Reflections and summary of the no-heat fix and timing belt swap, and coolant fill write-up.
03-02-2008, 07:24 AM
#1
AudiWorld Super User
Thread Starter
Reflections and summary of the no-heat fix and timing belt swap, and coolant fill write-up.
First of all, a big thanks to those who were there to help me through all the troubles I encountered. Specifically, I would like to thank Haime (HDIAS4), S4gasm, davenew, Chaddy, and Bracketracer. And to those of you who told me to give up and take it to a shop, well thanks for giving me motivation to figure it out myself. My car is now fully operational after being down for 3 months.
The final cause was determined to be an air-pocket in heater core. I discovered this when I realized the Bentley manual wanted you to fill the system with an adapter on the coolant reservoir. So, what I did was unbolt the tank from the chassis and manually hold it up way above everything else and filled it while I was holding it. Doing this caused coolant to come out of the bleeder hole on the outlet heater hose, which it never did before (because there wasn't enough pressure to push the coolant up the heater hose and push the air out of the core). This should have initially been apparent to me for 3 reasons:
1. When I tried to flush and re-bleed the system initially, the heat improved somewhat.
2. The heat worked before my mechanic did the t-belt and water pump job.
3. There was no heat at idle, but the engine did not overheat. The only possible explanation for this is an airpocket in the heater core preventing coolant from flowing up into it or a physical blockage (such as a waterpump impeller) stuck in the heater hoses.
But, my mechanic suggested the waterpump was bad, so being as stubborn as I was, I didn't believe it, so I decided to pull it apart myself to look at the water pump. As I suspected, the waterpump was fine, but the thermostat was old, so I replaced it. In order to look at the water pump, I had to remove the timing belt, so I followed the Audiworld guide for removing and replacing the timing belt. This guide is lacking in a number of areas, specifically, if you are using this guide, you need to keep in mind these following additions/modifications I would like to add:
1. You need to use both the Cam lock bar and the Crank lock pin. The crank lock pin is somewhat difficult to get in, but not that bad. You will need a 1/4" drive with 10mm socket to remove the plug on the engine to insert the pin (once you have rotated to TDC of course). I found that an offset ratcheting box-end wrench was the easiest to use (http://www.amazon.com/Fractional-Offset-Ratcheting-Box-Wrench/dp/B000HT4Z8C). You should be able to screw the crank lock pin in by hand (there is just enough room to fit your hand up in there). Once you have the crank lock pin in, install the cam lock-bar, detension the belt, insert pin into hydraulic tensioner and remove the belt. From this point forward, don't remove the cam lock bar for any reason until the new belt is installed and tensioned.
2. You absolutely must pop the sprockets off to install the new belt. The AW guide says not to do this, and it's totally wrong. First of all, it is extremely difficult if not impossible to stretch a new belt on without popping the sprockets. Your effort would be much better spent popping the sprockets, which takes only an extra whopping 5 minutes. You need to use either the special audi tool for popping the sprockets or use a two arm gear puller. I made do with a three arm gear puller from autozone, but ended up trashing one of the sprockets and destroying the gear puller. A 2-arm puller would be much easier. To pop the sprockets:
a. Loosen cam bolts (break loose and turn out 5 times). They are the 16mm bolts on the center of the sprocket.
b. Attach gear puller and tighten. The sprocket will "pop" off violently. You need to have the cam lock bar on. If you don't have the cam lock bar on, there is a good chance you will rotate the passenger side cam 45 degrees. If this happens (as it did to me), simply use the cam lock bar to put the spacer back in the horizontal position, and then put the cam lock bar back on.
c. Tighten the cam bolt by hand until the sprocket doesn't toe in or out, but can still be spun by hand.
d. Install the new belt, pre-tension the tensioner with an 8mm allen socket and a torque wrench to 15 N-m.
e. Tighten the cam bolts to 55 N-m. Lean on the cam lock bar while you tighten just to make sure it doesn't slip off.
f. Done. Remove cam lock bar, crank pin, and crank the engine by hand (clockwise) to make sure it's timed right. Put car back together following AW guide.
How to fill cooling system:
Filling the cooling system is tricky. Follow this method to get it right.
1. Remove shroud from under car. Remove lower radiator hose (on the front bottom passenger side of car). It helps to have the car on jackstands. It has a clip that you need to push back with a flat screwdriver. Pull HARD to get it off. Coolant will dump everywhere, so have a bucket to catch it and make sure the car is not hot.
