Call me stupid ~~ At least I am a newbie stupid.

2015vwgolfdiesel · Feb 14, 2016

Call me stupid ~~ At least I am a newbie stupid.

I just took the ol' girl out to punch it a little. It is not getting enough miles for its' own good. In love with that TORQUE

Along the way I was also testing how fast the car would get to a warm ~~ then a HOT temp.

It was not cold outside. Maybe 45 (F). Took about 3-4 miles to get HOT. I am used to a faster HOT in all my other cars. Wife's RAV4 is wonderful in one mile on a very cold morning.

Anyway, when I got it back in the garage, I was looking at the dash info.

STUPID me, after summer, I failed to turn off the AC on the control. The red light was on. Stupid me ~~ Stupid me.

Being a MPG super nut, and as I was adjusting the temp, for all I understand I might have been shaving MPG off of the results

I own the 2015 DSG Golf (S) model and I was constantly having to adjust the fan speed and the thermostat control.

At least I have hope the situation will be better in my future, and also hoping other newbies are helped with this post.

drucifer · Feb 14, 2016

So you'll learn from your mistake. No harm done and not too much fuel wasted. In fact it may be good practice to turn on the ac a couple of times during the winter just to keep the compressor lubricated.

fouillard13 · Feb 14, 2016

I don't get it. You drove around with heat blasting and the ac button on? I did that the other day. No big deal. One day it was hot and I actually needed ac in January in northern ab. The next day it was cold and I needed hot so I turned the heat knob. Didn't press the ac button though. What's the big deal?

2015vwgolfdiesel · Feb 14, 2016

drucifer said:
So you'll learn from your mistake. No harm done and not too much fuel wasted. In fact it may be good practice to turn on the ac a couple of times during the winter just to keep the compressor lubricated.

Thanks for the tip

2015vwgolfdiesel · Feb 14, 2016

fouillard13 said:
I don't get it. You drove around with heat blasting and the ac button on? I did that the other day. No big deal. One day it was hot and I actually needed ac in January in northern ab. The next day it was cold and I needed hot so I turned the heat knob. Didn't press the ac button though. What's the big deal?

Concern is the car is SLOOOOW to heat up.

Then It is hard to keep it a one comfortable temp ~~~~ As I was adjusting the thermostat and the fan, it seemed to be a mess.

Now that I have the AC off, maybe it will settle down.

Ski in NC · Feb 14, 2016

The ac compressor is variable displacement. So when cooling loads are low, it draws very little hp from the engine.

fouillard13 · Feb 14, 2016

Ah I see. Makes sense now.

tadawson · Feb 14, 2016

And AC should lock out if too cold anyhow - liquid slugging can destroy a compressor if allowed to run - just like a hydrolock.

- Tim

DanB36 · Feb 14, 2016

2015vwgolfdiesel said:
Concern is the car is SLOOOOW to heat up.

That's perfectly normal for a TDI, and if anything, running the AC would help it warm up (at least slightly) faster. It definitely wouldn't slow down the warm up process.

IndigoBlueWagon · Feb 14, 2016

Get it on boost and keep it there and it'll warm up. My drive home from work consists of a single right turn out of our office park and onto the freeway. Within about a minute of starting the car I'm going 70. It delivers heat pretty quickly. Warming up can take a while when driving locally. Wear gloves.

DriverJon · Feb 14, 2016

Exactly... It's a Diesel... It's a modern, very efficient Diesel... Its so efficient, it doesn't warm up as fast. I read in the Wikipedia article that a CR TDI motor is 49% efficient as a heat engine!!

So, idling, putting about town, not so much, but as IBW says, making it burn a lotta oil will.

UhOh · Feb 15, 2016

Having the AC on will result in running the engine cooling fans, which will slow the engine from warming up, which in turn will reduce fuel mileage.

2015vwgolfdiesel · Feb 15, 2016

UhOh said:
Having the AC on will result in running the engine cooling fans, which will slow the engine from warming up, which in turn will reduce fuel mileage.

Over all, being a MPG super nut job, I loath ANY lower MPG. And the issue of having less cabin heat (quicker-faster) is a double loco.

Thanks for the tip

meerschm · Feb 15, 2016

UhOh said:
Having the AC on will result in running the engine cooling fans, which will slow the engine from warming up, which in turn will reduce fuel mileage.

I do not think this is true for the system in the 2015.

IndigoBlueWagon · Feb 15, 2016

When I read the post about the fans I remembered that the fan on my old Mercedes (belt driven off the crank, clutched) is designed to run when the engine is cold to create drag and help it warm up. It stops running when the engine gets warm, and runs again (of course) when temp gets high enough to require it. Fans running with the thermostat closed will put demand on the alternator and may help the car warm up faster.

meerschm · Feb 15, 2016

http://www.sanden.com/pistoncompressors.html

https://www.youtube.com/watch?feature=player_detailpage&v=DPuYF0eNK6M

if you are interested in how the last couple generations of air conditioning compressors work.

there is no clutch, the drive belt is engaged at all times.

when it is very cold, there is little impact from activating the air conditioning in the car.

