[Mojuice98]

I have had low heat for past 2 yrs and this winter I am tired of not having heat until after 15 to 20 minutes of driving the car, longer if its colder.

Does anyone else have this problem? I just cardboarded up the front radiator and so far not making a difference.

I was thinking about replacing the heater core. Any suggestion is greatly and warmly appreciated.

 

[mattyd2009]

Hmm, not sure. I have a friend with a TDi, she says it takes a bit to heat compared to gas. But it could also be a stuck thermostat?!? Maybe someone else might know!

 

[Smileybug]

What kind of driving are you doing? TDIs do take extra time to heat up...they are more efficient so they have less heat they give off.


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[joep]

Change your t-stat. It will hold the coolant in the engine until it reaches operating temps. I have a Ram diesel as well as 2 beetles(1 gasser and 1 diesel). The gasser ran better with a new t-stat and the diesel will get a new one after I get the trans straightened out. Diesel needs heat to run properly.

 

[cha2ga]

Not sure what year you car is but change the thermostat if it hasn't been done in about three years.
I have a 2000 TDI and my heat was horrible. Last weekend I changed my thermostat, and flange and have very good heat now. It has made an incredible difference. I commute 31 miles each way to work and barely got hot by the time I got there. Now, I am getting some heat after 1.5 miles and fully warm after about 5 miles or less.
It's a very easy job. No specialty tools needed. Use a real VW oem thermostat and flange because the tabs will make the job 100x easier. I bought a flange, thermostat, and oring from idparts for less than $60 shipped. Got it in three days. You will also need a gallon of VW coolant. You will use about .75gallons and about .5gallons distilled water (grocery store). You can also get the coolant from idparts or your dealer. Do not use the wrong coolant as it can cause severe damage to your engine.
Up to 2003 the engine is an ALH engine so the parts for this task are the same.
Here are the parts:
http://www.idparts.com/catalog/product_info.php?products_id=3402
http://www.idparts.com/catalog/product_info.php?products_id=2067
http://www.idparts.com/catalog/product_info.php?products_id=1613
http://www.idparts.com/catalog/product_info.php?cPath=25_178&products_id=1974
Here are the instructions, you only need the thermostat instructions about half way down:
http://www.myturbodiesel.com/1000q/a4/thermostat-ALH-VW-TDI-engine.htm



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[Mojuice98]

I have a 2001 tdi beetle. I changed the thermostat when i got it 2 years ago, because at first it was overheating. Just had to replace the heater core adapter on the left side since it broke apart and coolant was leaking out everywhere.

It seems like i will have to get a block heater device or oil pan heater, but the ones I have found do not fit 2001 models. any suggestions? This is the wifes car and I really dont want her and the kids freezing every morning.

 

[cha2ga]

There is no block or pan heater for this engine. The beat solution, I'm told, is a frost heater. They are highly regarded over at tdiclub. BTW, in case you don't know, tdiclub is the place for tdi specific information. You would want to look on the MKIV forum since that is what you have. Where are you located? It is likely that if you go to one if the GTG in your area, that someone would help you install it for free.
Search google and tdiclub for FROSTHEATER
http://www.idparts.com/catalog/product_info.php?products_id=3111


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[cha2ga]

The frostheater warms your coolant and gets the thermostat open, that way when you start your at it is warm. I have never heard of anyone running one more than 4 hours. Most run them on a heavy duty timer ti come on in the night and be ready at leaving time. Most route and secure the plug into the lower grill area so you don't even have to open the hood.


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[jfoj]

I get a bit frustrated repeating myself, but I will state the obvious.

Thermostats fail ALL the time. They usually fail SOFT, the main spring gets weak and they open too early. The purpose of the thermostat is to keep a minimum engine temperature. Some thermostats only last 2 years, some last much longer. The only way to verify a problem thermostat is to check the engine temperature, see below.

I do not own a diesel, however, these should not be significantly different than most gas motors when it comes to thermostats.

Assume these cars require at least a 185F/85C thermostat? This is pretty typical, BUT when you check the engine coolant temperature with an OBDII scan tool, you will usually see the engine coolant temperature will run/display/read 15-20F higher than the thermostat spec. So most engines run around 205F/96C. The car should hold close to 200F/93C while cruising on the highway in colder ambient temperatures.

The difference in the thermostat temperature and the coolant temperature is because the coolant sensor is usually located in the return coolant path as it exits the cylinder head after the coolant has absorbed heat from the engine combustion process. Read in my signature below. So again, the coolant temps should be around 15-20F higher the thermostat temperature rating.

So before you worry about a heater core, block heater or what not, CHECK the engine coolant temperature. You need an OBDII tool that can read and display Live/Real Time data. $30 or less if you have a smart phone or Windows laptop. Read in my signature below.

