2003 Grand Prix Vapor Locking?

[GaryFenza]

i have a 2003 Pontiac Grand Prix GT 3800 Series II v6 with 121k miles. I am noticing some coolant seepage, and the base(gasket) of the uper intake manifold(plastic one) in the back of the manifold. Isnt this the sign of the all time famous Vapor lock. I put some Radiator stop leak in the radiator and then put some "Bars" powder tablets into the radiator, they supposedly stop the leaking of coolant, whats your opionons on this .

[BNaylor]

Fuel injection systems do not "Vapor Lock". A bad UIM or gaskets to include LIM may cause a "Hydro Lock" of the engine. But that doesn't appear to be your case.

You should never use radiator stop leak. Most of the time the stuff doesn't work or causes other issues.

[CrazyHorst]

True fuel vapor lock should not happen with a healthy fuel pump. There's a tremendous amount of abusive development testing by GM with winter fuels in desert climates to make sure that this isn't even a remote possibility.

Relative to sealants, GM actually puts 1 "dog turd" into each vehicle on the assembly line after the radiator is filled as an aid to stopping any weeping leaks.

As such, I think the product might work for a time, but I also think it is stopgap at best and you are just buying time before the problem gets rapidly worse. Personally I'd schedule a time to do some inspection and possibly teardown to see what's up.

I'd rather lay under the car for *hours* at a time in the comforts of my own shop with all the right tools & equipment a few feet away rather than be on the side of the road at night with the cars going by at 70mph searching for a flashlight and leatherman to work with...

[GaryFenza]

I have a 2003 Pontiac Grand Prix GT 3800 Series II v6 with 121K miles. Motor runs strong so does transmission. I was a little concerned about some seepage i noticed around the back end of the Uper Intake manifold. I did put some GM coolant tablets in the radiator. That leak is not going to turn into a hydro locking situation is it?? There is no coolant in oil and not sludge on oil fill cap and engine runs fine. what my situation here?? thanks

[CrazyHorst]

IMHO its very important to monitor your coolant level as the vehicle ages.

When you have mysterious loss then it's time to see what's up.

Any leak that gets into the oil is of course going to give a milkshake when you change it.

The other likely possibility is from the combustion chamber into the coolant jacket thru a weak point in the headgasket. In my experience this failure mode will boil off coolant for a long time (1000 psi vs. 10-50psi doesn't need a very large leak path) before it would develop into a steady stream that could lead to a hydrolock condition....so if you are paying attention to the level, you'd note that and schedule some downtime to make repairs.

You can also leak into the intake tract too (it washes the piston(s) shiny clean ) which would give a telltale of grey smoke out the exhaust.

There's certainly an upper limit to what the base engine and sealing of a gasoline engine can take....I'm stating my personal belief with current technology at around 200k miles when you should likely be thinking about a reman or refurbish...

[BNaylor]

GaryFenza,

Your new post has merged with the prior post you had which is the same issue being addressed. For the last time please do not to run separate or multiple threads on what appears to be the same issue. All it does is cause confusion and redundant replies.