Loud gurgling sound from coolant tank

Lately after driving the car, when I shut it off I pop the hood to cool off the motor faster (and possibly save my wiring harness some stress), a very loud gurgling sound can be heard near the tank and in the wheel well as the coolant level goes down in the tank. I know the expansion tank is in the passenger side wheel well area and my question is: is this a sign of future trouble in my '94 E320 wagon with 176,400 miles on it? The engine temp has been fine even in 90 + F days and the noise stops about 10 minutes after cooling down.

Thanks tkamiya. When the car is cold the fluid level is even with the seam in the tank. After driving the car for a while the fluid level is almost to the top of the tank - almost touching the cap. Maybe you're right and I need a new cap?

[sbourg]

'Gurgling' means the coolant is boiling - not good. Likely causes are a loss of pressure or incorrect coolant mixture. If pressure is dropping, you can hope a new resevoir cap will take care of it.

Steve

[DJNEWK2]

I agree to check your cap because that's the easiest route right now. Also, check to make sure your hoses are alright. Does your temps stay up while you're on the road or is it basically when you get off of the highway,etc and start to cruise (when the engine is all wound up).My 560 was doing the same thing when I'd shut the car off and would make the same sounds you could hear in the cabin.

I changed the coolant expansion tank (because the neck actually did have a slight weak spot and I'd see water bubbles seep from the old neck from the pressure). I also changed the thermostat, and finally I replaced the radiator which solved the high temps and she's not gone above 82 degrees since.

I thought it was the radiator but was reluctant to believe it because it was a "new" radiator that I'd installed not even a year ago.Check the little things first and then consider the radiator not letting your coolant circulate properly.Feel the radiator for cool spots after you take her off of the road. Also, make sure that the system doesn't have air in it . Hope its something minor but you never know.Good Luck!

Alan
High Engine Temp! Need Help Asap Guys!

[Rockman59]

I just had this same problem only with my 1992 GMC Suburban 350 V8 engine.....turned out it was a faulty thermostat. Water gurgled in the expansion tank when engine was turned off after high speed travel and filled the expansion tank until it overflowed. The heat guage had been reading higher than normal for several days but still within acceptable limits. Yesterday in finally moved up into the "red zone". The radiator and water pump were new in the past 20,000 miles so that pretty much narrowed it down to the thermostat...and that's what it was.

I can hear this noise in my cabin also. Cap is new, radiator is new. Car hits 90 c because I need a new fan clutch but normally stays at 82. The noise is not coming from the exp tank though, it's coming from behind my firewall. Is this also indicative of a coolant prob - poss related to the thermostat? I do not know if it was replaced. Coolant hoses could also be replaced in next 30k also.

Also, is there a way to determine the right coolant mixture? Can this be determined by the reading on one of those coolant temp droppers with the little colored balls inside?? I mean, if the reading is consistent with specs I would assume the right mixture and if it were below spec - add coolant instead of water??

Hey tkamiya - new coolant tank cap (~$7.60)= problem gone just like you said. Heavy driving today at +90 F ambient and level in tank was about 1/2 inch above seam with new tank cap. Thanks a ton!