So here is how my 1.8t gas motor works, blue cold engine light stays on for just over 1 mile of continuous driving from a cold start. The blue light goes out just around 135-137F displayed on my OBDII tool. Most engines should reach operating temperature in 10 minutes or less of DRIVING. The engine will take longer to heat up if left idling.

Again, I do not have a 1.9l Diesel, so there may be some minor differences as compared to my 1.8t, but until you check your engine coolant temperature and/or REPLACE your thermostat you are wasting you time doing anything else.

You also cannot flag a bad thermostat once the outside ambient air temp is at 70F or above unless you super cool the radiator with a garden hose and see if the minimum temperature starts to drift down.

Again, read the links below in my signature and for anyone that thinks that the ECU will flag a low engine temperature in a VW, do not hold your breath, my car was running 170F all day long and the ECU never flagged a low temperature problem. Also replacing the coolant sensor, which is ALL over the VAG boards, is a solution, this is not the solution, replace the thermostat.

 

[cha2ga]

I agree. That post is dead on and as you mention there is only a minor difference in tdi thermostat temp (87C). It is almost always the thermostat. I don't know where people get this notion that bad thermostats always cause overheating. I guess it's because you an see a catastrophic engine event (overheating) as opposed to the fact that most thermostat failures cause undersea ring and your car will usually run (albeit cold and bad mpg).

But if he is getting up to temp and simply wants faster inside heat, which tdi's are notorious or not having, then the frost heater is the solution.
If your car is not heating up, then it's the thermostat.


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[jfoj]

Kind of hard to also help someone out and understand their situation when they do not put a location in their profile or at least say they are from Fargo, ND!

I had a spare stat here for my 1.8t gasoline engine and the stat was stamped 87C which is 188F. So this being said, I would fully expect a Diesel engine coolant temp to read about 205F/96C as after about 10 minutes of driving. Again, the coolant sensor should read about 15F higher than the stat operating temperature.

I think what we keep running into is most Diesel owners are probably highway cruisers? Owners get these cars for the long distance fuel economy. So what happens is the thermostat is supposed to keep a minimum engine temperature, but in ADVERSE conditions, if you still have a good thermostat the radiator may need to be partially restricted? I assume the Diesels have a pretty big radiator, not seen one to date. But I think there have been so many complaints about the Diesels heat, everyone has decided that the Diesel's have poor heat. I would have to say that the Diesel's heat should be as good, if not better than a gasoline engine, but maybe someone can educate me on this.

So for the highway warrior, if the thermostat is soft, the cabin heat capacity will drop off as the car cruises on the highway if the stat is soft.

The ONLY way you can confirm engine operating temperature and if the thermostat is good is to use an OBDII tool that can display Live/Real Time data. EVERYONE needs one of these tools on hand. And for $30 or under most people can have an operational tool that will read and display Live/Real Time engine data.

Again, I would expect the engine to come up to operating temp in about 10 minutes of driving if the thermostat is good.

I am rather interested to see if my data points and comments are as true with the Diesels as with the gas engines. I would like to hear from some that have a "good" thermostat and an OBDII tool how quickly the engine heats up, how stable the coolant temperature is and how well the heat works. Because I would like to see the signature of a Diesel in the Winter. Make sure you also include the ambient outside temperature as a reference as well.

See a graph of what a car looks like with a good thermostat, this was not a VW Diesel, but it was a German make. This was not from a dead cold start, the outside ambient was in the mid 30F or very close to 0C and this was about a 40 minute drive. Also notice the vehicle speed. This is the type of coolant temperature stability you should see.

For those who do live in extreme climates, this type of oil/engine heater may be something to consider - https://www.wolverineheater.com/Engine-Oil-Heaters-for-Cars-s/1814.htm

 

[Mojuice98]

the car is getting up to temperature in the right amount of time, like jfoj said, however I just want better cabin heat like cha2ga said. I am located in Decatur GA by the way. The frost heater looks like the best thing to allow instant heat on cold mornings.

I was also wondering how hot other tdi beetle owners heat is because mine has never match any gasoline car I drive. the heat in the cabin that is. You have to drive for 30min on full blast before it really starts to heat the cabin up. In a gas car, in 10min of running heat on full you are cooking.

 

[jfoj]

the car is getting up to temperature in the right amount of time, like jfoj said, however I just want better cabin heat like cha2ga said. I am located in Decatur GA by the way. The frost heater looks like the best thing to allow instant heat on cold mornings.

I was also wondering how hot other tdi beetle owners heat is because mine has never match any gasoline car I drive. the heat in the cabin that is. You have to drive for 30min on full blast before it really starts to heat the cabin up. In a gas car, in 10min of running heat on full you are cooking.

