Ghost Coolant leak on my 04 Yukon XL 5.3... advice anyone?

[Mark-23]

I took it to the mechanic a few days ago, I just picked it up. It's had the leak for the past three months, I didn't find any milky color on the dipstick in the mornings, when I turn on the engine I wouldn't smell anything coming out of the exhaust.

 

He said it's either the head gaskets or it's a very small leak that's dripping into the engine and evaporates.

 

replacing both head gaskets would cost me $2000 but he suggested me to use the high-end stop leak.

 

What are you do folks suggest, should I use the stop leak?

 

Is there any other solution than replacing the head gaskets and using stop leak?

 

I don't have the budget to replace the head gasket at all, and this is my daily driver. I was planning on keeping it for a long time and fixing it up customizing it etc.

[Mark-23]

1. How much coolant?

2. Borrow a cooling system pressure tester from autozone.

3. Find another mechanic.

 

I forgot to mention that they did the pressure tester on the cooling system and the pressure didn't lose a single bit of the mark, it held its pressure and it was there the entire time.

[silveradosid]

did they pressure check when the engine was hot

[Jsdirt]

Right in this link that txab & 15HDriver posted earlier:

 

 

http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf

[Dnt]

Could just be a bad aftermarket water pump? With a real small leak it will evaporate before it even drips when driving along. I would take the mechanics advice and keep it filled up and drive for a while until the leak becomes worse so you can easily identify it. Sealer will only work on a non moving part like a radiator or heater core which you have pretty much eliminated as the problem with your pressure test being good. I would suspect a small leak at the water pump shaft with the engine running only. Water pumps tend to get worse pretty quickly so you will know soon.

[Justin101714]

Castech heads very possible! Replaced a bunch of these through the years.

 

 

Sent from my iPhone using Tapatalk

[Mark-23]

1. How much coolant?

2. Borrow a cooling system pressure tester from autozone.

3. Find another mechanic.

 

1.) I used up the entire 50/50 coolant and it was close to over heating within almost 3 weeks

 

2.) the shop did the pressure tester infront of me, for 15-20 minutes nothing came out. The pressure kept itself steady. Not a single leak or drop came out.

 

3.) I left my car at this mechanics shop for 2 1/2 days, he's a distant uncle of mine. Good guy. He thinks it's small very small leak, told me to add the expensive kind of Bars Leak and that should fix it up.

 

P.S. I'm just fishing for more advice before I make a proper decision

[Mark-23]

Add dye to the coolant and maybe find the leak that way. Checked thoroughly for the Castech issue?

 

http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf

 

Looked closely at the WP and gaskets for traces of dried coolant?

 

When I would turn on my car in the morning I'd take a look at the exhaust and even smell it... there is no color coming out of it, and no smell

[Mark-23]

You can buy test strips to dip into the coolant to check for hydrocarbon residue

I looked at the dipstick everyday for almost 2 months, no milky color at all... just normal darkening color of Motor oil.

 

My uncle told me just make sure I keep adding coolant when it reaches low levels and keep my motor oil clean till something weird happens. I left it at his shop for almost 2 days and they couldn't figure it out but they think it's both the headgaskets.

[Mark-23]

If you absolutely have to ... I've had good luck using K-Seal or Bars Leak in the past.

 

Aluma-Seal used to be great in the day - would be a permanent fix on anything smaller than a 1/4" gash in a radiator. Stuff was no joke! They changed the formulation to absolute garbage sometime after the turn of the millennium ...

 

My '86 Grand Marquis has been fed a steady diet of the stuff for the past 13 years & 170k miles to avoid replacing the heater core. Your truck isn't built like this thing was, so don't go crazy with the stuff. It can get you by until you have the funds to fix it permanently.

 

 

If you want to know for sure if that's your problem, find a garage with a 4 or 5 gas analyzer, and have them stick it in the coolant overflow bottle - if the HC starts to climb up over 200ppm, that's a confirmed head gasket leak.

 

These analyzers are STUPID expensive, so you might have tough time finding one willing to get the probe that close to coolant, but any garage worth a damn should be using it for this every day.

1.) Which StopLeak should I use on my 5.3? I don't even know where the leak is, it could be the radiator or water pump or head gasket which they said is most likely the head gasket. My uncle said to buy the expensive kind that's like $60...

 

2.) I don't know if they did the 5 gas analyzer on my Yukon XL. But I'm pretty sure they didn't and nor would they have one cause if they did they would've figured out what the problem was by now...

 

Does anyone have experience on this forum with Stopleak and the 2001-2006 5.3 vortecs?

[Mark-23]

Right in this link that txab & 15HDriver posted earlier:

 

 

http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf

Ok I'll check it out and see what kinda heads I got! Thank you so much!

[Mark-23]

Could just be a bad aftermarket water pump? With a real small leak it will evaporate before it even drips when driving along. I would take the mechanics advice and keep it filled up and drive for a while until the leak becomes worse so you can easily identify it. Sealer will only work on a non moving part like a radiator or heater core which you have pretty much eliminated as the problem with your pressure test being good. I would suspect a small leak at the water pump shaft with the engine running only. Water pumps tend to get worse pretty quickly so you will know soon.

The mechanic was my uncle, he said just keep driving it around till something happens. He said we can't identify anything at the moment because the leak is so small... but he did mention to use a heavy sealer.

 

And that's what he said!!! Exactly like you said it, he's like the leak maybe small but it probably drips and evaporates as you drive so perhaps that is why we don't see anything.

 

He like you got two choices, put in some expensive leakstop or keep driving it till the matter intensifies ect.

[Heavy 5.7]

Have you parked the truck with some cardboard overnight under the engine compartment?

Ethylene glycol doesn't burn completely so use your finger to feel if the inside of the exhaust pipe slimy.

Have you ever changed the intake gaskets?

[twistoffate]

Might be way too late for my experience but I had same problem....it was a hairline crack in the head. Heat from motor evaporated water from coolant. Left a jelly type congealed form of concentrated coolant in valve covers. If its been going on for months, Pull valve cover & you will know right away if this is the problem.

[txab]

Add dye to the coolant and maybe find the leak that way. Checked thoroughly for the Castech issue?

 

http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf

 

Looked closely at the WP and gaskets for traces of dried coolant?

[newdude]

I wonder if you have Castech heads on that truck...http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf