VW Coolant problems and overheating

Jparish8

New member
Joined
Aug 4, 2019
Location
Wisconsin and Ohio
TDI
2014 Passat
Hello all,
I am new to this and any on-line forum so bare with me. I have a 2014 Passat TDI and have spent a lot of money over the past year on repairs mainly due to the cooling system. I love this car, but cant keep having it overheat or the heater not function while I am away from home. I bought the TDI for the fuel mileage, interior space and longevity of the motor. I have 184K on it and rack up 30-40K a year on it. So I am completely out of every warranty. Two weeks ago the car started to overheat driving interstate through the flat state of Illinois. Took it to a dealer who over the last two weeks has replaced the thermostat and in the next few days the heater core again. I have had the core replaced once every year of owning it and now it only lasted from January until now with 22K since replacing it ( I think VW is just telling the dealer this because its a known problem I don't see how it is causing an overheating as when it was getting hot I could turn on the heater and wow was it hot). In December I had the timing belt, cam seals and water pump replaced due to mileage and the seals leaking oil. In January of this year I had no heat and had a dealer replace the heater core because the last dealer had bent the tubes when doing it so I could not get it back together myself and the dash had to be pulled. So any ideas on what is causing the vehicle to over heat? Also has anyone figured out if we can modify the cooling system to add in an external filter if that would help? One more thought should I test the alkalinity and put cooling system conditioner in the system if its too high? I cant get rid of the car as with the miles I still owe enough that I would take a loss, especially with whatever I get I will rack those miles up quickly. Also had the dealer in January perform the "clean" of the cooling system which is basically putting CLR (VW Version though) through the system to clean it out. Thoughts?
 

goodmonkey

Veteran Member
Joined
Mar 20, 2006
Location
Anchorage, AK
TDI
2014 Passat TDI, 2011 Touareg TDI
Welcome to the forums, sorry to hear of your issues. I also have a '14 with 91k and not your overheating issues that I've noted. Then again the temp gauge doesn't move from 190F, which it is designed to give false hope where you can't see those minor variations.

Heater core replacement is a norm though, which I've had done.

Do you have a Bluetooth OBDII reader and any smart phone apps to get better feedback? Torque does show those variations in coolant temps, and VAG DPF is one that can show when a regen is active. That could have been when the car overheated driving on the interstate.
 

06bluebeetletdi

Veteran Member
Joined
Sep 30, 2012
Location
Middlesex, NC
TDI
'14 Passat TDI SEL and '13 Beetle TDI
My 2014 passat has had 2 heater cores: 1/16 at 41,000 miles and 10/17 at 53,000 miles. It only had 4400 miles driven from 3/16 to 9/17. I have a polar fis on mine for the last year. Dash gauge stays at 190, polar goes up to 225-230, it runs the fan after every drive when the ambient temp is over 80. My commute is 32 miles each way, about 28 miles at 70 mph. It had the water pump and timing belt done about 500 miles after the 2nd heater core, nothing like walking out to your car to go to lunch and finding a large puddle under it. I am at almost 77k, all seems fine. It does make me a bit nervous as my ‘13 tdi beetle does not run the fans after I turn it off. But i have extended warranty until 122k or 9/22, so i drive on.
 

Jparish8

New member
Joined
Aug 4, 2019
Location
Wisconsin and Ohio
TDI
2014 Passat
Sorry for the delay I do have an OBD 11. Nothing except the temp being high was going on when it overheated. Dealer put in a thermostat and just yesterday because it was still getting too hot a heater core. Heater was just done and entire system flushed numerous times in January and 22,000 miles ago. I will be installing a coolant filter in the near future tired of heater core problems. Any advice on a coolant filter system. Found a old thread that talked and showed one installed on a 2012 that was meant for a 6.0. Emailed the guy who posted and he has not responded. Any advice is appreciated. Once I ensure it's good after a filter install I am going to get it the malone stage 2 with DSG tune.
 

wsc

Well-known member
Joined
Jan 3, 2015
Location
Cypress Texas (Houston)
TDI
99.5 Jetta, 06 Jetta (Totaled), 14 Passat.
My 14 Passat TDI has 65000 miles and just failed the inlet fitting to the heater core. My wife and I had to get towed about 100 miles home. The part that failed is a plastic quick connect fitting that connects the hose to the core on the firewall. It was severely deteriorated. I’m wondering if something about the diesel gate fix gets this fitting too hot. It is on the firewall close to the turbo. This is also a high point in the system and may have steam or gas collecting there. Post diesel gate fix, my fans run for about 5 minutes after shutting down the engine.
 
