Coolant leak and hissing. URGENT help needed.

rolotomassi44

Veteran Member
Joined
Dec 1, 2010
Location
West Lafayette, IN
TDI
2004 Volkswagen Passat GLS TDI
Hey guys,

So I already had a minor leak chocked up to the EGR cooler that I was going to replace anyway.

However last Friday (20th of July) I had a very minor fender bender where I rear ended someone. Arguably, the only known damage to my car was cosmetic (my bumper). However yesterday after I arrived at the local Target in the afternoon, I noticed a strong hissing sound (like my tire was punctured). I opened up my bonnet and saw that the sound seemed to be coming from the back of the engine. I've included a video that I took (just ignore the baby sounds as I was in the parking lot):

http://www.youtube.com/watch?v=hT-zF3dlkUY

When I arrived back home (my house is on a hill). I noticed a trail of coolant while I was driving slowly up the hill. My Mother then decided to point out to me that she noticed a small puddle of coolant in our garage before we left on our shopping trip.
I thought it might have been low coolant - so I topped it off (with distilled water).

I later went on a drive last night in Boston for about 10 miles or so. This is the first time I've seen my car overheat. The gauge was basically halfway between 190F and the redline, sometimes it seemed a little closer to the redline. I immediately drove back home. I listened to the engine bay and the hissing was still there albeit MUCH less pronounced.

For the record my car is pretty much running 100% distilled water temporarily and I've had no problem with the temperature going above 190F before. All that used to happen is the car would warm up pretty quickly. I've only been running this mixture for a few months while I saved up to fix everything on my car (I'm a poor student). I have 145K miles on it.

The thing is I have work on Thursday (I'm a delivery driver) and I need to get this fixed ASAP. I should be able to fix this myself as I am an aerospace engineer and naturally mechanically inclined.

Also I saw this wire touching the engine in the rear. Is it normal to be in this position?

http://imgur.com/f7iaf
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Minor damage on the front end can still pierce a hole in the radiator, crack a hose connector neck, etc. If your belly pan is still on, the fluid could be dropping on it at the front and running to the back of the motor.
 

turtle1026

Veteran Member
Joined
Feb 9, 2010
Location
Florida
TDI
2004 Passat
Since the hissing is from the back of the engine, you should look in 2 possible places for the leak. One is the coolant flange attached to the back of the head. It is very hard to see, but that is a common failure point. The other would be to remove the black plastic cowling to inspect the connections to the heater core. This is the large black plastic piece that covers the battery, A/C connections, etc. It is held in place by the black weather strip. Assume for the moment that the coolant leak is coincidental and not related to the bumper impact.

Keep it full of water if you have to make deliveries. Keep extra water with you and inspect the level in the reservoir periodically between stops. Don't use the temp gauge because it won't give you true readings. It should hold out until you can replace the flange, its seal, or replace whatever hose may have failed.

It is not ideal to ride around like that, but you have to do what you have to do.
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Sorry, missed the comment about coming from the back and cannot view Youtube video from work.
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
The hissing would concern me, particularly since you are just adding water to the reservoir, not opening the bleeder at the heater core. The hissing can be super heated steam from not having cyl head totally filled. As others have stated here, its likely the coolant leak is the flange/hoses on back of head. continued operation in this manner has the potential of expensive damage.
 

rolotomassi44

Veteran Member
Joined
Dec 1, 2010
Location
West Lafayette, IN
TDI
2004 Volkswagen Passat GLS TDI
What could cause the flange to fail though? Could overfilling the reservoir cause this? My car was losing coolant pretty badly because of the EGR already, when I lent my car to my friend for the past few months I have a feeling he topped it off to the brim.
 

aja8888

Top Post Dawg
Joined
Dec 25, 2007
Location
Texas..RETIRED 12/31/17
TDI
Out of TDI's
What could cause the flange to fail though? Could overfilling the reservoir cause this? My car was losing coolant pretty badly because of the EGR already, when I lent my car to my friend for the past few months I have a feeling he topped it off to the brim.
Rubber O ring fails (gets soft, etc). Then it leaks.
 

rolotomassi44

Veteran Member
Joined
Dec 1, 2010
Location
West Lafayette, IN
TDI
2004 Volkswagen Passat GLS TDI
I added a half gallon yesterday, drove 10 miles, now the STOP coolant low light has come on. That's how bad my leak is. I probably have to add another gallon or two.
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
there are shops in your area that can address your problem. As Tony just pointed out, not getting it fixed can and will cause severe damage.
 

jetlagmech

Veteran Member
Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
coolant not only is for freezing and boiling point of the radiator water but also corrosion prevention of head and block passages the coolant passes thru. wifes brother had a car we found a hole eaten thru block between water and oil passage, he had been using just water in it. I very much understand tight financial positions but realize that waiting might cost a lot more later.
 

rolotomassi44

Veteran Member
Joined
Dec 1, 2010
Location
West Lafayette, IN
TDI
2004 Volkswagen Passat GLS TDI
Yes I understand. I've been running 100% distilled water for the past few months only (hardly driving it at all). I'm driving it to Keith @ KMH Motors in Lowell, MA this morning to fix the problem.
 

rolotomassi44

Veteran Member
Joined
Dec 1, 2010
Location
West Lafayette, IN
TDI
2004 Volkswagen Passat GLS TDI
Well I just had the flange, temperature sensor (including deals and clips), and thermostat replaced. We are beginning to think there is either air in the system or the water pump has failed (which is strange since I have the metal impeller installed 25,000 miles ago). Thoughts? I really hope the pump hasn't failed especially seeing as it's been roughly a year since I had it replaced.
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
pressure test system to see if pressure builds from escaping exh gasses. its also likely unless the system is filled with the reservoir tank elevated, that air will be trapped in the heater core
 

rolotomassi44

Veteran Member
Joined
Dec 1, 2010
Location
West Lafayette, IN
TDI
2004 Volkswagen Passat GLS TDI
Yep guys, turned out to be air in the system. Drove around a bunch until air started to escape into the reservoir.

Flange was broken just like the other thread - was causing the noise.

Suspected air in the system/faulty thermostat was causing overheating.

Thanks a lot guys! Big help here.

Also I highly recommend Keith at KMH Motors in Lowell, MA. Top bloke.
 
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