2nd dead 3800 in 4 years.

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Jan 14, 2017
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I am one unlucky son of a gun. I just lost second engine in my Buick. The first one was my fault, the most recent one was just fate. But I have a quick couple of questions. The first is in regards to the lower intake gasket failing. I have coolant all in my oil, and the location of the breakage on the LIM gasket is around the ports on the LIM that are blocked off.

Second question, can failed piston rings really cause oil to make its way all the way up into the UIM? The lower ports were completely coated in an oil and carbon film while the upper just had a spots here and there on the runners. Was it a head gasket and piston rings or LIM gasket and piston rings?

I forgot to say, There's an exhaust flange leak that is causing the engine to run rich as can be. That's likely where the carbon in the LIM came from.

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That engine looks like the maintenance wasn’t kept up on it. The Buick 3800 is one of the most durable engines to date. Out of the 20?? or so I’ve had only one failed. A valve spring broke and trashed the cylinder. Occurred during a massive rainstorm with roads flooding. I suspect water got into the air intake and met a valve. I didn’t inspect it, just replaced the engine and moved on.

The other ones I had just needed the intake gaskets and manifold needed replacing on the Series II.

You could button it up with new gaskets and then do a leak down test if you want. Could be a waste of time if you have to tear it down for a rebuild though.
 
The core parts in the block and heads of these are really durable. It's premature to say the engine is shot because an intake gasket blew.

The intake would not need to be on to do a leakdown or compression test to assess mechanical condition.
 
Man!! I have a 2001 LeSabre and just did a complete upper and lower intake gasket job. Glad I did! Went with the a FelPro metal set. Love these engines, but they do have their failure points! Coolant elbows, DexCool, gaskets, etc. (Changed out the Dex for a conventional) Those pictures say it all. :(
 
Why not trying rolling new bearings in? Unless it spun there’s likely no damage to the journals
 
I loved my Series II L67 (supercharged). Once the lower intake gasket was replaced with the metal backed version it was bulletproof. IIRC there were some plastic coolant elbows that liked to fail, but mine never did.

The N/A Series II had the EGR stovepipe go through the upper intake which would cause gasket issues in that area.

Typical GM V6 gasket issues of the era and poor design / too aggressive bean counting. Dexcool gets a bad rap, but in reality it was cheap gasket materials. Once those problems were remedied assuming they were caught in time, this engine was tough as nails.

Head gasket issues were extremely uncommon on these engines as the block and heads were both iron. I doubt that had anything to do with your issue, or the piston rings for that matter.

How does an exhaust flange leak cause the engine to run rich? If the leak was so bad that the O2 sensor picked up false readings, I think it would be too loud to drive. One could just unplug the O2 sensor and run open loop if it was that bad, but something doesn't make sense here.
 
Well this probably sounds stupid as can be but I had to buy extra time with the engine. Can't find a a place to install that engine I ordered so I sent it back.

All I was able to do was install a new LIM gasket and change the oil. I ended up using 10w40 to raise the oil pressure. So far so good.
 
Didn't you think of that beforehand? And isn't the round trip shipping cost pretty large?
$300 Shipping. My mother said it was alright if I did it at her place but then I realized her landlord would be angry x1000 if she found out so i had it shipped back mid transit.
 
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The only thing GM can make worth a **** is a V8. Everything else is complete junk

The 3800 & 4.3L V6 are excellent engines, Intake gaskets are a known issue on both & you never install one without changing them.
Same thing as performing a leak down test & setting valve lash on a J-series Honda or Replacing the Bypass Hose & resealing the valley plate on a Toyota MZ engine before install.
 
The 3800 & 4.3L V6 are excellent engines, Intake gaskets are a known issue on both & you never install one without changing them.
Same thing as performing a leak down test & setting valve lash on a J-series Honda or Replacing the Bypass Hose & resealing the valley plate on a Toyota MZ engine before install.
Regardless I wouldn't own anything GM unless it's v-8. The japs excell at 4 and 6 cylinder engines
 
I lost one years ago to an intake gasket failure. Hydrolock the motor and threw a rod through the block
 
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