Help - Radiator blocked

[chursy]

Hi guys

I have an audi a4 2.0 sports auto with alt engine. I posted a thread two days ago with regards to water not regulating. People recommended that its possibly air problem and system needs bleeding. Went to my mechanic and basically everything is ok the water is regulating to the engine fine to but not so in the radiator. It's there , it's warm but just not flowing. Also after 30 mins or the radiator got warmed up.

The mechanic said the radiator is blocked possibly. The water pump works fine as the coolant was coming back in the reservoir from top hose, also pumps and belt changed at 75k. It's now at 96k. Air pressure bubbles released from the reservoir opened cap and also bleeped the system through the nozzle on top.

Can the radiator be flushed and cleaned to clear the blockage, using the special mixture and pressure washed etc or do I have get a new radiator ? Any help will be much appreciated

[MikTip]

Probably need new one....

[chursy]

Really. ??? Can this not be cleaned out and flushed?

[diagnosticator]

It is not the main engine radiator. The problem is air trapped in the heater core. Bleed the heater core by moving the hose toward the rear, on the upper heater return tube. there is a hole near the end of the metal tube to allow air to escape the heater. After bleeding the heater core, if the heater stops working again, after driving the car several times and parking overnight, then there is a coolant leak somewhere allowing air to leak into the cooling system as the system cools down after driving the car. In this case the leak must be found and fixed.

[MikTip]

Really. ??? Can this not be cleaned out and flushed?

Why isnt your mechanic advising you properly on this? Your paying him good money to troubleshoot and repair your Audi.....

The only way to tell if its blocked, is remove it and have it tested at a shop that specializes in radiators.

However the costs involved in removing, testing, and reinstalling will probably be more than simply replacing with a new one, if indeed it is clogged.

You also have the heater core. Its a smaller radiator, that are known to clog.

Much of this depends greatly on how well the coolant system was taken care of over the years!

What does your mechanic say about flushing out the coolant system?

[EBG 18T]

You can flush and then burp it to remove the pockets of air. Sometimes the cores are so logged that flushing it doesn't substantially improve the situation. At that point you just replace them and move forward.

[chursy]

Which hose are you referring you. There is a Black hose on top of the engine which has a hole that opens with the Allen key. I will get a picture and put it up today. Air was taken out from this holse last night while the engine was running. The Heater was on max and frankly works fine. The heat levels on max are not ideal but warms the car. The water is warming up and being circulated in the engine fine. Return pipes all are warm but just not going through the radiator. The radiator did warm up last night after like 15-20 mins of car being on idle and warmed up. There was bubbles coming out from the coolant tank last night which shows there was air in the system i presume. The car is not overheating as the temperature stays at 90!!

Is the radiator gone i dont know. Are you referring to the same hole above?. There are no leaks as its been pressure tested and all leaks fixed, the housing at the back was leaking!! I am really confused now.

[MikTip]

Which hose are you referring you. There is a Black hose on top of the engine which has a hole that opens with the Allen key. I will get a picture and put it up today. Air was taken out from this holse last night while the engine was running. The Heater was on max and frankly works fine. The heat levels on max are not ideal but warms the car. The water is warming up and being circulated in the engine fine. Return pipes all are warm but just not going through the radiator. The radiator did warm up last night after like 15-20 mins of car being on idle and warmed up. There was bubbles coming out from the coolant tank last night which shows there was air in the system i presume. The car is not overheating as the temperature stays at 90!!

Is the radiator gone i dont know. Are you referring to the same hole above?. There are no leaks as its been pressure tested and all leaks fixed, the housing at the back was leaking!! I am really confused now.

2.0 liter engine?

All USA model B6 Audi's have the 1.8t or 3.0 liter engines.

How do you know water is being curculated inside the engine? Yet not in the radiator?

Does the engine over heat?

[MikTip]

You mentioned white smoke on earlier posts...

Is it smoke or steam?

You also mentioned high oil consumption....

Oil burns into white smoke....water to steam....

High oil consumption can be caused by leaking valve guide seals and can cause white smoke.

Any unexplained loss of coolant/water?

