for about a week and at my last fill- up the mileage was up to 16 from 13, and my oil pressure seems ok (no more leak)
So, what kind of a risk do I run paying a shop to flush it (as in sludge clogging up passageways)? Would that be a better option than doing frequent oil changes with an additive like autorx or something stronger like seafoam?
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TECH Veteran
Joined: Dec 2008
Posts: 4,145
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From: Little Rock, AR
It's almost better to leave it alone, rather than to risk dislodging all that gunk and clogging something up. I think the Auto-rx product has a record of working slowly, so it might be the best bet. If most of the stuff is baked on and adhered, it is causing less of an issue than circulating lots of gunky oil. You might be surprised what a motor can look like on the inside and still run.
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thats awful! like shbox said its sometimes better to leave it alone. I couldnt do that tho. id pull whatever i could out of the engine. just imagine what your oil pan might look like....
your going to get different opinions on this i dont know if i would leave it or not my self. i have come across this several times and i have my own personal way of dealing with it. however i will not post it becuase i dont want any one damaging their engine becuase advice i gave.
TECH Resident
Joined: Dec 2005
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From: In a house
add a quart of MMO to engine oil and drive it for 1k miles and do couple short oil change with MMO. Use walmart oil or quaker state green bottle or mobil clean 5000, these oil is under 10 dollar for 5 quart.
TECH Addict
Joined: Jun 2009
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From: Tulsa, OK
Get a product called Essentialube from www.essentialube.com. It'll clean it up right purty. FOLLOW the directions.
Perfect examples as to why you should change oil faithfully and not leave it in for whatever the new fad/ridiculous 7 or 10K mile claim states...
The only way to get rid of all of it is to have the engine disassembled and hot tanked. A flush doesn't do ****.
The only way to get rid of all of it is to have the engine disassembled and hot tanked. A flush doesn't do ****.
As others have stated, you might have some problems if you mess with it too much.