Lack of Heat + Temperature Readings Low = ?
12-06-2010 | 02:13 PM
#1
Thread Starter
Audi Forum - Posts like an A4
Joined: Nov 2010
Posts: 117
From: Ontario
Lack of Heat + Temperature Readings Low = ?
Ok, I have been reading several of the threads on the classic "no heat in the cab" issue - along with anything else I could find on thermostats.
As I was driving home today - (25min) - I noticed that the car wasnt really WARM inside - even with the heater blowing full blast all the way home.
On another thread, I saw talk of temperature readings in the 90C range for the dash gauge. I am trying to remember, but I dont think mine gets much higher than 1/2 way between the 60 and 90 - I am going to check this further... if 90C is the mark, I might be off.
I also notice that if you stop, the heat doesnt really blow... put some power to the engine and you have WARM air agian.
It sounds to me like its a multi level problem...
The heater core DIY cleanout seems easy... going to try that.
I couldnt find any detail on the thermostat location on a 2.8 V6 (1998 A4), but it sounds like its difficult to get at. There was a thread somewhere, but they didnt add the content about actually changing the thermostat - so I was left unsatisfied.
Anyone have the location on the thermostat in the 2.8?
Chad
As I was driving home today - (25min) - I noticed that the car wasnt really WARM inside - even with the heater blowing full blast all the way home.
On another thread, I saw talk of temperature readings in the 90C range for the dash gauge. I am trying to remember, but I dont think mine gets much higher than 1/2 way between the 60 and 90 - I am going to check this further... if 90C is the mark, I might be off.
I also notice that if you stop, the heat doesnt really blow... put some power to the engine and you have WARM air agian.
It sounds to me like its a multi level problem...
The heater core DIY cleanout seems easy... going to try that.
I couldnt find any detail on the thermostat location on a 2.8 V6 (1998 A4), but it sounds like its difficult to get at. There was a thread somewhere, but they didnt add the content about actually changing the thermostat - so I was left unsatisfied.
Anyone have the location on the thermostat in the 2.8?
Chad
12-06-2010 | 04:23 PM
#2
Audi Forum - Posts like an A5
Joined: Oct 2010
Posts: 382
From: Republic of B.C.!
Re: Lack of Heat + Temperature Readings Low = ?
...I couldnt find any detail on the thermostat location on a 2.8 V6 (1998 A4), but it sounds like its difficult to get at. There was a thread somewhere, but they didnt add the content about actually changing the thermostat - so I was left unsatisfied.
Anyone have the location on the thermostat in the 2.8?
Chad
Anyone have the location on the thermostat in the 2.8?
Chad
Last edited by mksu19; 12-06-2010 at 04:28 PM.
12-06-2010 | 08:05 PM
#3
Thread Starter
Audi Forum - Posts like an A4
Joined: Nov 2010
Posts: 117
From: Ontario
Re: Lack of Heat + Temperature Readings Low = ?
how did you find that?
I was searching everywhere to come up with something like that information... I am weary about some of those "answer.com" type sites cause you get spam and other pop ups.
In any case I went ahead and pulled the heater hoses off the heater core and tried a limited flush of the system. I used some commercial rad flush stuff instead of the CLR that I was so tempted to try... but it said "do not use on aluminum" right on the package... didnt think it was wise to risk it with the horror stories of the heater core replacement I am hearing.
I didnt really get much of anything out of the core - I flushed with hot water, let the stuff sit for a bit, then cycled with the stuff though the core for a bit, then flushed with hot water for a bit more... I dont know that it improved at all.
I have attached a couple of pictures of where my temperature is at - from the sounds of things it is lower than where it should be.
If I rev the engine or drive at higher revs you can notice that it starts blowing warmer air... lower the revs, and it gets cooler.
When I was bleeding out the air from the heater core it seemed as though there wasnt much flow there... I dont know if that is just me, or if something is going on.
Can I upload pictures on the site? I dont really have a host for them...
In any case the temp went down to the 75 range while driving - sometimes over 80... when I sat in the driveway and worked up the engine for a bit (not moving) the temp went up to the 90 area.... but that was sitting for a minute or so doing 4000 RPM...