Ya might pull the spark plugs after the engine has cooled and see if theres any water/coolant on top of the pistons. Use a bright flash light....

[chursy]

Its a 2 litre engine indeed and European ALT version engine.

Now the oil consumption is ok to be honest it was me not reading the Dip Stick Correctly!!! This is my first Audi and I am using to seeing normal Dip sticks!!! everytime i checked oil i always read it as at the minimum level because that used to look like as if its bin dipped in oil and dripping. No issues with oil and i dont think its the head gasket and neither did the mechanic.

Water in engine is regulating as its not over heating and the return pipes and the top hose attached to the coolant tank has coolant returning back to the container showing that the pump is working fine. Now for the radiator its cold!!!!! it takes ages to heat up!!! The water does go in the radiator but doesn't run through properly. There is water going in to it, both pipes that go in the radiator are warm!!

Re Smoke - My mechanic seems ok with it and said that was normal and i was being paranoid but to me its looks more then normal for somereason. Its usuallly when the car has been driven for sometime and at idle though. I get the odd smoke in the morning at cold starts but i have driven the car and i am waiting or driving at 5MPH i see alot of white smoke through side mirrors or main mirror. Its not forming any clouds or anything as such.

The guy i showed it to said its the Radiator we have played around with the air valve to release any air etc. This is the second mechanic i have shown to , the first one was thinking that its the water pump and wanted to rip me off for the belts and pump!

[old guy]

If the radiator is staying cold or at best warm and the car isn't overheating I don't think you have a clogged radiator. It sounds more like your thermostat isn't working properly and either sticking open or opening too soon.

[chursy]

My Millage is fine infact great no issues there. Now on the thermostat if the car is not overheating would this still be a problem? Also the temperatures reflected by the thermostat are correct per the guage. The Garage who looked at it also looked in to this and confirmed that the temperatures per the thermostat were correctly being reflected on the guage. I have already pumpted alot of money in this and just lost for words now whats is going on! i hope its not the radiator!!!

[chursy]

How can you check its the thermostat though?

[old guy]

What exactly is your issue? If I recall your complaint was no heat. Is that correct? If your radiator "takes ages to heat up" the thermostat isn't functioning properly. With normal driving in London temperatures the motor should reach full operating temperature in under 5 minutes.

[chursy]

Let me rephrase this now. The car does reach normal working temperature in 5 minutes provided i am driving and even on Idle it hits 90 degrees fine.

I just drove 500 miles last night no issues with the temperature or overheating or anything. However the weirdest thing is on idle my car was on for 30 minutes, heating on max - The heater wasnt that strong and cold - Water was cold in the tank and also the radiator was cold too!!. Its just really weird. The water in the radiator is just there but not circulating and this is impacting the heating as well as its not that strong as it should be. The radiator inside did start warming up after ages though .

Once i start driving its all fine - Heating is there too but and temperature control works fine.

[old guy]

Coolant isn't going to circulate through the radiator unless the thermostat opens up. If your car is heating up normally and not overheating it sounds like the thermostat is doing its job. A thermostat stuck closed is going to cause the motor to overheat. A thermostat stuck open is going to cause the motor to take much longer to heat up and will probably cause the temperature gauge to drop below center when driving under low loads.

My guess is that you either still have some air in the heater core or the core is partially clogged and limiting the amount of coolant that can flow through it. When cruising on the highway the water-pump volume is obviously greater than at idle and consequently you will get more heat from the heater core. at idle the flow is greatly reduced and less heat transfer can occur through the heater core.

[chursy]

heater core is what exactly, the heater matrix see http://www.eurocarparts.com/heater-matrix?

I have tried to take out all air last night at the garage leaveing the cap open while the engine was started also from the hose. May need to take it to a specialist i suppose to use a pressure device or somthing to take all air out.

For the clogged heater core if it should i flush it and get it cleaned?

Should i drive the car around or is it a big NONO. I drove 500 miles all ok no issues though but is it going to ruin my engine. I hope not as you said the pump is working all ok.

[MikTip]

Sounds like its drivable....ya went 500 miles zero issues....

