I need experienced help re: Water pouring out exhaust

[MassHoe04]

Could very well be just a head gasket. Coolant could be passing between the block and the head and going right out the exhaust port.
If the truck is in generally good condition, the head is not cracked or warped and the block is not actually damaged... I would go the cheaper way out and give replacing the head gasket a try, before replacing the engine or getting rid of it.
The old cast iron blocks are sturdier than some might believe. If the issue is really limited to a gasket or two, maybe even a head... See if it makes economic sense to do whatever top end work might be required. No sense in throwing the baby out with the bathwater, if possible to avoid "atomic bomb" options.

 

[corvette744]

Could very well be just a head gasket. Coolant could be passing between the block and the head and going right out the exhaust port.
If the truck is in generally good condition, the head is not cracked or warped and the block is not actually damaged... I would go the cheaper way out and give replacing the head gasket a try, before replacing the engine or getting rid of it.
The old cast iron blocks are sturdier than some might believe. If the issue is really limited to a gasket or two, maybe even a head... See if it makes economic sense to do whatever top end work might be required. No sense in throwing the baby out with the bathwater, if possible to avoid "atomic bomb" options.

I would not replace the head gasket without getting the heads magnaflux and checked for leaks.Op said it would take at least a month before the shop can do that.Hopefully you have another car to use.SO 300 to check for leaks if found leak $200 for used head hope they also dont have a leak.All the gaskets your need to complete.So guessing your around 6-700 for replacing heads.He said he has found some low mile engines for around 1,000.Im going to guess with 360,000 miles your going to be replacing alot of stuff soon.With a nice used motor out of vehicle replace rear main and oil pan gasket and anything else you see and your 3-500 more for an engine with almost 250,000-300,000 miles less.I know what i would do.

 

[MassHoe04]

I would not replace the head gasket without getting the heads magnaflux and checked for leaks.Op said it would take at least a month before the shop can do that.Hopefully you have another car to use.SO 300 to check for leaks if found leak $200 for used head hope they also dont have a leak.All the gaskets your need to complete.So guessing your around 6-700 for replacing heads.He said he has found some low mile engines for around 1,000.Im going to guess with 360,000 miles your going to be replacing alot of stuff soon.With a nice used motor out of vehicle replace rear main and oil pan gasket and anything else you see and your 3-500 more for an engine with almost 250,000-300,000 miles less.I know what i would do.

Based on all the circumstances... I agree.

I was just thinking the odds (though a bit of a risk) might be at least halfway decent for a gasket to fail and still have a small chance that the block and the head escaped without harm. I was thinking, if this work was being done 100% DIY, trying a head gasket and crossing fingers might have some possibility of being successful. If it worked, he'd get off very cheap. If not, you'd have to bump repair efforts up to the next level anyway.

With a Magnaflux test not available for a month and a good used engine to be had for $1k and costs for the different repair options ending up that close, I can be swayed to agree with you on this. Probably best to drop a good running, lower mileage used engine in there.

 

[Blackcar]

After a 100 mile trip my 2003 Tahoe 5.3L vin Z engine started to overheat prior to my intended return trip home. I poured water in the reservoir while the engine was running and it was pouring out of the exhaust in the rear of the Tahoe as fast as i could pour it in.
I left the truck at my families house, and had it flatbedded home. I never let it overheat beyond the first time it got hot. I got to it before it pegged the temp. guage.
Put it in the garage at home and tore it down to the head gaskets and did not see what i thought i would see. There was NO water in the oil, the oil was fresh and not contaminated at all. this kind of stumped me. I dont like assuming, but I seen no visual indication that should have stood out given how quickly the water flowed out the tailpipe?
Alas, to the point of my post here. I have 360,000 miles on this engine. It runs like a top and has no misfire. Just a huge water leak...
Common sense says just replace the engine. I am willing to gamble and just replace a cylinder head. My question is this:
IS THERE ANY POSSIBLE WAY THAT THE BLOCK COULD BE CRACKED TO CAUSE THS ISSUE? In my mind, it has to be a cylinder head that is somehow cracked between the exhaust port and a water jacket, or else i would have water in the crankcase.I also have no misfire so I am to think it is not getting into the combustion cylinder(s)... any wisdom here? I appreciate it.

If this is leaking as bad as you said you could possibly get a thick piece of lumber put a layer of rubber (tire tube) c-clamp block side of head to board or metal plate set head at angle that it sets on engine pour water in coolant passage and see if it comes out somewhere in head. Try both head in same manner if one is leaking replace one head if neither then gasket would solve or its somewhere else quick and cheap.

