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  #1  
Old 01-10-2011, 09:24 PM
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Question Why does my car take forever to heat up? 1995 with 2.8L

Hey guys. It's winter and I'm cold. My car doesn't help me in that department. I have a 95 A6 with the 2.8L V6 with an autotragic.

My drive to work is 30 minutes long, back roads, going about 40 the whole time.

My car does NOT heat up enough for the heater to work. I'm freaking cold as heck.

By the time any other of our cars are fully heated up, my temp gauge has just left the bottom peg. It'll get up to about the first line and stop for a while. Then after about 20 minutes it'll move it's way up to the first bolded line, which I assume to be the bottom of the "normal operating range".

So then, it'll suddenly get cold again (and I mean fast too). It'll drop down to the first line or lower. I have no heat during any of this.

I have my ENTIRE radiator blocked off. The entire thing. I don't think the thermostat is stuck open because when it hits that second bolded line, it shoots back down which (I'm guessing) means the thermostat opened and the block gets cooled by the supercooled coolant that was sitting in the rad.

The only time I've felt heat from my car is when the temp was slightly above the first bolded line. When it's that warm, the heat works fine, great even. So it's not the heater core either. At least I don't think so.

It's not like it's even that cold. It does this anytime below 30 Degrees F!! Never mind the 8 degrees we had this morning. My oil temp is normally around... crap... the first line on the gauge past where it sits when it's off. I think it may be 60 Degrees C. Don't ask me why the engine temp is in degrees F and the oil temp is in degrees C... Don't get me wrong, the engine will EVENTUALLY heat up, but never above that first bolded line. Meaning I never have heat, because the heat doesn't work until the temp is ABOVE that line. It'll sit right below the line my whole drive home.

What can I do about this? Should I keep it in third the whole time on my way to work? Would that help? What else could be wrong? I bought this car for the sole reason of being a winter car. If it doesn't have heat, that may be a problem.

Please help guys, I hate driving when I'm cold.

EDIT: No, I do not have the heater on during any of this. I don't turn it on until the engine warms up. (Which is never) I even turned the temp down as I know in older cars the temperature gauge actually controlled the coolant going to the heater core, so by turning it down I stopped the flow. It didn't work.

Last edited by corrado33; 01-10-2011 at 09:26 PM.
  #2  
Old 01-11-2011, 12:50 AM
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When you have time, start the car and let it run 10-15 minutes.
Check both hoses going/coming from the heater core (you should be able to see them going through the firewall). If both are hot, then your heater core is ok and your problem may reside with either the exchange flap control or the climate unit itself.
If one of the hoses is cold (the return one, typically), either your heater core needs to be replaced, or your heater valve is bad (attached right on the "upstream" hose, before the plastic bleeder.)

Also, you may need a new Coolant Temp sensor (sender unit) since your gauge experiences what you described.
Good luck.
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  #3  
Old 01-11-2011, 09:37 AM
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Try this too:

Let the car idle until the temp gauge gets to normal operating temp (gauge should point to the middle).
If you need to rev to around 1500 rpm's then do it.

When the car is at temp, check the heat.
If you have heat, drive the car preferably on a highway or interstate and see if the temp goes back down.
If it does, your thermostat is stuck open.

Otherwise, it could be a combination of the temp sender, flap control, and/or heater core like chefro said.
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  #4  
Old 01-11-2011, 11:05 AM
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I agree either the heater core is plugged or it's possible your thermostat is stuck wide open.
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Old 01-11-2011, 04:28 PM
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Quote:
Originally Posted by soundguy View Post
Try this too:

Let the car idle until the temp gauge gets to normal operating temp (gauge should point to the middle).
If you need to rev to around 1500 rpm's then do it.
I've NEVER seen the temp gauge go above the second line. Even when letting it run for a while.

Thanks so much for all of the info guys.

Today as I was driving home, the temp gauge is smack dab on the second line. I try the heat on HI (digital climate control), and the heat was luke warm at best. I mean that air should be HOT like I can't hold my hand there hot.

And I was wrong, the oil temp goes to the line above 60 degrees C (whatever that line means...)

Alright, I will try everything you guys said, and get back to you. The heater core is pretty much (way) behind the glovebox (buried under the dash) like in a Corrado right?

EDIT: Nevermind, found your write up on it...

