Second coolant top-off in three months - Problem?

Papi325i · 12-23-2009, 12:32 PM

Hey everyone,

Quick question. I just topped off my coolant for the second time in three months. Should I be worried about this? I park in a garage and can't see any obvious leaks. Seemed a bit fast to me. Hope everyone has a great holiday.

Rudy

04 330ci
83k miles
So. California
Most recent service: Oil change in Oct.

eurodurance · 12-23-2009, 12:38 PM

How much coolant was missing each time?

GoingNuts · 12-23-2009, 12:48 PM

Aggressive topping off will get you an exploding tank.

Papi325i · 12-23-2009, 12:48 PM

At most a quart each time, probably a little less. Both times the light would come on then go off; I filled each time to the max indicated by the floater.

GoingNuts · 12-23-2009, 12:50 PM

Then you have a leak.

dmax · 12-23-2009, 12:51 PM

after topping off, start car, let warm up to op temp, and check for leaks again...expansion tank is oft. cited source of first leak...most say it never just goes catastrophically stranding you, but it certainly has happened to some.

Cooling system is closed and pressurized so the loss of coolant is certainly something to concern yourself with...unless you don't mind spending thousands for new head gasket ($1200-1500) or cylinder head (another $1000?) or engine ($$$$)

D

Papi325i · 12-23-2009, 12:57 PM

Perfect. Hopefully my CPO warranty will cover it. Thanks guys.

dave330i · 12-24-2009, 11:43 AM

Same issues for me...but I cannot find a leak, no cream in the oil either...I believe it is the tank though..will change it...rock auto has it for like $33

Papi325i · 12-24-2009, 11:50 AM

I found the leak last night. It's the coolant temperature sensor behind the left side of the radiator. Did some research and I have the classic ooze out the sides, and all the dried up coolant on the splash guard underneath. Hopefully that's just it; find out Monday.

hi its me alec · 12-24-2009, 01:55 PM

It's not very good to top these tanks off. The only time I've ever heard of them exploding is when people are having problems/leaks already, start topping off the fluid incorrectly (not saying you did it incorrectly or anything, but most people do) and overpressurizing the system.

Weird that it's leaking from your coolant temp sensor... was it ever removed, or did it just start leaking?

Papi325i · 12-24-2009, 02:31 PM

I've never touched it. But from what others have experienced I think the sensor's o-ring gets brittle and alllows coolant to leak under pressure. All the dried up fluid is right under it. Another one of those 25 cent flaws.

I know what you mean about accidentally topping off too high. Bmw's floater indicator isn't the most user friendly.

Phoenix330ci · 12-27-2009, 02:50 PM

Quote:

Originally Posted by hi its me alec

It's not very good to top these tanks off. The only time I've ever heard of them exploding is when people are having problems/leaks already, start topping off the fluid incorrectly (not saying you did it incorrectly or anything, but most people do) and overpressurizing the system.

Weird that it's leaking from your coolant temp sensor... was it ever removed, or did it just start leaking?

Yeah, mine did this too. Check my threads. Chased around this coolant problem for some time. Mine never hit the tray though, just steamed out or evaporated before hitting the tray.

After replacing enough parts (all parts not covered under CPO) I asked the dealer to look at it when it went in there for the alternator. Ended up getting a new expansion tank bracke, radiator and thermostat. The only two part now not changed in the entier heating and cooling system, is the water pump and heater core. Everythng else is new. Oh and not one time did I ever see a leak, see anything on the lower pan or find a leak trail.

12-23-2009, 12:32 PM	#1
Papi325i Registered User Join Date: May 2004 Location: Tempe, AZ Posts: 16 My Ride: 2004 330ci View My Garage	Second coolant top-off in three months - Problem? Hey everyone, Quick question. I just topped off my coolant for the second time in three months. Should I be worried about this? I park in a garage and can't see any obvious leaks. Seemed a bit fast to me. Hope everyone has a great holiday. Rudy 04 330ci 83k miles So. California Most recent service: Oil change in Oct.

12-23-2009, 12:38 PM	#2
eurodurance Registered User Join Date: Oct 2009 Location: Toronto, ON Posts: 63 My Ride: '03 330is, '87 535is View My Garage	How much coolant was missing each time? __________________ - Augustus the 2003 BMW 330i - Rachel the 1987 BMW 535is

12-24-2009, 11:43 AM	#8
dave330i Registered User Join Date: Jul 2007 Location: Hopatcong,New Jersey Posts: 559 My Ride: 2001 330i steel blue View My Garage	Same issues for me...but I cannot find a leak, no cream in the oil either...I believe it is the tank though..will change it...rock auto has it for like $33 __________________ 2001 330i 5sp Sport package ,steel blue, AA S/C , Remus exhaust, UUC Short shifter, UUC clutch stop, Braided brake lines, UUC Strut bar, Xenons, depo clears, Eagle Eye LED's

12-24-2009, 01:55 PM	#10
hi its me alec Registered User Join Date: Oct 2004 Location: Minneapolis, MN Posts: 14,790 My Ride: BMWs + 1988 Pathy View My Garage	It's not very good to top these tanks off. The only time I've ever heard of them exploding is when people are having problems/leaks already, start topping off the fluid incorrectly (not saying you did it incorrectly or anything, but most people do) and overpressurizing the system. Weird that it's leaking from your coolant temp sensor... was it ever removed, or did it just start leaking? __________________

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12-23-2009, 12:48 PM	#3
GoingNuts Just Nuts Join Date: Jul 2008 Location: London Posts: 7,254 My Ride: 2004 330Ci View My Garage	Aggressive topping off will get you an exploding tank.

12-23-2009, 12:50 PM	#5
GoingNuts Just Nuts Join Date: Jul 2008 Location: London Posts: 7,254 My Ride: 2004 330Ci View My Garage	Then you have a leak.

12-23-2009, 12:51 PM	#6
dmax Stay stock my friends! Join Date: Aug 2006 Location: Unit I Posts: 21,128 My Ride: '99 328i 1.03809 mu View My Garage	after topping off, start car, let warm up to op temp, and check for leaks again...expansion tank is oft. cited source of first leak...most say it never just goes catastrophically stranding you, but it certainly has happened to some. Cooling system is closed and pressurized so the loss of coolant is certainly something to concern yourself with...unless you don't mind spending thousands for new head gasket ($1200-1500) or cylinder head (another $1000?) or engine ($$$$) D

12-23-2009, 12:57 PM	#7
Papi325i Registered User Join Date: May 2004 Location: Tempe, AZ Posts: 16 My Ride: 2004 330ci View My Garage	Perfect. Hopefully my CPO warranty will cover it. Thanks guys.

12-24-2009, 11:50 AM	#9
Papi325i Registered User Join Date: May 2004 Location: Tempe, AZ Posts: 16 My Ride: 2004 330ci View My Garage	I found the leak last night. It's the coolant temperature sensor behind the left side of the radiator. Did some research and I have the classic ooze out the sides, and all the dried up coolant on the splash guard underneath. Hopefully that's just it; find out Monday.

12-24-2009, 02:31 PM	#11
Papi325i Registered User Join Date: May 2004 Location: Tempe, AZ Posts: 16 My Ride: 2004 330ci View My Garage	I've never touched it. But from what others have experienced I think the sensor's o-ring gets brittle and alllows coolant to leak under pressure. All the dried up fluid is right under it. Another one of those 25 cent flaws. I know what you mean about accidentally topping off too high. Bmw's floater indicator isn't the most user friendly.