DF

I have a 2000 SS with 138K miles. About 2K miles ago I replaced the radiator. Ever since then, Ive been able to hear a boiling sound from the radiator. I hear it after turning the car off. The boiling sound will remain for 1-2 minutes after shutting off the car. No leaks. THe temp reads normal on the dash meter.

Did I put too much water? not enough Coolant?

THoughts? other wise the car runs fine.

TIA!

Element

iTrader: (5)

Did you purge the air properly from the system after refilling the new radiator?

guy7bmwm83

iTrader: (5)

Mine did this too a few weeks ago while in Yosemite. I had changed the radiator over 6 months ago and had no issues. However, I did notice that my radiator cap was not fully closed. As soon as I closed it, it stopped making that sound. The arrow on the cap was pointing to the hose, but I had to turn the cap slightly more.

2001NBMZ28

Same thought here - radiator cap not holding pressure.

remauto1187

iTrader: (1)

Are you sure its coming from the radiator and not the A/C condenser coil mounted on the front of the radiator. (It looks like a smaller radiator). It is normal for you to hear a boiling noise after you shut a vehicle off that has had the a/c on. That sound is actually the refrigerant boiling.

killagt

iTrader: (3)

what kind of radiator cap do you use ? it happent to me when im using auto part radiator cap, swap for GM one, never happent again.

guy7bmwm83

iTrader: (5)

I purchased an AC/Delco one. But that was the only time that I heard boiling from the radiator and it actually spewed out coolant from the tank. It must have loosened.

Pony Exp.305

iTrader: (6)

check possible blockage or wrong cap..
Try Rad.pressure tester..

DF

Thanks everyone. I checked the fluid level and it was low. Low enough that I couldn't see the level of coolant. I added a pint or so of coolant. I also squeezed al of the hoses to make sure the air was purged. So far no boiling sounds.

I have the original rad cap. It doesn't look to be faulty. I do have 138k miles so maybe it's time for a replacement

guy7bmwm83

iTrader: (5)

This happend again, this time south of Mono Lake. Coolant was spilling out of the overflow tank, but the needle was at normal temperature. I am going to reinstall the old cap and see if I got a bad new cap. Maybe my car doesn't like the high elevations?

This doesn't seem to happen while operating the car in central Ca, which is nearly sea level.

guy7bmwm83

iTrader: (5)

This has happened again to me near the coast at an elevatoin of about 2500ft. Coolant spilled out of the recovery tank. The cap is less than two years old and is an Ac/Delco rc94. I am going to install a new cap since I am heading to Yosemite on Saturday and see if it does this again.

I would like to mention again that I do not have this problem at sea level.

raysadude

iTrader: (11)

I think there's water in your system, check the radiator cap, mine was cracked when I had this problem.

guy7bmwm83

iTrader: (5)

I switched to a non Ac/Delco style plastic cap. Its aluminum, but have not taken the car to high elevations. Time will tell and will report when I go to the mountains.

DisasterFormula

iTrader: (1)

Liquids boil at a lower temperature at higher altitudes. Physics. Might have too much water in your mix. Also, do you have all your hoses routed properly? Usually coolant comes out of the recovery tank b/c you have a pair of lines swapped.

guy7bmwm83

iTrader: (5)

I am using green antifreeze and kept it at a 50/50 mix. I will double check the hoses to make sure they are routed properly.

guy7bmwm83

iTrader: (5)

I would like to report back on this issue again. I have still not solved this. Since the last time I posted, the radiator was replaced, upper radiator hose, coolant recovery tank, and recovery tank hose. This issue has happened with two different radiators and three different radiator caps. Coolant mixture is 50/50. Boiling over sound has never happened at sea level. I do not have white smoke coming out of the tail pipes either and the coolant recovery hose is on top.

I got the boil over sound Friday night at 9pm (air temp ~ 50F) at 5000ft when I parked at a ranger station. I didn't experience this again until Saturday afternoon at 5pm (air temp ~80F) at 7200ft.

The operating temp has always been normal when I get this boil over sound and have never overheated. The Saturday episode did have the temp gauge a tick warmer than normal, but I was driving 10mph for about 45 minutes on a dirt road uphill.

I also drove the car to Sequoia National Park in May at elevations up to 7500ft and did not have a boil over sound the three days there while driving.

I drove the car at sea level when temps were about 110F for several days and never had issues. I also drove on some foothills around 1600ft when it was 110F and the temps did climb several ticks, but would decrease to normal; I am guessing when the fans would come in.

I have not changed the thermostat in like two years, could this be the problem? Should I be worried about this if it runs fine where I live?