Did thermostat toady with a compatible one for 2003 2.0 - It had no indicator at to whether it was upside down. My heater works better, but it was steaming/bubbling in the reservoir after I went around the block. Should I try and put it in tomorrow the other way or assume something else has gone wrong?
Thermostat
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See this for how to install a thermostat:
Volkswagen Workshop Manuals > Golf Mk4 > Engine > 4cyl. Injection Engine, (2.0 ltr. Engine) (Mexico) > Engine cooling > Removing and installing parts of cooling system > Removing and installing thermostat
The stock thermostat doesn't have a vent in it. If yours has one it should be up.
Volkswagen Workshop Manuals > Golf Mk4 > Engine > 4cyl. Injection Engine, (2.0 ltr. Engine) (Mexico) > Engine cooling > Removing and installing parts of cooling system > Removing and installing thermostat
The stock thermostat doesn't have a vent in it. If yours has one it should be up.
Filling the cooling system using the proper procedure is critical. The procedure is:
1. Slowly add coolant to the bottle until it is at the top of the normal range (near the center of the spherical container).
2. Replace the fill cap fully.
3. Start the engine and let it idle.
4. If the coolant level gets to the bottom of the bottle, shut off the engine and repeat the procedure.
5. Once the level is stable with the engine fully warm the car can be driven.
1. Slowly add coolant to the bottle until it is at the top of the normal range (near the center of the spherical container).
2. Replace the fill cap fully.
3. Start the engine and let it idle.
4. If the coolant level gets to the bottom of the bottle, shut off the engine and repeat the procedure.
5. Once the level is stable with the engine fully warm the car can be driven.
The 2.0 engines have a bad habit of the small 3/8" vent hose in the top of the expansion tank pathway get clogged/plugged in the engine somewhere.
If there is no coolant coming out of the small hose in the top of the expansion tank, then this path may be restricted/clogged.
This is how the engine bleeds air out of the cooling system.
Search on the forum here and you will see this happen fairly often.
If there is no coolant coming out of the small hose in the top of the expansion tank, then this path may be restricted/clogged.
This is how the engine bleeds air out of the cooling system.
Search on the forum here and you will see this happen fairly often.
YES! SUCCESS ~ the Auto Zone dude sold me the wrong thermostat, I was lucky to find the right one at NAPA today.. warmer heater for now.. and the coolant fans come on.. reservoir receiving return just fine and dandy... I am assuming the fluctuation in heat with acceleration has to do with the blend doors, heater core (which I am doing over Christmas vacation), the battery or fuse (but the fuse is not corroding at the battery terminal. I am just ecstatic today 
Glad to hear things are improving.
If you have a OBDII scan tool that can read Real Time data, check your engine coolant temp. Should be about 205F at idle.
Read this - http://newbeetle.org/forums/questio...le/60391-obd-scan-tools-software-options.html
If you have a OBDII scan tool that can read Real Time data, check your engine coolant temp. Should be about 205F at idle.
Read this - http://newbeetle.org/forums/questio...le/60391-obd-scan-tools-software-options.html
pressure in reservoir
After a 30 minute drive I expected the reservoir to have a bit more pressure behind it when I loosened it. I haven't the right tools or know how to observe the problem myself. Which hose do I disconnect to blow out the air (if any) Can someone put a post on here that might help me before I ask a small shop to check it out?
After a 30 minute drive I expected the reservoir to have a bit more pressure behind it when I loosened it. I haven't the right tools or know how to observe the problem myself. Which hose do I disconnect to blow out the air (if any) Can someone put a post on here that might help me before I ask a small shop to check it out?
You cannot base things on how much pressure the reservoir has. This is an expansion tank, so at the end of the day there should not be a lot of pressure built up in the tank. You need to watch the coolant level in the tank and if the small return hose has a good flow, and the car is not overheating, then do not worry about it.
Get yourself a scan tool that can read real time data and check and see what the engine coolant temp is running.
Interesting, when you said 205 I thought, well that is odd. My coolant temp was reading 80 Celsius which can't be that hot.
So I looked it up and according to what I read the TDI should be about 190 F, which is 87.78 C.
So time to change the thermostat again. Seems like these need to be replaced every 5 years.
So I looked it up and according to what I read the TDI should be about 190 F, which is 87.78 C.
So time to change the thermostat again. Seems like these need to be replaced every 5 years.
Be careful, what you are quoting of 190F/87C is the thermostat operating temperature, not the engine coolant temperature.
One most all cars and trunks the engine coolant sensor is located at the cylinder head water return to the radiator. So the temperature sensor is usually measuring coolant temps that are 15-20F higher than the actual thermostat operating temperature. So again, I would expect the engine temp to actually read 205-210F at the sensor at warm idle.
I do not have any baseline numbers on the TDI, however, it is likely in the range I am stating.
Cool running engines run richer, get far worse fuel economy, have issues with premature crankcase contamination.
You might see if anyone in the TDI section can confirm their engine operating temperatures.
Also I find that thermostats may fail as early as 2 years, so you really need to baseline your engine temp and then keep an eye on it with a scan tool every few months.
Let me know what you find for the final expected baseline warm idle coolant temp.
I looked it up at TDI club, should be reading 87 from the computer, while I'm getting 80, sometimes 78.
It's possible that the coolant temp sensor is faulty.
I'm actually going to have a mechanic take care of this for me as it's too late in the year to work on a car here unless you have a heated garage, which I do not.
It's possible that the coolant temp sensor is faulty.
I'm actually going to have a mechanic take care of this for me as it's too late in the year to work on a car here unless you have a heated garage, which I do not.
Have somewhat a hard time believing that the operation temp is the same as the thermostat operating point. Unless the temperature sensor is located directly on top of the thermostat, the engine temp should be 10-15F higher than the engine temp.
So basing my info on the fact that I looked up the thermostat and it indicated that the engine has a 87C thermostat, you always have a higher engine temp than the thermostat operating temp, this is normal.
OK, well no panic then.
I haven't noticed any issues, the temp light is off in a reasonable amount of time depending on how cold it is that day.
I think I almost was hoping to have an issue just to be able to fix it. Addicted to fixing cars? Is that a thing?
I haven't noticed any issues, the temp light is off in a reasonable amount of time depending on how cold it is that day.
I think I almost was hoping to have an issue just to be able to fix it. Addicted to fixing cars? Is that a thing?
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