Anyone experienced burning/"cooking" vacuum lines?

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
Anyone experience any burning/overheating vacuum lines? Not like "on fire," but rather like cooking (extremely heated).

I'm trying to track down the source of this smell that just popped up in the wife's car. The smell seems to be strongest around the area just below the vacuum pump (it's not coolant, pretty certain). The vacuum line running under the pump is badly frayed (yes, it's now on my list to replace;)) and the pump's seal leaks oil (it's on my radar to replace come next TB service- about 28k miles away).

When I recently replaced the clutch (and suspension), about 1,800 miles ago, I wiped that area up. Maybe I disturbed some of the line's outer cloth?

Unfortunately I don't have any time right now to do much of anything (not for another couple of days). I just swapped cars with the wife and drove hers to work.

Clutch and brakes are perfectly fine (car is otherwise performing flawlessly). There's no apparent loss of any fluids (other than whatever small amount of oil may be weeping out from the bottom of the vacuum pump). Smell is stronger in the engine compartment, so I'm pretty sure it's NOT the heater core. The smell is nearly impossible to explain- it is, as my wife described it, "a chemical" smell- yeah, overly broad description, but there's really no obvious underlying odor- rubber/insulation + oil + coolant(?)... ? radiator fans check fine; not really sensing it's anything to do with the exhaust.
 

flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
The vacuum lines should stay pretty cool as long as it's kept clear of the turbo.
Inside the car it could be the fan control resistors that fail eventually due to heat.
Some report actual melting at the connectors on top of the battery, too.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
The vacuum hose to the vacuum reservoir would appear to be getting pretty warm (hot?) as they go under the vacuum pump. The hose is attached to a bracket that mounts right under the vacuum pump. Just regular engine heat is fairly significant there. I'm thinking that with any oil on the hoses would tend to absorb more heat.

Isn't the cloth on the hoses to protect from heat? If heat is a threat to the actual hose then there seems to be more than strong possibility that this hose is the source.

A more detailed story was told to me, and that was that she had pulled into a parking garage (roadway was a moderate one, lower speed limit). It was raining, in which case there was water on the side windows and she rolled them down to help clear to gain better visibility as she went to park. It is when she rolled the windows down that she got a huge whiff of whatever it was. The smell, she insists, was coming from the car (not the garage). I questioned whether she might have burned the clutch and she was sure she did not (not slipping the clutch).

This may be no more than barking up the wrong tree, though for sure I need to do some hose replacing. The wife says that the smell is perhaps 1/10 as strong as what it was. This would kind tend to suggest that it was more due to an "event" than to a "condition."

The smell, as I could tell- keep in mind that it's significantly reduced, is not emanating from the grill or firewall areas, it's for sure strongest right there around that vacuum pump area (only other thing I could think of is that it's rising up from the transmission/clutch, but there's nothing pointing to either of these than it being a possibility). Can't get my nose close enough to that spot below the vacuum pump to verify. I kind of thought about a smell-o-scope (some long straws?):D

I've had a bit of electrical smells from my car when I had a bad wire to one of the cooling fans. Someone had not fully secured the wire harness to the large fan, which resulted in that harness getting spanked by the fan blades: PO's garage had replaced the radiator- most likely source for that screw-up. Over-heated/burned wire insulation is pretty acrid. This smell may have an element of that, but it's so faint with all the smells that occur from a hot engine (like trying to identify one particular perfume while exposed to a whole shop of perfumes!) that I really can't trace the essence down to any single particular type.
 

muzy

Veteran Member
Joined
Aug 19, 2012
Location
Southern Alberta
TDI
02 jetta TDI
Why is your engine hot? I'd bet a nickel it's just the clutch got a little hot.
Stop and go in the hills is tough.
Cheers
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
Oh, no, no hills. I know the area she was driving in and it's pretty flat: she'd just left her son's and his wife's place to go to the nearby market. None of the driving is any different than what she's been doing for quite some time. Car was doing the same exact things only a week prior (and without any complaint): all the work had been done prior to then.

Engine temps are not elevated. Run your engine up to full operating temps and stick your hand right next to the vacuum pump and you'll find that it's pretty warm (if your engine temps are in the 190 F range that is more than just warm!). Add in a bit of oil to maintain that heat and I'm sure it's a bit uncomfortable.

I can only think that there's been a little oil build-up since I'd wiped off the hose. If in fact I'd previously disturbed the outer layer then, after taking a while for sufficient enough oil to build up, the inner hose got stinky hot. BUT...

It just doesn't seem like it's a continuing thing. If it's something that's due to an event, then, yes, clutch would seem to fit. Just not seeing any issues with the clutch: usually I can have some doubt about work that I've done, but in the case of this clutch job things went really well (had all the right tools, so no make-shfiting going on): I did initially forget to install the clutch release fork, but, clearly, I resolved that mistake!:eek:
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
I figger the cloth on the hoses is more for abrasion protection than heat.

Maybe some water got on the clutch and steamed off but I'd think it would be gone pretty quick.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
Our cars are fairly well buttoned up, all having Pazer plates with the side jackets. Not waterproof, no, but they do a pretty good job of holding out road splash and debris.

It's really hard when one hasn't been exposed to the actual smell. I really have no idea what she smelled, other than there was for sure cause for alarm/concern.

I'll have another brief shot at driving it before handing back over to her. Not sure if I should beat the snot out of it and try to see if I can make the clutch slip or something break. I romped on it pretty hard (though from 4th gear) and showed no signs of problems at all.

Here's a picture of what I'm talking about. NOTE: I tried uploading the picture to this site but it kept failing on me (I've done it many times before w/o any problems, not sure what's up now).
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS
It appears that I'm barking up the wrong tree vis a vis the vacuum line; however, for sure, any smell is clearly originating in that area.

I ran the car pretty hard last night. No clutch slip, but there's a shudder when hitting it hard (from 2k RPM) in 5th. Don't recall it doing this before: I hadn't, however tried stressing it this hard. I'd seen a little dribble out of the clutch slave when I had things pulled, but I didn't think this was anything: maybe it's leaking? Anyway...

I'm going to skip out on this thread and pursue barking up a different tree:D
 
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