Anyone have any thoughts on what is going on?
I was searching everywhere to come up with something like that information... I am weary about some of those "answer.com" type sites cause you get spam and other pop ups.
In any case I went ahead and pulled the heater hoses off the heater core and tried a limited flush of the system. I used some commercial rad flush stuff instead of the CLR that I was so tempted to try... but it said "do not use on aluminum" right on the package... didnt think it was wise to risk it with the horror stories of the heater core replacement I am hearing.
I didnt really get much of anything out of the core - I flushed with hot water, let the stuff sit for a bit, then cycled with the stuff though the core for a bit, then flushed with hot water for a bit more... I dont know that it improved at all.
I have attached a couple of pictures of where my temperature is at - from the sounds of things it is lower than where it should be.
If I rev the engine or drive at higher revs you can notice that it starts blowing warmer air... lower the revs, and it gets cooler.
When I was bleeding out the air from the heater core it seemed as though there wasnt much flow there... I dont know if that is just me, or if something is going on.
Can I upload pictures on the site? I dont really have a host for them...
In any case the temp went down to the 75 range while driving - sometimes over 80... when I sat in the driveway and worked up the engine for a bit (not moving) the temp went up to the 90 area.... but that was sitting for a minute or so doing 4000 RPM...
Anyone have any thoughts on what is going on?
Last edited by voodooca; 12-06-2010 at 08:19 PM.
12-06-2010 | 08:31 PM
#4
Audi Forum - Posts like an A3
Joined: Oct 2009
Posts: 61
From: Mississauga
Re: Lack of Heat + Temperature Readings Low = ?
what i did with a buddies s4 was i flushed the heater core with CLR... put the full jug in the heater core and pushed it all clean with water, then blew it out with compressed air... then filled coolant, parked it on a hill with the cap off so all the air pockets surface, ran the car the next day and the heat was so hot hadda turn it down... now if you do this and find water/coolant in your rear seat floor... then you my friend need a heater core saddly...
also the thermostat i'd say do after you bleed the heater core cause the thermostat is behind the timing belt on the 2.8's and it wont be cheap to replace t-belt, tensinor, water pump and thermostat.
Good luck,
hope this helps
also the thermostat i'd say do after you bleed the heater core cause the thermostat is behind the timing belt on the 2.8's and it wont be cheap to replace t-belt, tensinor, water pump and thermostat.
Good luck,
hope this helps
Last edited by Oz_racing; 12-06-2010 at 08:33 PM.
12-06-2010 | 09:46 PM
#5
Audi Forum - Posts like a Q5
Joined: Aug 2010
Posts: 531
From: Calgary
Re: Lack of Heat + Temperature Readings Low = ?
OK
Do not touch the heater core and just forget that you have heater core alltogether for now.
It looks like you have dirt in your rad fluid and this dirt is causing the thermostat to be stuck. The dirt in the heater core comes from the engine and radiator so if you flush it, it will go away from the heater as well. There is an easy way to do it with the pipe on the front bottom drivers side of the engine, just unplug it and the fluid flows away. Than fill the system with water and do it twice.
When refilling buy some rad fluid that has no additives. If it says that it contains detergents and something else do not buy it. It is not for 98 Audi.
Also remember that it is water that causes the pressure in your system and heat in the cabin. Mix Glycol with water with high rate of water such as 2 parts Glycol and 1 part water or a bit higher.
This should free your thermostat and everything will come to normal.
You can use CLR if you flush the system many times after. CLR can not be flushed completely and in the long run it will burn your radiator into holes. If you use it neutralize it with soap and flush again. It is lotsa flushing!
AUDI does not have problem with thermostats in general.
In fact today I did the rad flush with this and I have sauna inside.
Do not touch the heater core and just forget that you have heater core alltogether for now.
It looks like you have dirt in your rad fluid and this dirt is causing the thermostat to be stuck. The dirt in the heater core comes from the engine and radiator so if you flush it, it will go away from the heater as well. There is an easy way to do it with the pipe on the front bottom drivers side of the engine, just unplug it and the fluid flows away. Than fill the system with water and do it twice.
