LS1 Sludge

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Originally Posted By: oldmaninsc
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.
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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.

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.


OK so a UOA shows coolant in the oil, and you fix the problem. Also note I said additive to clean the sludge not fix the bad head, [I mentioned mechanical problem as well] you've taken my point out of context. Are you going to tear the entire engine down to clean out the sludge after you fix the heads? A lot of extra work, and the potential for more problems. Especially when something like Kreen would do a good job of cleaning up whatever you didn't manually get after you pulled the heads.

BTW a pressure tester would have showed the coolant leak as well, but that's another topic.

Edit to add: I'm not the kind of guy who'd leave bad heads on an engine, and toss a band-aid at it. I'd fix it, clean what I could, and reach for something to do some additional cleaning. If the engine was a total mess inside I'd consider diving in a little deeper. I've seen enough of these problems to know just how far to dig in. I wouldn't rip into any more than I had to though. One could also say the engine really wasn't well maintained if a coolant leak was allowed to sludge up the engine, but I'd rather not go there. Not everyone totally on top of auto care.
 
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In addition to here, find the ls1 forums. Can't be the first time this has ever happened. Second, if you are losing that much coolant into the engine, the bearings would have been toast a long time ago. Bad IM gaskets were part of the '97-'03 3.1. 3.4 and 3.8 engine line-up. I would try a compression test before I start tearing anything else down.
 
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.


This was his first post.... but yes coolant is to blame.
 
Originally Posted By: demarpaint
Originally Posted By: oldmaninsc
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.


OK so a UOA shows coolant in the oil, and you fix the problem. Also note I said additive to clean the sludge not fix the bad head, [I mentioned mechanical problem as well] you've taken my point out of context. Are you going to tear the entire engine down to clean out the sludge after you fix the heads? A lot of extra work, and the potential for more problems. Especially when something like Kreen would do a good job of cleaning up whatever you didn't manually get after you pulled the heads.

BTW a pressure tester would have showed the coolant leak as well, but that's another topic.

Edit to add: I'm not the kind of guy who'd leave bad heads on an engine, and toss a band-aid at it. I'd fix it, clean what I could, and reach for something to do some additional cleaning. If the engine was a total mess inside I'd consider diving in a little deeper. I've seen enough of these problems to know just how far to dig in. I wouldn't rip into any more than I had to though. One could also say the engine really wasn't well maintained if a coolant leak was allowed to sludge up the engine, but I'd rather not go there. Not everyone totally on top of auto care.


If I misunderstood your point I apologize. Isn't the first two photos of the oil pan? It's hard to tell from the photos.
It's just you are so quick to recommend your "miracle in a bottle" solutions. All the short OCI in the world wouldn't have solved this problem.
I've rebuilt more engines in my life time than I care to remember. But the one thing I would never do is a half *** job. If people don't have the funds to fix it right, I wouldn't do it at all.
For the record - I'm not saying anything bad about the o/p here - it's his time and money and I can certainly understand his situation.
 
Originally Posted By: Gabe
It sounds like a bad intake manifold gasket - common on some GM engines.


Gen III and VI engines have dry intake manifolds, no coolant cross over.

That being said there definitely coolant getting in the oil somewhere. On LS engines that's pretty hard unless it's a failed head gasket. Front cover or cracked head it would seem..
 
Originally Posted By: LeakySeals
From your owners manual: "Your vehicle’s engine requires a special oil meeting GM Standard GM4718M". Were you were running one of the registered oils in the GM4718M High Performance oil Specifications ? Think Mobil 1 is listed on your filler cap.


What does that have to do with the problem at hand?
 
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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.


This is most certainly your problem and source of your sludge as others have mentioned. It wouldn't matter if you were running Unicorn Pee for oil, it still would have sludged up due to the coolant ingestion.

Get some UV dye and a blacklight and try and find the leak.

OR

Go all-out, put some better heads on it (AFR's perhaps) and in the process, you'll be replacing your headgaskets and the like, removing two potential problem points (cracked heads and a nuked head gasket).

That way, you at least end up with a power upgrade after all the grief.
smile.gif
 
Originally Posted By: The_Eric
Originally Posted By: LeakySeals
From your owners manual: "Your vehicle’s engine requires a special oil meeting GM Standard GM4718M". Were you were running one of the registered oils in the GM4718M High Performance oil Specifications ? Think Mobil 1 is listed on your filler cap.


What does that have to do with the problem at hand?

Oil that turned to an awful sludge because of (consensus) coolant. What oil was it? Curious.
 
