Coolant Temperature Light Flashing

swartzzz

Active member
Joined
Nov 22, 2009
Location
Pittsburgh, PA
TDI
None, yet
Wife got into the PTdi this morning started it, and the coolant light was flashing. Not sure if this has happened to anyone before, but the reality is that the display reads coolant low, but it is not! Also, the temperature climbed to 190, and not any further! Any thoughts? Should we monitor or make an appointment with the dealer?
 

Softrockrenegade

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Aug 25, 2011
Location
Howellbama, NJ
TDI
None...2011 Golf DSG (replaced by VW W/) 2013 Passat SE 6M(bought back) Current 2017 sportwagen TSI 4Motion.
Add some coolant ? Check your oil for contamination .
 
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tdiatlast

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Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
190 (straight up) is exactly where it should be after fully warm. The temp is actually fluctuating, but the gauge is "buffered" (it's an idiot light with a dial) so as not to alarm the average consumer.
In reality, my scangaugeII shows operating temp of 204-206...the dash gauge still reads 190.
As for the flashing light, are you certain about the coolant level?

Also, you might want to update your signature so we know what kind of car your asking about.
 

VeeDubTDI

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Springfield, VA
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Gauge will display 190 when the actual temp is between 165 and 225, so you can't rely on it for an accurate measurement.

Add a few ounces of distilled water and see if the light stops flashing.
 

edsiajb

Veteran Member
Joined
Aug 5, 2001
Location
Birmingham, Alabama
TDI
2012 Passat TDI SE
OK...so I just went downstairs to check it and yep, the reservoir is almost dry. I shined a bright light down to the belly pan and it's dry...can't see any moisture there. There is sticky moisture (like partially dried coolant) on parts of the inner fender (around the WW fluid reservoir).

This is so aggrevating on a car with 12000 miles...along with about 15 rattles that VW dealership has been unable to resolve.

I don't think this car is going to be anywhere near as reliable as my 2001 Jetta TDI. My wife's last car was an Avalon...we put over 200,000 miles on it without a single failure of anything. Would have kept it if not for being a family of five with three teenagers. The Avalon would probably do 300,000 before a failure. A current VW makes it a whopping 12,000.
 

ChadS99SVT

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Jul 17, 2012
Location
Parker, CO
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2013 Passat TDI DSG
OK...so I just went downstairs to check it and yep, the reservoir is almost dry. I shined a bright light down to the belly pan and it's dry...can't see any moisture there. There is sticky moisture (like partially dried coolant) on parts of the inner fender (around the WW fluid reservoir).
This is so aggrevating on a car with 12000 miles...along with about 15 rattles that VW dealership has been unable to resolve.
I don't think this car is going to be anywhere near as reliable as my 2001 Jetta TDI. My wife's last car was an Avalon...we put over 200,000 miles on it without a single failure of anything. Would have kept it if not for being a family of five with three teenagers. The Avalon would probably do 300,000 before a failure. A current VW makes it a whopping 12,000.
So what failed then?
 

edsiajb

Veteran Member
Joined
Aug 5, 2001
Location
Birmingham, Alabama
TDI
2012 Passat TDI SE
So what failed then?
I don't know yet, but I know they checked all the fluid levels (I visually confirmed) 2000 miles ago at my 10k service.

I don't have the required type of coolant, and my dealership is 35 miles away. Will I be able to make it to the dealership with an empty coolant reservoir?
 

kjclow

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Apr 26, 2003
Location
Charlotte, NC
TDI
2010 JSW TDI silver and black. 2017 Ram Ecodiesel dark red with brown and beige interior.
Put some water in the reservoir and start the car. Try to determine where the leak is coming from. It might just be a loose connection on one of the reservoir lines.

You can also pop off the radiator cap and visually inspect the level in the radiator. May want to do this before you start the car or at least before you get it hot. Your local autoparts store should have the correct antifreeze so you can top it off to get to the dealer.
 
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vwtrooper

New member
Joined
Mar 25, 2004
My light started flashing this morning as well. All the way to work. Needle is at 190. 11,200 miles on a 2012 Golf TDI. I just had it in for the 10k service at around 9800 miles. I'll have to walk out and pop the hood to check coolant. Inexcusable on a practically new car! :mad:

***Just went out to check and it's about 2.5 inches below the cold fill line. ***? Where did it go? If they properly completed the 10k service I'll assume it was topped off. I didn't have a puddle on my driveway.
 
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edsiajb

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Aug 5, 2001
Location
Birmingham, Alabama
TDI
2012 Passat TDI SE
Put some water in the reservoir and start the car. Try to determine where the leak is coming from. It might just be a loose connection on one of the reservoir lines.

You can also pop off the radiator cap and visually inspect the level in the radiator. May want to do this before you start the car or at least before you get it hot. Your local autoparts store should have the correct antifreeze so you can top it off to get to the dealer.
I just called our only auto parts store and they don't have the correct coolant. I can get some distilled water locally though....
 

edsiajb

Veteran Member
Joined
Aug 5, 2001
Location
Birmingham, Alabama
TDI
2012 Passat TDI SE
You probably have to live in Alabama (like me) to completely understand this, but when I called our auto parts store this morning this was the conversation:

Me: Do you stock G12+ coolant?

Them: What???

Me: G12+ coolant

Them: Whatsthatgoin?

Me: A 2012 VW

Them: Let me put you on hold and look that up

Me: OK

Them: (after about 4 minutes on hold) We aint never heard of that...what country was that car built in?