When refilling buy some rad fluid that has no additives. If it says that it contains detergents and something else do not buy it. It is not for 98 Audi.
Also remember that it is water that causes the pressure in your system and heat in the cabin. Mix Glycol with water with high rate of water such as 2 parts Glycol and 1 part water or a bit higher.
This should free your thermostat and everything will come to normal.
You can use CLR if you flush the system many times after. CLR can not be flushed completely and in the long run it will burn your radiator into holes. If you use it neutralize it with soap and flush again. It is lotsa flushing!
AUDI does not have problem with thermostats in general.
In fact today I did the rad flush with this and I have sauna inside.
Last edited by adamstasiak; 12-06-2010 at 10:03 PM.
12-07-2010 | 06:45 AM
#6
Thread Starter
Audi Forum - Posts like an A4
Joined: Nov 2010
Posts: 117
From: Ontario
Re: Lack of Heat + Temperature Readings Low = ?
Well I went back and read any post that I could find about heat (funny it always seems to be around December for these posts)...
1. System Flush
2. Thermostat
These seem to be the main problems.
I am going to inquire with someone who does the flushing professionally... I dont think the 20-30 minutes I worked on it last night did anything... and I am hesitant to use something like CLR - I know it works well, but I dont want to ruin the heater core.
Anyone else with some other ideas? The whole temperature thing is getting me...
1. System Flush
2. Thermostat
These seem to be the main problems.
I am going to inquire with someone who does the flushing professionally... I dont think the 20-30 minutes I worked on it last night did anything... and I am hesitant to use something like CLR - I know it works well, but I dont want to ruin the heater core.
Anyone else with some other ideas? The whole temperature thing is getting me...
12-07-2010 | 02:58 PM
#7
Audi Forum - Posts like a Q5
Joined: Aug 2010
Posts: 531
From: Calgary
Re: Lack of Heat + Temperature Readings Low = ?
Go to some liquor store and get a box. Fold the box and place it in front of radiator. Close the hood and drive. This way you will not suffer the cold in the car and fogged windows.
The car will not overheat as if it reaches 90 degrees the fan will kick in. This will also tell you if thermostat is a problem or not.
The car will not overheat as if it reaches 90 degrees the fan will kick in. This will also tell you if thermostat is a problem or not.
12-07-2010 | 07:24 PM
#8
Audi Forum - Posts like an A3
Joined: Mar 2007
Posts: 98
Re: Lack of Heat + Temperature Readings Low = ?
voodooca: Let me ask you this then, does the temp gauge move toward 60(temp. drop) when you drive longer stretches? And once you slow down to ~10-20 km/h does it move back up toward 90 at all? OR do you only get heat when your RPMs are higher than 3000?
12-07-2010 | 08:01 PM
#9
Thread Starter
Audi Forum - Posts like an A4
Joined: Nov 2010
Posts: 117
From: Ontario
Re: Lack of Heat + Temperature Readings Low = ?
We were talking about this earlier tonight and my friend was thinking thermostat... I honestly haven't tracked the temperature too much beyond the drive where I took those pictures... Most of my travels are short so I don't get time to build the heat up - are you thinking it might be thermostat related?
Chad
Chad
12-07-2010 | 09:21 PM
#10
Audi Forum - Posts like an A3
Joined: Mar 2007
Posts: 98
Re: Lack of Heat + Temperature Readings Low = ?
does the temp gauge move toward 60(temp. drop) when you drive longer stretches? And once you slow down to ~10-20 km/h does it move back up toward 90 at all
If it's this, then yes, your Tstat is toast.
only get heat when your RPMs are higher than 3000
If it's this, then I doubt you have air in the system. It is simply a matter of not getting enough circulation in the system. I myself have this problem.
Drive around a bit and see what the exact symptoms are.
If it's this, then yes, your Tstat is toast.
only get heat when your RPMs are higher than 3000
If it's this, then I doubt you have air in the system. It is simply a matter of not getting enough circulation in the system. I myself have this problem.
Drive around a bit and see what the exact symptoms are.
