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Ever use Liqui Moly engine flush?

TexasGem

TexasGem

Finder of Lost Things
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My '99 Z71 has 500,000+ miles on it. Always ran on synthetic oil. Last year during an oil change I noticed sludge in the filter. Ran some Seafoam through it, not a huge fan, did ok. A friend said to use Liqui Moly, pour it in the crankcase when the engine is warm, idle 15 minutes, immediately drain. I checked my oil yesterday, barely off the full mark. Today the " check oil level" light came on, pressure driving was under 40, I'm something is clogged. Been home a couple of hours, oil is still barely off the full mark. Anyone ever use Liqui Moly??
 
500k. Time for a rebuild. Liquimoly will not close bearing clearances. Will not make the oil pump tighter. If something were to be clogged, your oil pressure would go up to the pressure of the relief spring.
But hey, it needs a rebuild. Have at it with the goofy juice.
 
I am an old gear head from the 1960's BUT, not an expert. I will never admit to that. Disclaimer done with, it sounds to me you did it right. Always, always take the gradual approach to sludge. You have tried the two products that function in that approach. Sadly, it does appear something is clogged to reduce you oil pressure. If that old Chevy is still near and dear to you I fear it may require more professional help.

In the past I have left sludge alone and just ran the vehicle. I had a 64 Dodge Dart with the slant six I ran non detergent oil in it for years once the sludge appeared. It was still running after I sold it. Couldn't kill that engine if you tried.
 
waybomb said:
500k. Time for a rebuild. Liquimoly will not close bearing clearances. Will not make the oil pump tighter. If something were to be clogged, your oil pressure would go up to the pressure of the relief spring.
But hey, it needs a rebuild. Have at it with the goofy juice.
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Of course it needs a rebuild, not doing it during the 100° + summer. Sludge can drop oil pressure if the pick tube screen is clogged. I'm just trying gain time/life. Certain sludge cleaners leave hunks in in the motor. I was asking about a certain product because it breaks it down more and doesn't ruin seals.
 
TexasGem said:
Of course it needs a rebuild, not doing it during the 100° + summer. Sludge can drop oil pressure if the pick tube screen is clogged. I'm just trying gain time/life. Certain sludge cleaners leave hunks in in the motor. I was asking about a certain product because it breaks it down more and doesn't ruin seals.
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Your oil pick up being plugged with sludge can explain low oil pressure, but doesn’t explain low oil volume.
 
Then lift the engine and drop the pan. While in there change the oil pump and the bearings. Go 0.001 undersize on the bearings
 
So I'm probably just going to remove the oil pan and not run any flush through it! BUT, that's a huge job seeing everything that has to be removed to do it. Hubby is willing to help of course, not sure if that will make it easier, lol! I'm curious what's in the pan.
 
MY DEAR GOD there is a STUPID amount of stuff to remove to get the oil pan down on this truck. I actually QUIT, started putting it back together to sell cheap! Hubby said he'll do it, wish I said NO!
 
TexasGem said:
MY DEAR GOD there is a STUPID amount of stuff to remove to get the oil pan down on this truck. I actually QUIT, started putting it back together to sell cheap! Hubby said he'll do it, wish I said NO!
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Not funny!
 
Doc said:
The way you 'wish' you said NO to hubby make me smile. Sorry for the frustration. Been there done that with trying to take off parts auto engineers give no consideration to the home mechanic.
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I got a long way in there and like to work on my own stuff, but wow! No hard feelings, I was truly overwhelmed. When I was younger I wouldn't have blinked, but getting older makes this stuff harder. Hubby is a good mechanic, he can have at it!
 
Hubby is now fully engulfed in the nightmare of my truck! It's hotter than heck out, a little cooler in his shop, but I can't get him to take a break yet. He's hell bent on getting the oil pan down today 🙄🙄🙄!! Meanwhile, I'll be taking a nap in the A/C!
 
HE DID IT! The pan had a lot of sludge, nothing chunky, no metal (checked with magnet). There's a pan under it for the night, we'll see what all drips from it. Right now the drips look like decent oil. Will put a new pump in it to be safe, unless funky oil comes out, it's getting a few oil changes in a row after going back together!
 
The closest thing I did to flush was my 61 ford falcon it had low pressure my to-bee father in law said to flush it with kerosene run it for a couple minuets did that drained kerro/oil mix new filter some new 30WT and ran it for a couple hours of driving still low pressure did another oil and filter change pressure came up some but motor was nosier 🤷‍♂️ about 6 months later the timing chain jumped a couple teeth put new gears and chain in and and motor quieted down still lower oil pressure but a nice quiet motor so i guess the "gunk was keeping the timing chain quiet. I ran it another year or so until I was out of school and working and bought a new 1975 Vega Spirit of America model for the bicentennial it was like a GT model.
 
