VR6 overheating issue, boiling out of reservoir...

[CorradoFuhrer]

Cars constantly over heating, but before it registers on my gauge (it gets to half way like normal operating temps) then will just boil out of the reservoir and the readings will stay the same.

I grabbed the upper rad hose before it boiled out and it was hot, the lower is cold to the touch/ambient to weather...

Thermostat?

Waterpump is only a couple months old and is the metal impeller variety. I also see the water flowing from the nipper on the reservoir with the 2ndary water pump unplugged so I am assuming I have a clogged radiator or stuck shut stat.

I went to remove it but one of the stupid Allen's stripped out so I gotta break it and put on another housing to get the bolt out.

Luckily I have another housing.

Any bright ideas?

[Kenji]

If your thermostat is stuck closed, your coolant temperature gauge will usually show the coolant temperature increasing into the red on the gauge before the coolant boils over. Is it possible that the cap on your coolant reservoir expansion tank isn't holding pressure as well as it should?

[CorradoFuhrer]

Yeah my cap is all messed up; but it's never been a problem until it started boiling over. I can't get the guage to show over heating before it boils out... The first time it happened it showed up on the guage. Could also be that after it happened I put on straight distiller water not coolant.

Lower rad hose was staying ambient (cold) while upper was real hot. I'm leaning towards T stat, it was flowing at the reservoir with the 2ndary unplugged.

No smoke out of the tailpipe. Highest oil temp I saw was 268 when it was over heating after boiling out coolant.

Maybe a clogged rad? I'll be back at it tomorrow.

[CorradoFuhrer]

If the t stat was stuck closed, would the lower rad hose stay cold ( no flow? ) I hope my HG didn't go pressurizing the coolant system... But I have no other symptoms of a blown HG, the cold vs hot upper rad hoses is a pretty clear indicator that it's something with the cooling system.

Pump is new, leaves me with that expansion cap, rad, and t stat. My money's on t stat.

[Kenji]

If the t stat was stuck closed, would the lower rad hose stay cold ( no flow? )

Yes.

[CorradoFuhrer]

What else could cause this besides t stat?

[CorradoFuhrer]

that side allen bolt on the T stat housing is stripped out, the one right above the back lower coolant line. I have two extra housings, I hate breakin stuff to remove it. Is there a tool for removing the stipped 5mm allen besides an impact driver. I know a vice grips but the housing gets in the way. I mean I will try, but looking for something that will bite into around it or into it with a ratchet. Like the irwin reverse biting sockets are pretty cool, but this is an allen.

I hope this is it lmao, i have a new t stat as well but I think its a lower temp one, read some iffy things with them... that i should go with the lower fan temp switch instead of the T stat. Each of my two housings has a working T stat so its no problem.

[CorradoFuhrer]

i guess im gonna run a 71 C instead of a 80 C... keep things a bit cooler for my turbo car.

[dubdriver808]

is ur fan working???

[CorradoFuhrer]

it was my T stat... i replaced with a 71 Celsius Job, I want to get the lower fan switch to complement it for the summer. I've been driving it all day, picked up some purple coolant at the dealer, right now just running distilled water to see if anything else pops up...

So far so good. temps have been low with just water checking on the vag com, measuring block 7 or 8, mostly around 72 degrees C.

Coolant wasn't too bad at the dealer 22 bucks for a whole gallon. Gripped up two gallons of distilled water, because from my searching I read that the coolant system takes about 9.

I tried flushing the coolant system with a garden hose in the resevoir, and having the upper hose off the coolant housing off... ran out clear. Then I ran it with the hose off to get most of the tap water out, then filled it up with a Gallon of distilled water, did the trick.

[CorradoFuhrer]

Lower T stat didn't really do much that I noticed, prolly cuz im running hot a bit with the turbo.

I ordered a new lower temp fan switch to match 70-75, 77-82 whatever it is... My mixture might be off, or my 2ndary water pump isn't doing anything. Because I had all distilled water in my car, drove fine for an hour for school, parked up.

come back to car to start up, coolant fill light comes on, i fill it up with coolant. Drive it for 15 minutes, park it up, pop the hood... No fans, I could hear the coolant boiling in the upper part by the throttle, felt it in the upper rad bubbling.

1. It could be my res cap isn't sealing right / pressuring.

2. my 2ndary waterpump isn't doing crap, not sure how to check this. I have an extra one.

3. Thought it might be my fan switch not coming on, but then I jumped the fan's to make sure they were working with a paper clip, they work. - could be the switch.

So far she drives again! :-) Everythings sticky from coolant shooting everywhere/ boiling out, detail time this weekend.

I have no codes for coolant, crack pipe, new metal german waterpump, replaced the 2ndary o2 with a known working one.

with the fan not coming on at 92 C on my hand held vw/audi tool and not being half and half coolant this may just be normal.

your thoughts, always appreciated! at least shes driving again!

[dubdriver808]

Lower T stat didn't really do much that I noticed, prolly cuz im running hot a bit with the turbo.

I ordered a new lower temp fan switch to match 70-75, 77-82 whatever it is... My mixture might be off, or my 2ndary water pump isn't doing anything. Because I had all distilled water in my car, drove fine for an hour for school, parked up.

come back to car to start up, coolant fill light comes on, i fill it up with coolant. Drive it for 15 minutes, park it up, pop the hood... No fans, I could hear the coolant boiling in the upper part by the throttle, felt it in the upper rad bubbling.

1. It could be my res cap isn't sealing right / pressuring.

2. my 2ndary waterpump isn't doing crap, not sure how to check this. I have an extra one.

3. Thought it might be my fan switch not coming on, but then I jumped the fan's to make sure they were working with a paper clip, they work. - could be the switch.

So far she drives again! :-) Everythings sticky from coolant shooting everywhere/ boiling out, detail time this weekend.

I have no codes for coolant, crack pipe, new metal german waterpump, replaced the 2ndary o2 with a known working one.

with the fan not coming on at 92 C on my hand held vw/audi tool and not being half and half coolant this may just be normal.

your thoughts, always appreciated! at least shes driving again!

check the wiring to the fans it might be jacked up or connections is bad.. happens to my car wen the plugs get loose the fan doesn't turn on then temp goes up causing a boil over ..

[CorradoFuhrer]

check the wiring to the fans it might be jacked up or connections is bad.. happens to my car wen the plugs get loose the fan doesn't turn on then temp goes up causing a boil over ..

Fans are working but they seem off temp wise.

[k04jettajj]

i had the same exact problem do yourself a favor buy a new resivoir cap its not holding the right pressure

[CorradoFuhrer]

i had the same exact problem do yourself a favor buy a new resivoir cap its not holding the right pressure

Cool sounds good, gonna get a new res as well to freshen up the bay. Thanks

[b3 vr6]

Have the same problem but did my t stat gonna try a new cap also but the lower hose is still cool to the touch when top is hot. It's a blowout


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[CorradoFuhrer]

My t stat fixed my isse lower is now warm after driving... It boils out a bit when turned off. I got a lower temp fan switch coming. I'll have to check the local junkyards to make sure that a new cap is necessary. (it's pretty hammered atm)

[b3 vr6]

Mine was t stat and cap. All fixed just gotta figure out why the pump doesn't work or when its supposed to be on


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[CorradoFuhrer]

Mine was t stat and cap. All fixed just gotta figure out why the pump doesn't work or when its supposed to be on


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Doesn't it run while the fans are on and the cars off? Or does it run all the time? When my original one went bad it started to leak. I wonder if there is an obd-2 code for it, if it detects it of its faulty or not.

[b3 vr6]

I don't think it runs at all the po must of messed with the wiring cuz that part of it is all hacked looking if I run a jumper it pump so I'm not sure. I'm reading the Bentley lookin for wiring and maybe a fuse


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[CorradoFuhrer]

I don't think it runs at all the po must of messed with the wiring cuz that part of it is all hacked looking if I run a jumper it pump so I'm not sure. I'm reading the Bentley lookin for wiring and maybe a fuse


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So the best way to check is to run a jumper?

[b3 vr6]

Yeah I ran a jumper it pumps fine just not with the stock wires.


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[CorradoFuhrer]

When is it supposed to pump?

[Kenji]

When is it supposed to pump?

Are you talking about the auxiliary coolant pump? If so, the pump should run whenever the ignition is turned on, plus 10 minutes after you switch the ignition off.

[CorradoFuhrer]

Are you talking about the auxiliary coolant pump? If so, the pump should run whenever the ignition is turned on, plus 10 minutes after you switch the ignition off.

Thanks

[CorradoFuhrer]

I can hear it hissing out or the reservoir the cap is shot.

[denver412]

Replace that reservoir cap before you do anything else. Exact same issues I had and I diagnosed everything and finally realized my cap was screwed up. Boom, fixed all issues.

[CorradoFuhrer]

Replace that reservoir cap before you do anything else. Exact same issues I had and I diagnosed everything and finally realized my cap was screwed up. Boom, fixed all issues.

yea mines looking real hurt.

[b3 vr6]

Mine was a faulty t stat and a bad cap thank you everybody for your help. Much abliged


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[CorradoFuhrer]

Mine was a faulty t stat and a bad cap thank you everybody for your help. Much abliged


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mine is the exact same issue, I wonder if the bad cap made the T stat poop the bed?

[bomberbob]

No. thermostat is just a valve, with a piece of wax in there that expands when it gets hot (and forces the valve open). I see no way a bad cap could screw up a t-stat.

[CorradoFuhrer]

No. thermostat is just a valve, with a piece of wax in there that expands when it gets hot (and forces the valve open). I see no way a bad cap could screw up a t-stat.

Well it is overheating when turned off and boiling out... Not sure just a stab at it.

[curcor]

you may wanna look your waterpump, mine did the same thing, replaced no problem then. or you got a hole somewhere in your system.

[knoxvr6]

has anyone ever replaced the full radiator assembly on a 2001 vr6 jetta?
I need to know a couple details about the process. Much appreciated!

[CorradoFuhrer]

you may wanna look your waterpump, mine did the same thing, replaced no problem then. or you got a hole somewhere in your system.

it was my T stat, replaced that, then it was my resevoir cap not being tight enough because its all busted. i really tightened it and no more boiling out. also went lower fan switch and lower t stat while at it.