2. Allow coolant to drain.
3. Remove heater hose connections from heater core (just to the right of the battery).
4. Insert garden hose into each side of heater core connections and flow water through it until it comes out clean both ways.
5. Remove small inlet hose from coolant reservoir tank. Use air compressor to blow 20psi down this hose. Coolant should shoot out of the lower rad. hose (should still be disconnected).
6. Blow 20psi compressed air down heater hoses.
7. Reconnect heater hoses, lower radiator hose (push on HARD, then push clip in -- pull to verify it's locked), and coolant expansion tank hose. Re-install shroud on bottom of car. Lower car off jackstands.
8. Slide left heater hose (closest to the battery) off its connector partially so that the hole in the hose is just exposed.
9. Unbolt coolant reservoir tank from chassis (three phillips screws).
10. Manually raise coolant tank so fill point is high as possible.
11. Make 50/50 solution of distilled water and G12 or G12+.
12. Fill coolant reservoir tank while holding it up in the air until coolant shoots out of the hole in the heater hose (you do this so that you don't get an air pocket in the heater core).
13. Slide heater hose with hole in it all the way back on.
14. Remove inlet hose (the small one) from coolant expansion tank. Fill tank until coolant comes out of hose. Reconnect inlet hose.
15. Loosen bleeder screw to the right and below the TBB. You should hear air and see bubbles coming out of it. If no coolant comes out, continue to fill tank while holding it in the air until coolant comes out of bleeder screw without air bubbles
16. Tighten bleeder screw and reattach coolant expansion tank to chassis.
17. Fill up coolant tank with remaining G12/G12+ solution until it is between min and max marks.
18. Start car, turn heat on high. Let idle for 5 minutes. Either drive the car for 10 minutes or hold the rpms at 3000 for 5 minutes. Let cool for 5 minutes and check for coolant leaks.
19. Remove cap from expansion tank (watch out for steam and overflow) and let idle for a few more minutes with cap off.
20. Shut-off car. Put cap back on coolant tank. Done.
So there we are. If you have just had service done where your coolant was changed (t-belt and water pump job for example), and your heat doesn't work right anymore, you probably have an airpocket. Follow the steps above BEFORE you start digging into the car.
The final cause was determined to be an air-pocket in heater core. I discovered this when I realized the Bentley manual wanted you to fill the system with an adapter on the coolant reservoir. So, what I did was unbolt the tank from the chassis and manually hold it up way above everything else and filled it while I was holding it. Doing this caused coolant to come out of the bleeder hole on the outlet heater hose, which it never did before (because there wasn't enough pressure to push the coolant up the heater hose and push the air out of the core). This should have initially been apparent to me for 3 reasons:
1. When I tried to flush and re-bleed the system initially, the heat improved somewhat.
2. The heat worked before my mechanic did the t-belt and water pump job.
3. There was no heat at idle, but the engine did not overheat. The only possible explanation for this is an airpocket in the heater core preventing coolant from flowing up into it or a physical blockage (such as a waterpump impeller) stuck in the heater hoses.
But, my mechanic suggested the waterpump was bad, so being as stubborn as I was, I didn't believe it, so I decided to pull it apart myself to look at the water pump. As I suspected, the waterpump was fine, but the thermostat was old, so I replaced it. In order to look at the water pump, I had to remove the timing belt, so I followed the Audiworld guide for removing and replacing the timing belt. This guide is lacking in a number of areas, specifically, if you are using this guide, you need to keep in mind these following additions/modifications I would like to add:
1. You need to use both the Cam lock bar and the Crank lock pin. The crank lock pin is somewhat difficult to get in, but not that bad. You will need a 1/4" drive with 10mm socket to remove the plug on the engine to insert the pin (once you have rotated to TDC of course). I found that an offset ratcheting box-end wrench was the easiest to use (http://www.amazon.com/Fractional-Offset-Ratcheting-Box-Wrench/dp/B000HT4Z8C). You should be able to screw the crank lock pin in by hand (there is just enough room to fit your hand up in there). Once you have the crank lock pin in, install the cam lock-bar, detension the belt, insert pin into hydraulic tensioner and remove the belt. From this point forward, don't remove the cam lock bar for any reason until the new belt is installed and tensioned.