How can you confirm the engine is getting up to temperature in the right amount of time? The only way to do this is with a proper tool to read the OBD data stream. BTW, you cannot use the Blue engine cold light at a specific reference as it turns off at about 135-137F. I am dealing with a 2.0l that they just installed a new thermostat in it and the engine coolant temp is registering 140F and they claim since the new thermostat they now have heat?? Need to find out if they actually also have a bad temperature sender or just a DOA thermostat that was better than the one they replaced??

If the engine is actually at 205F and you have no heat, there is something else wrong, a restricted water path to the heater core or a bad heater control valve.

So before you waste time and money on a Frost Heater, spend $35 or less, get a OBDII tool that will read the temperature info and make 100% sure the engine is operating at the proper temperature.

 

[cha2ga]

I'm not to far from you, I'm just outside of Clemson SC. The last two mornings have been upper 20's low 30's. I can roast you out of my car in 15minutes. As hot as my 2001 Blazer 4.3, my 2007 Passat 3.6, 2006 Audi A4 cabriolet.
Before I changed the thermostat a couple weekends ago, the heat never got this hot.
Change the thermostat. Use oem parts. Use oem coolant mixed 50-50 or up to 70-30 max.



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[jfoj]

I'm not to far from you, I'm just outside of Clemson SC. The last two mornings have been upper 20's low 30's. I can roast you out of my car in 15minutes. As hot as my 2001 Blazer 4.3, my 2007 Passat 3.6, 2006 Audi A4 cabriolet.
Before I changed the thermostat a couple weekends ago, the heat never got this hot.
Change the thermostat. Use oem parts. Use oem coolant mixed 50-50 or up to 70-30 max.

^ +1

Since they won't listen to me, maybe they will listen to a fellow Diesel owner.

Heck, what do I know anyway, I have no idea what I am talking about???

 

[janitz]

Something is likely wrong, that amount of time to reach warm to your senses in the cabin when you're driving in T-shirt weather like that is not right.

My 98 TDI has a oil pan heater and battery warmer to keep it from freezing in winter. Can't start without them here. At -40 outside it will take about as long as you're describing to get the cabin warm to the senses.

I suggest taking it to a trusted TDI mechanic to check the car over unless you are mechanically inclined and wish to do the work yourself. Might be something like the blend door not opening properly, not a T-stat problem at all.

 

[jfoj]

I thought about a blend door issue, however, I did not even want to mention this until the thermostat/engine temp is verified first before he next step is taken. Engine temp is the key thing that is required for good heater performance. You can try all the bandaids you want, but why not replace the $10-$15 thermostat if it is bad.

My 2003 convertible 1.8t may have a blend door issue??? but that car has the hottest heater of any car I have ever owned. It may be that it is also the ONLY car in the fleet at the moment that does not have auto climate control so I may be a bit skewed about how hot the heater is because I have to turn the temp dial down before I burn up.

 

[Mojuice98]

How can you confirm the engine is getting up to temperature in the right amount of time? The only way to do this is with a proper tool to read the OBD data stream. BTW, you cannot use the Blue engine cold light at a specific reference as it turns off at about 135-137F. I am dealing with a 2.0l that they just installed a new thermostat in it and the engine coolant temp is registering 140F and they claim since the new thermostat they now have heat?? Need to find out if they actually also have a bad temperature sender or just a DOA thermostat that was better than the one they replaced??

If the engine is actually at 205F and you have no heat, there is something else wrong, a restricted water path to the heater core or a bad heater control valve.

So before you waste time and money on a Frost Heater, spend $35 or less, get a OBDII tool that will read the temperature info and make 100% sure the engine is operating at the proper temperature.

I'll see if one of my friends have one I can borrow. So do I hook up the OBDII reader while driving the car and get that data or hook it up after I have driven it awhile?

 

[Mojuice98]

I thought about a blend door issue, however, I did not even want to mention this until the thermostat/engine temp is verified first before he next step is taken. Engine temp is the key thing that is required for good heater performance. You can try all the bandaids you want, but why not replace the $10-$15 thermostat if it is bad.

My 2003 convertible 1.8t may have a blend door issue??? but that car has the hottest heater of any car I have ever owned. It may be that it is also the ONLY car in the fleet at the moment that does not have auto climate control so I may be a bit skewed about how hot the heater is because I have to turn the temp dial down before I burn up.

what is a blender door issue?

 

[jfoj]

I'll see if one of my friends have one I can borrow. So do I hook up the OBDII reader while driving the car and get that data or hook it up after I have driven it awhile?

Hook it up and before you start the car, turn the ignition on and see if the tool actually displays Live/Real Time date, not all tools do, only the better quality ones.

Then drive the car and watch the engine temp, should get close to operating temp within about 10 minutes of driving.