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Bad Oil Sludge

4K views 28 replies 10 participants last post by  Sinister 
#1 ·
So I pulled off the driver side valve cover and had to scrape whatever I could out from the head, it was layers on layers. I change my oil every 7 to 8k miles with full synthetic. I'm gonna open up the passenger side tomorrow and see, if its bad its probably everywhere. I cleaned my oil pan when I replaced my pan gasket chasing an oil leak, I'll probably do the UV trick eventually. but what would you guys do shorten the oil & filter interval?
 
#2 ·
What would you guys do, shorten the oil & filter interval?
Damnit YES. Cut your oil change intervals in half NOW.
Even if every single mile I ever drove was highway miles, if I changed my oil every 8k miles, I'd kick me in de nyutz.

You probably also need to change your PCV Valve NOW.
When you do, use the Gen4 SBC PCV thingy (12572717) instead of the mid-'90s LT1 PCV Valve that dates back to 1987.
 
#3 ·
use the Gen4 SBC PCV thingy (12572717)
Could you explain your reasoning behind recommending the fixed orifice valve for his car?
My thinking is , in his application, there will be LESS breathing and vapor purging.

The breather, separator under the LT1 manifold , least in my experience , works quite well.
Are you seeing a lot of oil in LT1 PCV suction hoses?

The downside to the production LT1 , IMHO, is the lack of air circulation in the left cover.
 
#6 ·
Could you explain your reasoning behind recommending the fixed orifice valve for his car?
My thinking is , in his application, there will be LESS breathing and vapor purging.

The breather, separator under the LT1 manifold , least in my experience , works quite well.
Are you seeing a lot of oil in LT1 PCV suction hoses?

The downside to the production LT1 , IMHO, is the lack of air circulation in the left cover.
I THINK it's been id'ed as the magic bullet for the "sucking too much oil into the intake and gunking it up" problem. This was the most official looking hit searching that part no.:

I've not made the change to either of my cars yet, but seeing the greasy soot and varnished up inside of my old FWB intake years ago after only 80,XXX I will make the change with the next maint. cycle.
 
#8 ·
If you are frequently adding oil you have problems that need addressed. Is it leaking out or burning it? I’m going to assume it is burning it since the engine is filled with sludge from poor maintenance. How many miles on the engine?

If it is using oil I definitely wouldn’t be wasting money on synthetic oil. I use the cheapest oil I can find and change it every 3k. 210k mile engine that is spotless inside and uses no oil between changes.
 
#11 ·
Yes it leaks im going to try and clean everything and let it run in my garage usually it'll have a drop after 20 seconds. I replaced the oil pan gasket but it was while the engine was in there and not lifting it at all so it could be questionable, the crank and opti seal went in perfectly but the water pump drive seal was tricky and I unfortunately did not get the specialty tool to install it might do that again when I'm in there again. So before I changed the PCV valve the threads of my spark plugs had oil all on the threads now with it changed it doesn't do it anymore and my NGK's look nice after a couple hundred miles. I need to compression test to see if it's rings or just valve seals or how big a can of worms it will be. I will be buying cheaper oil and changing it more often because it leaks full synthetic anyway it does no good on the ground. Your engine sounds like its perfectly happy. Only 140,000 miles on the original engine it's been through a family who owned it majority of it's life (I've owned it now 6 years best thing I could have asked for as a first car it's been dependable I was young and dumb with somethings but I'm getting better from this forum and you all) but it sat outside in beach climate for multiple years and started to get bad visually with roof rust and moss. Thank you for the honest advice along with everyone else it means a lot.
 
#9 ·
My experience: Synthetic tends to have more detergents in it and will wash sludge out faster than conventional. I would stock up on cheap oil filters from Rock Auto (like $1.50 each), and buy an oil filter cutter tool from a race car supply place. Change the filter at 500 miles and see how full of sludge it is. If it's not full, run the next one a little longer.

