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496 overheating issues!!! Please help

Dirty Daytona

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Yes peter I bought the $8 cap and it did the same shit!!!! So now I have a spare cap and an overheating motor still lol. I’ve got a lot of great suggestions on here so it looks like I’ve got some work to do.
 

CobraDave

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Did you get this resolved. I was curious as to what problem was discovered.


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Dirty Daytona

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Did you get this resolved. I was curious as to what problem was discovered.


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Yes sir I did. It’s got a blown head gasket. I pressure checked the closed side and it wouldn’t hold pressure. I then tested for the presence of exhaust in the coolant and it tested positive in a micro second. So this weekend I start the tear down.
 

MagicMan

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Yes sir I did. It’s got a blown head gasket. I pressure checked the closed side and it wouldn’t hold pressure. I then tested for the presence of exhaust in the coolant and it tested positive in a micro second. So this weekend I start the tear down.
Hopefully you get issue resolved quickly. Im curious how many hours on your engine? Is this a quick fix replace gaskets or do you have to rebuild?
 

Dirty Daytona

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I have 220 hours. I won’t know until I get the heads off if I need machine work. It’s pretty rare for iron heads to be warped but I will see. I will have a machine shop check the heads for cracks and warpage before I put them back on.
Hopefully you get issue resolved quickly. Im curious how many hours on your engine? Is this a quick fix replace gaskets or do you have to rebuild?
 

Singleton

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I have 220 hours. I won’t know until I get the heads off if I need machine work. It’s pretty rare for iron heads to be warped but I will see. I will have a machine shop check the heads for cracks and warpage before I put them back on.
Time to upgrade if your building. Call @BoostPower and talk to Axeli and what upgrades can be done to the 496
 

Dirty Daytona

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Time to upgrade if your building. Call @BoostPower and talk to Axeli and what upgrades can be done to the 496
The only upgrade I need is the cherrypicker performance upgrade. Unbolt the 496, hook it to a cherry picker and drop a blue motor in. Until I can afford that I am fixing the 496 and running it some more.
 

CobraDave

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Such a low hour motor such a bummer. It could be worse I guess. You don’t read on this happening too much with a 496. It sounds like you got it handled though. At least it’s not a mystery now.


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Dirty Daytona

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Such a low hour motor such a bummer. It could be worse I guess. You don’t read on this happening too much with a 496. It sounds like you got it handled though. At least it’s not a mystery now.


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Yeah I’m glad too. I’m pretty sure it’s a small blowout because it only rears it’s ugly head when the motor gets up to full temp and ran for a bit. That leads me to believe the gasket is only opening up when the metal expands so I’m hoping for no or minimal damage. We shall see. Break out another thousand right? I thought Harley’s were bad lol
 

mjc

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Such a low hour motor such a bummer. It could be worse I guess. You don’t read on this happening too much with a 496. It sounds like you got it handled though. At least it’s not a mystery now.


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when mine did the same thing I talked to some of the shops in town and this is about the only thing they ever have happen to the 496's. the motor uses the torque to yield head bolts and I think some of them yield way to early. that is why I went to the ARP head stud kit on mine so that won't happen again.
 

Dirty Daytona

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when mine did the same thing I talked to some of the shops in town and this is about the only thing they ever have happen to the 496's. the motor uses the torque to yield head bolts and I think some of them yield way to early. that is why I went to the ARP head stud kit on mine so that won't happen again.
That’s surprising for such a mild, low compression motor. I don’t think I will spring for the head stud kit but I will probably use new head bolts.
 

robby dmax

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Will be cheap insurance to do the ARP head studs and Cometic MLS head gaskets and be done ✅
 

mjc

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That’s surprising for such a mild, low compression motor. I don’t think I will spring for the head stud kit but I will probably use new head bolts.
you have to replace them no matter what, it is required by GM. a new set is only 38 per side. I just got carried away when I did mine figured if I replaced all the wear part I would get another 500 hrs.
 

Dirty Daytona

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you have to replace them no matter what, it is required by GM. a new set is only 38 per side. I just got carried away when I did mine figured if I replaced all the wear part I would get another 500 hrs.
How much was the stud kit?
 

mjc

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How much was the stud kit?
441.99 from summit. I can look at my orders and get you all the P/N you would ever need. I got most of engine parts from summit and Merc parts from Quality here in
Havasu.
 

MagicMan

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Anyone know if there is something you can do to prevent blown head gaskets. Being this is the only major issue with 496 engines?
 

namba860

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YTT head bolts must never be reused. Throw them in the trash and buy a new set.
 

BoostPower

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Between Whipple, boostpower, pro charge and Raylar I think I can get about 1200 horsepower. Lmao
There are definitely good upgrades available however the motors need to come apart to perform all. We use the block, some cracks (depending on serial number) and the bare castings and all outside accessories. Everything else including valves, pistons rods bearings seals calibrations cam lifters rocker v cover spacers push rods etc etc get replaced. Then it’s a king size LS and kicks butt


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Dirty Daytona

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There are definitely good upgrades available however the motors need to come apart to perform all. We use the block, some cracks (depending on serial number) and the bare castings and all outside accessories. Everything else including valves, pistons rods bearings seals calibrations cam lifters rocker v cover spacers push rods etc etc get replaced. Then it’s a king size LS and kicks butt


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I was being sarcastic. I’ve heard you guys do great work but I’m going to put as little lipstick on that pig as possible until I can afford a real motor.
 

BoostPower

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I was being sarcastic. I’ve heard you guys do great work but I’m going to put as little lipstick on that pig as possible until I can afford a real motor.
All good. It’s a frowned on motor in general but we make success out of em. And we had no choice as there are hundreds of thousands of 8.1’s around


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Runs2rch

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I was being sarcastic. I’ve heard you guys do great work but I’m going to put as little lipstick on that pig as possible until I can afford a real motor.
Writing is on the wall. You are going to have more issues band aiding.

After Alexi is done with it. You will have a mill that will be better than a 525efi.
 

Runs2rch

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All good. It’s a frowned on motor in general but we make success out of em. And we had no choice as there are hundreds of thousands of 8.1’s around


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Good for what they are. Just not going to push a 28 deck into the 70's.
 

Dirty Daytona

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Writing is on the wall. You are going to have more issues band aiding.

After Alexi is done with it. You will have a mill that will be better than a 525efi.
I think you might be a little ambitious in saying replacing a head gasket on a motor with 220 hours is a band aid. As long as the heads are checked out before re install that motor has lots of life left in it. The source of the initial overheat and coolant loss was the heat exchanger gaskets and those are repaired. Of course I would love to spend the money at boostpower but the 496 is what it is.
 

02HoWaRd26

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All good. It’s a frowned on motor in general but we make success out of em. And we had no choice as there are hundreds of thousands of 8.1’s around


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I’m still awaiting that call back on doing my 496 lol.
 

LargeOrangeFont

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Anyone know if there is something you can do to prevent blown head gaskets. Being this is the only major issue with 496 engines?
Keep a good impeller in the boat and make sure the cooling system is in good shape.
 

Dirty Daytona

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Yeah I’m glad too. I’m pretty sure it’s a small blowout because it only rears it’s ugly head when the motor gets up to full temp and ran for a bit. That leads me to believe the gasket is only opening up when the metal expands so I’m hoping for no or minimal damage. We shall see. Break out another thousand right? I thought Harley’s were bad lol
Shylbntro you were absolutely correct!!!!
 

Dirty Daytona

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I guess all that pink liquid in the bottom of the bilge wasn’t kool aid.
 
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