1998 Suburban 5.7 Burning Coolant HELP! - Chevrolet Forum - Chevy Enthusiasts Forums

1998 Suburban 5.7 Burning Coolant HELP!


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botlebruiser's Avatar
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February 12th, 2011, 12:44 AM   #1  
1998 Suburban 5.7 Burning Coolant HELP!

So my fiance's mom has a 98 Suburban. She looses a ton of coolant each week. It uses a little oil too. It has 125k on it. I don't know how well it was maintained before i was around but I would like to figure this out as it is in good shape and she doesn't have the cash to buy a new car right now. There is absolutely no sign of a coolant leak and there is a sweet smell when it idles. Of course I'm hoping for a cheap fix. Any ideas?

 
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February 12th, 2011, 12:44 PM   #2  
Welcome to the forum. Coolant can go three places, on the ground, into the crankcase, or out the exhaust. On the ground is usually the cheapest option. If it's going in the oil for weeks, then that's going to be expensive as is out the exhaust.

 
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February 12th, 2011, 1:06 PM   #3  
Sounds Like you have an internal coolant leak, most likely a head gasket or a crack inthe head or block. try checking your oil for any sign of coolant in there. (oil looks like milk chocolate if you have coolant in there) you can also check for exhaust fumes in your coolant with an inexpensive tester from an auto parts store

 
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February 12th, 2011, 1:22 PM   #4  
get your radiator cap tested jiffy lube dose this for free or try a new radiator cap there about 6 bucks, if is not holding pressure it will just evaporate and smell as is its burning off. second the radiator might have a small hair line crack in it usually on side's and can do this for weeks before it gets worse and actually leaking on the ground. iv personally gone through 3 radiators do do my cap holding to much pressure. but to buy me some time i left the cap cracked open to vent and over about a weeks time i would need to add a hole jug of coolent. but a $6 part is worth looking into.

 
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February 12th, 2011, 6:41 PM   #5  
Posted By: sheldon 97suburban get your radiator cap tested jiffy lube dose this for free or try a new radiator cap there about 6 bucks, if is not holding pressure it will just evaporate and smell as is its burning off. second the radiator might have a small hair line crack in it usually on side's and can do this for weeks before it gets worse and actually leaking on the ground. iv personally gone through 3 radiators do do my cap holding to much pressure. but to buy me some time i left the cap cracked open to vent and over about a weeks time i would need to add a hole jug of coolent. but a $6 part is worth looking into.
I'm pretty sure its coming out of the exhaust. The exhaust smells sweet, its white and the coolant is dissapearing fast. I guess I can have the pressure test done. How much is a set of reman'd heads for one of these things? I change the oil in it, its definetly not in the crankcase. I think its disapearing too fast to be leaking and there being no sign of a leak.

 
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February 12th, 2011, 8:05 PM   #6  
Might not be the heads, just the head gaskets.

 
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February 13th, 2011, 7:19 PM   #7  
Anyone have any idea whats involved or a guestimate of what this will cost to be fixed. I am not familiar with these engines. I know diesels pretty well but not the the most common engine in america, lol the 350. I would rather just have it done right and pay someone to do it.

 
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February 13th, 2011, 9:05 PM   #8  
Kind of depends on what the problem is but I'm guessing it's going to be a lot since the bearing are shot, maybe cam too. Bores may need boring oversize which means new pistons. And that hasn't even fixed the root cause.

 
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February 15th, 2011, 4:13 PM   #9  
So how much is "a ton of coolant" ? about 240+ gallons?
Just because the oil is not milky, does not mean it is not leaking into the oil. Although if oil is clear, it would be a very small leak. Look under the oil filler cap for droplets.
It should be dry.
You will see plumes of white moisture evaoporating until everything is nicely warmed.
You might also have a O.E.M. intake gasket leak at the very back of the block, the 5.7L from the 90's are notoriously famous for that.
You might have a pin hole leak in a rad hose or the rad. Although if your in a cold climate you should see a steam trail.
Pull spark plugs, if the leak is into a cylinder bad enough, the plug will be different color than the rest.

 
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