5.7GLI slight vibration at idle and knocks 2500-3300 rpm
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TexasCobaltGuy
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Forgot to submit that post above yesterday... so just did and after reading PM with a vote of go for it and offer to virtually help I am going to move forward and start the project. (So thank you all in advance for your input and help!)
On a side note the full engine model is a 5.7GLI PLKDCE (or on parts site 5.7GLIPLKDCE with SN: 4110146604 and this number under that 3868732
Here is the start of the plan (Still researching and modifying this plan):
- Drain Oil and inspect for Water (Note Dip Stick looks as clean as brand new oil) - Already ordered new oil and oil filter on volvopentastore.com
- Drain water from engine, cooling system and manifold (includes removal of thermostat as I plan to replace it) (already ordered new thermostat kit from volvo penta site)
- Remove exhaust manifolds and risers from both sides ( Still need to order these gaskets as riser gasket - 3863191 & exhaust gasket 3852468)
- set engine on top dead center (top of Compression stroke on cylinder 1)
- Remove all spark plug wires (and label) and spark plugs (Already ordered all new spark plugs from volvo site, will inspect wires and decide on those after removal)
- Remove 2 screws on distributor cap and remove (note screws are not kept by cap so be careful not to drop them)
- remove Distributor cap (inspect for corrosion and wear and determine if new one should be ordered)
- Remove Rotor (Inspect) - Take a picture for reassembly
- Remove holding screw on distributor - Take a picture of alignment for reassembly
- Pull out distributor cap (this is my 1st concern if there is enough clearance to pull this out of the engine without pulling the engine)
...
- Pull the intake manifold (Need to order Intake Gasket Kit (Have to get from dealer))
- Pull the heads (Need to order head gasket)
On a side note the full engine model is a 5.7GLI PLKDCE (or on parts site 5.7GLIPLKDCE with SN: 4110146604 and this number under that 3868732
Here is the start of the plan (Still researching and modifying this plan):
- Drain Oil and inspect for Water (Note Dip Stick looks as clean as brand new oil) - Already ordered new oil and oil filter on volvopentastore.com
- Drain water from engine, cooling system and manifold (includes removal of thermostat as I plan to replace it) (already ordered new thermostat kit from volvo penta site)
- Remove exhaust manifolds and risers from both sides ( Still need to order these gaskets as riser gasket - 3863191 & exhaust gasket 3852468)
- set engine on top dead center (top of Compression stroke on cylinder 1)
- Remove all spark plug wires (and label) and spark plugs (Already ordered all new spark plugs from volvo site, will inspect wires and decide on those after removal)
- Remove 2 screws on distributor cap and remove (note screws are not kept by cap so be careful not to drop them)
- remove Distributor cap (inspect for corrosion and wear and determine if new one should be ordered)
- Remove Rotor (Inspect) - Take a picture for reassembly
- Remove holding screw on distributor - Take a picture of alignment for reassembly
- Pull out distributor cap (this is my 1st concern if there is enough clearance to pull this out of the engine without pulling the engine)
...
- Pull the intake manifold (Need to order Intake Gasket Kit (Have to get from dealer))
- Pull the heads (Need to order head gasket)
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1997 Cobalt 200 5.7GLI DP
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
I would wait on ordering all parts till it is apart just in case. Unless Everything can be returned. Just me but I'm hoping it's just head gaskets. Yes if it over heated that's what toasted this. The knock isn't a double type knock is it? I'm hoping it's just from ignition. I don't know how much room you have as it much diff then my boat to get a dist out. but cross your fingers.
Good luck we will be on this journey with you. Also check the manifold Surface for being flat if it got that hot. Not good.
Good luck we will be on this journey with you. Also check the manifold Surface for being flat if it got that hot. Not good.
03Cobalt220 8.1gxi DP
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
"Kids in Tow2"
"Pot The Jus" Originator :-)
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#ItsBu'sfault
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- akorcovelos
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
I've done a full top end tear down on a Merc 260 5.7 in a boat with tons of room to work and it was a pain. Honestly, if I were you, and I'm not, I would pull the engine to do all this, especially if you're already concerned about room to work. Lifting the heads out without trashing the interior will be a pain. Also, I hate to say it, but if it overheated that bad and it's knocking under load, you're likely going to need a new long block anyway. If you can do the work yourself it's not crazy expensive to get a long block from Jasper, less than the dealer quoted to repair yours.
https://www.jasperengines.com/marine-engines
Here is the thread from when I did my old 5.7, not a Volvo but much of what you see will be the same: https://forums.iboats.com/forum/engine- ... -questions
https://www.jasperengines.com/marine-engines
Here is the thread from when I did my old 5.7, not a Volvo but much of what you see will be the same: https://forums.iboats.com/forum/engine- ... -questions
1996 252 Whipple tuned 454 Magnum MPI, 496 exhaust, Corsa Captains Call, B3 w/Simrek drive shower.
‘Direct Deposit Too’
Antioch, IL
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
That's good reading. I think I read it 1 other time. Some of you guys have lots of patience.akorcovelos wrote: Fri Apr 03, 2020 10:34 am I've done a full top end tear down on a Merc 260 5.7 in a boat with tons of room to work and it was a pain. Honestly, if I were you, and I'm not, I would pull the engine to do all this, especially if you're already concerned about room to work. Lifting the heads out without trashing the interior will be a pain. Also, I hate to say it, but if it overheated that bad and it's knocking under load, you're likely going to need a new long block anyway. If you can do the work yourself it's not crazy expensive to get a long block from Jasper, less than the dealer quoted to repair yours.
https://www.jasperengines.com/marine-engines
Here is the thread from when I did my old 5.7, not a Volvo but much of what you see will be the same: https://forums.iboats.com/forum/engine- ... -questions
Nice job though.
03Cobalt220 8.1gxi DP
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
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TexasCobaltGuy
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Project has started. Here are a few pictures.
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1997 Cobalt 200 5.7GLI DP
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
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TexasCobaltGuy
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
More pictures
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1997 Cobalt 200 5.7GLI DP
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
- Big Block Power
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
That manifold to riser gaskets been leaning awhile.
Is amazing what these engines look like compared to a cars engine. Without coolant these engines take a beating.
Is amazing what these engines look like compared to a cars engine. Without coolant these engines take a beating.
03Cobalt220 8.1gxi DP
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
.
Wow
Fantastic documentation for the site TCG!
Keep ‘me coming.


