Help me diagnose a no heat problem?

[cavillac]

The car is a 95 TSi AWD, when I bought the car the previous owner told me it had a cracked radiator.. It did in fact have a large crack in the end tank as well as some of that lovely stop leak garbage. I replaced the radiator last year and flushed the heater core with a hose for like 2hrs and that gave me heat but the air was cold at idle, I inspected the TSTAT and it was pretty nasty with stop leak so I replaced it. After that it didnt make much better heat.

I've replaced the heater hoses as one of them also was leaking,TSTAT, cap (.9bar), water pump (When I did the timing belt) and have done many flushes.

The car makes acceptable heat above 1500 rpm but its still nothing great. It is full in the overflow and in the water outlet and the control levers/blend doors operate fine.

Is there something I'm missing, I'd let my 90AWD idle for 15 minutes on the coldest day and it would have scorching heat, I let this car Idle for 15minutes and the needle is barely off the bottom of the guage.

I wouldnt think this to be a TStat problem or a Heater core problem..

anyone have any Ideas or experianced the same thing?

 

[95greentsi]

if you had to flush the heater core for 2hrs to get it unclogged/ heat working, i would say pull the heater core and see what sludge is in it. also, check the hose to the turbo, those are common to have small leaks on them. also is it overheating? I also have a 95tsi, and it does take a while to get heat (prob 10 min). But after that its hot as hell

 

[Kastigir]

Sounds like a stuck open thermostat. Replace the thermostat and try again. It is entirely possible to get a bad *new* thermostat.

 

[Defiant]

Sounds like a leaking thermostat. With stop leak in the system, all bets are off.

 

[MrGriff750]

Make sure u have all of the air out of the coolant lines, including the block. The way i did that is by removing the thermostat, reconnecting the upper radiator hose, and letting the vehicle get to operating temperature. Be sure to have the radiator cap off so air bubbles can escape and u can observe the coolant flow. Doing this allows the air bubbles to get out of the block and wont get stuck behind the thermostat, causing it to stay closed. Hope this helps; it worked for me

 

[cavillac]

Sounds like a leaking thermostat. With stop leak in the system, all bets are off.

What thermostats are you guys using? Mine looks like this

You must be logged in to view this image or video.

They also sell one that looks like this, I wonder if there is any difference, One has the pellet and probably different spring rates? They are both 180 degree's..

You must be logged in to view this image or video.

 

[Kastigir]

Mine looks like the top one.

 

[Black 95 TSI]

Are both rad hoses hot? Are both hearter hoses hot? I would bet you have a pluged heatercore tho.

 

[cavillac]

I installed a new thermostat (Top one in my pictures) and it makes pretty good heat when driving, now its just to see how long it takes to make heat on a 10 degree morning tommorow.

I would not be suprised the heater core is plugged full of that damn stop leak, I dont know why anyone would use that crap, But I've flushed the core like 5 times for hours on end so I am having a hard time believing it can be plugged.

 

[JStrateger]

Mine does something similar, it takes about 10 minutes to warm up but even when the temperature gauge is at operation temperature my heat sucks. I've taken out the heater core and have inspected the whole vent system; all checked out.

It's warms but definitively not as warm as it should be, I'm going to do a coolant flush and replace my thermostat this week, I'll get back to you after that.

 

[cavillac]

Maybe the 2g's just dont make good heat for some reason, my 1g would scald my hand if I kept it over the vent for too long.

 

[Jeff99GS]

Maybe the 2g's just dont make good heat for some reason, my 1g would scald my hand if I kept it over the vent for too long.

NO...my 2g is blazin hot too. Could be the heater core flowing poorly, or leaking.

Check the passenger floor carpet and see if its damp.

Do you ever lose coolant?

 

[92ts1]

There is an acid that they sell at most auto parts stores. You disconnect one heater hose from the core, leave the other connected but disconnect it from the water pipe. You poor a certain amount into the heater core. Let it sit and it eats away all the build up that is in the core. We use it at work alot when people have the same complaint. Works well, but make sure you wear some kind of gloves cause it can tear up your hands.

 

[asexton6969]

I would also have to agree on the heater core being plugged or flowing poorly. If that stop leak gets coated on everything, its not gonna allow the greatest heat, its gonna repel it. I would suggest to replace it, if you have taken it out and inspected it, you know what your doing.

As for that acid, never used it. My thoughts are, its a 10+ year old car. I would just go ahead and replace the heater core.