Thread: Lower End appears to have seized.. now what to do?

I have a 2001 Grand Prix GT L36 with 158k. Recently, cruising at 60mph the motor just quit, no major noise, poor performance or indication of trouble beforehand, acted just like you had turned off the key. Could not get it to crank or turn over, battery was fine, no charging system issues. Towed it to my mechanic and it appears the motor has seized (breaker bar cannot turn the crank). Now earlier at 133k it burned a valve, since the body / interior were very clean and the trans was rebuilt at 110k, I went ahead and replaced the rear head and had a valve job on the other one. My experience with other high mileage 3.8L and 3.1L based GM cars lead me to think their lower ends were pretty reliable.

Anyway I do need to verify the mechanics findings but my first thought was to find a shortblock and transfer my fairly new upper end. Most of the other postings here appear to be against going the rebuild route. Thoughts?

Originally Posted by BillBoost37

Give this a read. http://www.grandprixforums.net/97-03...ure-60667.html

That's my gut instinct as well.

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Thanks for the info, I searched the forums first for related topics and the hydrolock issues was certainly one thing to check, but this post nicely outlines the technical details.

BTW, where is the best place to get a shop manual for this model?

Originally Posted by BillBoost37

I bought mine from ebay. Went the full boat by getting the GM ESI dvd. It's everything anyone could ever want. If paper is more your thing, you should also be able to find the full GM manuals for just your car on ebay as well by searching for the year/model and Service manual. It's usually 2-3 books

UPDATE: Finally the mechanic had the time to look at this, pulled the plugs and it is not a hydrolock problem. He says that even with the plugs out the crank will not turn in either direction with a breaker bar. I plan to dig into it further myself. Plan is to get a better idea of what is the issue is before pulling the motor.

So what are the other possibilities, albeit remote, besides a crank issue, spun main bearing, main bearing cap failure? Looking at what is attached to the crank you have

Timing chain
Flywheel
Rods

BTW how difficult is to remove the timing chain cover or drop the oil pan on this model? Thanks

You have to remove the nuts on the motor mount, jack the motor up and remove the u-bracket from the engine and then you can drop the pan. Also remove the oil level sensor from the side of the pan so it doesn't catch on the pickup tube.

Not sure on the front cover.

Did you have the upper intake manifold checked? For awhile the 3.8 had a problem with the stovepipe for the EGR and the plastic intake. Basically it would over time cause the plastic to turn to mush and finally let coolant into the intake and eventually enter the oil pan and size the bearings.

Originally Posted by blackspike2710

X2 If it is seized then it's seized and there is nothing you could do to make it worth fixing.

Yes, hard to argue with that logic Well finding a good used engine is a task in itself especially out here on the West Coast. Any tips on locating one?

car-part.com

Originally Posted by BillBoost37

Since you are NA.. lookup say 2007 NA GP engines. Here they are very cheap with low miles. Put on your UIM and fuel rails and off you go.

As far as locked up. Here's my take. You can pull the engine and trans together then pull the trans off and fight the engine on the hoist to unlock it to get your converter off. (engine has to turn to get converter) Or for $100 you simply get a new converter, fresh engine and poof.. you're back in action.

@ BillBoost37 Thanks, searching for a used L26 yielded a better selection. Looks like these models used them

• 2004–2008 Pontiac Grand Prix
• 2005–2009 Buick LaCrosse
• 2006–2008 Buick Lucerne

Now you mentioned in a previous thread
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L26'ing requires a TB adapter, different intake and a pcv hose where you likely drill/tap the TB. Not horrible, but more than some want to do.
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So are there modifications to deal with using the original UIM to circumvent ? Thanks again

Thanks for the info. Good stuff. Searching for 3800s in 2007 I see there is a "2" and a "4" for the 8th digit on the VIN for these motors, what is the difference
3.8L, (VIN 2, 6-231)
3.8L, (VIN 4, 6-231)

Thanks