Heater problem

[johnca]

Hi guys, I am having trouble with my heater in the car when put on high. A few weeks back i put in a new thermostat because when i was stood still with the heater on hi the temp gauge would drop right down to just under the first mark but when the heater was on a warm setting it would very slowly drop away over 15 mins. So i then replaced it again for a better one which worked for 2 months and then started doing it again :aargh4: Today i went to the dealer and got one from there and i can have the heat setting on high but the blower can only be on 2-3bar setting because if i put the blower any higher the needle will drop down again :zx11:

The waterpump and timing belt was changed about 4k ago and i also fitted the water pump with the alloy propeller so that i didn't suffer with the plastic one coming away. So i am stummped now because i cant understand why the temp is dropping away when the blower is on 5 bar. In all the years i have been fixing cars this one is just trying to send me over the edge because it has to be the thermostat causing this.



Any help to solve this will be fantastic guys before i take a hammer to it :zx11::aargh4::aargh4::zx11:

[zollaf]

what i would do is connect my computer and see what the actual temp is thats being recorded by the ecu. then you will know whether the gauge is telling the truth and the engine is in fact getting colder , or if its lying to you. does the air coming out stay hot though ? and what make was this water pump.

[arman123]

Hi guys, I am having trouble with my heater in the car when put on high. A few weeks back i put in a new thermostat because when i was stood still with the heater on hi the temp gauge would drop right down to just under the first mark but when the heater was on a warm setting it would very slowly drop away over 15 mins. So i then replaced it again for a better one which worked for 2 months and then started doing it again :aargh4: Today i went to the dealer and got one from there and i can have the heat setting on high but the blower can only be on 2-3bar setting because if i put the blower any higher the needle will drop down again :zx11:

The waterpump and timing belt was changed about 4k ago and i also fitted the water pump with the alloy propeller so that i didn't suffer with the plastic one coming away. So i am stummped now because i cant understand why the temp is dropping away when the blower is on 5 bar. In all the years i have been fixing cars this one is just trying to send me over the edge because it has to be the thermostat causing this.



Any help to solve this will be fantastic guys before i take a hammer to it :zx11::aargh4::aargh4::zx11:


when you fitted the thermostats did it lock into the housing were the two tabs on the housing there that's were the stat twist and locks into the housing with the o ring very common for them to break and go missing and sometime when the new stay goes in its not sitting correctly letting coolant past also was the coolant temp sensor ever changed

[johnca]

The water pump is a after market one that euro car parts sell and tbh i have fitted loads of them without any problems in the past. I also forgot to put in my other post that i also fitted a temp sensor switch when i did the last thermostat but it was not an original audi one. When the temp is on 90 the heater is red hot but when the gauge drops the heat seems to also cool but i am not sure if its just my hand getting used to the heat. I will plug into it tomorrow and see what happens and report back with the results because its got to be something stupid causing this OR audi cars do this and i have never noticed before as this is my first A4.

Thanks zollaf for the reply

[johnca]

There is no tabs on the plastic side of the housing or in the block so i placed the stat in the middle of the block hole and used some sealer around the rubber O ring just to make sure it sealed up. I can see what you mean about a gap and it also makes sense about water passing but tbh it looked like there was no gap around it before i bolted the plastic housing back on.

[johnca]

Just another thought which end fits into the block side ? deep or shallow ? i fitted the deep end into the block each time as that's how it came out the first time. Not sure if it will fit the other way round but its something to think about.

[arman123]

Deep side into block I had a similar problem as were the temp guage would not sit at 90 tried many thing and in the end it was the housing bought new housing fitted no problems since old housing had no tabs plus the first stat was fitted by dealer when I went back saying the car was overvcooling they diagnosed faulty rad I just said yeah ok and walked out had a look my self and it was the tabs missing on the housing

[johnca]

Thanks for the help, i will plug into it tomorrow and see if the computer temp matches the gauge and if not then its got to be the sensor. Failing that i will order the plastic housing and give that a go because its got to be either one of those causing the problem i think. Winter is around the corner now and i want to get the best out of the heater but if i cant sort this out its going to be useless once the temp gets very low traveling 22 miles each way to work.

[johnca]

Update: i have changed the thermo housing so it now locks into place and its made no difference. I have also plugged in with live data and the temp is reading the same as on gauge so i have covered both of those and its still the same. What next should i try because when i spoke to my local dealer who supplied me with the bits they are also stumped and said to book it in there so they could check it out. The way i see it is that its over cooling and in my eyes it has to be the thermostat not closing to keep the correct temp but after 2 cheap units and now a dealer part i am no further forward with this.

[johnca]

I did notice that my car also has a housing on the back of the head but when i took this one off there was nothing inside so can anyone tell me if that's right to be like that or is there supposed to be a small thermostat inside there ?



