Neeed help

mathd

mathd

solid fixture here in the forum
We got a problem i think its serious but hope not.
Its with a Pontiac Grand Prix GT 1998 with the 3800(3.8liter) serie II engine.
Yesterday we drove to the gas station it seemed to lack a little power, on the way home it started to somehow missfire and blue smoke, check engine on(scanned and got code fr missfire on cylinder 1)
So we shut it off, tryed to start.. no crank.. tryed a bit later and had a knock.
Now the engine wont crank at all, starter is trying but the pulley just barelly move 1/2 inch then it return where it was when we release the start key.

Where to start? i did think about a compression test but since it wont crank... am a little lost:/
I do think its a broken connecting rod.
 
step one pull all the spark plugs and have a buddy hit the starter while you watch under the hood, it SOUNDS LIKE you might have a blown head gasket that filled the cylinder with coolant, so see if coolant pukes out of the spark plug hole, if it does chances are good its a head gasket
 

You might have water in the cylinders, preventing the engine from turning over. Those engines
are extremely bad about the plastic intake plenum eroding and leaking water.

Pull the plugs and see if you get water out the plug hole.

 
Thanks you, will check that this afternoon and i will update here about it.
 
Ok pulled the spark plugs,it did crank and lots of coolant pushed out of the spark plug hole.
:):)
Thanks, that made my dad very happy.
 
Ok, am just done pulling that intake plenum, there where no hole where the arrow are pointing but, as soon as i poked with a screwdriver it went right thru it.
So i guess that was the cause, intake was full of coolant :/
On to the reassembly this afternoon. will get some coolant and sparkplug tomorrow, everything is closed today, i think i will change the oil also, seem like the oil level went up a little, not going to risk running it with coolant in the oil.
 

While you got the plugs out go ahead and do a compression test. You would hate to
get it together and find out it also had also blown head gasket. You would get some
more practice at R&R ing the intake manifold to get at the heads.

You mentioned it was making a knocking noise, so I would be listening very carefully
to the engine while you are cranking it over for the compression test. You might
have bent a connecting rod when it was hydraulic locked from water in the cylinders.


 
Indycars, makes a good point, its hardly rare to bend a connecting rod or break a piston ring when a cylinder full of coolant locks up an engine, so check that with a compression test
 
When we cranked it withoutbspark plus to get the coolant out there where no knocking it crankquietly. It did not hydrolock while running just the starter had notion enough power to crank once we stopped it. Will try to give a try for a compression test if i can reach the right/dash area spark plug hole. What a lainfull area to get to.
 
Did a compression test today on a dry cylinder that did not get coolant into it was about 130 psi
Then did a compression test on the cylinder that got flooded with coolant, it was at 110 psi, i guess the remaining coolant in the cylinder made a little lower reading(broken ring would make it much lower?)
Anyway we started it(did not let it reach operating temp we needed to go for lunch), it run really smooth no knocking, smoked white for a few minute. will re-do a compression test this afternoon on that cylinder now that all the coolant is probably out of it, but i think(or hope) everything is fine.
 
youll know for sure after the first long drive at highway speeds , that lasts more than 30 minute's, when you try to start the car after it sat and cooled off for a few hours between running, times after reaching full operational temps, then cooling down, and coolant leaks should be obvious
 
We drove it today to get it back home, it reached operating temp twice, and tonight we are back from a long trip but on the city not much highway it run smoother then before no more loping at idle.
What i notice is, when we got back home after we stopped it tonight the radiator hose was soft, hot but soft, if this normal?

EDIT: i just taken the coolant reservoiry cap off, and when we press and depress the coolant hose we can hear some coolant/air comming out and in of the coolant reservoir hose that go from the coolanr reservoir to the radiator cap. sounds like a bad radiator cap?,.
 
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