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wsc

Well-known member
Joined
Jan 3, 2015
Location
Cypress Texas (Houston)
TDI
99.5 Jetta, 06 Jetta (Totaled), 14 Passat.
So the heater core is plugged up per the known issue with these cars. VW is changing the heater core on their account. No games from them.

So the outlet of the EGR cooler goes directly to the heater core. When the coolant stops flowing, the EGR cooler must make steam that bubbles up to the heater core. It made a burning smell inside the car in my case and it did not leak. So do they have antifreeze that does not form solids, or can the EGR temp be turned down? Is this a diesel gate fix related issue caused by increased EGR rate, or higher EGT? I can’t believe VW testing on the original tune would not have caught this.
 
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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
IMO delete the EGR cooler and tune the car to not toss a CEL and most of the coolant issues will greatly be reduced.

Only way to keep NOx happy (without tanking MPG) is to do crazy EGR which just bakes the coolant.

As been proven in the past VW testing proves it works on their test bed but is far from addressing every issue as the cars age.
 

Jparish8

New member
Joined
Aug 4, 2019
Location
Wisconsin and Ohio
TDI
2014 Passat
So is that a malone tune? With all the rental cars I have had to get for work and the added repair they are saying of the oil cooler being plugged I am in this for over $3,000. The issues I have had with the emissions before the diesel gate repair and water pump I could have bought another car. I love the car and MPG, but it has to end.
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
yeah, give them a call or email they should be able to help you out.

Again it may not be the silver bullet to solve all you're issues but it'd have to help.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I think this is why any fixed CKRAs end up getting at least some form of aftermarket tune. The EGR duty cycle post-fix is just too aggressive, and the heat transfer to the coolant via the EGR cooler is just too much.

The only way to fix this issue would be to take and run the coolant after coming out of the EGR cooler through an additional radiator (like the A4 VR6 cars got) and perhaps through some form of serviceable filter. Meaning, adding even MORE plumbing to the already excessively complex nest of hoses and pipes and fittings stuffed under the hood of these poor cars.
 

wsc

Well-known member
Joined
Jan 3, 2015
Location
Cypress Texas (Houston)
TDI
99.5 Jetta, 06 Jetta (Totaled), 14 Passat.
https://static.nhtsa.gov/odi/tsbs/2016/MC-10106581-9340.pdf


The Service Bulletin says the coolant is becoming acidic with time and causing the formation of solids. Doesn't say anything about increasing the frequency of coolant replacement. Only says to change it if the heater core plugs up.

IMO, need to change out the coolant in these cars more often to prevent failures on the road. Other problems like water pump seals being worn out prematurely from the fine solids, or thermostats getting stuck, other coolers being plugged, fittings being eroded out (like happened on mine) can be reduced. I'm thinking I'll change mine every 30 k miles or so.

The video link from jrm above https://www.youtube.com/watch?v=sG7ni0lEr94 says a lot about what the problem is and how it is relatively easy to change the heater cores in these cars. Still, you don't want to have one plug off on a long trip at 80 MPH because it will blow the EGR coolant discharge hose and leave you stranded.

Alert! on 2.0 TDI's flush and change your coolant every 30 k miles, no guarantees but it might help.
 

goodmonkey

Veteran Member
Joined
Mar 20, 2006
Location
Anchorage, AK
TDI
2014 Passat TDI, 2011 Touareg TDI
What do you end up doing with this frequently flushed coolant? (How are you disposing of it?)
 