Last edited by corrado33; 01-11-2011 at 04:58 PM.
  #6  
Old 01-11-2011, 06:17 PM
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Quote:
Originally Posted by corrado33 View Post
I've NEVER seen the temp gauge go above the second line. Even when letting it run for a while.
In that case check the thermostat it is either stuck wide open or completely missing or just the wrong one all together.
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Old 01-11-2011, 07:36 PM
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I would imagine that the easiest way to tell if the T-stat is stuck open is by "feeling" the hoses temperature. 10-15 minutes is more than suffice to feel the hoses HOT.
If they're not, then probably you do need a new T-stat.

However, did you buy the car just before the "winter" started? One idea... have you tried to bleed the system? I'm just wondering that maybe you have an/some air pocket/s in the system and the coolant doesn't reach your heater core?
Is a little "work" involved (to find the rear main pipe's bleeder down in the wire jungle), but it is worth a try, along with checking your heater hoses.
Keep us posted, pls.
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  #8  
Old 01-12-2011, 08:40 PM
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Quote:
Originally Posted by soundguy View Post
When the car is at temp, check the heat.
If you have heat, drive the car preferably on a highway or interstate and see if the temp goes back down.
If it does, your thermostat is stuck open.
.
Car was at the first bolded line today (highest I've ever seen it), and I got on the highway. Went about 65 for about 5 minutes, and it dropped down below the first line.

When I was having this problem in my rado, my brother (x VW/audi/Mercedes trained mechanic) told me to let my car sit there and warm up. The bottom hose should get hot before the top hose. If not, your thermostat is broken.

Quote:
However, did you buy the car just before the "winter" started? One idea... have you tried to bleed the system? I'm just wondering that maybe you have an/some air pocket/s in the system and the coolant doesn't reach your heater core?
Yep, right before winter. Could you provide me any more info on bleeding the system? I'll search, but I'm being lazy at the current moment.
  #9  
Old 01-12-2011, 09:44 PM
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It's actually pretty simple. Run the engine until hot and locate the heater core valve bleeder (you need to take the cowl off). Unscrew gently 2-3 turns. You should get a steady stream of coolant. You'll get steam escaping - which is ok. If you get fizzing, hissing, gurgling, it means you have air in the system. Screw back and then repeat several times until you get a steady flow.
Next step is to loosen the main rear pipe bleeder. You need to locate it first and leave in it a socket + extension + rathcet - is like a 5 or 6 Allen (metric).
You should be able to find it close by the coolant temp sensor - you see it on the coolant line in the photo.
I include a pic so you know what you're looking for.
(By the way, if you follow hose labeled number 1 (in the pic) through the firewall you should find the heater clore plastic bleeder.
Don't forget to top off with coolant after you get done.
Attached Images
File Type: jpg heater-hoses.jpg (77.8 KB, 35 views)
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Last edited by chefro; 01-12-2011 at 09:48 PM.
  #10  
Old 01-13-2011, 09:29 AM
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Chefro where is the t-stat located on a 95 2.8???
Is it easy to get to?
My 3.0 is easy my 4.2 couldn't have been in a more concealed location.

I'm positive it's the t-stat with Low engine temp/no heat. What else could it be.
It probably broke on the last guy and they just pulled it out to get home.

The problem is your cooling too much. The t-stat at rest is closed so the coolant in the engine heats up. When the coolant gets hot enough(~190) the heat will cause the t-stat to open an allow the coolant to flow to the radiator where it gets colder and cycles back to the engine.

There is only one way the engine can stay cold like that. The T-stat is missing or stuck open. It is very common for them to stick half open when they fail. That happened in my car. In the summer you will see the opposite the half opened t-stat will prevent coolant from circulating and you will overheat.

For example you start the car and it's 15 degrees out.

The T-stat is closed and the cold coolant is trapped inside the engine and you will have no heat because the climate system uses the heat from the coolant to heat the car.

When the engine reaches approximately 190 degrees the spring in the t-stat assembly weakens and allows the valve to open releasing the pressurized colder coolant from the radiator into the engine.

When the spring cools off it strengthens and closes the valve blocking the flow of coolant and maintaining 190 degrees.

If it does not close or open properly it can not maintain ~the 190 temp.
In your case it is not closing.

THE QUESTION IS; Where is your T-stat located?

I would think Advance auto would have one.

here's a link.

http://www.ecstuning.com/Audi-C4_A6-...ng/Thermostat/
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Old 01-13-2011, 09:29 AM
 
 
 
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