Blackstone Oil report portends doom for my 256k L67; Rebuild mine or ?

I don't know how to create a new topic, so I'm replying to this one, which is along similar lines:  I'm going to need another engine soon according to my newest Blackstone Laboratories oil analysis report which show metals in the oil have increased dramatically in the last 4000 miles.

Does anyone have recommendations for the  rebuilding my engine, buying a crate motor or buying a low mileage used engine?

Although I could rebuild the engine, that would take the most time, and I have little of that to spend.

If I bought a crate motor, does anyone have a recommended supplier?  My cursory search of the web seems to indicate that crate L67's aren't readily available.  The Series III (L36 ?)  appears available, but my understanding is that requires a new PCM as the '96 PCM can't support the Series III.  And the Series III PCM is not designed to support my '96 transaxle which is partially vacuum controlled.

Can anyone suggest a source of low mileage (and guaranteed) used L67's?

I just made a 1100 mile trip from Washington to Montana in this Riviera and it performed flawlessly at speeds up to 100 mph.  So, it was a surprise when the Blackstone report tells me I'm ready to spin a bearing (see below).

I had been hoping to make 300k on the engine, which is not to be, I guess.

Any advice or recommendations are welcomed.  Thanks in advance.

I would check your oil pressure and engine vacuum with good gauges.  The 3800 engine has excellent oil pressure.  My engine currently has 208K on it.  With 10W/30 oil, oil pressures with the engine fully warm (30 minutes on the highway) is about 63 psi at anything over 1000 RPM, and no less than 37 psi at an in gear idle.

If you have significant bearing wear, your pressures will be less than that.

I would also measure engine vacuum.  My engine maintains 20" of vacuum fully warm, at idle, in Park, and sometimes in gear.

How does the engine sound? Any knocking or tapping?

Hi Brutusk. Blackstone notes sodium/potasium (coolant). Do you know if this is from a leaking OE LIM gasket? If you're not sure, pulling the plugs and checking for residue is a way to confirm. Coolant in the oil contributes to wearing of bearings, rings, etc. When mine started showing high levels of coolant, I did oil changes every 2500 miles for over a year until I was finally able to address the LIM (during rebuild).

Larry70GS and AA,

There is no engine knocking or ticking or even squealing from any of the belt pulleys.  The engine seems to be running great.

As to the indications of coolant in the oil (sodium and potassium), I'm at a loss to understand what the source could be.  I changed out the LIM gasket with the improved metal version after I saw the oil report from the 3/7/2016 sample.  Those values (3/7/2016, Sodium =  121, Potassium = 153) improved immediately after the LIM gasket replacement.  But I note that they never reached the "Universal Average" values.  

The LIM has a coolant passage as I recall, and I changed out the "O" ring seal between the LIM and the Supercharger when I changed the gasket.  Does the throttle body have a coolant passage too (I don't recall)?

I wouldn't think it was the head gaskets, and since I'm away from home on a trip, I don't have access to my leak down tester, vacuum gauge, compression gauge, etc...

Any idea where the coolant leak could be coming from?

Incidentally, I found some ethanol-free premium 92 octane when I filled up south of Cour de laine, Idaho. I drove from there to Butte, Montana with highway construction where my speed varied from 35 mph to 85 mph and achieved 27.7 mpg over 322.7 miles. With ethanol polluted premium I bought in Washington I achieved 24.4 mpg without about the same change in elevation over 364.1 miles. The ethanol-free fuel was less expensive too. I always used to get about 27-28 mpg when I first got the car in 2005 and I couldn't understand why my mileage went down to 23-24 mpg on the highway a few years later. Yeah, ethanol doesn't contain the same energy as gasoline. I'm convinced now, that 10% ethanol was the difference.

If you've already upgraded the LIM gasket, I'd think the only way coolant could get into the oil would be the head gasket. Yes there is a coolant passage through the TB, but I've never heard of a leak from there that would cause what you're seeing. The only way I know of to confirm coolant is getting into the bores (and oil) is to pull the plugs and inspect for residue.

If the engine is running fine and your plugs look clean, I'd change the oil in another 3k miles and send in another sample. If the new sample is clean and Blackstone can't explain why the previous one was such an outlier, I'd assume they made a mistake, and you might discuss a refund for that analysis with them.

Looking over the results, many of the numbers are consistent with your previous results, so seeing the spikes where they are does seem to indicate the problem they've identified. There's a good chance you'll see more of the same on your next analysis, in which case it's almost certain your engine is on borrowed time. But as we know a 3800 might run for a LONG time in less then ideal condition!