Thank you.
.
Wow
Fantastic documentation for the site TCG!
Keep ‘me coming.
Thank you.
.
2002 Cobalt 262
&
2005 Cobalt 263
496 MagHO
(sold )
Erie, PA
Currently boatless (for now)
will fly for food
(CChat moderator)
&
2005 Cobalt 263
496 MagHO
(sold )
Erie, PA
Currently boatless (for now)
will fly for food
(CChat moderator)
Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Hello Tex.TexasCobaltGuy wrote: Fri Apr 03, 2020 8:08 am I have never torn down an engine.
In talking to the dealership over the phone they guessed it would probably run ~3k for everything.
it overheated many years back to the point that the paint burnt off one side
I did notice a slight vibration last season from the engine which is worse now but it still can run but the big difference this season is under load it knocks...
Been following this thread as you have support from two sharp “ done it.. been there” members with AK and BBP.
But let’s recap even with the very non- descriptive diagnosis your dealer gave you.? ( what are they doing?).
Without a proper leak down before you pull the heads you may be missing a lower end issue.
As one pic shows water intrusion and detonated pock marks on the exhaust valve I worry you may have a broken piston or ring land that may have collapsed.
A lighted bore scope through the cylinder in question may show a wash or metal transfer on the piston top.
In short as much as these members have done this before fearlessly.. we don’t want you putting $$ on a dead player.
High temps can glaze rings and leave you with a poor performing engine with new cylinder heads.
Let’s revisit the proper diagnostic and plan a replacement.
Just my 3 cents.
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2008 272 , 496 HO fo SHO
California Delta
Table Rock Lake
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California Delta
Table Rock Lake
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TexasCobaltGuy
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Continuing to remove and get down to heads and intake.
About to take out the distributor... fingers crossed there is enough room
Had to spin the motor clockwise a couple times with the valve cover off on the #1 cylinder side to watch the exhaust and intake valves move to figure out the TDC on the compression.
About to take out the distributor... fingers crossed there is enough room
Had to spin the motor clockwise a couple times with the valve cover off on the #1 cylinder side to watch the exhaust and intake valves move to figure out the TDC on the compression.
You do not have the required permissions to view the files attached to this post.
1997 Cobalt 200 5.7GLI DP
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
- Big Block Power
- Fleet Admiral

- Posts: 17930
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Nice at least it has vortec heads. That's a bonus. Keep it coming.
03Cobalt220 8.1gxi DP
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
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TexasCobaltGuy
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Got the distributor out!
And the rain started so had to cover everything up and wait out this rain.
And the rain started so had to cover everything up and wait out this rain.
You do not have the required permissions to view the files attached to this post.
1997 Cobalt 200 5.7GLI DP
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
- Big Block Power
- Fleet Admiral

- Posts: 17930
- Joined: Sat May 07, 2016 8:05 pm
- Location: Neenah,Wi
- Contact:
Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
At least that looks clean. Glad she came out. I wasnt worried 

03Cobalt220 8.1gxi DP
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
"Kids in Tow2"
"Pot The Jus" Originator :-)
Neenah Wi
#ItsBu'sfault
#FARCON Marine CC Core!
-
TexasCobaltGuy
- Commander

- Posts: 103
- Joined: Wed Mar 13, 2019 7:16 am
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Got everything disconnected from the intake and broke it free from block and heads. Ran out of daily light so starting early in the morning with removal of the intake and start the process of unscrewing the heads. Created a cardboard sheet that I punch all the screws into to keep them straight as they all appear to be different lengths. Will do the same with the heads. Excited to see the blowout between the middle heads. Btw. Not sure if you can see this but the exhaust gasket between the center cylinders also blew out between those ports. So fingers crossed the blowout isn’t too bad between the cylinders.
Machine shop guy (AJ) at www.enginesxtreme.com in Lewisville told me this is very common for this engine.
Got pricing from the dealership today for all the parts. The water path on the intake is very corroded little worries about that throughout the engine. Also very corroded in the exhaust and riser.
Going to take everything to machine shop and see about cleaning all of it up if possible.
Machine shop guy (AJ) at www.enginesxtreme.com in Lewisville told me this is very common for this engine.
Got pricing from the dealership today for all the parts. The water path on the intake is very corroded little worries about that throughout the engine. Also very corroded in the exhaust and riser.
Going to take everything to machine shop and see about cleaning all of it up if possible.
1997 Cobalt 200 5.7GLI DP
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
“Alexica Jean”
White with Hunter Green stripe
Mt Vernon, Texas
Lake Cypress Springs
- akorcovelos
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Re: 5.7GLI slight vibration at idle and knocks 2500-3300 rpm
Don’t put those manifolds back on that engine. Does it look like it was leaking inside the water jacket? Is that the same side as the low cylinder?
1996 252 Whipple tuned 454 Magnum MPI, 496 exhaust, Corsa Captains Call, B3 w/Simrek drive shower.
‘Direct Deposit Too’
Antioch, IL
Fox Chain O' Lakes
‘Direct Deposit Too’
Antioch, IL
Fox Chain O' Lakes
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