Thermostat stuck...open?

[pleopard]

The temperature is slowly dropping here in SW Ontario and the temp gauge on my 1.6L turbo engine barely moves from the stone cold position, even after driving on the highway (~100km/h) for long periods of time.  This is at outside temperatures between 0 and 5 degrees C.  I also notice there is more engine vibration when accelerating the engine past 3000rpm from a stop.

Is the temperature issue normal?  Could my thermostat be faulty?

[jimbrown618]

Are you getting any heat out of your vents? Bentley manual says that abnormal cooling reading on gauge could be bad thermostat, bad temp sensor, or bad cluster gauge. If your not getting any heat from your heating vents then perhaps it is your thermostat. My 97 Golf TD normally runs at 90C (centre of gauge0 during normal operation. Cheers.

Jim

[pleopard]

Thanks for the response.

I get plenty of heat out of the vents and I'm almost certain the gauge is functioning normally.  The temp needle rises when I sit idling, such as while in the drive-thru line at Tim Hortons  During those times it will go right up to half.  It's only when I'm in motion that the gauge doesn't show any heat.  Sometimes it's below the lowest mark!

[jtanguay]

trust me.. if your thermostat was gone, there would be little to no heat coming out the vents on the highway (i had an old jetta like this.. I had to drive 120km/h just to get heat!!!)

in town would be lukewarm after say... 20-30 min warmup??? i'd also assume that the extra vibration could be due to moisture in the air, amount of oxygen, etc.  (hot humid weather makes a diesel run like crap, so I'm guessing the other extreme will do the same)

I went and got oem vw thermostat... I can tell you that it heats up way faster than before!  Best way to check your thermostat is to have the coolant expansion tank open and have a digi thermometer in there (yea some coolant may leak, but all in the name of science and testing.) when the thermometer reaches 86C or so, the temp should drop about 2-3 degrees.  if it climbs higher, or opens earlier, then you have a bad thermostat, which i doubt.

[pleopard]

That's a very interesting idea.  Thanks for the reply jtanguay.  I'll give that a shot as soon as I find an appropriate thermometer.  So, I'm at the point where I'm almost ruling out the thermostat and gauge as being the problems...  What else could it be?

I get plenty of heat after a reasonably short period of time, without even driving on the highway.  The needle generally remains pegged on the hard stop unless I really push it on the highway.  During the summer, it does rise to the first or second notch and it will also rise even now approaching winter when I sit idling for a long enough period.  

The note about the atmospheric conditions being the root of the small vibration I feel on acceleration is likely correct.  

Anyway, otherwise the car/engine is marvelous!  It's an excellent piece of machinery.

[burn_your_money]

I think it's your thermostat. If it heats up to normal when you aren't moving all that means is air isn't benig pushed through the rad to cool it, but when you are driving highway speeds, say 100kmh the engine isn'tr producing excessive heat so the temp drops, but when you push the car harder it heats up more, which is why you see a temp rise.
My thermostat just failed and I had the exact same symptoms. I replaced it and it was perfect, until the HG failed.. but that's unrelated

[pleopard]

Anyone know what a thermostat replacement will cost me?  It should be simple, but I don't have any tools or the time to do it.

Thanks.

[burn_your_money]

parts $10, new coolant $5? labour 1/2 an hour

so $40-50?

All you need to do it is a flat head screwdriver to remove the clamp, and a 10mm socket. Extremely simple to do

[pleopard]

Yeah, I should really get my ass in gear and just learn how to do it myself!   VW quoted me over $100 ($30 part + 1 hour labour and some other random BS) Thanks for the note.  I appreciate it.

[addautomotive]

parts $10, new coolant $5? labour 1/2 an hour

so $40-50?

All you need to do it is a flat head screwdriver to remove the clamp, and a 10mm socket. Extremely simple to do

Unless you have power steering

[jtanguay]

well i can tell you that with a bad thermostat, and no rad fan... it will take a while for your car to warm up... even in the summer.  I was simply amazed at how fast my car produced heat with the new thermostat.  Make sure you get the OEM one, and not some junk one that opens too soon, or leaks.

ah yes... power steering... that piece of shyt assembly lol... i couldn't get the adjuster off because it was rusted there good... so i just took off the whole arm piece.  easy to come off, but holy not fun getting it back on  and yea I believe its a 10 mil socket to get the plastic neck piece off.  it might be a little bit of a pain to get the rubber o-ring to stay in place when putting it back on though... but its all good.

and about the clamp... i wish i could express my anger for the 'clip' clamps on the coolant hoses... but it would anger me so much that i would need a new lcd monitor.  (i loved being able to punch my old crt... hehehe)

[burn_your_money]

Vise grips work amazing on those crappy stock hose clamps. They open wide, and lock. They're perfect. If they don't work I use my dremel. :lol:

They are defintly 10mm. The only thing that can go wrong really is if one of the bolts break off in the pump housing. It happened to me. Adds like an hour to your total time

[jtanguay]

i was just going to mention that the bolts may break off.  have to be real gentle the bolt heads on mine looked like one wrong move and... crumble  :shock:

I find that even with vice grips there is still a tendancy for the clip to slip off.  everytime i remove one, i quickly replace it with a nice thick hose clamp