AA,

Now it comes to mind that I have been seeing white "smoke" coming from the tailpipes after starting the car even when it is fairly warm when you wouldn't expect to see the water vapor from combustion, as you might in a "cold" environment.  I had been thinking that it was a little oil that had seeped past the valve seals in a high mileage engine.

In my 77 Datsun B210 there would be large clouds of white "smoke" wafting from the tailpipe when I had a blown head gasket (warped head).  So much coolant leaked into a cylinder that one piston couldn't pass Top dead center due to hydraulic lockup when I tried to start it one time.

So, as unlikely as it used to seem to me, a bad head gasket is likely the culprit on the Riviera, since it would explain the white "smoke" coming from the tailpipes.

I'll replace the head gaskets then do another oil analysis to see if the coolant and metals values improve.

Thanks

I'm sure it's happened, but I can't remember a head gasket reported going bad on a SC 3800 engine. It's rare. My comments were based on process of elimination - how can coolant seep into the oil supply? Your theory about the valve seals is possible; I hadn't considered it. Still the white exhaust is concerning if it continues after the engine has warmed up. Might mean a very small head gasket leak. Is the engine running any warmer than usual?

AA wrote:

. Is the engine running any warmer than usual?

No, and the coolant level in the overflow tank has held constant for several years.

brutusk1 wrote:

AA,

Now it comes to mind that I have been seeing white "smoke" coming from the tailpipes after starting the car even when it is fairly warm when you wouldn't expect to see the water vapor from combustion, as you might in a "cold" environment.  I had been thinking that it was a little oil that had seeped past the valve seals in a high mileage engine.

In my 77 Datsun B210 there would be large clouds of white "smoke" wafting from the tailpipe when I had a blown head gasket (warped head).  So much coolant leaked into a cylinder that one piston couldn't pass Top dead center due to hydraulic lockup when I tried to start it one time.

So, as unlikely as it used to seem to me, a bad head gasket is likely the culprit on the Riviera, since it would explain the white "smoke" coming from the tailpipes.

I'll replace the head gaskets then do another oil analysis to see if the coolant and metals values improve.

Thanks

Do you have or can you get a leakdown & compression test kit? If not, Summit Racing has starting at about $50. For about $120 you can get Summit's leakdown/compression test kit.

In 22 years of driving the Riv I can't think of one head gasket failure - however - it's also the kind of thing that might creep up on someone after a serious overheat. The other thing is there are more places than the head for a leak. Leak where coolant passes the intake manifold for instance.

Thinking out loud, I would do the following:

- do that leakdown and compression testing to rule out engine problems.
- do you think you might have a bunch of water in the tank? You might put a couple bottles of HEET (dry gas) in your tank and see if you can burn off that water.
- TB gaskets are cheap and plentiful, might as well get one and plan on changing it. If there is a leak it could very easily spray into the intake.
- if you are using DexCool and you have not changed it every 100,000 miles or so, my guess is your LIM gasket is compromised by the coolant pass-thrus.

So... if you pass the compression & leakdown tests then you know you're in for an afternoon of regasketing the top end.

If you don't pass those tests, you're in for a good used engine, or a head gasket... maybe.

There is one other thing.

Don't forget that GM used to have their dealers put stop-leak tabs in the 3800 engine as *part of routine maintenance* with a coolant change - I still do that myself because the one time I didn't (at the coolant change just after the GM no-stop-leak guidance) my coolant slowly vanished. I was down not quite a quart in a couple months. First thing I did was put the tabs in, the vanishing stopped. I might have posted comments on this site about that at that time, along the lines of exactly what was GM thinking (or smoking) that by changing their guidance they could all of a sudden ignore block porosities and they would go away? SMH.

Maybe you just need some stop leak tabs.

I'll give you a flaming hint: ACDelco still *sells* them - see https://www.amazon.com/ACDelco-10-108/dp/B0026JK8C8.

We'll see.

Albertj

Albertj,

I remember you telling me about the "stop (leak) tabs" when I had a coolant leak that I couldn't figure out. I used them, and they helped. But the problem turned out to be a crack in my "new" AC Delco radiator. I changed out that radiator and haven't had a problem with coolant levels since (probably three or four years).

I have a leak down tester and compression tester at home, about 1200 miles away. At this point, I just need to make sure I can make it home to do any required repairs.

I got the Blackstone report once I'd reached my destination in Montana. I thought the "metal" numbers would have improved since the last report, not gotten dramatically worse.