2. You absolutely must pop the sprockets off to install the new belt. The AW guide says not to do this, and it's totally wrong. First of all, it is extremely difficult if not impossible to stretch a new belt on without popping the sprockets. Your effort would be much better spent popping the sprockets, which takes only an extra whopping 5 minutes. You need to use either the special audi tool for popping the sprockets or use a two arm gear puller. I made do with a three arm gear puller from autozone, but ended up trashing one of the sprockets and destroying the gear puller. A 2-arm puller would be much easier. To pop the sprockets:
a. Loosen cam bolts (break loose and turn out 5 times). They are the 16mm bolts on the center of the sprocket.
b. Attach gear puller and tighten. The sprocket will "pop" off violently. You need to have the cam lock bar on. If you don't have the cam lock bar on, there is a good chance you will rotate the passenger side cam 45 degrees. If this happens (as it did to me), simply use the cam lock bar to put the spacer back in the horizontal position, and then put the cam lock bar back on.
c. Tighten the cam bolt by hand until the sprocket doesn't toe in or out, but can still be spun by hand.
d. Install the new belt, pre-tension the tensioner with an 8mm allen socket and a torque wrench to 15 N-m.
e. Tighten the cam bolts to 55 N-m. Lean on the cam lock bar while you tighten just to make sure it doesn't slip off.
f. Done. Remove cam lock bar, crank pin, and crank the engine by hand (clockwise) to make sure it's timed right. Put car back together following AW guide.
How to fill cooling system:
Filling the cooling system is tricky. Follow this method to get it right.
1. Remove shroud from under car. Remove lower radiator hose (on the front bottom passenger side of car). It helps to have the car on jackstands. It has a clip that you need to push back with a flat screwdriver. Pull HARD to get it off. Coolant will dump everywhere, so have a bucket to catch it and make sure the car is not hot.
2. Allow coolant to drain.
3. Remove heater hose connections from heater core (just to the right of the battery).
4. Insert garden hose into each side of heater core connections and flow water through it until it comes out clean both ways.
5. Remove small inlet hose from coolant reservoir tank. Use air compressor to blow 20psi down this hose. Coolant should shoot out of the lower rad. hose (should still be disconnected).
6. Blow 20psi compressed air down heater hoses.
7. Reconnect heater hoses, lower radiator hose (push on HARD, then push clip in -- pull to verify it's locked), and coolant expansion tank hose. Re-install shroud on bottom of car. Lower car off jackstands.
8. Slide left heater hose (closest to the battery) off its connector partially so that the hole in the hose is just exposed.
9. Unbolt coolant reservoir tank from chassis (three phillips screws).
10. Manually raise coolant tank so fill point is high as possible.
11. Make 50/50 solution of distilled water and G12 or G12+.
12. Fill coolant reservoir tank while holding it up in the air until coolant shoots out of the hole in the heater hose (you do this so that you don't get an air pocket in the heater core).
13. Slide heater hose with hole in it all the way back on.
14. Remove inlet hose (the small one) from coolant expansion tank. Fill tank until coolant comes out of hose. Reconnect inlet hose.
15. Loosen bleeder screw to the right and below the TBB. You should hear air and see bubbles coming out of it. If no coolant comes out, continue to fill tank while holding it in the air until coolant comes out of bleeder screw without air bubbles
16. Tighten bleeder screw and reattach coolant expansion tank to chassis.
17. Fill up coolant tank with remaining G12/G12+ solution until it is between min and max marks.
18. Start car, turn heat on high. Let idle for 5 minutes. Either drive the car for 10 minutes or hold the rpms at 3000 for 5 minutes. Let cool for 5 minutes and check for coolant leaks.
19. Remove cap from expansion tank (watch out for steam and overflow) and let idle for a few more minutes with cap off.
20. Shut-off car. Put cap back on coolant tank. Done.
So there we are. If you have just had service done where your coolant was changed (t-belt and water pump job for example), and your heat doesn't work right anymore, you probably have an airpocket. Follow the steps above BEFORE you start digging into the car.
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03-03-2008, 03:35 AM
#9
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The advice of others to take it to a mechanic was good advice.
Had you done so at the beginning then your car would not have been down for three months and you probably wouldn't have spent that much more than you did spend. To do all that you did just because the heat didn't work is rediculous.
Congrat's on getting your heat back. :-)
Stephen
Congrat's on getting your heat back. :-)
Stephen
11-21-2008, 06:58 AM
#10
Only thing I'll add is - slide the radiator hose clips to closed position *before*...
trying to slide the hose back on. The clip will slide up over the lip and audibly *click* into place letting you know it's on far enough. Otherwise it can be hard to tell if you've got it on far enough. The click is an easy way to be sure it's on.