car dumps coolant

lieast · Post by **lieast** » 08 Mar 2012, 20:59

i have a 2004.5 volvo s40 T5

i have been having a problem with my antifreeze over flowing and dumping out...seems to happen once i shut the car off or just idling almost seems like a bad thermostat that doesnt open and the hot coolant just dumps out the over flow...

the only thing that gets me is that the gauge inside the car doesnt show "over heating" and i cant "make it happen" i sat with the car for a long time and nothing would happen... it happened 2X then didnt happen for about two weeks and happened again today.... im thinking therostat is going so plan on changing it with the ECT sensor but just want to see if you guys have any opioins....

fan does kick on with AC and kicks on here and there but doesnt stay on if i shut the car off.. if i can add anymore info let me know ill try to fill you guys in as much as possible.

Post by **zulu-v40** » 09 Mar 2012, 05:43

Seems like you're on the right track to me, but admittedly I'm no expert. Do you have a CEL? How many miles are on the car? Is there any history of the thermostat or ECT being changed previously?

Post by **regent** » 09 Mar 2012, 05:59

It would not hurt to check the actual coolant temperature and replace the T-stat with a known good one. Also, verify that your radiator fan operates at all speeds. Sometimes the ECT Sensor fails at the same time when the T-stat does, and then the gage will 'fool the system', too. I would start by eliminating one suspect at a time.

In addition, overpressure in the cooling system may be due to a blown head gasket and subsequent leak of compressed gases into the cooling system. With the expansion reservoir cap removed, start the cold engine and let it idle. Observe the coolant in the tank; as the engine runs, in most cases you may notice bubbles due to compressed gas mixture leaking into coolant. The rate will usually vary with block temperature and engine RPM.

Hope this helps

lieast · Post by **lieast** » 09 Mar 2012, 10:26

I'm gonna start with the T stay and ect sensor frist I don't think it's ever even changed and car has 170,000 on it.... There's no CeL I checked yesrterday.

Besides this problem car runs perfectly fine.. So i don't think it's the head gasket the res tank looks fine while running no crazy buddles or oil residue

Thanks ev

Post by **regent** » 09 Mar 2012, 16:18

OK, sounds like a good plan. Make sure your fan is fine, too. Also, at 170 k you want to verify that the timing gear has been serviced before, if you can't then you want to do that ASAP with this mileage!

lieast · Post by **lieast** » 09 Mar 2012, 16:44

Yea the timing belts have been changed that's all good...

Now the ect sensor is that the sensor that would keep the fan on after the car is shut off? Cuz the fan kicks on like if you kick the AC on so I know it works but it NEVER stays on after the car is shut off.. I know it's not that hot out right now 50* s but still.

I have a new ect sensor and t start coming Monday... But it dumped out on me 2x seems like when I shut the car off

Post by **318mike** » 09 Mar 2012, 16:45

Having a similar problem.Just drove for two hours on a trip and when I arrived at destination I noticed coolant on the ground opened the hood and coolant was being forced out of the radiator cap, gage reads 3 0'clock steady.A couple of weeks ago I replaced thermostat and ect because temp needle would move up and down randomly.Now the temp gage is fine.Could you let me know how you make out..thanks

Post by **318mike** » 09 Mar 2012, 16:59

you can search(ect) in the search box and get an idea how the ect works

Post by **318mike** » 10 Mar 2012, 12:24

I changed the thermostat on mine and it seems to have fixed that same problem,good luck.Could you let us know

ed7 · Post by **ed7** » 10 Mar 2012, 12:42

Don't ignore the cap. It probably needs to be replaced.
Ed