Jparish8

New member
Joined
Aug 4, 2019
Location
Wisconsin and Ohio
TDI
2014 Passat
Ok all here is the update on this vehicle. After 5 weeks and these repairs: Thermostat, heater core, oil cooler and transmission cooler I am now the owner of a 2019 Jetta 1.6l. Supposedly per VW they have only seen one other car with this problem and they cant figure out what's going on. So after talking with the service manager and technician they both advised I off load the car. It has been a very expensive 5 weeks and I hope the gasoline jetta has longevity as I drive 3,000-4000 miles a month all highway. So far I am getting 40 mpg. Thank you all for the help just couldn't afford to save the car.
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
btw it's a 1.4t not a 1.6t :p
 

wsc

Well-known member
Joined
Jan 3, 2015
Location
Cypress Texas (Houston)
TDI
99.5 Jetta, 06 Jetta (Totaled), 14 Passat.
Sad to see a TDI get replaced by a gasser! My son still rocks my 99.5 ALH with 250K on it. Don’t get me wrong, I did plenty of work on it, (broke the turbo, valve job, injection pump, heater core) but is was fun. And it is really fun to go 600 miles on a tank of fuel. Gassers and electrics won’t do that.
 

wsc

Well-known member
Joined
Jan 3, 2015
Location
Cypress Texas (Houston)
TDI
99.5 Jetta, 06 Jetta (Totaled), 14 Passat.
I keep seeing posts from others with the same issue I had, but people are not successful getting VW to pay for it. Cooling system failures on diesel gate cars are emissions related. Make it clear you understand this and you should be able to get them to pay.
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
Are there more issues with this after stage 2? g12 or g13?
 

ApriliaNut

Veteran Member
Joined
Jun 4, 2008
Location
SoCal
TDI
06 pkg 1 Jetta 191k w/Malone Stage 2
Ok all here is the update on this vehicle. After 5 weeks and these repairs: Thermostat, heater core, oil cooler and transmission cooler I am now the owner of a 2019 Jetta 1.6l. Supposedly per VW they have only seen one other car with this problem and they cant figure out what's going on. So after talking with the service manager and technician they both advised I off load the car. It has been a very expensive 5 weeks and I hope the gasoline jetta has longevity as I drive 3,000-4000 miles a month all highway. So far I am getting 40 mpg. Thank you all for the help just couldn't afford to save the car.
Stay on top of the direct injection caused carbon build up on the valves and what not. I think Liqui Moly has an additive.

https://products.liqui-moly.us/additives/valve-clean.html

Video: https://www.youtube.com/watch?v=d71WLXHYuvI

As one of the comments states, change the oil after doing the process, since it's a brand new car you might do it b4 the 1st oil change to get a head start b4 things go the wrong direction!
 

