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SAD DAY for my Grand Prix

dbextreme

dbextreme

New member
I am not sure exactly what I did wrong, but I just hydro locked my 3800 NA motor.....

I went to change the lower intake manifold gaskets and ended up with worse issues.. I bolted everything back together, started the car and backed it out of the garage to fill it up with water and check for leaks. Car was running fine, no service engine light, no miss, reved nice, I was excited.. I pulled the thermostat cap off, filled up the radiator and block, buttoned it up, started it up to let it warm up and burp it. The car ran fine for about 20 seconds then it started missing and shaking. Before I could shut the car off I hear a loud BANG from the front of the motor and now the motor is locked up. I can back the crank up a quarter turn or so then it will spin freely for a few then lockes up again.. I assume a broken rod catching every now and then. Guess my options are open now. Rebuild my motor, find a L67 with trans, scrap it for a Honda (ha this will never happen, just trying to find something to make me laugh.. LOL)... Not feeling really good on my ability to change intake gaskets at the moment because I am puzzled as to what happened.. I mean there were some misc orings and such, some used some not.. Just at a loss..
 


even if he did that, it wouldnt just cause the motor to pop that fast.

maybe the gaskets were installed wrong?

did you drain the oil after doing the job?

It could be many things.
 
I did not replace the oil. I was going to run the motor for a bit to "flush" any junk out then change the oil. There was NO water in the oil before the change, it was not milky or anything. As for the coolant, after I backed the car out of the garage I shut it off. I removed the thermostat cap and pulled the thermostat out, filled the radiator up until it poured out of the the hole where the thermostat was. I stopped, put the thermostat back in and cap back on. I started the car and begin filling up the radiator when it all happened. I don't see how the gaskets went on wrong either, all the bold holes lined up and the nipples on the back of the gaskets were seated in the holes in the head as they should be... I'm at a loss...
 


Yep, put the RTV on the corners twice. Once before I put the pieces down and once again after. I agree with the oil change, but there was no water in the oil, other than the amount that might have dripped in from pulling the lower intake off which was pretty well dry inside. The lifter area had minimal water spots which I wiped up. I will take the UIM off in the morning to see what it looks like and the lower as well again for fun I guess.
 
I don't know if starting it up the short time I did without coolant in the system did anything to it, it wasn't running long enough to get the exhaust manifolds warm.... I know for sure I am not getting a honda.. LOL I'll post pics tomorrow when I get the top end apart.
 
I know someone that had something similar happen to them. Turns out they dropped a washer/bolt into the wrong place and never noticed. The motor started, ran for a bit, and then went BANG, and it was dead.

Oh, and it was a Honda.

It can happen to anyone, and on any car. Honda or Pontiac. I have both by the way. I've owned several Pointiacs and several Hondas.

I also just redid my UIM and LIM gaskets. All success here, except the cat died at the same time, and I'm just turning it into a race pipe with a u-bend delete... for now.
 
I know this is gonna sound like a dumb question but did you let the silicone dry before you started the car? Idk if that would have made your engine go bang though.
 


Hi everyone. :th_lipssealed2:

DB, I don't believe it's something you did. I think it's one thing you didn't do. The NA motor is known for it's plastic upper (before 2004) developing a hole in the hole where the EGR passes through it. That crack/hole has a coolant port on the other side. A little bit after you put the cap on, pressure builds and pushes through that crack/hole and fills the lower intake manifold, then into the cylinders it goes. The UIM should be replaced or the coolant ports plugged when you do LIM gaskets.

As for draining the oil...unless you dumped coolant in, it shouldn't be an issue and one of our motors shouldn't lock up from water in the oil, it should start to knock after being driven. Won't cause a lock up w/o hearing it coming.

As for RTV not curing.. sorry, no. I put it on things like T stat gaskets and fill in under a minute. That RTV you use on a LIM gasket in the corner is to seal oil from seeping out the end of the block. Nothing to do with locking up.

Not putting enough coolant in before starting it up. Our motors will start to clank and then stall if they get too warm and are idling. Then you can fill them and fire right back up typically w/o any problems at all.

Not sealing the LIM bolts, will result in seepage onto the LIM in the valley's where the bolts sit over time. No chance that would cause this issue.

Dropping something into the motor. You'd usually hear it pinging around in a cylinder. Not typically an item that will cause a lock up.

Pull the UIM off. If the LIM is full of coolant/water, that's what happened. There is a chance the motor is ok. If you pull the UIM and the LIM is full of coolant. Go buy some JB Weld and brake cleaner. Clean the coolant passages of the UIM and fill them with JB weld. Pull the plugs and let the coolant drain/dry. Blow out the cylinders with air if you can. There will be a lot of water in them. Crank the motor over as well. Put it back together with the plugged coolant ports. Get it running. I say get..because you'll have to keep drying the plugs and work to get it started.

