09 CR Heat dropping while driving and cabin fan on

A05C

Well-known member
Joined
Jul 1, 2015
Location
South Lyon, Michigan
TDI
2009
Good Morning,

Wanted to see if I'm looking at a semi-common issue.

09 CR Jetta
136k
Stage 2 car (DPF delete, tune)
Stock otherwise.

Timing belt was changed about 6k ago (friend and I did it). Didn't want to do the water pump yet as we didn't have a good way to purge the air out.

Not sure if the coolant is breaking down, if the water pump is needing changed, the heater core is starting to plug. Or the thermostat is starting to stick some.

What's happening is, its been extremely cold here lately (Michigan). Semi slow to warm up, but doesn't over heat at all. Gets to 190F and sits there, but when the fan is turned on above position 2, while driving it will slowly lose engine coolant temperature.

Maybe I'm paranoid but just wanted to see if anyone else has seen this or heard of this. I don't have any hand tools up here (live in an apartment), more or less just asking if anyone else has seen/heard of a similar problem happening.
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
That's normal and to be expected in very cold conditions. You could block the grille with pipe insulation or a cover to retain more heat.
 

A05C

Well-known member
Joined
Jul 1, 2015
Location
South Lyon, Michigan
TDI
2009
That's normal and to be expected in very cold conditions. You could block the grille with pipe insulation or a cover to retain more heat.
Good to know, I figured that it could be a possibility that a simple method of covering the radiator partially to help with keeping some heat in.

Was reading that there's a problem with the heater cores plugging, and who knows if something else could be causing it.

Thanks.
 

narongc73

Veteran Member
Joined
Nov 14, 2005
Location
VA/OH
TDI
2006 Jetta TDI
You're not seeing 190. that's just the dummy gauge, it's probably about 179. That's what I see in extreme cold. My scangauge would show 165 and the car's dummy gauge would be right at 190.
 

crazyrunner33

Veteran Member
Joined
Jul 11, 2006
Location
NC
TDI
'10 Golf(bought back)
Also, check your engine fans to see if they're running all the time. I'm having that issue on my MK5 and need to diagnose the issue.
 

dandywriter

Veteran Member
Joined
Jul 18, 2007
Location
Ottawa (Kanata), Canada, eh?
TDI
2014 Golf Wagon 6M
The more load you put on the engine, the better. Running electrically heated seats and electrical window defrosters helps. I'm happy with my winter front (I see they're out of stock at ID Parts), but don't run the fan at all if I can help it, or on 1 if I must. Cracking windows very slightly allows heated/moist air to escape -also, I leave the door open for a few extra seconds when I'm going to be leaving the car for a while. Not letting snow build up inside (kicking snow off boots) so it doesn't melt and add to the humidity inside also helps.
Most things will affect mileage in the winter - but I'm worth it! I love the heated seats.
 

narongc73

Veteran Member
Joined
Nov 14, 2005
Location
VA/OH
TDI
2006 Jetta TDI
I don't get heated seats. Ok so it warms your ass. My ass is never cold. Warming your ass does not warm the rest of your body. I had heated seats once, and never used it.
 

pdq import repair

Veteran Member
Joined
Nov 6, 2016
Location
idaho
TDI
09 Jetta
My 09 plugged the heater core. i have seen that vintage have coolant issues too. Just to be thorough drain and flush your cooling system, install a new factory thermostat to see if that helps.
You can try flushing the core too, but that rarely helps much if it has already filled with debris. you can pull the cover under the dash left side and get at the heater core to feel temps in and out, my guess is the core is due for replacement.
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
A plugged heater core makes a pretty lousy heat exchanger. The fact that his heater core is pulling the coolant temps down out of the optimal range is a pretty good indicator that it isn't plugged, and is functioning as intended.
 

pdq import repair

Veteran Member
Joined
Nov 6, 2016
Location
idaho
TDI
09 Jetta
I misread, you are right, if it is drawing down temps with the heater on you have other issues. Start with a thermostat and coolant flush.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
with a dpf delete, probably also did away with the low pressure egr.