I had an LT1 the previous owner very rarely changed the oil on. I pulled the intake manifold at 104k and you literally couldn't see the lifter spider. Over 1/2" of sludge in it that felt like chunks of rubber when I dug at it with a screwdriver. I ran synthetic and changed the oil filter at 600 miles, then changed the oil 600 miles later, and repeated that back and forth until the filters stopped filling with crap. The motor ran perfectly the whole time until the car rusted out at 191k. At around 160k, the next owner didn't like a little lifter tick it had, so he pulled the valve covers off, took a steam cleaner, removed the oil drain plug, and steam cleaned the top of the motor. Once the water and crap stopped flowing out of the oil pan, he put the drain bolt back in, filled it with oil, started it up, and let it idle for an hour to boil off the moisture. And it ran fine. I had a lot of respect for that oil pump, as ALL that crud had to flow through it to get to the filter.
 
#12 ·
My experience: Synthetic tends to have more detergents in it and will wash sludge out faster than conventional. I would stock up on cheap oil filters from Rock Auto (like $1.50 each), and buy an oil filter cutter tool from a race car supply place. Change the filter at 500 miles and see how full of sludge it is. If it's not full, run the next one a little longer.

I had an LT1 the previous owner very rarely changed the oil on. I pulled the intake manifold at 104k and you literally couldn't see the lifter spider. Over 1/2" of sludge in it that felt like chunks of rubber when I dug at it with a screwdriver. I ran synthetic and changed the oil filter at 600 miles, then changed the oil 600 miles later, and repeated that back and forth until the filters stopped filling with crap. The motor ran perfectly the whole time until the car rusted out at 191k. At around 160k, the next owner didn't like a little lifter tick it had, so he pulled the valve covers off, took a steam cleaner, removed the oil drain plug, and steam cleaned the top of the motor. Once the water and crap stopped flowing out of the oil pan, he put the drain bolt back in, filled it with oil, started it up, and let it idle for an hour to boil off the moisture. And it ran fine. I had a lot of respect for that oil pump, as ALL that crud had to flow through it to get to the filter.
I will buy a tool for that, I was curious if there was metal at all and I checked and it was good but it was filtering out junk, i didn't squeeze all of it out with a vice but you could tell some crud got stopped. I will do that too buy cheap filters and see how long it takes to fill it up with sludge. I was expecting it to be cleaner that it was cause I only put full synthetic in it so to see this I want to help it. That's impressive it had that much sludge and was still moving unfazed just a little lifter clatter I do have a respect for these cars and all that makes them unique. I didn't know you could do that with a steam cleaner I might try that in the future if needed. Thank you for the help !
 
#13 ·
Be careful that you do not end up with a 1 inch layer of gunk in the bottom of your oil pan.

I put a catch can on my PCV system. It stops almost all of the oil from going into the intake. I have a clear drain line on the bottom with a valve to allow for easy draining.

I agree with the frequent changes using regular oil, and a filter with each oil change.
 
#15 ·
Hopefully from dropping the oil pan 5 years back and checking to see what was in there it should be spotless but from me thinking I can leave it in there longer almost 2x as long from having a oil consumption problem, having to check it frequently and topping it off thinking it always had fresher oil but I might have had the wrong look at things from the start I'm grateful to ask you knowledgeable people for help for my own R&D. Did you make that system yourself I'd love to see it, I'd like to do that on this engine or for a future freshened up one thank you Fred! I'm starting to see just use regular oil and service it more to keep the sludge away forever will help a lot. I've heard of tranny fluid, A quart added to 4 quarts of new oil or I'm just now seeing someone say put straight ATF 5 quarts and let it clean but do not put a load on it so it's very encouraging.
Does anyone think Seafoam in the new regular oil will also help breakdown the gunk or just do the tranny fluid trick, transmissions are usually spotless w/ regular maintenance.
 