Then you can hope the bearing(s) didn't take that hit too harshly. If it didn't...enjoy your car and off ya go. If it got hurt..you'll know in about 50-500 miles and you'll need a motor.
 
BillBoost37 said:
Hi everyone. :th_lipssealed2:

DB, I don't believe it's something you did. I think it's one thing you didn't do. The NA motor is known for it's plastic upper (before 2004) developing a hole in the hole where the EGR passes through it. That crack/hole has a coolant port on the other side. A little bit after you put the cap on, pressure builds and pushes through that crack/hole and fills the lower intake manifold, then into the cylinders it goes. The UIM should be replaced or the coolant ports plugged when you do LIM gaskets.

As for draining the oil...unless you dumped coolant in, it shouldn't be an issue and one of our motors shouldn't lock up from water in the oil, it should start to knock after being driven. Won't cause a lock up w/o hearing it coming.

As for RTV not curing.. sorry, no. I put it on things like T stat gaskets and fill in under a minute. That RTV you use on a LIM gasket in the corner is to seal oil from seeping out the end of the block. Nothing to do with locking up.

Not putting enough coolant in before starting it up. Our motors will start to clank and then stall if they get too warm and are idling. Then you can fill them and fire right back up typically w/o any problems at all.

Not sealing the LIM bolts, will result in seepage onto the LIM in the valley's where the bolts sit over time. No chance that would cause this issue.

Dropping something into the motor. You'd usually hear it pinging around in a cylinder. Not typically an item that will cause a lock up.

Pull the UIM off. If the LIM is full of coolant/water, that's what happened. There is a chance the motor is ok. If you pull the UIM and the LIM is full of coolant. Go buy some JB Weld and brake cleaner. Clean the coolant passages of the UIM and fill them with JB weld. Pull the plugs and let the coolant drain/dry. Blow out the cylinders with air if you can. There will be a lot of water in them. Crank the motor over as well. Put it back together with the plugged coolant ports. Get it running. I say get..because you'll have to keep drying the plugs and work to get it started.

Then you can hope the bearing(s) didn't take that hit too harshly. If it didn't...enjoy your car and off ya go. If it got hurt..you'll know in about 50-500 miles and you'll need a motor.
Click to expand...

Bill's analysis is SPOT on. This is exactly what happened to my Bonneville. I thought my LIM gasket's were leaking and it turned out to be a hole in the EGR port on my UIM. I didn't know this and replaced the LIM gaskets only to have the engine hydro lock after I put it back together. I ended up breaking the starter from trying to start it while it was hydrolocked. I can almost guarantee your UIM is shot and is dumping coolant into your engine. Do exactly what bill said. If you don't get all of the coolant out of the engine and oil, plan on getting a new motor. Mine had too much coolant in the engine for too long and washed the lower rear main bearing out. Once this happens, the motor is shot.

Good luck !
 
I have my fingers crossed, sounds legtit to me just I am concerned about the loud "clunk" I heard before it seized... I have not fooled with it today at all.. I did check the throttle body for fluid running out which there was none and the oil is still spotless, nothing other than oil on the dipstick.. When I pull the motor apart I'll post pics.

Bill's you mentioning JB weld, should I put it on the upper or lower manifold? I am assuming you are talking about the two holes behind the EGR pipe sticking up? Who designed this, really? LOL

Thanks
 
yeah exact thing happened to me. i changed the lim gaskets, started the car, it stalled and then locked. changed the uim next day and whadda ya know...it runs fine. whenever you replace the lim gaskets on an na when close to or over 100k...replace the uim no matter what, cuz like bill said, the pressure makes that thing go boom. and youll be surprised when you take it off cuz im betting you wont see a hole in the egr tunnel..but the hole is there. itll probably be pin hole size, but with the vac pressure in the motor, its enough to suck it all out and dump it in the cylinders. now when you tear it down again, your going to have to get all the coolant out of the cylinders..

1.) pull plugs and wires out completely.
2.) unplug fuel inector connectors, you dont want them dumping fuel in.
3.) crank the car a few times with the plugs out and the injectors unplugged. this will spit most of the coolant out on its own.
4.) get a socket big enough to fit the crank pulley bolt, should be a 19mm i think. take an air/blow gun with a 1/4" hose attached to the end, and stick it in the plug holes, turn the crank manually till the valves are closed. spray air into the plug holes so it will shoot the coolant back out of the holes more. do this to all the cylinders.
5.) replace uim when you know all the coolant/ or when like nothing is spraying out.
6.) change the oil. fill the coolant and start it
 


I will do this!!! I'll run a compression test to after the coolant gets removed to make sure no rods got bent in the process..
 
trust me on this one too, take your time and youll know when the valves are closed on each cylinder, itll blow straight back out the hole. if the valves are still open, youll hear the air rushing through the engine. and make sure you dont have the hose in the hole...:lulz:..... when your turning the crank, you dont want the piston to come up and grab squeeze it, possibly breaking it or getting it caught lol
 
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