5.7L head gasket replacement

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'93 Chevrolet Caprice, 5.7L with 105K miles
When the engine is cold and I hit the highway, the temperature gauge shoots into the red after a few minutes. Stays there for about 1-2 mins, then T-stat opens, and it goes back to normal. I replaced numerous T-stats, bled the system and eventually realized that it is the head gasket. It throws air into the system. I can see tiny bubbles no matter how much I bleed it. This air into the cooling system makes the T-stat open a bit slow. But after 5 minutes of driving, there is no overheating no matter how long I drive, even in city driving.
The passenger side head gasket has been replaced during engine install. How hard is it to replace driver's side head gasket on L05? Is this a DIY project? I have swapped some stuff in engine bay but nothing of that caliber.
Second question, is it dangerous to drive like that, will this condition where I run for 1-2 mins with temperature in the red damage something like crack heads? Is it really overheating?
Lastly, this issue entirely goes away with 160F T-stat, but I run 195F for better mileage.
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Before you change the head gasket, you may want to change the water pump..I know it's totally off the wall, but I have seen quite a few..There's a problem in the pump causing cavitaion and an air pocket is created.... it's a lot cheaper than a head gasket job... Bobo

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project?
where
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The water pump is nearly new, so that's not the issue. The head needs to come off. I need to know the sequence of things to remove to get to the head. Is there a good web site that shows how to do this? A book?
I have turned some wrenches, one time I even removed a whole engine but it took me about 3 days to find all the bolts and connections. Thanks.

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On Thu, 9 Oct 2003 21:17:08 -0400, An Metet

I am having the exact same problem with a 92 Caprice and a 5.0l engine. If I drill a small hole in the edge of the T-stat, the problem goes away. I have raised the front of the car up high on ramps and have bled the system. T-Stat has been replaced several times and is not the problem.
The system acts like there is a pocket of air in there that collects at the T-stat housing causing a sluggish t-stat.
Here is how it fails:
Get in cold car and start driving. Temp gauge starts going up till it goes just shy of the red and then drops like a rock back to normal. After it goes through this gyration it will *usually* be fine for the rest of the trip. However, sometimes it won't open and i have to pull over and squeeze the upper hose a few times to get the t-stat to open.
Again, radiator/heater core t-stat are all fine.
I'm starting to think it is the water pump because I don't think the head gasket is blown. No oil/coolent mixing and no sweet exhaust fumes. Also the coolant level doesn't drop at all.
But like I said drilling a little hole in the edge of the 195 degree t-stat fixes the problem.
I was also thinking of putting a bleeder screw on the t-stat housing like some cars have.
Anyone have any other ideas?
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psycho snipped-for-privacy@yahoo.com wrote:

[.....]
I have a head gasket leaking some compression into the water jackets. The pressure inside the cylinder is enough to push air into the cooling system; however, the pressure inside the cooling system is not enough (15 PSI) to push water into the cylinder. This is probably the case with your Caprice, too. A leak down test is necessary to prove this.
It could be a cracked head, or a crack in the water jacket.
Something you can do is install a 160F thermostat. I haven't had any problems with overheating with it. The reason I ultimately removed it is because the PCM is programmed for 195F. With 160F, you would have to reprogram that computer. I hear that with 160F, you get more HP, but less mileage. I like my engine to run as hot as possible for best mileage, but 160F T-stat is a popular performance enhancement.
Also checking compression is a good idea.
Checking for exhaust in the cooling system is another idea.
In my case, there is no real easy fix, the head needs to come off.
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it is a matter of turning wrenches it could be a cracked head too
: NOTE: This message was sent thru a mail2news gateway. : No effort was made to verify the identity of the sender. : -------------------------------------------------------- : : : : '93 Chevrolet Caprice, 5.7L with 105K miles : : When the engine is cold and I hit the highway, the temperature gauge shoots : into the red after a few minutes. Stays there for about 1-2 mins, then T-stat : opens, and it goes back to normal. I replaced numerous T-stats, bled the : system and eventually realized that it is the head gasket. It throws air into : the system. I can see tiny bubbles no matter how much I bleed it. This air : into the cooling system makes the T-stat open a bit slow. But after 5 minutes : of driving, there is no overheating no matter how long I drive, even in city : driving. : : The passenger side head gasket has been replaced during engine install. How : hard is it to replace driver's side head gasket on L05? Is this a DIY project? : I have swapped some stuff in engine bay but nothing of that caliber. : : Second question, is it dangerous to drive like that, will this condition where : I run for 1-2 mins with temperature in the red damage something like crack : heads? Is it really overheating? : : Lastly, this issue entirely goes away with 160F T-stat, but I run 195F for : better mileage. :
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