wonder the car warms up at all.

get a scangauge or other monitor,

and plug up the grille with some pipe insulation.

motor on

or just wait till next weekend.
 

dzldoctor

Veteran Member
Joined
Sep 27, 2011
Location
MN
TDI
02 Jetta 2006 Jetta manual 2004 Touareg TDI V10
Are these cars that bad for warming up. My wifes car is an 09 stock at this time. Will not build engine heat on the gauge. I just installed a new OEM thermostat and issue is no better. Its been real cold here in MN lately and the car is miserably cold to drive. Flushed heater core out and helped but will not get to operating temp. Blocked some airflow to radiator and didn't really help much either. Need help. Unhappy wife. lol
 

MonsterTDI09

TDIClub Enthusiast, Veteran Member
Joined
Jul 3, 2009
Location
NoVa/NJ
TDI
2010 Jetta DSG/ up keep on 2009 Jetta DSG 2006 Jetta Pag 2 in North SEA Green
Are these cars that bad for warming up. My wifes car is an 09 stock at this time. Will not build engine heat on the gauge. I just installed a new OEM thermostat and issue is no better. Its been real cold here in MN lately and the car is miserably cold to drive. Flushed heater core out and helped but will not get to operating temp. Blocked some airflow to radiator and didn't really help much either. Need help. Unhappy wife. lol
You really need seal it up to keep the air out. Take your time and cut insulation to fit the curves on the grill to make tight fit. Cover up the bottom part of the grill even behind the licensing plate. Depending on how cold it’s you can start covering the top part of the grill little by little.
 

narongc73

Veteran Member
Joined
Nov 14, 2005
Location
VA/OH
TDI
2006 Jetta TDI
Are these cars that bad for warming up. My wifes car is an 09 stock at this time. Will not build engine heat on the gauge. I just installed a new OEM thermostat and issue is no better. Its been real cold here in MN lately and the car is miserably cold to drive. Flushed heater core out and helped but will not get to operating temp. Blocked some airflow to radiator and didn't really help much either. Need help. Unhappy wife. lol
Well you didn't tell us how far your wife has to drive. If it's under 5 miles, it will not warm up much but you should still see the gauge move. Even on a warm day it can take my jetta 5 miles to warm up. On cold days I have my coolant heater running.
 

dandywriter

Veteran Member
Joined
Jul 18, 2007
Location
Ottawa (Kanata), Canada, eh?
TDI
2014 Golf Wagon 6M
You might consider getting a FrostHeater. I love mine - on for two hours, I have full temp right away no matter the temp. Before I got the winter front, it would go down pretty quick around zero F if I put the heat on above fan speed 1. After, it still goes down a bit, but as the car warms it improves. Load on the engine with rear defrost and electric seats, and running 2000+ rpm helps. Comfort balances loss of mileage in the winter.

Added bonus - since the heater core is warmed by convection, if you leave the vent in windshield setting, it helps some to defrost the windshield too.

Less time on the frostheater still shows max temp but it is an illusion since the block and heater core haven't had time to heat.
 

trevinator

Member
Joined
Oct 26, 2016
Location
Calgary, Canada
TDI
2009 Jetta Sedan
Are these cars that bad for warming up. My wifes car is an 09 stock at this time. Will not build engine heat on the gauge. I just installed a new OEM thermostat and issue is no better. Its been real cold here in MN lately and the car is miserably cold to drive. Flushed heater core out and helped but will not get to operating temp. Blocked some airflow to radiator and didn't really help much either. Need help. Unhappy wife. lol
is the electric heating element burnt out? Mine keeps the interior above the "OMG it's freezing" level at least for most people on those 40 below days. combined with the heated seats I'm never been cold.
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
If DZL Doc has an 06, I don't believe they have the grid heater for the HVAC system of the 09-14 TDIs.
 
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