Me: The fair Republic of Tennessee

Them: Hell



At least I found some good humor in my disparaging moment....
 

kjclow

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Apr 26, 2003
Location
Charlotte, NC
TDI
2010 JSW TDI silver and black. 2017 Ram Ecodiesel dark red with brown and beige interior.
My light started flashing this morning as well. All the way to work. Needle is at 190. 11,200 miles on a 2012 Golf TDI. I just had it in for the 10k service at around 9800 miles. I'll have to walk out and pop the hood to check coolant. Inexcusable on a practically new car! :mad:

***Just went out to check and it's about 2.5 inches below the cold fill line. ***? Where did it go? If they properly completed the 10k service I'll assume it was topped off. I didn't have a puddle on my driveway.
It might only leak when running. I had a 90 Ford that had a master cylinder leak (replaced it 3 times in 13 months) that only occured while running and applying brakes. You could see the damage from the brake fuild but could not tell where it was coming from.
 

kydsid

Veteran Member
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Apr 18, 2012
Location
Texas
TDI
2012 Passat
I just called our only auto parts store and they don't have the correct coolant. I can get some distilled water locally though....

Stores don't always know what G12 means, that is the specification, they know by car, or trade name.

I know at least OReilly Auto Parts will have it, just ask for Pentosin Pentofrost++

Expensive stuff though, so you may want to run distilled water till you find the leak.
 
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armstrongtrucks

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Aug 5, 2005
Location
Butler,PA
TDI
2015 PASSAT SEL TDI
I lost all my antifreeze a month ago. There is a small hose on top of radiator left side that blew off. It stayed in the hole, looked ok. It just kept leaking. About 3/4 '' if I was guessing, it goes to the block. There is a wire clip holding it on. I blamed the body shop for not installing it correctly! ? Would love to post a picture, just never any luck getting them to post. They bought the antifreeze to refill it.
 

edsiajb

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Aug 5, 2001
Location
Birmingham, Alabama
TDI
2012 Passat TDI SE
I may have discovered the issue. When I removed the cap, there was a long blonde hair that the cap had been closed on (but no blondes in my family...the dealership technician who did my 10k service was a young guy with shoulder length blonde hair...lots of it). Maybe that kept it from sealing well? And that would explain why the coolant residue is on the fender underneath the reservoir....

If so, it was not a failure with my car but a mistake/blunder by the dealership technician.
 

VeeDubTDI

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Springfield, VA
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We have low coolant, too. Not low enough to make the light come on... It has been like that for a while, though.
 

TheGrove

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S Central PA (Breezewood)
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I've had the light come on the last 2 mornings but not yesterday afternoon or anytime before that. I figured it's just the cold really contracting the coolant. I'll get it topped up this am while it is being serviced.


Sent from my iPhone using Tapatalk
 

Hypermile

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Nov 22, 2013
Location
Toronto, Canada
TDI
2013 Passat TDI DSG Comfortline+Sport Pkg
I just check MY car this morning and it is low too, all I see is a small pool of pink in the bottom of the tank. I'm surprised that the MY coolant light did not come on though.

My buddy called the dealer last night and they are saying that there were about 20 cars with the same issue. Dealer says it's due to the cold weather evaporating the water. I have a hard time believing that!

I know coolant will evaporate over time but to go almost empty from 0KM to 3000KM is concerning and my buddies car has even lass mileage. I thought the cooling system was a sealed system. I never even had to top up the coolant in my B7 A4 and its got 185000KM and 6 years of driving.
 

VeeDubTDI

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I think they were under filled from the factory and the cold weather is making the coolant contract enough to trip the low level alarm. Simply add some coolant and keep an eye on it to make sure it isn't disappearing.
 

Hypermile

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I think they were under filled from the factory and the cold weather is making the coolant contract enough to trip the low level alarm. Simply add some coolant and keep an eye on it to make sure it isn't disappearing.
Do you know what level it needs be be for the alarm to go off? Mine never came on.
 

tdiatlast

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Hypermile: Your coolant did not "go almost empty". Keep in mind you're looking at the overflow reservoir, and even if it were empty, there would be no problem with the cooling capability of the system.

I agree with VeeDubTDI: Low coolant? No big deal. The water didn't evaporate (impossible in a sealed system), there's probably no leak. It's simply coolant contracting because of the extreme cold, and a possible underfill from the factory. Top it off and move on!
 

VeeDubTDI

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It needs to get very low in the reservoir to trip the low level sensor... I'd say within an inch of the bottom, but I don't know for sure.
 

kjclow

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Apr 26, 2003
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Charlotte, NC
TDI
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The coolant system is not a sealed system. At least it is not a completely sealed system. Your resevior cap does not form a complete seal to allow for expansion and contraction of the water and coolant mixture. Your AC system is a sealed system so that you're not harming the environment by leaking ozone depleting chemicals into the atmosphere. Your brake system is a sealed system so that you always have the correct level of fulid to react to the pressure on the brake pedal.

I think when my coolant light went on, the resevior was completely empty. Still only took a little over a quart of mixed solution to fill to the full hot line.
 
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VeeDubTDI

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Well... sort of. The cooling system is sealed so that it will pressurize in order to resist boiling. If it over-pressurizes, the cap will relieve pressure. Unless you remove the cap or the cap is relieving pressure, the system is essentially sealed.

As for the brakes, the pressure side of the system is sealed (obviously, in order to form hydraulic pressure), but the reservoir is not (small air vent in the cap).
 

Hypermile

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Nov 22, 2013
Location
Toronto, Canada
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I think they were under filled from the factory and the cold weather is making the coolant contract enough to trip the low level alarm. Simply add some coolant and keep an eye on it to make sure it isn't disappearing.
Thanks! Got it topped up at the dealer after work today. Will watch and shoot.
 
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