Internal antifreeze leak
 

Mechanic says I have a leak in the engine. Die shows no external leak and when you pressure test it, pressure drops fast. Is this a cause of the antifreeze GM uses. Any easy fixes?
Thanks

What?

If the pressure drops fast during a pressure test, then you need to find the leak. First place to check it the radiator, radiator hoses, heater hoses and radiator cap. If not one of them, then it's probably internal. What color is the oil in your car?

How does the exhaust smell and look, Is the oil level higher than normal? Does it look like chocolate milk? The only way it will leak internally is if its getting in the oil, or getting burned in the cylinders. Either way the head is gonna come off to fix this. you could try a bottle of stop leak in the radiator but i doubt it will help at all, and long term affects will be more costly.

Everyone is asking about the oil because if it looks like a milkshake then it is antifreeze mixed w oil, and likely indicates a blown head gasket. Same deal with the coolant being a milkshake: likely head gasket.

Per Scoffman, if you smell a sweet odor from the exhaust, but no white smoke is visible, , it is likely the very early stages of a head gasket failure. If there is white sweet smelling smoke (not water vapor) pouring out the tailpipe, that means antifreeze is leaking into the cylinders and burning.

Also, you could have a crack in the head where oil and coolant channels are near each other and a crack in the head may have developed in between, allowing them to mingle.
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Or the pressure gauge was not properly/completely attached when the test was done, and the leak was actually at the point where the gauge was attached.
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If your oil is at the normal level, your coolant level is at a normal level, and neither look like milkshakes, pay a few $$ to get the cooling system pressure checked somewhere else.

• Do NOT tell them you suspect a problem--they may use it to lure you into $$$ of unneeded work if they are dishonest. Tell them it's something you have done every so often for piece of mind.
• Don't tell them you are losing coolant unless you are.
• If they see traces of dye, tell them the system always has residual dye from previous leak tests
• The goal is to get a true 2nd measurement and an opinion without them having any idea what you've been previously told
• Ask them to show you the pressure gauge reading during the test--tell them you'd like to learn about it

One post on the forum and nothing in response to the suggestions; I don't think they are coming back.
I.A.D.S.
It's A D@mn Shame

posted on the 18th, last logged on on the 20th.

Probably posted on multiple boards and is back and forthing with them.

Whatever.

Outlook 2008 XR 3.6 Liter Engine, I had a water pump leak that never showed up on the ground. Once the level in the overflow reservoir dropped down near the bottom, the leak slowed significantly.
This started at around 60,000 miles, I wasn't to eager to tear into it, where the pump is, so kept supplying it with coolant. After looking on line, I found where this was a common problem, front water pump seal/bearing (no radial play though in the fan), and GM had authorized dealers to replace the water pump up to 120,000 vehicle miles. So at 110,000 miles, when the valve body on the transmission decided 2nd gear was best for all of us, I had that fixed ($1400), and they did the water pump too, very happy with GM standing behind their products.