Another heater core?

jafische

Veteran Member
Joined
Dec 1, 2012
Location
Pace, FL
TDI
2013 (A3) TDI SEL Premium (Reflex Silver / Moonrock)
2013 @165k miles.
If I had to do it over again every 50,000 mi I would do a complete radiator flush with g13.
A mechanic charge me $950 to replace the heater core!!! I would have done it myself but it comes with a 5-year warranty. I figure that is worth the insurance.
 

Penst8grad

Active member
Joined
Nov 24, 2017
Location
Pa
TDI
2015 Passat TDI SEL
2013 @165k miles.
If I had to do it over again every 50,000 mi I would do a complete radiator flush with g13.
A mechanic charge me $950 to replace the heater core!!! I would have done it myself but it comes with a 5-year warranty. I figure that is worth the insurance.
I'm just buttoning up doing mine myself for the 1st time today. I think it was made more difficult by the previous techs having bent pipes and used screwdrivers to separate the core from pipes. I would have gladly paid $950 for a 5 year warranty.
 

Brad95

Veteran Member
Joined
Aug 9, 2012
Location
Arizona
TDI
2013 Passat TDI SE Manual since 09/28/12-04/05/18, 2015 Passat TDI SE Manual Since 03/29/2018
Mixed/contaminated coolant can clog up cores on the gassers, too. I just flushed one on a 2015 2.slo Jetta that had been previously messed up by morons. So yeah, it can happen on those.

I have been reasonably successful with flushing them the opposite direction of flow with a garden hose after soaking them with Permatex Heavy Duty radiator cleaner.


That stuff is powerful, and it works. I *JUST* put it in the heater core/pipes, and not anywhere else. Yes, I know it says not safe for aluminum, and yes I know the pipes and core are made out of aluminum. I don't leave it in there for very long, and if it messed something up (never has, but if) you'd be back to replacing it anyway, so what is the harm in trying?

Here is how I do it:

Disconnect both quick couplers at the heater core pipes on the firewall, and move them out of the way and secure them so nothing else gets in them.

Get two lengths of bulk hose, about a foot or so long, 3/4"/19mm ID, and slip them on to each pipe, and angle them UP.

Pour the cleaner down both hoses until they are both full. If the core is not completely clogged shut, which they usually are not, just pouring it in one hose is enough, as liquid seeks its own level and it will come back up the other. Try not to spill any. One quart bottle is enough to do it a couple times at least.

Let it soak for about 20 minutes. You may see some bubbles and foam come up as it dissolves the solids inside. Pull the hose off from the TOP pipe connection, leave the lower one in place.

Rig up a garden hose to fit in the hose that is still attached to the BOTTOM pipe, then turn it on full while watching what comes out of that top connection. You'll see a black/brown slurry of filth come pouring out... keep the hose running until it comes out clean and clear.

Turn the water off, remove the hose, reconnect the quick couplers, refill the system with G12 mix, put anything back together you had to remove to get at the firewall, take the car for a drive and make sure the system is full.
had same situation as many, it started blowing Luke warm air right after timing belt job,.thanks oilhammer!.followed above instructions, flushed heater core with Permatex Radiator cleaner as per Brian's Instructions and i am happy to report after 1k mile it still measured 140°F temp at both vents. Disconnecting heater core's quick connect couplers was hardest part for me,. disconnected turbo inlet hose, breather hose etc to have enough room to have access to quick couplers. did coolant bleeding afterwards using VCDS.
 

MB2VW

Veteran Member
Joined
Jun 8, 2000
Location
Lighthouse Pt., FL USA
TDI
2015 Passat SEL,
Mixed/contaminated coolant can clog up cores on the gassers, too. I just flushed one on a 2015 2.slo Jetta that had been previously messed up by morons. So yeah, it can happen on those.

I have been reasonably successful with flushing them the opposite direction of flow with a garden hose after soaking them with Permatex Heavy Duty radiator cleaner.


That stuff is powerful, and it works. I *JUST* put it in the heater core/pipes, and not anywhere else. Yes, I know it says not safe for aluminum, and yes I know the pipes and core are made out of aluminum. I don't leave it in there for very long, and if it messed something up (never has, but if) you'd be back to replacing it anyway, so what is the harm in trying?

Here is how I do it:

Disconnect both quick couplers at the heater core pipes on the firewall, and move them out of the way and secure them so nothing else gets in them.

Get two lengths of bulk hose, about a foot or so long, 3/4"/19mm ID, and slip them on to each pipe, and angle them UP.

Pour the cleaner down both hoses until they are both full. If the core is not completely clogged shut, which they usually are not, just pouring it in one hose is enough, as liquid seeks its own level and it will come back up the other. Try not to spill any. One quart bottle is enough to do it a couple times at least.

Let it soak for about 20 minutes. You may see some bubbles and foam come up as it dissolves the solids inside. Pull the hose off from the TOP pipe connection, leave the lower one in place.

Rig up a garden hose to fit in the hose that is still attached to the BOTTOM pipe, then turn it on full while watching what comes out of that top connection. You'll see a black/brown slurry of filth come pouring out... keep the hose running until it comes out clean and clear.

Turn the water off, remove the hose, reconnect the quick couplers, refill the system with G12 mix, put anything back together you had to remove to get at the firewall, take the car for a drive and make sure the system is full.
Glad I found this post again. I'm motivated to try this method on the CVCA Passat. Will try after I check head gasket leakage...
 

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
I'm just buttoning up doing mine myself for the 1st time today. I think it was made more difficult by the previous techs having bent pipes and used screwdrivers to separate the core from pipes. I would have gladly paid $950 for a 5 year warranty.
I'm facing the same thing. Dealer has put 2 heater cores in, and I'm on my first one doing it myself. Dealer warranted the $35 core last time and charged me $750 in labor. Should have drove it up their arse then. Anyhoo, my heater pipe is no longer round and having a hard time getting the heater core pipes in. What did you use to re-round the pipes? I'm working with wood dowel, but not having much luck. I've also cut the ends off my old heater core, and trying to get them on but I can't seem to get any force to push them in. By any chance, does anyone know if you can pull the pipes and replace? I'm guessing it looks like the engine would need to come out for the clearance, but anyone?
 

AverageAndy

Veteran Member
Joined
Sep 14, 2020
Location
Phoenix, AZ
TDI
2013 Passat TDI SEL, 2013 Golf TDI 6MT, 2013 Jetta TDI 6MT (R.I.P.)
If you mean this part Water Pipe - Volkswagen (561-819-857) then I would think you could, but not sure which way it would come out. I have have seen someone on YouTube use 1" heater hose and worm gear clamps to connect the core to the pipes when he couldn't get them to fit.
 

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
If you mean this part Water Pipe - Volkswagen (561-819-857) then I would think you could, but not sure which way it would come out. I have have seen someone on YouTube use 1" heater hose and worm gear clamps to connect the core to the pipes when he couldn't get them to fit.
Hi Andy,
That is absolutely the one I'm referring to. My plan today was to use my cut ends from the old heater core, connect 5/8" hose as it fits nicely, clamp, and then cut my ends off the new core to put the other end of the hose on, but I can't get one of my ends back in the aluminum pipe as it's out of round. So my next thought was exactly what you're mentioning, take my dremel to the pipes end, and just use the 5/8" radiator hose to connect to the core from where I cut the pipes. I'm not completely averse to this hack, but if I can't get new pipes in easily enough, I'll probably think about it for a while longer. lol! I do hate hacking something if it's near impossible to fix. I'll look for that YT video. Thanks!
 
Last edited:

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
Hi Andy,
That is absolutely the one I'm referring to. My plan today was to use my cut ends from the old heater core, connect 5/8" hose as it fits nicely, clamp, and then cut my ends off the new core to put the other end of the hose on, but I can't get one of my ends back in the aluminum pipe as it's out of round. So my next thought was exactly what you're mentioning, take my dremel to the pipes end, and just use the 5/8" radiator hose to connect to the core from where I cut the pipes. I'm not completely averse to this hack, but if I can't get new pipes in easily enough, I'll probably think about it for a while longer. lol! I do hate hacking something if it's near impossible to fix. I'll look for that YT video. Thanks!
Oh snap! I found it:
Oh, man, that is ugly...Hummmm
 

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
Well, so here's my hack. This will give me time to look up whether I can replace the water pipes ( 561-819-857 ) without having to drop the engine. Also let's me have time to flush, flush, and flush. I basically just did a core bypass, looping it back to the outlet pipe.

 

Penst8grad

Active member
Joined
Nov 24, 2017
Location
Pa
TDI
2015 Passat TDI SEL
How is the core bypass working? Now I'm on to actuator replacement. Went from no heat to only heat on the driver's side. Ugh...If this car didn't get 53mpg it would have been gone long ago.
 

watatrp

Veteran Member
Joined
Feb 29, 2008
Location
South Bend, IN
TDI
04 Jetta tdi (gone) 2013 Passat SEL TDI
Does the coolant continuously run through the heater core even if heat is not called for? I wonder if the flow through the heater core "long term" causes the blockages? It would be nice to have a bypass valve so that you could open it only when you might need heat. My theory is that if you cut the flow through the heater core would it lengthen the life of the heater core before becoming clogged?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Does the coolant continuously run through the heater core even if heat is not called for?
Yes, which is the same for most cars, and most every water-cooled Volkswagen of the modern era.

Some cars will employ a valve that bypasses the flow of coolant through the heater core when the temp selection knob is moved to the full cold position, to help the air conditioner not have to work so hard to remove heat from the cabin when it is extremely hot outside. But these cars do not use such a valve.
 

watatrp

Veteran Member
Joined
Feb 29, 2008
Location
South Bend, IN
TDI
04 Jetta tdi (gone) 2013 Passat SEL TDI
It would be nice to have a small 3-way valve with a solenoid that could bypass the heater core with the push of a button. Of course fixing the source of the problem would be the best solution.
 

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
How is the core bypass working? Now I'm on to actuator replacement. Went from no heat to only heat on the driver's side. Ugh...If this car didn't get 53mpg it would have been gone long ago.
So far so good. I found some 90 degree barbs, and thought about changing out the loop of the hose to square corners that would fit more tightly, but haven't yet. Wife drives the car M-F about 70 miles a day and so far it's holding together. Did add a little distilled water to the tank over this weekend, hoping a bubble came out as not seeing or smelling anti-freeze anywhere else. Fingers crossed. If this continues, probably will start the flush parade before too long. Also, have not found any info on replacing the water pipes through the firewall, but local pick -n- pull had a 2014 passat with engine out a while back. Should be easy to get to and hoping it's still there as I can try to figure out if can change in tight quarters.
 

Poellot

Member
Joined
Jun 2, 2022
Location
68729
TDI
Passat
I bought my car with 28k. It was spring. That fall I noticed the right side of the window would not defrost as fast. Then my friend rode with me and said it was cold. I googled it and heater core plugged was the most common. I changed it, put in new g13. A year later same thing. I got pentocin brand this time. Flushed with distilled. Changed the heater core. Now it's been 2 years with no issues. Getting ready to do a timing belt kit. From ecs they included vw brand g12 evo. Time will tell but it would seem the vw g13 is the problem.
 

JohnStone

New member
Joined
May 1, 2024
Location
Arizona
TDI
2013 VW Jetta
Second time around with no heat, check engine light, and the P2457. Only problem this time is according to my local dealer the extended warranty ended last year on my kid’s 2013 TDI and he’s working a summer job near Fairburn Georgia. That’s pretty much the other side of the world for me. He said the light went on about 500 miles before the state line and but the only then he noticed was the light and then his friend said her feet were freezing on the passenger side of the car. Since basically the cost to repair is just a bit less than what he’s making this summer; does anyone have a shop suggestion he can take it to south of Atlanta? I don’t think he should drive it, and he keeps hearing a gurgling sound every now and then. Dealer is okay, just don’t want him loosing his shirt, especially since this was replaced less than 10k miles earlier (car was sitting in the garage for all but a few months a year since he’s been away at school).
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Richard Bryan is in Rutledge (north of Atlanta). He knows TDIs inside and out, and will treat your son well. PM me for his phone number if you want to get in touch with him.
 