DanB36 · Feb 15, 2016

UhOh said:
Having the AC on will result in running the engine cooling fans, which will slow the engine from warming up, which in turn will reduce fuel mileage.

Even if it results in running the fans, they won't do anything until the thermostat opens. Still won't delay getting heat to the cabin. And, again, the (minimal) extra load might result in the engine warming up marginally faster.

DanB36 · Feb 15, 2016

2015vwgolfdiesel said:
Over all, being a MPG super nut job, I loath ANY lower MPG.

Then your goals are incompatible. Running the A/C compressor will (slightly) increase the load on the engine, which will cause it to burn (slightly) more fuel, thus causing (slightly) worse fuel economy and (slightly) faster warm-up. Running the radiator fans will have the same effects (any additional cooling of the coolant in the radiator will be irrelevant until the engine warms up enough to open the thermostat). For that matter, so will operating the heated seats, but that has the side benefit of actually warming you up. If you want faster warm-up, you're going to burn more fuel to do it, which means reduced mileage.

It's normal that diesels warm up slower than gassers. They're more fuel-efficient (i.e., higher MPG), but that largely comes from wasting less heat--and it's that "wasted" heat that warms the coolant, which is what warms you.

IndigoBlueWagon · Feb 15, 2016

It's 0F here this morning. I started my car in the garage (about 30F), drove 2 miles to the highway, and then got up to 75 just as the temp gauge came off the low peg. within 5 minutes I had full heat and a warm cabin. Winter front helps, but my son's car behaved similarly the other evening when it was nearly as cold, with no winter front.

The great thing about TDIs is they give good FE relative to other cars regardless of how you drive them. So I don't worry about it. And I still average 45 MPG.

turbobrick240 · Feb 15, 2016

My car also warms up quickly once some load is introduced.

UhOh · Feb 17, 2016

DanB36 said:
Even if it results in running the fans, they won't do anything until the thermostat opens. Still won't delay getting heat to the cabin. And, again, the (minimal) extra load might result in the engine warming up marginally faster.

It would be interesting to test this all out. Have to wonder whether the fans running help pull more cooler air in towards the engine, which would cool the block and such, slowing down the warm-up.

Might all be insignificant.

My old Ford IDI's fan pulls like 2 gazillion cubic feet per minute: definitely doesn't help in the warm-up process- which is why it came with a radiator block-off. If you could turn that thing around you could use it as a hover craft!

Radiator block. Get in and get some rpms going as soon as possible (w/o slamming it, until warmed up).

I'm still trying to get it through my wife's head that turning on the heat right away doesn't help produce heat.

This brings up another point- allow the engine to warm up as much as possible before cranking on the heater: this is when heated seats help!

DanB36 · Feb 17, 2016

UhOh said:
It would be interesting to test this all out. Have to wonder whether the fans running help pull more cooler air in towards the engine, which would cool the block and such, slowing down the warm-up.

Hmmm. I hadn't considered the effects of blowing cold air at the block. Most likely it's negligible, but then again so is the extra load from running the fans.

The net effect of the AC compressor and fans on the OP's engine warm-up time is minimal at most, and quite probably immeasurable. It could well have affected how long it would take to feel heat at the vents though.

2015vwgolfdiesel · Feb 17, 2016

Hello put there

Warm-ups?

Just looked at the weather ~~ tomorrow it will be 84 in Tulsa

VeeDubTDI · Feb 17, 2016

2015vwgolfdiesel said:
Concern is the car is SLOOOOW to heat up.

Then It is hard to keep it a one comfortable temp ~~~~ As I was adjusting the thermostat and the fan, it seemed to be a mess.

Now that I have the AC off, maybe it will settle down.

Direct injection diesels have always been very slow to warm up. Manufacturers do all kinds of things to speed up the process, but they are still slower than gasoline engines due to their increased thermal efficiency.

As for adjusting the temperature control constantly, some Volkswagen climate control temp knobs are actually thermostats. If you set it at 70, it will blow very hot until the cabin reaches 70, and then it will automatically calm down. If your car behaves this way and you don't realize it, then you will be constantly fighting with it. I don't know if your car is like this or not, but I'm sure another 2015 S owner can chime in.

2015vwgolfdiesel · Feb 17, 2016

VeeDubTDI said:
Direct injection diesels have always been very slow to warm up. Manufacturers do all kinds of things to speed up the process, but they are still slower than gasoline engines due to their increased thermal efficiency.

As for adjusting the temperature control constantly, some Volkswagen climate control temp knobs are actually thermostats. If you set it at 70, it will blow very hot until the cabin reaches 70, and then it will automatically calm down. If your car behaves this way and you don't realize it, then you will be constantly fighting with it. I don't know if your car is like this or not, but I'm sure another 2015 S owner can chime in.

