hello everyone. i need help. right off the bat i will tell you that i`m not a very good mech. i can do the simple things like tune ups and changing the alter and other little things. anyways heres my problem when ever my truck sits it leaks antifreeze. i cant tell where its coming from but it appears to be coming from the reaqr of the motor. i dont know if this is blow back from one of my hoses or freeze plugs or what. if it is the freeze plugs what kind of damage are we looking at? also the truck doesnt run hot. the water pump was changed 3yrs ago but this has been a on going problem. any help would be greatly appreciated.................

 

Rear of the motor sounds like head gasket.

 

would it not show up in my oil too?

 

Not necessarily. It depends on where the leak is. The head gasket can leak in a few different ways. You can get cross contamination between oil and coolant, then yes it would show up in the oil too. The coolant, or oil,can leak to outside. Or, coolant or oil can leak into the cylinders.

Try to clean around the gaskets, run the engine and see if you can see any fresh coolant leaking to get a better idea of where exactly it's leaking.

 

What year is the truck- if you got a 350 or 305 and still have the ****ty dex cool in it you either need new intake or head gaskets. After changing them fill with regular green antifreeze- solved all my problems anyways

 

it`s vortec 6cl 4.3 1999. and yes it has the orange coolant

 

Replaced a lot of lower intake gaskets for this kind of leak.

 

Pressure test it but I would put money on it being the intake gaskets very common in that motor. Never had the problem come back after switching away from dex cool.

 

This is from wikipedia:

DEX-COOL specifically has caused controversy. It is causally linked with intake manifold gasket failures in GM's 3.1L and 3.4L and with other failures in 3.8L & 4.3L engines. Class action lawsuits were registered in several states, and in Canada, to address some of these claims. The first of these to reach a decision was in Missouri where a settlement was announced early in December, 2007. Late in March 2008, GM agreed to compensate complainants in the remaining 49 states.

There are rumors that mixing Dex-Cool with standard green (non-OAT) coolant causes a chemical reaction that produces sludge in the cooling system. According to the DEX-COOL manufacturer, however, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch’s change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."

According to internal GM documents, the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as Dex-Cool). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently.