car runs too cool...SOMETIMES

[nathan_b]

only way to get a genuine VW thermostat around here is to get raped by the VW service shop..and none of those guys know SQUAT..
QUOTE

that's a bit harsh. They know a lot you don't know, thye just don't obsess about 80s diesels..
Not everything from the dealership is too expensive. You get what you pay for. Comes out of the same pile that got put onto your car when on the assembly line. The one that lasted for 15 years before it was replaced with auto zone crap that opened too soon.

BTW, 99.999% DO NOT "STICK OPEN" they just open too soon as the spring fatigues

[maxfax]

o..and none of those guys know SQUAT..

Sounds like the one dealer here..  I swear I've seen a few of those guys working at Advance Auto in the past.. (Yes Bob, they did put a diesel in a 2004 Beetle.. Seriously!  ) Thank goodness the other one has competent people..

IF you can find a source, the genuine VW thermostat is a good investment.. The majority of after market (German made or not) have been crap..  That isn't isolated to just the ones made for VWs either..  I got a bucket full of Wahlers I'm considering dumping in the cannon and firing at the neighbors..   

[R.O.R-2.0]

only way to get a genuine VW thermostat around here is to get raped by the VW service shop..and none of those guys know SQUAT..
QUOTE

that's a bit harsh. They know a lot you don't know, thye just don't obsess about 80s diesels..
Not everything from the dealership is too expensive. You get what you pay for. Comes out of the same pile that got put onto your car when on the assembly line. The one that lasted for 15 years before it was replaced with auto zone crap that opened too soon.

BTW, 99.999% DO NOT "STICK OPEN" they just open too soon as the spring fatigues

this is a service shop, not a dealer.. and they FU@#$% up my toyota 4runner before i got it.. they installed the thermostat backwards when they did the timing belt, and cooked the engine..

no dude, there is one guy who DOES know alot about old VWs.. he absolutely loves my Rabbit..

alright, enough of that tho.. the service shop is run by idiots. ive been told that there were VW parts that were NLA, then i walked a block to Napa.. and guess what?! it was in stock!! napa never stocks any parts i need.. lol.

as for you saying t-stats dont stick open, then why does my engine cool down soo much if the thermostat is fatigued?

wouldnt that make it open too soon? it opens at about 192*... its a 180* thermo..

and if it werent closing all the way, i think it would keep more heat in the engine than it does..

it pulls the temp gauge right down almost to the cold peg. the heater loses heat also. i know the engine is actually cooling down to much, and not my gauge being funky..

[blackbird82]

you have a symptom of a very efficient cooling system
when you go up a hill, with the engine making a lot of heat, its flowing to beat hell.  because they will overheat if its not flowing good!

As soon as you put out the fire goin downhill, boom. no fire, tons of wind, and believe it or not. t-stats do not close instantly.  you have the heater on you say? Did you know the heater in most VW's can keep the engine cool, when a T-stat fails closed? I know because I went a whole winter without realizing my t-stat was stuck, until it warmed up.....

Bottom line, change your t-stat, buy the right one from VW and it its still cooling too fast with heater on going downhill, block your rad

I live north of Winnipeg, and when its -22 celsius and I drive to work, if I have the heater on, never gets full temp in a hour of driving at 115 kmph
blocked my rad, no problem holdin temp constant
forgot it was on there in spring, didn't realize! cause it didn't overheat!

[nathan_b]

Just look at a thermostat and you will see that unless it is physically broken (no real chance) it will not "not close all the way" it is just that the spring gets worn by heat cycles and stops working as it should because the metal is fatigued.  So sometimes pressure alone, or less than originally specified heat open up the "bypass valve."

[8v-of-fury]

I agree with the above two posts!

Super efficient cooling system. Kinda what I said earlier.. They make no heat going downhill and coasting... So its gonna cool down. Happens to my na too, in the 25* summer even! Just looses all engine temp down hill

[rodpaslow]

I know the last T-stat I bought for and mk2 na I had didn't have a small hole in it like the gasser stats do.  I think that's so it warms up better when cold - I don't know if the aftermarket ones have that?  I don't know about where you are, but I'm like the guy from Winterpeg.  I love north of him and in -20 to -30 deg C my car cools off to 160 deg F if not driving about 40-50 mph.  My .02$

[damac]

I have been seeing the same thing on my jetta since I got it back on the road.  I think my system is healthy since I started fresh with new parts and coolant.