[chursy]

thanks man ya i think so. But what exactly is a heater core? is the small radiator inside the big one? would be great if you can show me some pics here

[old guy]

Agreed. Your car is safe to drive. Where did you bleed the system? To bleed the heater core you need to pull back on the hose in the pic. There is a small hole in the hose. Just pull back far enough to expose the hole. Once the air purges and coolant spurts out push it back in place.

[old guy]

thanks man ya i think so. But what exactly is a heater core? is the small radiator inside the big one? would be great if you can show me some pics here

Look at the pic in my previous thread. Those two hoses supply coolant to the heater core. The heater core is located inside the front cabin behind the center console. Coolant flows in the lower hose, through the heater core and then back out through the upper hose. Air is blown through the heater core to transfer heat into the cabin.

[chursy]

Mine i an ALT setup. There was pipe next to the Engine which has an Allen Key hole is it and he just losened it a bit and the coolant and air bubbles came out. Do i need to take off the covers next to the battery to see these two pipes? I dont think we took the air out from this hole?

[old guy]

Mine i an ALT setup. There was pipe next to the Engine which has an Allen Key hole is it and he just losened it a bit and the coolant and air bubbles came out. Do i need to take off the covers next to the battery to see these two pipes? I dont think we took the air out from this hole?

Yes you need to remove the rain tray to access the heater supply lines. You bled the air from the upper coolant return hard pipe. That doesn't always get the air out of the heater circuit. Clicky click

[chursy]

Man do you have a picture for this? I am not sure what you you are referring to there. Yes did bleed the thing from the Return Hard pipe indeed its solid black steel pipe. I need to do this definately.

[chursy]

When do i need to do this, first thing in the morning or once i have driven the car around for a while? Do the engine need to be started when i am doing this first thing?

[old guy]

Here is a DIY on how to flush the system. Clicky click. but before you go that far try bleeding it to see if that corrects your problem. Read the DIY and note the hose pick. A pick or something similar makes pulling back on the hose much easier. Here's two bleeding methods:

Safe way: This can be done with the car hot or cold. Remove the single Phillips head screw holding the coolant reservoir in position. Lift up on the front edge of the reservoir so you can disconnect the two tabs that hold the reservoir to the firewall. Take the reservoir cap off to relieve pressure and tilt the reservoir up 90°. This will increase the static pressure on the coolant. Squeeze the constant force hose clamp on the upper heater core return hose as shown in post #20 and pull the clamp back to release the hose. Use the hose pick or similar to pull back on the hose far enough to expose the bleeder hole in the hose. After all the air purges and coolant starts to come out push the hose back in place. Reassemble everything and cross your fingers!

Quick and easy way: Disclaimer: Don't blame me if you get burned! Get the car up to temperature. Leave the cooling system under pressure. Release the constant force hose clamp and slide it down the hose (toward the front of the car). SLOWLY pull back and squeeze the heater return hose. Have a rag ready. The cooling system will be under pressure and at some point the air is going to spurt out of the bleeder hole in the hose followed by a stream of 200° coolant. Push the hose back in place and open the reservoir cap to relieve the system pressure. Put the hose clamp back in place. done.

[chursy]

cheers

[diagnosticator]

Which hose are you referring you. There is a Black hose on top of the engine which has a hole that opens with the Allen key. I will get a picture and put it up today. Air was taken out from this holse last night while the engine was running. The Heater was on max and frankly works fine. The heat levels on max are not ideal but warms the car. The water is warming up and being circulated in the engine fine. Return pipes all are warm but just not going through the radiator. The radiator did warm up last night after like 15-20 mins of car being on idle and warmed up. There was bubbles coming out from the coolant tank last night which shows there was air in the system i presume. The car is not overheating as the temperature stays at 90!!

Is the radiator gone i dont know. Are you referring to the same hole above?. There are no leaks as its been pressure tested and all leaks fixed, the housing at the back was leaking!! I am really confused now.

The hose I am referring to goes from the heater at the firewall to the engine cooling system, and is the return flow from the heater core in the cabin. 'The heater return hose connects to a metal tube, and has a hose clamp at the joint. By sliding the clamp away from the joint, the hose is moved toward the end of the tube, uncovering the bleed hole near the end of the tube. this bleed hole is provided specifically to vent air trapped in the heater core in the cabin.

