2015 Several Coolant Issues


Nov 24, 2014
2015 Jetta TDI SEL
Looking for some help and to see if anyone else has encountered any problems.
I'll post the raw data below the story.

It started in July, a slow coolant leak. It was troubleshot by the dealer to a pump in the coolant system. The part was ordered, and by my next regular service in December, the pump still had not arrived. At this time, I was adding coolant about every 1,000 miles.
During the regular servicing in December, it was determined it was a leaking water to the radiator, so it was replaced at the time. By this time, 8,000 miles have elapsed since the start of issues in July.

After the repair, I was adding coolant about every 75-100 miles. VW had my car for 7 weeks, a VW Engineer was contacted by the dealer and it was suggested the coolant bottle be replaced. The bottle was replaced, I was able to enjoy 338 miles of driving before the next coolant loss.
Another line blew, the engine overheated and had smoke pouring out, the car was towed back to VW.
Inlet water hose to the heating core was replaced, before it blew again after 575 miles and a second overheat with smoke, and a tow back to the dealer.

After the second overheat and two to VW, they've found coolant leaking into the EGR cooler and the car is now throwing codes for the DPF.

Has anyone ran into anything like this before?

Add Coolant7/7/2295,013
Add Coolant7/22/2296,017
Add Coolant / Inspection at VW7/27/2296,227
Add Coolant8/31/2297,855
Add Coolant10/3/2299,765
Add Coolant10/14/22100,713
Add Coolant11/14/22101,817
Add Coolant12/9/22102,986
Water Hose Replacement12/19/22103,547During inspection, found vehicles coolant pipe is leaking coolant.
Cleaned and pressure tested the system to confirm the pipe is infact actively leaking.
Replaced the coolant pipe to correct, cleaned coolant, filled and re pressure tested, no further leaks present. Allowed vehicle to run to ensure no air pockets are in the system.
Add Coolant12/24/22103,751Empty Reservoir
Add Coolant12/26/22103,837Empty Reservoir
Add Coolant12/27/22103,848
Repair1/4/23103,919Coolant System Bleed
Pressure tested the cooling system, no external leaks present.
System held pressure for several minutes with no external leaks present. Visually inspected, no leaks are present at this time.
Bled cooling system twice with vw scan tool to ensure no air pockets are left in the system, test drove vehicle 20+miles, marked coolant bottle where levei was prior to driving, vehicles coolant level
Inspection1/16/23104,404Inspection After Massive Coolant Leak - No Issues Found by VW
Add Coolant1/18/23104,598Empty Reservoir
Add Coolant2/22/23105,419Empty Reservoir
Add Coolant / Drop Off at VW for Repair3/2/23105,701Empty Reservoir
Repair4/20/23105,837Replace Coolant Bottle Cover & Tank
Pressure & Leak Checks with Dye
Pressure tested the cooling system, no leaks found. scanned for faults, no faults pending or present.
Opened VTA case with vw with
concerns and history and was advised to pressure test the system while the engine is hot and allow the engine to cool down fully allowing the cooling system to be tested under all temps. If no leaks are present during this test, advised to replace the coolant bottle and cap and retest.
Replaced the coolant bottle at no labor charge and added dye.
test drove the vehicle over 100 miles, and inspected after every drive, no leaks or dye present
Have customer return in 1000 miles for re
inspection if needed to see source of leak with the coolant dye.
Add Coolant4/21/23105,892
Add Coolant4/24/23105,944
Add Coolant / Engine Overheat4/30/23106,175Reservoir Empty
Tow / Add Coolant / Inspection5/1/23106,178Inlet Water Hose Replacement
verified concern, pressure tested the cooling system, as soon as the system was under pressure, found the inlet water hose is cracked and spraying coolant in the engine bay.
Replaced the inlet hose, cleaned engine bay and underside completely. pressure tested the system again, no leaks present, system is currently holding pressure as needed.
Advised customer after test drive, can feel the heat is mildly warm and may eventually blow cold air from heater core failure. Advised customer vehicle will need a heater core.
Add Coolant / Engine Overheat5/14/23106,758
Last edited:


Jul 25, 2022
Bloomington, IL
2015 Jetta SEL TDI
Yup. Been there and back. Two blown heater hoses and two tow truck rides. So the 2015 CVCA has a history of coolant issues with several individuals. Myself included. A lot of it is due to the emissions on the diesel and the super heating that occurs in the EGR cooler. The VW G13 coolant simply doesn't hold up and degrades quickly.

Here's a thread where myself and a few others all talked about the same issue: https://www.vwvortex.com/threads/2015-jetta-tdi-cvca-heater-hose-issue-round-3.9458243/

Coolant loss: While I don't necessarily agree with coolant loss on pressurized systems, it does happen for various reasons. Mostly just due to boil off. You'll know it's boiling off if you check the pressure cap and there is a sort of build up on the threads. This is due to either A.) the coolant cap not holding pressure to raise the boiling point, or B.) the system exceeding the pressure of the cap (20 psi I think?) and venting through the cap up the threads.

I think in the first 5 years of ownership of my 2015 Jetta TDI I had to add on average 200-300ml of coolant per year. Usually in the winter.

Based on where you are now and what you likely may need to do:
  1. Replace your heater core. It's for sure clogged and is causing the heater hose to burst. It's shockingly an easy thing to replace if you are a DIYer. The dealership will charger around $1,200 to do it.
  2. If you've driven any amount of time with a clogged heater core, buy another heater hose supply line and either replace it or keep it on hand. Chances are it's already getting heat blasted by coolant from the EGR.
  3. After those are done and the car is 'stabilized'. Take the care out of the 30 mile loop on the interstate. Monitor oil temperature. If the oil temperature is outside of the 210F-230F range. 240+, you can assume your oil cooler is also clogged. Buy an Engine Oil Filter/Cooler and replace that.
  4. You're at 106k miles and they still can't get you a water pump? Go with an aftermarket one that's non-variable. Car will run perfectly fine with a non-variable one it just will take a little bit longer to heat up on those super cold winter days. 10 degrees or colder. If you are in that range, you mine as well go for a timing belt considering you have to take the timing belt off to get to it.
  5. Flush the coolant system thoroughly. Some debate here, but a chemical flush from liqui moly may be worth while, up to you. Run the chemical flush for two-three days and then flush the system thoroughly with distilled water. Distilled water part is critical! (You ever put non distilled watecr in a steam cleaner and thought it woudl be okay? Same thing with the coolant system.) It's a $1 a gallon at walmart.
    1. The CVCA is a complicated coolant system and requires some dilligence to properly flush. You'll need some hose clamps to properly flush all circuits (low temp coolant circuit, warm up circuit, normal load circuit, and full load circuit.) The flush procedure requires alternating clamps from various bleed lines to ensure you flush the block, heater core, intercooler, and raditor.
  6. Get a new coolant reservoir and cap. (Do not put the silicate packets back in!)
  7. Once done with all of that, I believe the general recommendation is to fill the car with something other than G13 coolant. Seems the glycerin based coolant can't keep up with the torching the EGR happens on these cars. G12+++ seems to be acceptable as it's glycol based. (Zerex G40, etc.)
Be prepared to flush the coolant thoroughly every 5 years. Despite VW saying G13 is a lifetime coolant, it's only 5 years relistically and then it falls apart.

If you are going to pay the dealership to do all of this, it's several thousand to do, but if you pay the $30 bucks for a day pass to erwin and get all the factory service information, you can probably do all of the above for a reasonable amount. You'll also need VCDS and an vacuum coolant filling tool to properly get the coolant system filled without air pockets.