One thing I thought about: I have been working remotely since March 2020, when the Covid-19 panic began. So my trips in the Riv have often not even reached normal operating temperature. I would expect the engine wear to be greater under those conditions.

Thanks.

brutusk1 wrote:

Albertj,

I remember you telling me about the "stop (leak) tabs" when I had a coolant leak that I couldn't figure out.  I used them, and they helped.  But the problem turned out to be a crack in my "new" AC Delco radiator.  I changed out that radiator and haven't had a problem with coolant levels since (probably three or four years).

I have a leak down tester and compression tester at home, about 1200 miles away.  At this point,  I just need to make sure I can make it home to do any required repairs.

I got the Blackstone report once I'd reached my destination in Montana.  I thought the "metal" numbers would have improved since the last report, not gotten dramatically worse.

One thing I thought about: I have been working remotely since March 2020, when the Covid-19 panic began.  So my trips in the Riv have often not even reached normal operating temperature.  I would expect the engine wear to be greater under those conditions.

Thanks.

Thanks for the feedback.

If your coolant levels are no kidding not moving at all but you're still getting water vapor out the back end, I'd suspect a combination fo short trips and wet gas.

Albertj

If you are not losing coolant, then there is no head gasket or intake leak. The catalytic converter makes water vapor all by itself. Short trip driving builds up water in your exhaust system.

LARRY70GS wrote:

If you are not losing coolant, then there is no head gasket or intake leak.  The catalytic converter makes water vapor all by itself.  Short trip driving builds up water in your exhaust system.

That's what's curious - the coolant level isn't going down, so why are the sodium and potassium levels in the oil so excessive?  Short trips will generate water condensation in the exhaust and crankcase that don't get boiled off, but that condensate wouldn't have sodium or potassium in it.

Thinking aloud:

Potassium levels are about 1/3 of those before I replaced the LIM gasket.

I'm thinking now, that before LIM gasket replacement, the coolant loss I was seeing was mostly due to the "new" AC Delco radiator crack leak.  I think that radiator was cracked and leaking from the moment that I installed it. But I attributed the coolant loss to the old composite LIM gasket. So the old LIM gasket wasn't leaking all that much compared to the radiator, and by itself wouldn't have created a noticeable coolant loss.

So I think I do have a coolant leak which is about 1/3 as much as the old LIM gasket was seeping, which by itself wouldn't have been noticeable.

I think it's time to order some "Stop (leak) Tabs" again.

I've done a search of the site to see how people have installed an oil pressure gauge, but didn't find anything useful.

For the short term and ease of installation for the moment, I'm thinking a mechanical gauge mounted in the engine compartment.  Long term, I'd like to install it in an A-pillar pod along with an aeroforce scan gauge.  Does, anyone have any advice to give on that subject?  I'm not sure how to make an electric gauge interface with the stock oil pressure sending unit.

Thanks.

I eliminated the ashtray and installed an Autometer mechanical oil pressure, and Boost gauge.

To add the oil pressure gauge, I used a simple brass fitting.  I did this many years ago, if I remember correctly, the threaded opening in the block is 1/4 NPT.  I used a tee and installed the stock sender, and the pressure copper line using an 1/4 to 1/8 NPT reducer.

https://www.amazon.com/Joyway-Fitting-Barstock-Street-Female/dp/B07FK8GHPP?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A1AOZNO078ITBS

https://www.amazon.com/Megairon-Reducing-Reducer-Bushing-Stainless/dp/B071V7P13X

My engine has 208,000 miles on it. I use Synthetic 10W/30 oil. When I first start the engine, the pressure is about 70 psi when driving the car. Fully warm on the highway, a bit over 60 psi at 1500 RPM. At an in gear idle, it has never gone below about 37 psi.

That should give you a baseline to compare. Any bearing wear will reduce those pressures.

Larry70GS,

I like your installation. Unobtrusive most of time, but readily visible when you're curious.

I will look into doing the same. Certainly easier than custom fabbing an A-pillar cover with built-in pods and trying to find stock looking ruby red fabric to cover it.

Thanks!

brutusk1 wrote:

That's what's curious - the coolant level isn't going down, so why are the sodium and potassium levels in the oil so excessive?

For what it's worth, your potassium/sodium numbers aren't much different from mine with the LIM gasket leak (mine were Pot: 31, Sod: 56). I didn't notice coolant any level drop over several months. Could have been a small change in the reserve tank, but nothing notable over ~3k miles.

Good tip from Larry on the oil press gauge. I added one to my GTO (along with oil temp) and wish I'd done the same with my Riv. Very useful info on a higher mileage vehicle.