stevelikes2fish

New member
Joined
Jul 29, 2018
Location
New Jersey
TDI
2015 Passat
Good morning all,
Well,
After spending months of troubles and money, here's my take on my 2015 Passat TDI SEL. Purchased the vehicle brand new in April of 2015. Bought it on a recommendation of a good friend very familiar with vw diesels. I commute approx 170 miles round trip to work 5 to 7 days a week. I got it for the suggested fuel economy. I am now 65 years old, still traveling the same distance every day and will say what started out as the best vehicle I ever owned has turned into a nightmare of unbelievable proportions.
I was traveling home one day when the vehicle suddenly overheated. At that point I only had 135k miles on it. Got it towed to the dealer 5 miles away. Was told it was the heater core. I found that u usual as I have owned numerous vehicles with well over 135k miles and never once ever had a heater core go. So, $2400 later, new core. I kind of got over it. Yeah, I went through the entire ordeal with the emissions scandal. Kept the vehicle. VW performed the mods in 3 steps. Received a lump sum of money. Figured I was ahead of the game. November of 2018 the radio stops working. It was displaying some weird message on the screen about a software download or something. Dealer said the radio had to be replaced at a cost of about $2200. I decided for that price to purchase an aftermarket radio. Did so at about $700 and had a person who has been installing radios in high end vehicles for over 40 years. He called me a day after troubleshooting the problem and said there is nothing wrong with the radio however the amp that is under the drivers seat was shot. He stated he could bypass the amp and just install the radio which has all the bells and whistles. Happy again as I now have an even better radio than the stock radio. Now here's where the sage begins.
September 24th of 2020 the car over heats again. Mine you y vehicle is well maintained at the dealership. Oil changes every 6k miles even though the recommendation is at 10. Even before I rolled over 200k miles I always had my oil changed at 8k. Routine trans flushes, etc. Always had the required work performed as recommended. I get the car to the dealer and they call 4 days later on the 28th and say the thermostat needs to be replaced. They say the bad news is that "it is inside the engine" and the coat will be $2400. Ok, need to order the item, service techs shorthanded. Three weeks later after a short rental car, a borrowed car and then finally a loaner car from the dealer they call and say well, it's still overheating. Looks like the water pump isn't functioning as it should. Will need a new pump and might as well do a timing belt too. Ok, another $2400. Have to order parts and wait for a tech to be available. It now beginning of November. I receive a call saying it's still overheating and we will need to pull the head. I ask them if they performed a compression test. They said yes and it passed but we need to check the head for flatness. At that poi t I contact VW corporate and get them involved. After a week or two they agree in chip in $1500. Early December I get a call saying the car is all done. I show up on a Saturday with $7300 cash in hand. It was a warm day for our area. Was so excited to finally be back in my car. I drove out of the lot with the windows partially open and drove 3 blocks to my house and parked it. The following morning I awake and go out to go to the store. It was cold overnight so I started the vehicle and turned on the defroster and rear defroster. Within a minute I noticed some problems. The blower switch which when turned all the way up and has i believe 7 or 8 lights on it started to go down all the way to no lights at all and the rear defroster shut off after only 30 seconds or so then some lights on the dash came on signalling battery. My battery was newly installed only 12 months ago. Upset now i returned the vehicle the following day after getting yet another loaner vehicle. They called the following day and said well the alternator now need to be replaced. I'm thinking how is that even possible. Did they get some antifreeze spilled onto it or whatever. Go ahead and replace that now. Have to order more parts and schedule a mechanic to do the job. I finally get my car back, 3 months to the day of first bringing it there and hand over another $1200 for the alternator. Drive the car to work and on the way home BINGO. Cold air starts coming out of the passenger side vent then all the other vents and the engine oil temps starts climbing up about 20-25 degrees more than the normal. The coolant temp is kind of stuck at 190, which I saw at an earlier post above. I slow down to 45mph and the oil temp drops down to the normal range. Drop off vehicle again. They call a week later and say it needs another heater core. At that point I finally pull the car out of there and bring it to a recommended repair facility. It's been 2 weeks now and this new place cant seem to locate the problem. They did say they believe there is a clog somewheres within the cooling system and were going to remove the dash to get a closer look. Corporate has basically wrote me off as all they do is give me details as to what the dealer is saying. I have too too much money thrown into this right now to just walk away. I hope the new place can fix my vehicle. I am thinking about going to a lawyer when all is said and done. A car I absolutely loved has just wrecked me and my regards to VW.........
 

ticaf

Veteran Member
Joined
Nov 15, 2018
Location
US Mid-Atlantic
TDI
Stock 2015 Golf SW S Manual TDI
This is very strange for a car that I believe is mostly driven on highway. Run as fast as you can from that dealership. If you decide to keep the car, i believe a 6k miles oil change interval extremely overkill. Since you are doing mostly highway, 10k is just fine. You could even push it further, safely by doing oil analysis.
 