Zambee500

Veteran Member
Joined
Jun 29, 2008
Location
Atlanta, GA
TDI
2005 Passat TDI GLS, 2014 NMS Passat TDI SEL Premium
Agree with option noted above. Another option might be Roger Feldt who would be much closer to your son. Only thing is Roger tends to have a long backlog of work so not sure how quickly he could get to it (I am still waiting to have him do a couple things for my B5.5 TDI). Roger is basically 1 town/suburb over (Fayetteville) southeast of Fairburn. Rutlege is 45 minutes (or longer in rush hours) east of Atlanta, while Fairburn and Fayetteville are maybe 30-45 minutes south of Atlanta.

But either of those guys would treat you right and be much more effective and affordable compared to the local VW dealership in Union City.
 

Zambee500

Veteran Member
Joined
Jun 29, 2008
Location
Atlanta, GA
TDI
2005 Passat TDI GLS, 2014 NMS Passat TDI SEL Premium
Trusted Mechanics list in 101 section of Forums:

 

JohnStone

New member
Joined
May 1, 2024
Location
Arizona
TDI
2013 VW Jetta
Agree with option noted above. Another option might be Roger Feldt who would be much closer to your son. Only thing is Roger tends to have a long backlog of work so not sure how quickly he could get to it (I am still waiting to have him do a couple things for my B5.5 TDI). Roger is basically 1 town/suburb over (Fayetteville) southeast of Fairburn. Rutlege is 45 minutes (or longer in rush hours) east of Atlanta, while Fairburn and Fayetteville are maybe 30-45 minutes south of Atlanta.

But either of those guys would treat you right and be much more effective and affordable compared to the local VW dealership in Union City.
Thank you. I’ll have him give both a call. Luckily he’s working six days a week so I think he can wait it out. But really appreciate it since he’s not from the area.
 

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
So far so good. I found some 90 degree barbs, and thought about changing out the loop of the hose to square corners that would fit more tightly, but haven't yet. Wife drives the car M-F about 70 miles a day and so far it's holding together. Did add a little distilled water to the tank over this weekend, hoping a bubble came out as not seeing or smelling anti-freeze anywhere else. Fingers crossed. If this continues, probably will start the flush parade before too long. Also, have not found any info on replacing the water pipes through the firewall, but local pick -n- pull had a 2014 passat with engine out a while back. Should be easy to get to and hoping it's still there as I can try to figure out if can change in tight quarters.
Latest update: I went ahead and did the flush this weekend, vacuuming it out of the expansion tank. Rigged up my shop vac attachment that went to the bottom of the tank, and used a cup with duct tape in the bottom to form a tight seal on the wand. 1st flush with distilled water. Drove it up at temp for a few miles, came back home and vacc'ed out again. Re-filled with tap water, and ran the engine with the top expansion tank line to rad going to my bucket. Ran clear right off and ran for a bit this way. Then vacc'ed out again and re-filled with the G12 evo premix from the dealership. Got about 7/8's of the gallon into it. Drove it 70 or so miles, topped up a bit after cooling over night, and have topped up one more time. Hoping no more topping up's. But this raises a question for me. I see coolant capacity is listed as 8 liters online places. But even with topping it off, seems I can only get about 4 liters in. Obviously, my core is still out, so guessing that holds 1/2 liter or so. But is 8 liters for real or is it closer to 4 liters? Pic of my handy seal

 

bbaecht

Member
Joined
Sep 1, 2017
Location
Lawrence, KS
TDI
2003 jetta, 2015 passat
Yesterday went to the new Buc-ee's in Springfield, MO. Drove through the pumps to see the price of diesel and found another TDI Passat with their family around it. We exchanged glances and smiles recognizing our sister cars. I pulled up by the door to go in and picked up a few things. As I was walking back out to my car, saw the same family coming in. We recognized each other and started talking about our Passats. Don't know if they are on this forum, but if so, please message me as would like to stay in touch with you and your mechanical challenges with our cars. Short conversation was replacing DEF tank with one from Napa which should make it the last time will need to change out the DEF tank. Also discussed the intercooler fun and heater cores. They had mentioned that they did the rubber hose replacement to put their heater core back in, which I am planning on doing before too long. Basically cut off the flared ends on the pipes coming through the firewall so can then hook the pipes to the heater core with 5/8" heater core hose. Anyhoo, if you happen to be reading this, please message me. Thanks! Getting ready to change my passat oil tonight or Monday pending outdoor temps.
 
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