 

[rockola1971]

I would not replace the head gasket without getting the heads magnaflux and checked for leaks.Op said it would take at least a month before the shop can do that.Hopefully you have another car to use.SO 300 to check for leaks if found leak $200 for used head hope they also dont have a leak.All the gaskets your need to complete.So guessing your around 6-700 for replacing heads.He said he has found some low mile engines for around 1,000.Im going to guess with 360,000 miles your going to be replacing alot of stuff soon.With a nice used motor out of vehicle replace rear main and oil pan gasket and anything else you see and your 3-500 more for an engine with almost 250,000-300,000 miles less.I know what i would do.

You cant magnaflux an aluminum head. Theres no iron in it.

 

[rockola1971]

Could very well be just a head gasket. Coolant could be passing between the block and the head and going right out the exhaust port.
If the truck is in generally good condition, the head is not cracked or warped and the block is not actually damaged... I would go the cheaper way out and give replacing the head gasket a try, before replacing the engine or getting rid of it.
The old cast iron blocks are sturdier than some might believe. If the issue is really limited to a gasket or two, maybe even a head... See if it makes economic sense to do whatever top end work might be required. No sense in throwing the baby out with the bathwater, if possible to avoid "atomic bomb" options.

The OP has coolant/water "pouring out the tail pipe". If its that bad then when the engine is turned off after being atleast warm and probably cold too, it would fill the affected cylinder since there is no way to to get to the exhaust valve without going into the cylinder first. (This is assuming the head itself isnt cracked). And if the cylinder is getting coolant/water into it to get into the exhaust then when the engine is shutoff the water/coolant will make its way past the piston rings and into the oil pan and then you have a skunk stripe on the dipstick because your oil is floating on top of that water/coolant.

 

[rockola1971]

I’d never spend money on an engine with 360k on it. And I’d think twice or more to be sure the chassis is worth the cost of a transplant. Might be better to spend the money on a new to you ride.

It of course depends on the area a person lives and the market for machine shops but sometimes it can be very effective to have a local shop rebuild a 5.3L to OEM or just above that specs. Most 5.3L iron blocks can be bored to 5.7L (LS1) specs too but the block has to be screened for that. A master rebuild kit isnt too expensive. But for the most part and very little hassle a rebuilt long block from whomever "you" choose provides less headaches but there are machine shops out there thirsty for your business and will do the job right.
Pull the engine, yank off all accessories, intake, valve covers, oil pan and drop it off at the machine shop and go for the expedited shipping on the rebuild master kit once its decided what the bore is going to be, cam choice and bearing size requirements. Next thing you know in a week or two you have a "brand new" long block ready to go. Get to assembling.
But like you said, if the chassis is no good then move on. Cant do much with a chassis thats about to rust in half. All depends on whether OP needs to spend as little as possible or can spring for another K chassis thats ready to roll.

 

[corvette744]

You cant magnaflux an aluminum head. Theres no iron in it.

So pressure test or use a dye kit would never install any head ever without knowing it has no cracks. period.

 

[Donal]

Does the Tahoe have a rear heater? I cannot find a clear path for coolant to flow out the exhaust of the engine while pouring the coolant in the overflow container. I can see a clear path for coolant to freely flow from the heater pipe/hose that is located near and above the exhaust outlet on vehicle with a rear heater.

 

[MassHoe04]

The OP has coolant/water "pouring out the tail pipe". If its that bad then when the engine is turned off after being atleast warm and probably cold too, it would fill the affected cylinder since there is no way to to get to the exhaust valve without going into the cylinder first. (This is assuming the head itself isnt cracked). And if the cylinder is getting coolant/water into it to get into the exhaust then when the engine is shutoff the water/coolant will make its way past the piston rings and into the oil pan and then you have a skunk stripe on the dipstick because your oil is floating on top of that water/coolant.

OP said oil was clean, so I was thinking fluid that may have escaped through the head slowly exited as steam, then condensed in the muffler/exhaust to the point there was enough to come out the tail pipe as water.

I used to drive some Interceptor Crown Vics for the PD. They ran fine (pay no attention to the orange light on the dash- no budget to fix until new fiscal year), but step on the gas there was a tidal wave (definitely exaggerating here) of water blowing out both pipes! We're talking columns of water pushing out the end. With the engines running at idle for so many hours sitting on a traffic detail, the condensation just kept collecting until it got "aired-out" on the highway.

It was actually funny. You could hear the water in the muffler and exhaust gurgling while it idled, because the water level inside the system just barely allowed the exhaust gases to finds their way out ver the water. If you were the person taking over that detail and standing too close behind the cruiser, you got your feet washed. I had to warn people after it happened unintentionally the first time.

Unfortunately, that Interceptor blew the engine before the new fiscal year and we were down a cruiser for next several months...