Thanks for the help guys

[arman123]

is your car a 1.9tdi?

[johnca]

yes it is mate 2003 model

[arman123]

So thermostate was changed genuine one new housing with o ring what about the temperature sensor was it changed with a genuine green one also how is the needle when it falling and rising is it erratic I'm stumped if you done all the above and it's still overcooling what about purging the coolant could have an airlock did you scan it for fault codes

[johnca]

I gave up with the after market stuff and replaced sensor and thermostat + housing from the dealers. The needle stops at 90 if the heater is set at 18-21 and the blower on number 3 but if i take the heater above 21 and blower up to 4-5 then the needle slowly drops away over a space of 5 mins standing still. If i put the heater on HI setting driving or standing still the needle moves down to 70 ish much faster. I had the live data plugged in doing the same as above and the needle matched the same temp as the gauge when dropping so i really don't know what to try next. The timing belt and pump i changed myself about 6k ago and i would of thought if it was the water pump doing this it would over heat not cool the car the way it is. Don't get me wrong its still warm when the temp is set to 21 but now winter is on the way its probably going to cause me issues when the screen is frosted over on a morning and i also like to put the heating on high after doing a 10hr shift outside to warm me up a bit lol

Thanks again for the help :)

[johnca]

Also scanned for faults and nothing. The car has only covered 108k from new with full history so its been well cared for.

[johnca]

I think tomorrow i will try back flushing the heater matrix just to see if that makes things better ( doubt it ) because when its sat at 90 and put the heater on HI it cooks you untill the temp drops away again.

[arman123]

When it drops always does it go back to 90?

[johnca]

Yes it will go back to 90 if i turn the heating back down again. I also told the dealer this thinking it could be a thermostat problem but he said they have never had a problem with them ever and even using the cheap units it was doing the exact same thing so that rules it out really.

[johnca]

Talk about a head scratcher lol

[arman123]

I know this is very frustrating but if I were you I would change the stat again Are you sure that some of the silicon you put on when you first done it is not stuck somewhere in the stat keeping it open I just can't think of any other thing causing the overcooling of your car it totally up to you but I would do the stat again

[nevo]

Even new stats can be bad.

[wmccann]

Hi,

If your water is heating to 94 degrees i.e. normal then the problem is more than likely somewhere else.

1) the thermostats from Eurocarparts are garbage - have had dreadful problems with them. For the cost saving - not worth it - go Audi.

2) have you checked the control unit. if it is digital you will see an opening in it top centre (3/4 bars). inside this there is a small pc fan which blows air from the car over a temperature sensor that is connected to the PCB. this fan can go (mine did) or it can get blocked up. Get some compressed air (canister should do) and spray it in, then see what happens, otherwise take the unit apart and see if the fan works (bit tricky though to do this).

3) Scan the eircon unit with vagcom and see if the accentuators for the air are all working correctly - you might have a misreading from the warm air intake one.

W.

[arman123]

what that got to do with what his temp guage is reading:confused: that sensor your talking about isn't that to control the temp in the car when you got the air con on auto
the reading on the dash comes from the coolant temp sensor one signal to ecu to control fueling and one to dash to read car coolant temp

[wmccann]

what that got to do with what his temp guage is reading:confused: that sensor your talking about isn't that to control the temp in the car when you got the air con on auto
the reading on the dash comes from the coolant temp sensor one signal to ecu to control fueling and one to dash to read car coolant temp

Apologies, misread the original post. Thought that after 15 mins the aircon was blowing cold.

[johnca]

Thanks for all the help guys. Finally got it sorted and it was a blocked pipe at the back of the head. I said to myself give it one more go before taking it to a dealer so i pulled every pipe in the cooling system and shoved the hose through them. The one at the back of the head the same size bore as my hose was full of crud and when i put the hose on a load of rust and what looked like paper shot out. So i then put everything back and run it up to temp and it now sits at 90 with the heater on HI even after 30 mins :) i am now one happy audi owner again because i really was worried about the winter coming and not being able to clear the windows.

Also for a few weeks i have had a noise coming from the N/S/F and it sounded like someone flicking an empty can of pop but again i could not find where it was coming from and it was only doing it for 10 mins when the car was cold and the odd time when going round corners. I found today that the engine subframe had come loose ! so after doing back up 3 bolts the noise has gone and i am so pleased i found it as it was doing my nut in trying to find where it was coming from. I know a few lads with golfs who have also had this problem and they all said its common for it to happen so if you ever get a noise like someone flicking a empty can check the subframe is tight first before you start chucking money at it to solve the problem.


I would like to say a big thank you to everyone who helped me with info to solve my heating problem and i hope i can return the favor in the future.