Radiator hose popped off

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
On the highway today about an hour into a drive, -20C outside and suddenly lost all heat. Had just enough time to say *** before the coolant level alarm sounded.

Pulled over and popped the hood, coolant had sprayed pretty much the entire engine bay - the upper radiator hose had popped off at the radiator. Both plastic fittings were intact and the clip was in the correct position, so how did it come apart?

I did replace the radiator 7 months and 15,000km ago. I find it difficult to believe it took that long to blow off if I did not get the clip in the slot then, but I can't think of another explanation.

I reassembled the connection, drove 15km without coolant to the nearest crappy tire, bought coolant, poured it in, and drove another 150km without issue.
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
if you ran low on coolant enough... it can flash boil in the engine making some intense pressure.
Runt he car up to temp. park it. after a few hours take the cap off, a tin y ppst is no big deal but a big pssssssssst or woosh of pressure with hard coolant pipes is clearly either a EGR heater failure a head gasket issue.
had a few issues myself in various cars and the #1 thing they all have in common was that after i drove it even slightly that the heads all wrapped and these engines are specifically susceptible to wrapping heads form low or no coolant running for even a short distance. hope you got lucky!
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
At these temperatures even a tiny psst after a few hours would indicate a major problem. I checked it after 10 minutes, hoses were soft and there was only a little residual pressure.

Looks like I might have dodged that bullet despite driving it with essentially no coolant - it took 4l to refill. I know the CTS probably wasn't accurate while in steam, but it only peaked at 110c
 

fatmobile

Veteran Member
Joined
Jul 16, 2019
Location
north iowa
TDI
an ALH M-TDI in a MK2, a 2000 Jetta, 2003 wagon
" wrapped and these engines are specifically susceptible to wrapping heads form low or no coolant runnin "
I think he means warped and from
You'd think the coolant reservoir pac would let off pressure bbefore it got hgih enough to blow a hose.
Does the coolant reservoir cap have a pressure release?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
" wrapped and these engines are specifically susceptible to wrapping heads form low or no coolant runnin "
I think he means warped and from
You'd think the coolant reservoir pac would let off pressure bbefore it got hgih enough to blow a hose.
Does the coolant reservoir cap have a pressure release?
Yes but typically they cant Handel that much steam that fast. 1 drop of water is 6000 droplets of steam... happens fast
 

turbodieseldyke

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Joined
Jun 6, 2010
Location
Free Mustache Rides
TDI
Big ol' honkin' tdis
If the radiator is aftermarket, and the outlet barb is just small enough and the clamp is just weak enough, it could allow the hose to slip before the expansion tank gives way. You could use a screw clamp to make it tighter.
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
There is no barb or clamp involved, it's two concentric pieces of hard plastic pipe held together by a wire clip in a slot.

That's what I don't get - if I didn't assemble it properly when I changed the radiator, how did it hold for 7 months not leaking a drop?
 
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