Changing thermostat in a 2003 jetta tdi?

Oleolson

Member
Joined
Mar 21, 2012
Location
Ojai
TDI
2003 Jetta
I have been looking for video of how-to change a thermostat in my 2003 tdi getta, Only finding gas ones on you-tube. Does any one have a or know of link? Or any other helpfully ideas for changing the thermostat??

Thanks, Ole
 

jcrews

Top Post Dawg
Joined
Jul 28, 2007
Location
Round Rock, TX - VCDS
TDI
All gone
It's very easy. Get a new thermostat with o-ring, preferably genuine/OEM.

Place a catch pan under the radiator and open the drain by twisting it and pulling it out until it stops. Open the overflow reservoir cap to speed up draining. Close the radiator drain once the water stops draining Use spring clamp release pliers to release a hose from the oil-water heat exchanger below the oil filter housing. Replace the hose once the water stops draining.

You can skip the above if you put a large catch pan under the engine and allow the water to spill out of the thermostat housing, but it will make a big mess.

Just below the injection pump, remove the plastic water nipple from the water pump housing on the engine block using a 10 mm 1/4" drive socket and long (6 inch) extension. Carefully try to release the nipple from the thermostat by twisting it.

Clean the sealing surface on the engine with a rag.

Install the new thermostat and seal in the nipple. There are two tabs that hold the thermostat in place. If those are broken, remove any loose pieces and use a loop of string or wire to hold the thermostat in from the open end. The string or wire will be removed once the nipple is secured in place with the screws. Do not overtighten the screws.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
It's very easy. Get a new thermostat with o-ring, preferably genuine/OEM.

Place a catch pan under the radiator and open the drain by twisting it and pulling it out until it stops. Open the overflow reservoir cap to speed up draining. Close the radiator drain once the water stops draining Use spring clamp release pliers to release a hose from the oil-water heat exchanger below the oil filter housing. Replace the hose once the water stops draining.

You can skip the above if you put a large catch pan under the engine and allow the water to spill out of the thermostat housing, but it will make a big mess.

Just below the injection pump, remove the plastic water nipple from the water pump housing on the engine block using a 10 mm 1/4" drive socket and long (6 inch) extension. Carefully try to release the nipple from the thermostat by twisting it.

Clean the sealing surface on the engine with a rag.

Install the new thermostat and seal in the nipple. There are two tabs that hold the thermostat in place. If those are broken, remove any loose pieces and use a loop of string or wire to hold the thermostat in from the open end. The string or wire will be removed once the nipple is secured in place with the screws. Do not overtighten the screws.
Yep, follow the above steps, it doesn't get much easier.
Oh, one thing. I recommend an OEM stat. I've tried a few others and so far haven't been happy with any except 1 out of 2 Wahler (which isn't good average). The OEM ones are about the only ones that work with the clips/tabs in the coolant flange. They aren't neccessary, but do make it a bit easier.
 

Oleolson

Member
Joined
Mar 21, 2012
Location
Ojai
TDI
2003 Jetta
It's very easy. Get a new thermostat with o-ring, preferably genuine/OEM.

Place a catch pan under the radiator and open the drain by twisting it and pulling it out until it stops. Open the overflow reservoir cap to speed up draining. Close the radiator drain once the water stops draining Use spring clamp release pliers to release a hose from the oil-water heat exchanger below the oil filter housing. Replace the hose once the water stops draining.

You can skip the above if you put a large catch pan under the engine and allow the water to spill out of the thermostat housing, but it will make a big mess.

Just below the injection pump, remove the plastic water nipple from the water pump housing on the engine block using a 10 mm 1/4" drive socket and long (6 inch) extension. Carefully try to release the nipple from the thermostat by twisting it.

Clean the sealing surface on the engine with a rag.

Install the new thermostat and seal in the nipple. There are two tabs that hold the thermostat in place. If those are broken, remove any loose pieces and use a loop of string or wire to hold the thermostat in from the open end. The string or wire will be removed once the nipple is secured in place with the screws. Do not overtighten the screws.
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When you say seal in the nipple, what type of sealint should I use?

Thanks, I take a look and see if I can figure that out, would be really nice if you new of a video...I could watch...anyway I'll take a look..Thanks!
 

Oleolson

Member
Joined
Mar 21, 2012
Location
Ojai
TDI
2003 Jetta
Yep, follow the above steps, it doesn't get much easier.
Oh, one thing. I recommend an OEM stat. I've tried a few others and so far haven't been happy with any except 1 out of 2 Wahler (which isn't good average). The OEM ones are about the only ones that work with the clips/tabs in the coolant flange. They aren't neccessary, but do make it a bit easier.

OK...thanks for the Tip!
 

DieselOx

Veteran Member
Joined
Mar 10, 2007
Location
Spokane, WA
TDI
2003 Jetta Sedan 5sp 342,000mi
Make sure the o ring is outside the t stat, under the housing.mine stock to the block and I thought thats where it went, took days to finally figure out.

Also, got my stat from napa, made in france, fit the clips, 17 bucks, works great.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
Make sure the o ring is outside the t stat, under the housing.mine stock to the block and I thought thats where it went, took days to finally figure out.

Also, got my stat from napa, made in france, fit the clips, 17 bucks, works great.
That's interesting. The one I got from NAPA was a US made Stant brand (didn't fit the clips) and it was "rated" at 195F but I had to remove it as it was running up over 205 (and climbing, even with the cabin blower fan running full tilt) in the warmer 60* temps.
 

Laura0957

New member
Joined
Apr 22, 2018
Location
California
TDI
2003 Jetta
video on changing out thermostat/sensor 2003tdi jetta

Is there a video on how to change out the thermostat and sensor on the 2003 TDI Jetta?
 
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