Originally Posted By: oldmaninsc


If I misunderstood your point I apologize. Isn't the first two photos of the oil pan? It's hard to tell from the photos.
It's just you are so quick to recommend your "miracle in a bottle" solutions. All the short OCI in the world wouldn't have solved this problem.
I've rebuilt more engines in my life time than I care to remember. But the one thing I would never do is a half *** job. If people don't have the funds to fix it right, I wouldn't do it at all.
For the record - I'm not saying anything bad about the o/p here - it's his time and money and I can certainly understand his situation.


No need to apologize. I wasn't exactly crystal clear. After pulling the heads and doing a clean up and repair, dropping the pan, if its easy would be a good idea and do some additional cleaning. It all depends on skill level and desire. This IMO is a good candidate for a cleaning product especially if the OP isn't into ripping into the engine any more than he has or wants to.
 
Originally Posted By: LeakySeals
LOL skipped right over "mobile", thanks.


Of course it's still mobile. A little coolant intrusion doesn't instantly destroy a street engine. Come on man! Get with it man!
 
This is very sad to see. I bought a 2004 S2000 that I hope to keep and have fun with until I can't drive anymore. I knew when I bought it I would probably never be able to afford or justify buying another new sports car. I suspect that you have the same intentions and wanted to maintain it well.

I suspect that coolant ingress is a contributor to your problem. Did your engine ever overheat? Is the water pump or thermostat manifold leaking? Does it have a PCV system that may have gotten clogged up? Did you ever do used oil analysis? If so, could you tell us what contaminants were identified?

Good luck, and I hope you find a solution soon. And welcome to BITOG!
 
I believe the steps you have taken are appropriate. If the problem was head gaskets or a warped head, it should be resolved. If it's a one in a million problem like the block cracking or opening up some other passage for the coolant to get into the oil, you'll find out soon enough.

If you find you can't get the price you want for an 8 year old 'vette with that many miles, an engine swap might be in order. There is no shortage of builders. If you could live with only 300 HP, you could even go with a new GM 5.3 dressed crate motor for under 3K, and see if you can squeeze 35 MPG out of that daily driver.
 
Man great forum, very thoughtful replies. I've been on the Corvette forums with both the coolant leak, and with the sludge pics, but I've seen better and more thoughtful replies here in 24 hours than i did there in months.

i was out of pocket tailgating and watching an unbelievable football game yesterday, so i'll try to answer some questions and pose a couple more (sorry Ga Tech fans if there are any out there, you really did probably deserve to win that one):

I have always used mobile 1, and changed at the interval "recommended" by the engine. There is an oil change algorithm built in to the engine computer which counts down "% oil life remaining", and starts giving warnings at 5%. I think it does so based on driving conditions, and when I do a lot of highway driving it gives a slightly longer interval - alwasy in the 10k to 11k range. I have always changed before it hits zero, and I have always used Mobile 1 10W-30 or 5W-30, as specified in the owners manual.

When the coolant leak was ongoing, and I must emphasize it was a very slow consumption, not really a "leak", I put a pressure pump with gauge attached at the radiator overflow tank with a specially adapted cap, pumped to 16 psi, and waited for a leak to show up. Overnight. NO pressure drop, no leak. I pulled the plugs and pressure tested the cylinders. All in spec. I did not find any UV fluorescent products at Advance, so I didn't do that. There was absolutely no time at which the engine temp read over about 220 F and idiot lights never came on...

With regards to the heads themselves, they have been machined by a very experienced machinist. When I first brought them to his shop and told the story, he immediately mentioned the intake manifold, then the valve guides. He cleaned up the heads and freshened up all the mating surfaces (by this I mean he tested for flatness and then machined on an end ill to 0.001", I believe), installed new valve seals and springs and was unable to detect any flaws.

I could dig deeper, but to what end? If there is a micro-crack in the block somewhere, am I going to find it? and if I do, am I going to weld it or replace the block, putting on all of these old parts? I thought that any substantial crack in the block always resulted in more or less a catastrophic failure, or at least a much more disabling situation than this very indolent quart per 1500-2000 mile coolant consumption. I think that if I identified such an engine block issue, I'd just buy a crate engine and be done with it. Money isn't really a huge issue, rather time and experience, skill level.

I think I will forge ahead with my reassembly over the next couple of weeks. I think the head gaskets (I bought Felpro)and oil pump (I got a replacement) are about 95% of the most likely to be the culprit here. I like the idea of Kreen or Auto-rx, and a 1000 mile interval change? Can someone tell me the difference between these products?

Finally, thanks for not jumping all over me here. I am a newb in many respects, but I have spent a lot of time trying to fix this thing, and have simply laid it out for all to see and be critical of. While my experience level with engines isn't huge, I am 62 years old, and had my first car, a 1958 MGA 1500 torn apart and laid out in my parents' garage floor twice, when I was in high school! I have built and flown an airplane, I run a 42 foot sailing yacht and care for her marine diesel, and generally like to dig in and fix my own stuff when it breaks. You've really been quite reasonable and helpful, for the most part, and again, thanks.