#14 ·
Automatic Transmission Fluid has TONS of detergents/dispersents in it - For an initial "flush" I'd drain the engine oil, fill with ATF and a new filter, run that for an hour or so in the driveway at light load, can rev it up to circulate/splash around, but stay at low load. Drain, change filter, refill with engine oil and continue as above checking filters every 500-1000 miles. Seen this done a few times and it does a good job at getting a lot of stuff out quickly.
 
#16 ·
That is amazing and I'll probably do this for the initial flush and see how much the cherry red color changes and keep going, I did not know you can run straight ATF but only at light load that should really clean it. I'd feel better doing that trick and just keep fresh regular oil in rotation to stop the gunking up. My driver side valve cover was bad, I have to see and show what's on the other side before I do all this. I would think the top end crevices are harder to clean since it splashes on the piles of crud caked in the cylinder head. Thank you FUB!
 
#17 ·
Very true that DexMerc3 / Dex6 has lots of detergents in it. That's why I'm such a strong proponent of regular flushing through the cooler lines and NOT swapping the filter in the pan.

Honestly though, if you did NOTHING but just run regular oil and swap and inspect the oil filters often, that will keep the particle size small and the motor will be just fine.
 
#20 ·
I'm excited to just do conv. oil and keep it changed at most 4k miles and check out the media in filter every time. I live in Ventura, CA and I saw in my owners manual it says to put 10w30 in it instead of 5w30 does anybody else think its okay since it never gets below 40 degrees Fahrenheit. Thank you
 
#19 ·
Make sure vacuum lines, elbows to the PCV do not leak vacuum. Sometimes they are loose or have cracks. Check your throttle body, you may find oil in it too.

Even with 80% of high speed highway driving, change oil light turns on in less than 4000 miles. I would take that number as a reference point and change oil and filter AT LEAST every 4000 miles. The old PF52 filter was much better than new PF52E. Occasinally, you can see that old PF%@ available for about $4 at Advance autoparts.
 
#22 ·
Make sure vacuum lines, elbows to the PCV do not leak vacuum. Sometimes they are loose or have cracks. Check your throttle body, you may find oil in it too.

Even with 80% of high speed highway driving, change oil light turns on in less than 4000 miles. I would take that number as a reference point and change oil and filter AT LEAST every 4000 miles. The old PF52 filter was much better than new PF52E. Occasinally, you can see that old PF%@ available for about $4 at Advance autoparts.
I won't go over that number anymore thank you for telling me that. I'll check with brake clean for vacuum leaks I shouldn't have any but its hard to know until you recheck cause of the age of parts. Really the only lines that are deteriorating are the gas tank EVAP lines almost all of them, Cali gas destroy's the stock rubber lines and o-rings and the stock injectors so I have to probably address that before it gets worse. I checked the throttle body recently I have a picture but very little trace of a oil trace. Thank you for that part # the big and small version are the same price at $8.
 
#23 ·
I would not run 4k intervals; the oil change light is unaware of YOUR motor's condition. I'd watch the oil and filter very closely to see what is washing out of the motor before deciding how long to run it. I don't know how expensive regular oil is where you live, but it's $13 a change at my local Walmart, and that's way cheaper than engine work.

10w30 is fine for a temperate climate. The first number is indeed the cold number; the second number is the hot number.
 
#24 ·
Another idea (not saying it's a good one :)) would be to put one of these in the oil cooler line mounted up somewhere that you can easily see it. A 4" one would be plenty big and you can get various screen mesh sizes (they're cleanable) down to 28 micron which is right in line with what a factory oil filter works at.


I've used these filters quite a bit (ironically, never on an engine though...) and can attest to their high quality. No affiliation, just a satisfied customer.
 
#29 ·
Interesting. I have been using 10w-30 for decades, even in my multiple LT1 cars. Only the 2 new cars in the driveway get what is on the cap because they are under warranty. Force of habit I suppose as I have never looked at the cap or owners manual.
 
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