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Engine Specific Info and Questions => IDI Engine => Topic started by: R.O.R-2.0 on March 07, 2011, 03:00:21 pm
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ok boys and girls.. my rabbit is having problems staying up to temp.
whenever i coast down a long hill, the engine comes down from operating temp. it usually sits at about the 5th mark on the temp gauge. when i coast for a ways, it will go down past the first mark, and get close to where the gauge needle rests when its cold.
am i on the right track thinking that my thermostat is sticking open?
motorad brand 180* (82*c) thermostat. no idea how old it is.
heater gets about luke-warm when it does this.
its always dropped like 1 line on the gauge going down long hills, but never almost all the way to the cold peg. and now it wont stay up to temp going 55 down the road. it was like 47* yesterday.. ???
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Sounds like a t-stat to me.. Make sure the housings aren't corroded around that area...
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My T stat always acts weird when it goes from cold outside to hot and back. It does it a couple of days and then seems to act normal again.
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IS it the fail safe version of the Motorad t-stat? I had one on my Toyota that got hot enough once to lock it open (with the fail safe feature) and it was that low heater output and low operating temp that clued me into checking the t-stat (and yes it was locked open).
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Only a few things.
Low on coolant? (not likely)
Water pump leaking? (water pump no circulating enough) (not likely)
Thermostat stuck open. (likely)
Radiator cap not holding pressure, coolant boiling. (not as likely)
I put money on thermostat, get a 90*C/195*F t-stat, give your engine the highest temp to get hot.
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I think my thermostat is sticking open too. Really makes me angry because I checked it 4 times before I put it in the engine, and now I have to remove my power steering bracket again and the coolant flange and all that junk and put more coolant in it. Grr.
I can watch my temperature gauge go down when its up to temperature (if it ever gets that far) when I turn the blower fan on full speed.
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Sounds like a t-stat to me.. Make sure the housings aren't corroded around that area...
housings not corroded.. but the bottom water neck now has a drain plug.. i was so excited when i saw the drain plug thread..
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IS it the fail safe version of the Motorad t-stat? I had one on my Toyota that got hot enough once to lock it open (with the fail safe feature) and it was that low heater output and low operating temp that clued me into checking the t-stat (and yes it was locked open).
no idea.. took my thermo out yesterday, boiled it, and it opens a tad before 190, and is fully open at a tad over 200*
i drilled a small vent hole in it before i re-installed it too.
and just so we are clear, this is the thermostat that i bought my car with..
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If your engine is loosing heat off load, and your thermo opens and then therefore must close at around 190.. I lean towards the cold air coming in through the front and physically cooling the motor as it passes by it and out through the bottom. Piece of cardboard in front of your rad, with the half that the hoses go in (passenger side) uncovered. Try it out.
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If your engine is loosing heat off load, and your thermo opens and then therefore must close at around 190.. I lean towards the cold air coming in through the front and physically cooling the motor as it passes by it and out through the bottom. Piece of cardboard in front of your rad, with the half that the hoses go in (passenger side) uncovered. Try it out.
dont you think it woulda done it way worse when it was frigid (low 20's) and not now, when its in the mid 40s?
like i say, its always done this A LITTLE BIT (move down one mark on the gauge) but now it almost goes back down to where it would be if the engine were just started..
i doubt my 45* air is cooling my engine down that far..
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Alright, then whats wrong with it ;)
Its not over heating, so the pump is circulating. Thermostat works correctly. No corrosion in the housings.
Upon thinking it over one of two, or both things have happened. You need a new temp sensor, or temp gauge. Its either not giving the correct resistance, or not seeing the correct resistance. Sounds plausible eh!
And yes on a diesel coasting downhill should remove a ton of heat, as your are producing practically ZERO while coasting.. other than that created by friction of the pistons and cylinders..
How does it run.
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Alright, then whats wrong with it ;)
Its not over heating, so the pump is circulating. Thermostat works correctly. No corrosion in the housings.
Upon thinking it over one of two, or both things have happened. You need a new temp sensor, or temp gauge. Its either not giving the correct resistance, or not seeing the correct resistance. Sounds plausible eh!
And yes on a diesel coasting downhill should remove a ton of heat, as your are producing practically ZERO while coasting.. other than that created by friction of the pistons and cylinders..
How does it run.
runs great. has power, still makes heat, but you can feel it in the heater when it starts coming down from operating temp. the heater gets luke-warm.
and yes, im aware these cars inject no fuel while coasting.. hard to build heat with no fire..
i kinda thought about it being a bad sender, but i kinda doubt it now. if it were constant/predictable, i would think maybe it were the gauge or sender. but its soo sporadic that im thinkin the thermo is just sticking open occasionally..
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I'm guessing the luke-warm heat symptom came at the same point the temp dropping started which means indeed it's cooling down.. But, old electric factory gauges (put there as merely a suggestion of what's going on) can do all sorts of things too.. From my experience, constant and predictable is not the more common symptom of a gauge problem.. I have an aftermarket mech gauge taking a reading from the same housing as the factory gauge... They rarely coincide...
The last thermostat in my car was a screwball for sure.. Engine ran hotter in colder ambient temps.. ??? It wasn't a bad thing at least.. Maybe it was from being well lubed from all the oil in there...
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Get a genuine VW thermostat. Thermostats tend to not be massively expensive and its one thing for piece of mind if you have a genuine article in there.
I am pretty sure it should be the type that opens at 86deg C.
