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View Full Version : Considarations when doing headgasket



Auddii
02-10-2013, 06:29 PM
First some back story I guess,

I've been dealing with a coolant leak and low vacuum with my car for a while now. I don't get a lot of time to mess around with it, thank god this is my second car.

I originally thought that the leak was the coolant flange on the back of the head. I replaced it and it didn't help anything. Tonight I decided to take the intelligent approach and stick a small mirror back there and look. Sure enough it wasn't the flange because I could actually see coolant bubbling out of the head gasket.[headbang]

I find it odd that I don't have white smoke or oil and coolant mix. The only bad symptoms I have are the leak, low vac and it obviously idles and runs like complete crap. My compression isn't horrible but I think a couple cylinders might have varied somewhere around 10 or 15 psi with the top pressure being 180psi in cylinder 4 which I think is weird since that's closest to the leak. The compression probably isn't ideal overall.

So now on to the questions, [confused]

1. Should I get the head rebuilt? I'm guessing its pretty standard to get a machine shop to at least check it out. Car is 125K miles.

2. What else should be replaced while I already have everything torn apart?

3. Is there anything special to consider on the AWM 2001.5 automatic?

4. Should I buy the Bentley manual?

5. Are there any tips or tricks anyone would like to share so I don't look like an idiot at some point.


I am a mechanically knowledgeable person when I understand what I'm doing or looking at and my brother is a mechanic so I have good help. I am still a bit nervous since I've never done head gaskets before. I've actually had a lot of firsts with my 1.8t so at least I'm learning.


I seem to only be finding b6 DIY's for this. I might have to search harder.

As always any answers are much appreciated and I know this post is sort of scrambled. Thanks guys.

Seerlah
02-10-2013, 06:43 PM
Are you positive it is coming from the HG?

With the head, you would want to get it pressure tested by a machine shop. If it checks out, them have them deck the surface. You can clean your block itself with various methods. My method is the 3m roloc wheel. You can piece it together on ebay for cheap.

http://www.ebay.com/itm/3m-07527-3in-roloc-bristle-disc-grade-80x-yellow-cleaning-disc-gasket-removal-/290824326028?pt=LH_DefaultDomain_0&hash=item43b67b0b8c&_uhb=1
http://www.ebay.com/itm/3-ROLOK-ROLOC-Disc-Holder-/200860715225?pt=LH_DefaultDomain_0&hash=item2ec43b48d9&_uhb=1

Use this to clean the short block surface. This is the technique I use anyways. You will also want to clean out the HG bolt holes. What I do is fill each hole with brake cleaner (use the straw to throttle in it), let them sit for a couple min, use an air compressor to blow out the holes dry (place rag around the hole before doing so, because it is going to squirt out), then chase the threads with an old bolt that you cleaned off and have some brake cleaner on it. Blow out the holes dry when done. After that, place on head gasket (read: properly) and torque down head bolts to spec with them lubed (choose how you want to go about this as it is debatable. I used ARP assembly lube). Be sure you use a quality torque wrench that is known to be accurate (don't cheap out here and do something like lick up an Autozone torque wrench). Make sure all surfaces are dry (head, block, and HG) when placing the engine back together.

Good Luck!

Auddii
02-10-2013, 06:49 PM
I'm positive its the head gasket. I could see that it obviously wasn't leaking from the flange and could see the bead of liquid on the HG and bubbles.

Thanks for the input seerlah. I never thought about the various ways to clean up the block.



I just thought of another thing, my engine maintains normal oil pressure but it has a good amount of sludge. Is there anything special I can do to fix that? I know I could drop the oil pan and replace the pick up tube but can the head be cleaned as well?

If I'm spending all of this time and money I want it to run like new.

Seerlah
02-10-2013, 06:55 PM
You can have your machine shop clean it for you. My machinist cleaned mine for free both times I had a head pressure tested and decked. Then drop the oil pan, and replace the pick up tube. As far as a sludge goes, don't confuse that with just burnt oil residue on the walls.

this is how I received my head back, and did not ask for it to be cleaned. he cleaned all the flanges also. did it with the other cylinder head I brought him also. the color of the cam caps is the color the casing walls of the head used to be.

http://s11.postimage.org/oadpco08j/DSC03733.jpg

98A4TurboAWD
02-10-2013, 06:57 PM
The 1.8t that Audi made is the easiest head gasket job I have ever encountered. For somebody who has done it before it could be done in an hour.

