My coolant temp seems to be a little high? - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• My coolant temp seems to be a little high? by mk2vr6 on 01 Jan, 2007 07:20
• Hey guys.
  
  My other diesel that I owned (stock 92 N/A 1.6) would usually hold a temperature (according to the coolant temp gauge on the cluster) slightly higher than the middle temp mark, and would go higher if I was going up steep hills, fully loaded car, etc.
  
  This newer TD reads a temp around half-way between the middle temp mark and the 3/4 temp mark.  I realise this is hotter than its supposed to be but I don't know if its the cluster or temp sensor reading poorly.  To top it off, the fans don't come on until it hits a temp of around 3/4's, and then when it does, its for about 15-20 seconds andthen stops for about 2 minutes before it comes on for another 15-20 seconds, which doesnt seem to do much.
  
  Is this normal for the turbo diesels or should I look into replacing a coolant temp sensor or even a thermostat?
• #1 by RabbitJockey on 01 Jan, 2007 12:34
• look into replacing the coolant temp sensor, if the fan comes on at 3/4's and ur gauge hangs around there normally it sounds like thats about normal it should actually read in the middle, both of my cars don't have the fan come on until the temp sensor is a bit past the middle.
• #2 by jtanguay on 01 Jan, 2007 16:00
• i'm going to be getting a gauge that will give me a good accurate reading of the actual temperature of the coolant.  i dont like how the gauge doesn't really have any numbers to judge by...
  
  but my thermostat opens in between the middle and 3/4 mark.  on the highway and on really cold days it will reach the 3/4 mark and hold it there.  in the summer i was seeing it slowly climb further with a/c on... i may have a faulty thermoswitch
• #3 by zagarus on 01 Jan, 2007 16:01
• i think i have the same problem, im going to be replacing my thermostat soon too.  I dont like seeing it stay at 3/4 all the time.
• #4 by mk2vr6 on 01 Jan, 2007 16:07
• Quote from: jtanguay

  i'm going to be getting a gauge that will give me a good accurate reading of the actual temperature of the coolant.  i dont like how the gauge doesn't really have any numbers to judge by...
  
  but my thermostat opens in between the middle and 3/4 mark.  on the highway and on really cold days it will reach the 3/4 mark and hold it there.  in the summer i was seeing it slowly climb further with a/c on... i may have a faulty thermoswitch

  
  
  What do you mean by faulty thermoswitch?  Is it a big pain in the butt to replace?
  
  I've done thermostats and such before, but I just don't want to be taking crap apart and fixing a problem that isnt there.  I replaced a thermostat in a VR6 which turned out to be a faulty sensor.  That wasn't too fun.  Definitely the hardest thermostat to have to get to.
• #5 by RabbitJockey on 01 Jan, 2007 16:13
• thermoswitches are easy, but if comes on you're fine.  but all you do is unscrew it make sure you have something to catch the antifreeze, then screw the new one in
• #6 by zagarus on 01 Jan, 2007 16:14
• i have powersteering in the way, probably why i havent done it yet
• #7 by RabbitJockey on 01 Jan, 2007 16:23
• ? it's on the drivers side?
• #8 by zagarus on 01 Jan, 2007 16:24
• well i was told there is a bracket for the power steering that is in the way of getting to the thermostat.  but no it would be on the passenger side. by the water pump right
• #9 by mk2vr6 on 01 Jan, 2007 16:47
• So you're referring to the switch that turns the fan on, at the bottom of the rad on the drivers side?  
  
  Ya, my fan comes on, but it seems kind of intermittant which is why I was leaning towards it being a coolant temp sensor problem.  Does that make any sense?
• #10 by dover on 01 Jan, 2007 16:55
• My fan motor (91 ECO-D) has 3 circuits. There are 2 balast resistors built into the end of the motor. At least one was burnt and I've trashed the other trying to fix it.
  This COULD be why the fan kicks on at a high temp. It may be tring a dead leg at the middle temps.
• #11 by mk2vr6 on 01 Jan, 2007 16:57
• OK, so how could I fix this or test this??  Or more importantly where could I get a replacement resistor?  I have that as well on the back of the fan motor and obviously soldering the wires on to a new resistor is easy (although mine has spade connectors anyways so that wouldn't be necesary).
• #12 by dover on 01 Jan, 2007 17:23
• my spade connectors had fried off. If yours are intact it should be an easy fix. The resistors are integral to the motor under a riveted plate. I'm going to try to use some off the shelf bablst resitor.
  Has anybody here ever measured the resistance or seen a writen spec?
• #13 by zagarus on 01 Jan, 2007 17:37
• i would assume it would say on the resistor, that is if it hasnt been rubbed out.
• #14 by dover on 01 Jan, 2007 17:45
• they are thin Stainless foils without markings. They were sandwiched between mica sheets, between 2 Al plates stood off the back of the motor a few mm.
  The labels on the motor were long gone and the harness connector was half melted and half embrittled. There are lug numbers but no boiler plate.
  The actual numbers aren't that important. The motor will run at some reduced speed(s) and the R's will either last or they won't. I'll try to expose them to some airflow without letting them get wet (NOTE: "Try")