Expansion tank and coolant reservoir in 2007 pontiac torrent.could one of them have a small hole in it , i lose fluid on driver side fender well

SOURCE: Losing coolant thro the expansion

Hi,
Not too familiar with this model but.... First some questions! Has the fault started after the pipes & rad replaced or were they replaced to remedy problem? If fault happened since work then i'd suggest an air lock in the system in which case you will need to 'bleed' the system of air. Make sure the expansion tank is the highest point & look for any bleed valves on the hoses - usually near the heater matrix. Sometimes it may be necessary to help the process by removing the temperature guage sender unit to allow the air to escape as air cannot pass through a closed thermostat. If the fault was there before, does the expansion tank seem to build up pressure very quickly? Do lots of air bubbles appear with the engine running & the pressure cap off?

Marvin

• 85242 Answers
• Posted on Feb 25, 2009

SOURCE: ECT sensor 2007 Pontiac Torrent

no just lower the level or be quick about plugging in the new sensor, that is what I do, u may lose a cup of coolant but much less hassle than draining the radiator.

SOURCE: Water leak from top of expansion tank.2000 BMW 316i se

The water (coolant) in the expansion tank will rise and fall with the engine temperature. What the expansion tank does is collect and return coolant to and from the engine. When the engine warms up the coolant gets hot, builds up pressure and opens up the radiator cap. The coolant then goes into the expansion tank. Now when the engine cools down the pressure drops in the cooling system and the pressure drop (vacuum) pulls the coolant back into the engine via the radiator cap. The radiator cap allows the cooling system to build up pressure and by doing so increases the boiling point of the coolant, but when that pressure exceeds the caps rating the cap opens and the coolant goes to the expansion valve. The cap has another part to it that when the engine cools down and a partial vacuum is created in the cooling system a "valve" in the radiator cap opens and allows the coolant to be drawn back into the engine. I would look at your radiator cap to see if any gunk or build up is on it, and check the rubber gaskets for cracks. It's easiest just to replace the cap because they are inexpensive and easy to replace (2-10 dollars). The expansion tank should have two hoses on it. The one on the bottom comes from the radiator and the one on the top (possibly part of filler cap) runs down and is open to the ground. That way if it is overfilled or becomes overfilled it will slowly leak onto the ground. When and if you change your radiator cap, make sure the engine is cooled down, remove cap and start engine and turn heater to full blast, full heat. Leave the cap off and let it run until engine warmed up. This should burp out any air pockets that may have happened when coolant was changed. Also top off the coolant in the radiator while it is running. Hope this helps and good luck

SOURCE: Water leaking from top of expansion tank.

have you replaced the bleeder screws? and the expansion tank cap they both have O-rings that compress and will fail over time also check the hose at the top of the exp tank it also has o-rings inside it

SOURCE: have oil in my radiator fluid reservoir tank (1996 v6 3.8)

Twice in two years now my Saab 9-5 has had a pin-hole in the oil cooler, which has caused oil to flow into the reservoir. A way to tell is if coolant/oil is coming out of the reservoir cap. The reservoir cap is rated for the pressure of the coolant system, which is significantly lower than the oil pressure. When there is a hole in the oil cooler, oil will be forced out at relatively high pressures, causing the reservoir to fill and then over pressurize and spill out of the cap.