Tom in PT

Veteran Member
Joined
Jun 7, 2017
Location
Twilight Zone, WA State
TDI
2005 Passat sedan - SOLD; 2013 Passat DSG; both purchased new
Consult an attorney. Read the repair guarantee language on the original work order (thermostat replacement).
 

jriets

New member
Joined
Jan 19, 2021
Location
Grand Rapids, MI
TDI
2015 Volkswagen Passat TDI
2015 Passat TDI owner here driving 4k miles a month w/ 130k on engine experiencing the same issues mentioned in this thread. 2 heater cores replaced in the last 10 months, radiator line deteriorated summer of 2020 causing a blow in the line and left stranded on side of road 70 miles from home, and most recently thermostat issue (left open or closed along with recommendation of radiator replacement). After reading through this thread as well as others, it is blatantly apparent there is a connection between the said issues and emissions with the system running too hot.

My car has been at the dealership for 3 weeks now and onto my third phone call VW customer service area rep to help with a solution to the issues going on and WHY as well as how can you assure the following issues won't appear again in a few months. She is playing ignorant and it's a he said she said with her and the dealership. Has anyone had any luck with getting Volkswagen to take care of these issues, if so how, and what is the general consensus on assuring this won't continue to be an issue?
 

jriets

New member
Joined
Jan 19, 2021
Location
Grand Rapids, MI
TDI
2015 Volkswagen Passat TDI
The deletathon soldiers on, LMAO....
Deletathon as in...? Please elaborate oilhammer..

I understand if this is repetitive, simply asking if there has been any experience of finding a solution? It seems all too common to just let go and continue paying for an inevitable re-occurring issue. Thank you for your response.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Delete meaning removal of all the troublesome components and tuning them out. Result: more reliable, more fuel efficient, peppier, and you can forget about your monthly visits to the dealer. This is "illegal" (disclaimer). But lots of people do it, simply because they need reliable transportation, and have no desire to know the entire dealer service staff on a first name basis. ;)
 

wsc

Well-known member
Joined
Jan 3, 2015
Location
Cypress Texas (Houston)
TDI
99.5 Jetta, 06 Jetta (Totaled), 14 Passat.
Update from my 2019 post above. in August 2020 my oil cooler started leaking. The plastic housing was eroded from solids flow. When I replaced it, there was a lot of solid granular material in the coolant passage in the block. I dug it out, enough to fill a coke can about one quarter. This year the water pump seal failed, at 85,000 miles. Something you would expect form solids. There is solid material in these systems. I have never seen the stuff before. They say it is from either 1) flux material left in the cylinder heads at the foundry, or 2) cooked anti freeze.

Be ready to inspect or replace all of your plastic parts with high flow velocity, heater core, water pump, and change your coolant.

P.S. I loaded the stage 3 Malone tune this year, definitely worth the money!
 

eugene89us

Veteran Member
Joined
Mar 17, 2014
Location
Southern USA
TDI
2014 Volkswagen Passat TDI SEL Premium
@wsc I posted a few threads recently with this. I have always seen particulates in my coolant. My original factory coolant went 60k miles before original heater core plugged. Little did I know, since prior to that I hardly ever paid attention to quality of coolant. Just checked its level, which was always constant. At 60k, it was orange, almost brownish orange. I was surprised to compare it to fresh one Heater core changed, coolant flushed, all was well. At 90k, another heater core fails. Coolant still pink but again with particulates in expansion tank. I did that heater core myself, not too hard, but was still weird to me.

What scared me is when I did the oil cooler DIY. The cooler was 100% plugged. Literally tried to blow through coolant line in the cooler - Complete blockage. I am surprised I never had car complain, until the cooler started to leak due to plastic degradation. That is where I found *innumerable* amounts of sediment that clogged it. I should have kept the sediment to see if any commercial radiator cleaner would dissolve it in a test tube. But alas, did not. Then I did the timing belt recently and replaced coolant pump. There were no particulates there thankfully, except it started to ooze around the seal, and that dry ooze collected around that area. But not to the same point as the oil cooler. I can live with that amount for sure.

Since second heater core clogged, got the car Kerma tuned. All emissions in place and road legal, just less crazy. It runs a lot cooler too, averages 97C coolant now compared to 100 to 101C before. Definitely cooking coolant on dieselgate tuns. Aftermarket tune is the only answer.

 
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