My mk3 golf had issues with warm up and on the motorways it would barely get above the 5th little marker at the bottom of the gauge (basically the warm up bit or white bar depending on your gauge). I changed the thermostat and it warms up to 70deg C on motorway cruises and only round town does it get to 90(the middle). my mk6 tdi runs at 90c all day long, they are designed to run at that temperature for optimum performance/economy.
I always change the thermostat if its a different engine I am installing and havent changed it before, almost like changing the oil filter/fuel filter.
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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..
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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..
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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
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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.. ;D ;D ;D
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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..
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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..
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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!
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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."
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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
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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$
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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.
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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.
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maybe the impeller on the wpump?
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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.
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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.
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maybe the impeller on the wpump?
nope, its a metal impeller. and i checked it when i boiled the t-stat.
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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..
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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..
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Kevin, just replace the damned t-stat already! ;D
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Truth be told, the more heat you get when idling is a sign of a more in-efficient engine.
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Kevin, just replace the damned t-stat already! ;D
with what money? im about 20 bucks short of a new one... hahaha
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Truth be told, the more heat you get when idling is a sign of a more in-efficient engine.
Indeed.. Around freezing none of my 1.6's never saw more than 160 if started cold and left idling.. Once driven the temp would pop right up and hold...
Kevin, just replace the damned t-stat already! ;D
with what money? im about 20 bucks short of a new one... hahaha
Fair enough... I head kidneys aren't fetching what they used to.. ;D
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Truth be told, the more heat you get when idling is a sign of a more in-efficient engine.
If that statement is 100% true, then a malfunctioning thermostat makes your engine more efficient.... but I see your point,
still, there is no reason why an idi shouldn't make great heat. even at idle.
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still, there is no reason why an idi shouldn't make great heat. even at idle.
With coolant temp at 120 the windows will start to defrost.. 10 mins of idle with a coolant temp of 160 and it gets hot in there..
I've found that some of the el cheapo crappy water pumps don't circulate worth a damn at idle which will kill the heater output real quick.. Oddly, the Prothe pump I'm running at the moment works rather well...
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I should be knocking on wood but my water pump on my car with 285000k is original, so is the alternator. the t-stat is VW .
All I meant was a diesel, any diesel IDI or DI that makes a lot of heat at idle is inefficient. More heat going to the water jackets in the engine than is pushing the piston.
We have a kenworth with a 10.1L Cummins, and 3 t-stats in it. Never reaches full temp even in summer unless you pour the coal to her.
Now a really cool design in the 4.5L four cylinder John deere engine in yard tractor (6030 series)
It has 3! thermostats!
one for 87C and 2 for 95C
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Hey ROR, you figure your tstat issue out yet?
I got a funky one goin on here.
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(http://img.photobucket.com/albums/v306/Trev0rbr/DSCN0479.jpg) had to use some card board to stay warm for a couple weeks till i put the new t stat in haha
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Hey ROR, you figure your tstat issue out yet?
I got a funky one goin on here.
well, it hasnt been running cool, its been either not acting up, or running slightly warm. i havent had the funds to go buy a new thermostat yet..
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I have a water guage in my car, and I changed out my t-stat to a 190, when it idles in the morning it gets to maybe 160, while its running it gets to 190-200, and when i climb the hills is hits 220-230 (the dash guage needle is over 3/4 at that point) when I coast down hill the temp will drop to 180deg showing under the 1/2 way mark on the dash guage. This is also with a non intercooled k14 at 5psi norm and 12psi on the hills.
My question is, what benifit do you get from running a 190 vs a 180 stat, as i already blew the top off of 1 coolent resivor after a long mountain pass and now have to really watch my temps so i dont do it again. I got lucky and had extra coolent and a resivore in the back, so as soon as all the coolent ran out, I refilled and circulated it to prevent any engine damage.
I also have to run the heater while climbing, and in another month its gonna be 115+ degrees out here. (Phoenix Arizona) Im thinking of changing back to a cooler t-stat to keep temps in check and then look at getting a larger radiator before I damage something to remove the extra heat.
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Yeah, I blew the 3 way hose on a ride home with a brand new tstat that was runnin on the warm side.
would be just past half on the dash gauge, push it hard and it would rise
blew the hose, got another one from my parts car. put the old tstat back in (both from VW)
and now it runs around the 80C mark on the dash gauge consistantly
I boiled both on the stove and they both opened.
although the old one opened farther i believe
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To upate my previous post in this thread, I changed to a new thermostat one hotter over stock and left it alone with no drilled hole.
Now the car gets warmer idling on the driveway so that some heat starts to come out of the vents :) Just idling it is just a bit under the halfway mark on the stock gauge.
Then when I start driving it nice and hard my new normal temp is when the needle is on the high side of the led, just barely blocking the edge of it. I have never seen it rise beyond that point whether I am stuck in traffic or going up/down the mountain or cruising at 70mph on the freeway.
The weather is changing and temps do get to 100 during the summer but I am hoping that will not have a direct effect on temps on the car, but we shall see I guess.
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To upate my previous post in this thread, I changed to a new thermostat one hotter over stock and left it alone with no drilled hole.
Now the car gets warmer idling on the driveway so that some heat starts to come out of the vents :) Just idling it is just a bit under the halfway mark on the stock gauge.
Then when I start driving it nice and hard my new normal temp is when the needle is on the high side of the led, just barely blocking the edge of it. I have never seen it rise beyond that point whether I am stuck in traffic or going up/down the mountain or cruising at 70mph on the freeway.
The weather is changing and temps do get to 100 during the summer but I am hoping that will not have a direct effect on temps on the car, but we shall see I guess.
in the summer time i like to run a cooler t-stat.. because every degree cooler that the coolant is, helps in low speed or sropped situations..