Thank you VeeDub

I own the cheapest one ~~ a (S) as far as I understand it ~~ I have one knob for fan speed ~~ and one other knob for RED-BLUE.

At least for now ~~ I have the AC red light OFF.

Seems to help, a little. Over all I am getting better at being relatively comfortable.

Wife's RAV4 LIMITED is a winner 1 mile from the house. It even has personal right and left TEMP controls. BUT, the payments are-were about $100 more than my little sweetie.

Thanks again

turbovan+tdi · Feb 17, 2016

tadawson said:
And AC should lock out if too cold anyhow - liquid slugging can destroy a compressor if allowed to run - just like a hydrolock.

- Tim

A/C comes on in defroster mode for the windsheld, its a dehumidifier, keeps the windows clear. Never heard of an A/C system freezing.

UhOh said:
Having the AC on will result in running the engine cooling fans, which will slow the engine from warming up, which in turn will reduce fuel mileage.

Depends on the stategy. Fans are usually controlled by high side pressure and if its cold outside, then the condenser won't be needing much cooling.

meerschm said:
http://www.sanden.com/pistoncompressors.html

https://www.youtube.com/watch?feature=player_detailpage&v=DPuYF0eNK6M

if you are interested in how the last couple generations of air conditioning compressors work.

there is no clutch, the drive belt is engaged at all times.

when it is very cold, there is little impact from activating the air conditioning in the car.

Worked on an 09 TDI the other day, it had a clutch. Unless its a BMW/Mercedes thing, I've never seen a clutchless compressor.

VeeDubTDI said:
Direct injection diesels have always been very slow to warm up. Manufacturers do all kinds of things to speed up the process, but they are still slower than gasoline engines due to their increased thermal efficiency.
.

IDI's too, all diesels suck at warming up in the winter. Block heaters etc work great for speeding up the process.

VeeDubTDI · Feb 17, 2016

turbovan+tdi said:
A/C comes on in defroster mode for the windsheld, its a dehumidifier, keeps the windows clear. Never heard of an A/C system freezing.

VW AC systems disable the compressor at low outside temperatures, even in defrost mode.

IDI's too, all diesels suck at warming up in the winter. Block heaters etc work great for speeding up the process.

All of my IDIs have produced impressive heat, especially my 1991 Jetta Ecodiesel.

tadawson · Feb 17, 2016

turbovan+tdi said:
A/C comes on in defroster mode for the windsheld, its a dehumidifier, keeps the windows clear. Never heard of an A/C system freezing.

Depends on the stategy. Fans are usually controlled by high side pressure and if its cold outside, then the condenser won't be needing much cooling.

Worked on an 09 TDI the other day, it had a clutch. Unless its a BMW/Mercedes thing, I've never seen a clutchless compressor.

IDI's too, all diesels suck at warming up in the winter. Block heaters etc work great for speeding up the process.

Then you may need to get out more

I never said freeze, and and I have no idea where you came up with that. The issue is that below a certain temp refrigerant stays liquid, and AC compressors (much like piston engines) don't much care for compressing liquid. So, you either use a temp switch to lock it out, or replace a lot of compressors. And the last Benz I worked on had a clutch as well . . .

- Tim

turbovan+tdi · Feb 17, 2016

tadawson said:
Then you may need to get out more I never said freeze, and and I have no idea where you came up with that. The issue is that below a certain temp refrigerant stays liquid, and AC compressors (much like piston engines) don't much care for compressing liquid. So, you either use a temp switch to lock it out, or replace a lot of compressors. And the last Benz I worked on had a clutch as well . . .

- Tim

I have friends who work up North and they've never replaced an a/c compressor in any of their vehicles due to the cold.

OE's test their stuff in extreme temps.

turbovan+tdi · Feb 17, 2016

VeeDubTDI said:
VW AC systems disable the compressor at low outside temperatures, even in defrost mode.
All of my IDIs have produced impressive heat, especially my 1991 Jetta Ecodiesel.

How cold? Haven't seen it around here.

My 6.2 IDI sucks getting warm but once warm, its ok. Winter front really helped keep the temp as without it, was hard to keep the heater warm.

Call me stupid ~~ At least I am a newbie stupid.

Top Post Dawg

Veteran Member

Veteran Member

Top Post Dawg

Top Post Dawg

Top Post Dawg

Veteran Member

Veteran Member

Veteran Member

TDIClub Enthusiast, Principal IDParts, Vendor , w/

Veteran Member

Top Post Dawg

Top Post Dawg

Top Post Dawg

TDIClub Enthusiast, Principal IDParts, Vendor , w/

Top Post Dawg

Veteran Member

Veteran Member

TDIClub Enthusiast, Principal IDParts, Vendor , w/

Top Post Dawg

Top Post Dawg

Veteran Member

Top Post Dawg

Wanderluster, Traveler, TDIClub Enthusiast

Top Post Dawg

Top Post Dawg

Wanderluster, Traveler, TDIClub Enthusiast

Veteran Member

Top Post Dawg

Top Post Dawg