Coolant leak
- Thread starter mtbugbee
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Steadily decreasing coolant level in the overflow bottle would be an indicator, though if there's a leak, it might not be very reliable. Unfortunately, many GM vehicles have no radiator cap that would allow direct monitoring of coolant level. Your only sure-fire way to avoid, or at least minimize, pending catastrophe is an oil analysis.
If the overflow bottle keeps going down and there is no sign of a leak + no sign on the oil report does it just evaporate in the hot summer. I think this may be whats happening on my truck this summer. I changed the cooling system fluid, a new water pump and thermostat. The truck has been used infrequently lately and it seems to be responding by the overflow going down.If it were a head gasket there would be more symtoms.The prestone I changed every 2 years since new.
I don't know if the 3.4's had the intake gasket problem that the 3.1's and 3.8's had, but keep a look out on the oil to see if any water mixed in and keep an eye to the right of the valve cover for a little puddle that slowly forms in that crevice.
This sounds just like my f150. I need to get an oil analysis done but the motor has Exxon Superflo in it so I was advised to change brands due to the sodium in the Superflo. Now I have to wait 3 or 4 months for the UOA b/c it's used only on weekends.quote:
Originally posted by LubeOiler:
If the overflow bottle keeps going down and there is no sign of a leak + no sign on the oil report does it just evaporate in the hot summer. I think this may be whats happening on my truck this summer. I changed the cooling system fluid, a new water pump and thermostat. The truck has been used infrequently lately and it seems to be responding by the overflow going down.If it were a head gasket there would be more symtoms.The prestone I changed every 2 years since new.
I also was thinking about the evaporization, but others report the level doesn't drop in their cars. Does that mean the cooling system circut is closed, so there would be no way for the water to escape?
Of course the level gradually drops (despite what some claim) - the cooling system is considered closed, but only to a point. The pressure cap releases at 1 bar, or slightly above, into the overflow bottle or the system would blow out a hose or waterpump seal. So, there will inevitably be some water evaporation, since coolant, once out of the sealed system, is being shuttled in and out of the overflow bottle at normal atmospheric pressure, but if the system is operating correctly, the loss will be negligible to the point of only needing top-up during temperature extremes, and at that, maybe after several months in those conditions. I changed out the factory coolant in my Sonata last September 3. It's now down in the overflow bottle when cold about 8 oz. from where it was when I refilled nearly a year ago in spite of a rather warm So-Cal summer this year. Where you are, you could reasonably expect a bit more loss.
Addendum: it just occurred to me that while my car's overflow bottle is not pressurized, many domestic, European, and some Japanese vehicles use a seperate pressurized expansion tank in liew of a removable pressure cap on a radiator with an integrated expansion tank. Still, the cap used will allow venting to the atmosphere when the internal pressure exceeds the nominal pressure rating of the cap. Any water vapor present in the pressurized expansion tank will be subject to partial expulsion when venting occurs. So, though these vehicles have a somewhat different system, there will nevertheless be some gradual water content loss.
[ August 31, 2005, 01:14 AM: Message edited by: Ray H ]
Addendum: it just occurred to me that while my car's overflow bottle is not pressurized, many domestic, European, and some Japanese vehicles use a seperate pressurized expansion tank in liew of a removable pressure cap on a radiator with an integrated expansion tank. Still, the cap used will allow venting to the atmosphere when the internal pressure exceeds the nominal pressure rating of the cap. Any water vapor present in the pressurized expansion tank will be subject to partial expulsion when venting occurs. So, though these vehicles have a somewhat different system, there will nevertheless be some gradual water content loss.
[ August 31, 2005, 01:14 AM: Message edited by: Ray H ]
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