But I blindly drilled almost a 1/8" hole on the body of my thermostat because I could have sworn the people on the "forum" said that was best to do.

Our winter only gets down to the teens, and I find my car pretty much can't warmup on the driveway so its annoying because it runs smoother when warm.  After I drive off and use moderate rpms going up and down mountains I have also seen my gauge swing wildly which is coupled with cool air at the heater.  If Im going 70mph on the freeway its pretty consistent.

My old ford diesel will kick down off of high idle within 10 minutes in the cold, and its heater will make you sweat before that so it makes me wonder if my jetta is setup right.

[rabbitman]

I don't go for drilling the t-stat, some say it helps get the air out but I've never had a problem. With a completely drained system I fill it through the reservior and can usually hear a hissing as the rising coolant level pushes air through the skinny return hose. Any coolant trapped in a low spot in that hose also gets pushed through.

[tfodel]

maybe the impeller on the wpump?

[nathan_b]

all I have to say is that my 1.6/1.9 td with a stock rabbit cooling system and stock rad and stock oil cooler will hit max operating temp in 10 min of idling. It drops slightly if I go down a  long hill, but hardly noticeable.

in my caddy, the heat and def easily rivals that of my mk3 2.0 jetta.

[R.O.R-2.0]

you have a symptom of a very efficient cooling system
when you go up a hill, with the engine making a lot of heat, its flowing to beat hell.  because they will overheat if its not flowing good!

As soon as you put out the fire goin downhill, boom. no fire, tons of wind, and believe it or not. t-stats do not close instantly.  you have the heater on you say? Did you know the heater in most VW's can keep the engine cool, when a T-stat fails closed? I know because I went a whole winter without realizing my t-stat was stuck, until it warmed up.....

Bottom line, change your t-stat, buy the right one from VW and it its still cooling too fast with heater on going downhill, block your rad

I live north of Winnipeg, and when its -22 celsius and I drive to work, if I have the heater on, never gets full temp in a hour of driving at 115 kmph
blocked my rad, no problem holdin temp constant
forgot it was on there in spring, didn't realize! cause it didn't overheat!

i could understand this problem, but why on earth did my car have no trouble staying warm when it was 20* F outside, but now when its 50*f outside, it cant stay warm to save its life..

yes, i know it takes a second for a t-stat to close.. thats how it used to be, i would go down a hill and the gauge would drop one mark, not 6 marks.

and yea, i know about the heater in my cars, they are efficient.

[R.O.R-2.0]

maybe the impeller on the wpump?

nope, its a metal impeller. and i checked it when i boiled the t-stat.

[R.O.R-2.0]

I have been seeing the same thing on my jetta since I got it back on the road.  I think my system is healthy since I started fresh with new parts and coolant.

But I blindly drilled almost a 1/8" hole on the body of my thermostat because I could have sworn the people on the "forum" said that was best to do.

Our winter only gets down to the teens, and I find my car pretty much can't warmup on the driveway so its annoying because it runs smoother when warm.  After I drive off and use moderate rpms going up and down mountains I have also seen my gauge swing wildly which is coupled with cool air at the heater.  If Im going 70mph on the freeway its pretty consistent.

My old ford diesel will kick down off of high idle within 10 minutes in the cold, and its heater will make you sweat before that so it makes me wonder if my jetta is setup right.

i drilled a tiny hole in my thermostat before i put it back in my car, and for some reason i have not been able to get it to act up..

its been running on the 4th mark on the gauge now since i pulled the thermostat out and boiled it.

anyway, i went to the VW service shop yesterday, and a Wahler thermostat is 23 bucks.. not bad, considering Napa can only get a Behr thermostat, and its around the same price. and i can get way more temp choices with the wahler..

[R.O.R-2.0]

all I have to say is that my 1.6/1.9 td with a stock rabbit cooling system and stock rad and stock oil cooler will hit max operating temp in 10 min of idling. It drops slightly if I go down a  long hill, but hardly noticeable.

in my caddy, the heat and def easily rivals that of my mk3 2.0 jetta.

pfft, i can leave my car idling for a half hour and still not have it be up to temp..