Possible Head Issue

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msaluta

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I bought my 1997 C1500 5.7 Vortec about 4 months ago.

The previous owner stated that they had to replace the head gasket, and that it overheated.

It has been running great for the last 4 months, temp always stable, but I recently noticed a slight drop in coolant.

I recently changed the oil and there's no milky residue, there's no visual smoke in the exhaust, there's no residue on the oil cap.

I pulled into a gas station after taking it for a 20 minute drive, popped open the coolant reservoir, and noticed a few bubbles coming up.

Today I'll be renting a head gasket tester from AutoZone to see if those bubbles are in fact exhaust gasses.

If it is discovered that there are exhaust gasses in the coolant, and the previous owner stated that they had the head gasket replaced, and the truck overheated, I suspect the heads are warped at minimum.

I'm trying to understand what a smart/frugal person would do sequentially in this case. I intend to keep the truck for many years, and haven't heard great things about head gasket sealants so not really interested in that route.

I've seen garage resurfacing of warped heads using 80-120 grit sandpaper on panes of glass.

I've looked at buying new heads from Summit.

I've looked at full reman 5.7 engines.

I've never done serious work inside of an engine, though I've done many other jobs from suspension, AC, brakes etc. so I'm a bit apprehensive so any advice you guys can give is greatly appreciated.
 

Drunkcanuk

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I bought my 1997 C1500 5.7 Vortec about 4 months ago.

The previous owner stated that they had to replace the head gasket, and that it overheated.

It has been running great for the last 4 months, temp always stable, but I recently noticed a slight drop in coolant.

I recently changed the oil and there's no milky residue, there's no visual smoke in the exhaust, there's no residue on the oil cap.

I pulled into a gas station after taking it for a 20 minute drive, popped open the coolant reservoir, and noticed a few bubbles coming up.

Today I'll be renting a head gasket tester from AutoZone to see if those bubbles are in fact exhaust gasses.

If it is discovered that there are exhaust gasses in the coolant, and the previous owner stated that they had the head gasket replaced, and the truck overheated, I suspect the heads are warped at minimum.

I'm trying to understand what a smart/frugal person would do sequentially in this case. I intend to keep the truck for many years, and haven't heard great things about head gasket sealants so not really interested in that route.

I've seen garage resurfacing of warped heads using 80-120 grit sandpaper on panes of glass.

I've looked at buying new heads from Summit.

I've looked at full reman 5.7 engines.

I've never done serious work inside of an engine, though I've done many other jobs from suspension, AC, brakes etc. so I'm a bit apprehensive so any advice you guys can give is greatly appreciated.
Vortec heads are very prone to cracking.
Take them off and send them in for inspection. And don't be shocked when they tell you they are caput.
 

Drunkcanuk

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Assuming they are, what should I look for for replacement heads? How complex of a job is replacing them?
It all depends on how much you want to spend.
A few hundred for a OE style replacement, or $1000+ for some whizbang aluminum replacement ones. So only you can make that call.

Whoever you get to check them out may even have a set on the shelf just waiting for someone like you with a cracked head. Or can get some brought in quickly and for a decent price.

I have never pulled a set of Vortec heads, but I'm assuming it's not the hardest job in the world. I'm sure YouTube University has videos on it.

There are probably threads on here about it.

There are factory service manuals available for download in the "sticky" section of the engine and performance section on here.
 

Schurkey

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Drove 20 minutes, and see turbulence in the overflow bottle? May be normal.

Keep a close eye on the coolant level.

You see turbulence in the overflow bottle while the engine is still warming-up, or after it's been at operating temp for an hour, you've got problems. After 20 minutes...not so sure.
 

rebelyell

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Either new or Known good, not-cracked Vortecs can be sent to cryogenic metal treatment; that will toughen them up and they will be much more resistant to cracking. It's become a well-proven tech. Cost of cryo has come down quite a bit. There are many small & large providers throughout USA. Ask Your local auto machine shop, local metal heat treat shop or google.

You'll get google hits for cryogenic "therapy" ... apples & oranges.
 

Erik the Awful

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I've seen garage resurfacing of warped heads using 80-120 grit sandpaper on panes of glass.
I've seen it done to get a race car back on track, but I wouldn't do it, and I do stupid stuff.

If the head comes off, get it magnafluxed and inspected by a trusted machine shop. You'll save a ton of money if you disassemble the head yourself, and you might as well replace the valveseals while you're in there. If the valvesprings have over 200k on them, you'll want to replace them as well.

When it comes to replacement heads, you're really limited. Vortec heads have taller ports. You absolutely want to go back with Vortec heads, or you're going to have a lot of parts swapping to do.
 
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