DT MacMillan
Blacksburg, VA
 
When M1 becomes contaminated with Dexcool does it change color? What were your oil pressure readings? Should be around 28 at idle with a hot engine.The reason I ask is in my experience of restoring literally dozens of terribly abused air-cooled VW's,this looks very similar to the black tar like appearance of the burned up oil I would routinely find after splitting the engine cases that obviously had not been coolant contaminated. Seems like moisture contaminated lube usually takes on a brown or whitish appearance if memory serves. Less than 3 qt. oil sump and no filter in these old Type 1 motors.. This maybe a dumb statement,but I assume you are going to physically clean the sludge out of the pan BEFORE reinstalling it! I think your condition might have been reduced by ignoring the OLM and changing oil at 12 months or 6K in this hot running,high compression motor. I have owned 3 C5's and own a C6 LS3 now. I run German Castrol 0w30 (known as GC on this board) and my oil pressure is 30PSI on a 100 degree day at idle. I bought a new Benz in 99 and it too had an OLM which indicated that I could go as long as 12k OCI - I was not going for it and continued with my 5K intervals. My neighbor and very close friend who was the service director of our large MB dealership informed me that a few years later these were coming regularly in with fried motors due to the extended oci's. I think there may have been a recall as well. Never had a problem with mine. By the way,I am 63 and had an MGA back in the day when you could pick one up for $500 in good shape! I remember those old door cables on the inside....cold in winter,hot in summer....
 
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Originally Posted By: hal2626
When M1 becomes contaminated with Dexcool does it change color? What were your oil pressure readings? Should be around 28 at idle with a hot engine.The reason I ask is in my experience of restoring literally dozens of terribly abused air-cooled VW's,this looks very similar to the black tar like appearance of the burned up oil I would routinely find after splitting the engine cases that obviously had not been coolant contaminated. Seems like moisture contaminated lube usually takes on a brown or whitish appearance if memory serves. Less than 3 qt. oil sump and no filter in these old Type 1 motors.. This maybe a dumb statement,but I assume you are going to physically clean the sludge out of the pan BEFORE reinstalling it! I think your condition might have been reduced by ignoring the OLM and changing oil at 12 months or 6K in this hot running,high compression motor. I have owned 3 C5's and own a C6 LS3 now. I run German Castrol 0w30 (known as GC on this board) and my oil pressure is 30PSI on a 100 degree day at idle. I bought a new Benz in 99 and it too had an OLM which indicated that I could go as long as 12k OCI - I was not going for it and continued with my 5K intervals. My neighbor and very close friend who was the service director of our large MB dealership informed me that a few years later these were coming regularly in with fried motors due to the extended oci's. I think there may have been a recall as well. Never had a problem with mine. By the way,I am 63 and had an MGA back in the day when you could pick one up for $500 in good shape! I remember those old door cables on the inside....cold in winter,hot in summer....


Unfortunately the oil only turns brown if you have copious coolant ingress. This can lead up to the "milkshake" appearance as well.

With the coolant loss he had, it would have been easy for the engine to boil off the coolant in the oil, getting rid of the moisture, but of course the oil is still contaminated with the alcohol and additives, thinning it, reducing its effectiveness, overwhelming its additive package and preventing it from keeping the engine clean.

And unfortunately the OLM cannot account for coolant ingress. So while it is telling him to run the oil to 11K miles, the oil has been compromised, its add-pack depleted, and it NEEDS to be changed out.

Likely, had the oil been changed at 5K increments, regardless of use, even with the coolant consumption, it would have stayed clean because the oil wouldn't have been destroyed yet.

I would have been very interested in a UOA on the oil that came out, as it likely would have pointed a finger here.
 
My oil pressure reads just below 30 when warmed up - higher of course when cold. I too wondered about the difference in color from the lighter brown in the images. Mine was definitely very dark brown, or even black. I cleaned the sludge - came away after scooping out the bulk, then with soaking in carb cleaner, generous amounts of brake parts cleaner, and MEK. It was no fun, but the oil pan cover looks like a new casting now.

I am not sure, of course, whether the solids represent components of the antifreeze(I favor this) or the result of breakdown of components in the oil. Thgere has been no gross overheating, but of course there could be some localized hot spots with all that gunk floating around.

I, too wish I had caught some of the oil in a clean container for analysis, in retrospect.

Still wondering whether to go with auto-rx vs kreen, if there are any opinions out there.
 
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