[diagnosticator]

Yes you need to remove the rain tray to access the heater supply lines. You bled the air from the upper coolant return hard pipe. That doesn't always get the air out of the heater circuit. Clicky click

Thanks "old guy", I forgot to mention that the hoses are in the plenum.

[chursy]

Thanks Guys!!! Will give this a shot. I am pretty sure its this now and no wonder the car drives fine hence otherwise i would have thought the system would have been cooked by now if the radiator was blocked

[diagnosticator]

Thanks Guys!!! Will give this a shot. I am pretty sure its this now and no wonder the car drives fine hence otherwise i would have thought the system would have been cooked by now if the radiator was blocked

Yes, that is a key factor with the situation here. Remember if the heater stops working again after bleeding and driving the car and parking overnight a few times, there is a leak in the cooling system allowing air to get into the coolant as the system cools down after parking. One way to find the leak is to add special UV sensitive dye to the coolant, Then drive the car to mix the dye in the coolant, then park and allow the coolant to cool down, then use a cooling system pressure tester and pressurize the system to normal operating pressure, with the cooling system at ambient temperature, use a black light to look for the glowing dye where the leak is located.

[chursy]

Thanks for this. I believe all leaks were fixed as the mechanic i showed to earlier did a pressure test on this and all ok. I am going to try and bleed this. Could it be that the air conditioner needs servicing may be? Do they bleed the system when servicing this.

Does the rain cover come off easily? is there a DIY for this, dont want to break any clips!!

[Dubsport Inc]

The a/c should have nothing to do with cabin heat unless you have it all the way cold... :) The rain tray comes off by first removing seal at the face of the engine bay and then gently lift up and pull towards the front of the car... check for a cabin filter/pollen filter diy in that section!

EDIT: here you go!
http://www.audizine.com/forum/showth...Pollen-Filter)

[chursy]

thanks - At lunch i was passing by a garage was in a suit so thought will pop in and get him to bleed it. He is like that has poisonous gasses i am not going to take the hoses off and bleed the system!!! :p. I explained to him the problem and went on about saying that it could be the pump or the radiator!! :P. I just said thanks for your help and walked out!! I will try it tonight myself

[walky_talky20]

ROFL @ "poisonous gases". WHERE are you finding these mechanics? You need to go to a place which has mechanics that know how to fix cars and stuff.

[chursy]

guys i dont know what it is but i have tried a few mechanics now in the span of a week. No one really knows about bleeding the heater core :P. When i mention the word bleed to them, they look at the cap and the coolant return hose hole. That is the end of their specialists skills. All kept asking me who is telling you all this information!!!.

Also i rang the mechanic this morning who wanted me to change the Pump and the belts ! and told him the systems needs to be bleeded as its got air in it. He is like ok , how do you know the pump is working ? i was like well the top hose in the coolant reservoir has coolant coming in so the pump is fine and more importantly i just drove 500 miles dispite you telling me park the car somewhere. ALSO this idiot broke one of the hoses on my PCV valve and put in like a plastic purple hose instead. The mechanic i got the PCV valve fixed over the weekend said who did that!!! :P ... I so wish i was a mechanic!!!

thank you to your guys i am much more educated about this then i was a few days ago!!! this forum is excellent!

[walky_talky20]

Remind me to start up my own repair shop if I ever move to London. I could make a killing by merely knowing what I'm doing, lol.

Interestingly, I've just finished watching the 1st season of "The Tube", a BBC documentary series on the London Underground (subway). Fascinating stuff.

[chursy]

Let me know when you do - I will be the first person walking that door with my A4 =).

[chursy]

Hi guys

But of an update on this. Its been raining here so didnt get a chance to bleed the system however i noticed that the passenger side mat was wet it had water on it which was drpping in form the left hand sode under the glove box......Eh any insights on this? Am i in trouble?

[walky_talky20]

Probably not related. Your Audi merely has multiple simultaneous problems (join the club!).

Most likely the battery drain is backed up with leaves and such, or the sunroof drain is clogged. Take a quick look at those 2 items. If all that looks good, get a friend and a hose and do some investigation.