LS1 Sludge

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OK I am looking for recommendations on how best to address this problem:

Sludge

Here's the story:

My 2004 Vette daily driver, 165,000 miles, started making noises like a stuck (collapsed, bled-down, whatever you want to call it) lifter, and for about a half year had been consuming coolant (dex) at the rate of maybe a half gallon every 3000 miles. I had tried unsuccessfully to find the "leak" but never could. When the lifter noise started becoming more frequent and lasting longer, I decided to open up the engine to see what I could find. You can see the results. The sludge in the oil pan cover (you have to drop almost the entire front suspension to remove the oil pan, and I am not keen to do that) was fully an inch deep in most places.

Careful inspection by myself and my machine shop man, who is very experienced with the LS1 engine, has not revealed any source for the coolant contamination, either in the heads, the head gasket, or the water pump, which i am replacing.

At this point, I have had the heads trued up, replaced valve springs and stem oil seals, new lifters, and of course cleaned the oil pan cover. I can't really get at the crank and have, at least at this point in time, no energy left to remove the timing cover on the front of the engine. I am getting ready to reassemble the thing, and my plan is:

Reassemble, fill with a good detergent oil such as rotella t, start and run up to normal driving for 20-30 minutes, drain the oil, inspecting more carefully than I usually do (mind you, I have followed the oil change recommendations given to me by the DIC since owning the car, and have always used the recommended mobile 1 with each oil change), and repeat until I can be satisfied that the sludge will not be a problem. I know there are a lot of sludge removal products, but I think the use of a good high detergent oil will be sufficient, at least initially.

I intend to watch the coolant like a hawk, and if/when there is the first sign of continued consumption, I will use a can of stop leak, which i intend to add as directly to the block as i can. I do not intend to tear any further into the block at this point, and if I haven't fixed the problem with maybe 50 hours of my labor spread out over 2 months, and about $850 in parts, I will just trade in the old girl. She's in pretty good shape, new seat covers, but needing tires, and I am probably going to go with a C7 after they have been out for a few years (as long as they do not look too much like the new Camaro)

DT MacMillan

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Just curious...did you buy this car new? I assume the oil life monitor indicated that your oil be changed at 10 to 12K intervals,is that about right? If you did not buy new,did the previous owner use M1 at reasonable intervals?
 
You need to get a UOA of the oil after some miles to see if there is coolant present. I would use Auto-Rx to clean and rinse. I would not use any sealer in the coolant. Find the problem. Maybe some UV dye in the coolant to help spot the leak if its not in the oil.
 
Pressure test the cooling system to verify if it is leaking or not, and fix ASAP if it is. Kreen works very well and fast for cleaning up an engine of sludge and varnish.
 
Bought it new, and have pressure tested...

I've read a little about auto-rx, but even for extreme sludge, the program seems to allow for 3k miles right away. I know there is a history between auto-rx and bitog, so i am kind of in a quandry as to the best course to take.
 
Originally Posted By: demarpaint
Pressure test the cooling system to verify if it is leaking or not, and fix ASAP if it is. Kreen works very well and fast for cleaning up an engine of sludge and varnish.


Right!
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Originally Posted By: 2004Corvette
Reassemble, fill with a good detergent oil such as rotella t, start and run up to normal driving for 20-30 minutes, drain the oil...

Not sure what you're expecting this to do for you...?
 
Originally Posted By: Bottom_Feeder
Originally Posted By: 2004Corvette
Reassemble, fill with a good detergent oil such as rotella t, start and run up to normal driving for 20-30 minutes, drain the oil...

Not sure what you're expecting this to do for you...?


Really! A perfect waste of good oil IMO, unless it would be used to wash an engine flush out, no mention of that though. Even then I'd opt for something really cheap for a 20-30 minute run to rinse out a flush.
 
So you probably have sludge from coolant contamination.

I would.. fill with oil.. at 1000miles change the oil. So you have flushed out almost all oil oil remnants.

then refill and get a uoa at 1000-2000 miles to see if you have continuing coolant contamination.
 
I have been on this forum now for almost a decade but this is the first time I am seeing sludged vehicle which was purchased new by a BITOG'r :-( The most logical explanation is that coolant contamination has caused this and there was not much that OP could have done to prevent it i.e. OCI's are not be blamed here.
 
If you own a GM V8 or V6 its a given that you will eventually have internal Dexcool leaks due to their low grade gaskets.Nobody wants to hear it,but if I owned one of the effected,I would be pro active and do head gaskets and manifold gaskets at 80K with a quality brand and avoid GMs own like the plague.Every vehicle has its known quirks (like Triton V8s spark plug issues),knowing that going in and accepting the costs involved is part of owning that particular vehicle.Toyotas sludge,Chrysler 2.7s sludge,Ford VV carb was a disaster,Odyessy and Sienna have tranny problems,MINIs have power steering fires,Subarus have head problems,old 90s Fords had alternator fires,later Fords have cruise control issues....the days of the "perfect" car without issues is a dream.
 
Originally Posted By: Vikas
I have been on this forum now for almost a decade but this is the first time I am seeing sludged vehicle which was purchased new by a BITOG'r :-( The most logical explanation is that coolant contamination has caused this and there was not much that OP could have done to prevent it i.e. OCI's are not be blamed here.


Good point Vikas, and an example of why we never, should say never, to engine cleaning products.
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If the engine is in fact well maintained, had a mechanical issue beyond the owners control here's a perfect example where an additive to clean an engine up might just come into play. Even if you're one of those all you'll ever need is a good oil kind of guy.
 
Originally Posted By: demarpaint
Originally Posted By: Vikas
I have been on this forum now for almost a decade but this is the first time I am seeing sludged vehicle which was purchased new by a BITOG'r :-( The most logical explanation is that coolant contamination has caused this and there was not much that OP could have done to prevent it i.e. OCI's are not be blamed here.


Good point Vikas, and an example of why we never, should say never, to engine cleaning products.
27.gif
If the engine is in fact well maintained, had a mechanical issue beyond the owners control here's a perfect example where an additive to clean an engine up might just come into play. Even if you're one of those all you'll ever need is a good oil kind of guy.

No - you are going at it all wrong. This is not an example of an "additive" coming into play - it is a case where a UOA have have shown the problem. Then one would FIX the problem (in this case the heads) instead of trying to put a band aide on a gaping wound.

Vikas is right - OCI's are not be blamed here.
 
It sounds like a bad intake manifold gasket - common on some GM engines.

When you reassembly the engine, you should spring for the Felpro intake gasket with the aluminum spacer. Most likely, it doesn't come in a head gasket set but well worth the additional $80.

I also recommend a very short OCI. No matter how careful you were pulling the heads, you got a significant amount of additional coolant in the oil.
 
this engine doesn't have intake gasket like people are thinking from 1999 and older 5.7's as this is not a 5.7, oil changes have nothing to do with this problem and coolant leaking in to the oil from where ever have every thing to do with the coolant/oil sludge mix. make sure the oil cooler, cylinder heads etc. are not pumping coolant in to the oil system.
 
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