I am normally a do it myself gal....yep, even the big jobs. But I truly didn't have it in me to take down what had to be taken down just to drop the oil pan. If I didn't have Hubby, I would have done it if it took me two weeks!! But he got it done! Oil pump replaced, everything cleaned of sludge, new pick up tube gasket, and new oil pan gasket. Sounds like a new motor! Real drive to town in the morning. I appreciate everyone's advice, and @tiredretired , your's was the best! Updates when I get home from work tomorrow morning!!
 
I was told many years ago the best "engine flush" was clean oil.

Sludge is usually caused by short trip driving, less than 20 or 30 minutes. It takes that long for the contaminants pushed into the oil at start up to burn off.

As far as oil pressure - if it's OK at start up and drops when the motor is warmed up that's a sure sign of worn bearings.

I've been wrenching on cars for 60 years, and have even pulled and completely rebuilt a few engines in my time.
Today's engines will last a long time if you change oil and filter when you're supposed to and don't leave every red light like it's the 1/4 mile start line.

My current ride is a 2007 GMC pickup that I bought brand new and she's got 320,000 miles on it. Still holds 40 psi oil pressure at idle when warmed up. For the last 10 years I've used nothing but full synthetic oil and Wix brand filters.
5.3 V-8 with GM Performance cold air intake, and GM Performance cat-back free flow exhaust.
 
rice paddy daddy said:
I was told many years ago the best "engine flush" was clean oil.

Sludge is usually caused by short trip driving, less than 20 or 30 minutes. It takes that long for the contaminants pushed into the oil at start up to burn off.

As far as oil pressure - if it's OK at start up and drops when the motor is warmed up that's a sure sign of worn bearings.

I've been wrenching on cars for 60 years, and have even pulled and completely rebuilt a few engines in my time.
Today's engines will last a long time if you change oil and filter when you're supposed to and don't leave every red light like it's the 1/4 mile start line.

My current ride is a 2007 GMC pickup that I bought brand new and she's got 320,000 miles on it. Still holds 40 psi oil pressure at idle when warmed up. For the last 10 years I've used nothing but full synthetic oil and Wix brand filters.
5.3 V-8 with GM Performance cold air intake, and GM Performance cat-back free flow exhaust.
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This morning after the new oil pump and cleaning the sludge out of the pan it was 30 at idle and 50 driving. I'm really happy with this 5.3 with a half a million miles on it!! Felt like itself again! I'll do a few oil changes pretty quick. I too love Wix filters and this truck always ran on full synthetic. The biggest thing was all the stuff that had to come down to get the pan off!! I'm very thankful Hubby jumped in and did it!
 
TexasGem said:
This morning after the new oil pump and cleaning the sludge out of the pan it was 30 at idle and 50 driving. I'm really happy with this 5.3 with a half a million miles on it!! Felt like itself again! I'll do a few oil changes pretty quick. I too love Wix filters and this truck always ran on full synthetic. The biggest thing was all the stuff that had to come down to get the pan off!! I'm very thankful Hubby jumped in and did it!
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Mine is 4X4 with off road option.
a LOT of stuff has to come down to do anything!!
Example - I need driver's side motor mount. The whole front differential has to be unbolted and dropped down just for access. And even then access is extremely limited.

I had to have the rear oil seal replaced - a common thing on GM 5.3's. The labor bill on that was $600 and the mechanic gave me a break because we're long time friends and he knows we are poor. High cost because of the time required to move everything out of the way.

The 5.3 is a very good engine, and as you can attest, 500,000 miles and more is possible IF it's taken care of.
 
rice paddy daddy said:
Mine is 4X4 with off road option.
a LOT of stuff has to come down to do anything!!
Example - I need driver's side motor mount. The whole front differential has to be unbolted and dropped down just for access. And even then access is extremely limited.

I had to have the rear oil seal replaced - a common thing on GM 5.3's. The labor bill on that was $600 and the mechanic gave me a break because we're long time friends and he knows we are poor. High cost because of the time required to move everything out of the way.

The 5.3 is a very good engine, and as you can attest, 500,000 miles and more is possible IF it's taken care of.
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Mine is a Z71, front differential had to come down for removing the oil pan. I'm hoping for many more miles.
 
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