Disconnect all the wiring, pull the fuel rail out of the way, lift the head out with the intake and exhaust attached.

Clean the block and lay down a new gasket.

What you do with the head is up to you.

Seerlah
02-10-2013, 07:03 PM
And if you don't understand what is meant by cleaning the block, you want to have all that black left over residue from the old gasket removed. Here is what a clean surface looks like.

cylinder head decked by machine shop

http://s12.postimage.org/vnn2od12l/DSC03676.jpg

short block surface cleaned using the 3m roloc wheel method. could have been made cleaner, but this was good enough. I ended up redoing it later on anyways, and cleaned it really well.

http://s3.postimage.org/9uzx2e9b7/DSC03680.jpg

better

http://s12.postimage.org/m5rx224rx/DSC03691.jpg

Auddii
02-11-2013, 07:22 AM
The couple of head gasket kits that ECS sells come with both the valve seals and camshaft seals. Is this something I need to replace? I thought it was really hard to replace either of those. Is that something a shop will have to do?

Also is there any specific brand of head gasket I should buy? I'm thinking OEM might be the best bet.

98A4TurboAWD
02-11-2013, 08:26 AM
The couple of head gasket kits that ECS sells come with both the valve seals and camshaft seals. Is this something I need to replace? I thought it was really hard to replace either of those. Is that something a shop will have to do?

Also is there any specific brand of head gasket I should buy? I'm thinking OEM might be the best bet.

The kit is too expensive, buy the gasket alone. If you want to do valve seals its not difficult. Cam seals are even easier.you don't need to do either though.

I bought a victor reinz gasket, they are an OEM supplier. You'll hear varying opinions. Some complain, most stand by them. I went with victor reinz

Auddii
02-11-2013, 05:30 PM
How much of the turbo needs to come off? Is it possible to just disconnect it from the exhaust manifold and pull the head off? I'm trying to make a list of all the gaskets and misc stuff I have to order.


The biggest headache right now is the fact that I have no experience with timing belts and their removal and re-installation. Every head removal diy glazes over it so I'm pretty unsure. I'm definitely ordering a Bentley manual haha.

98A4TurboAWD
02-11-2013, 05:36 PM
How much of the turbo needs to come off? Is it possible to just disconnect it from the exhaust manifold and pull the head off? I'm trying to make a list of all the gaskets and misc stuff I have to order.


The biggest headache right now is the fact that I have no experience with timing belts and their removal and re-installation. Every head removal diy glazes over it so I'm pretty unsure. I'm definitely ordering a Bentley manual haha.

There are 3 bolts that go downward from the exhaust manifold into the turbo manifold. Just remove those three. You can pull the head with intake and exhaust attached.

To do this job all you need is head gasket, head bolts, poly drive to install new bolts, 12 point drive to remove the old head bolts, intake and exhaust manifold gaskets.

Auddii
02-11-2013, 05:42 PM
Mine being the AWM I think the head bolts are poly drive to begin with(?). Thanks for confirming on the turbo. I guess its a consolation that I don't have to rip out the turbo I replaced less than 3 months ago.

After I complete this job I imagine a couple months from now the bottom end will next to explode. Older cars and especially Audi's are something you have to care about I guess otherwise mine would be in the dump.

Seerlah
02-11-2013, 05:57 PM
With stated above, you will need o-ring for the rear coolant flange. With the TB, read DIYs and you will be fine. Mark the gears with belt before removal and you will be fine.

http://www.audiworld.com/tech/eng35.shtml

The diy is pretty entailed, but I would mark it different. Use white out to mark both the gears and the belt. Then simply match the white out upon reinstallation and you will be fine. I assume you will be wanting to place on a new belt at this time (do it, along with water pump and tensioner). Same thing applies with the white out. Place the old belt that would have the white out on it against the new belt and place white out onto the new belt. Count the amount of teeth between them to make sure you marked it correct and it will go on perfect the first time you place it on (unless it was already off).

98A4TurboAWD
02-11-2013, 06:00 PM
Mine being the AWM I think the head bolts are poly drive to begin with(?). Thanks for confirming on the turbo. I guess its a consolation that I don't have to rip out the turbo I replaced less than 3 months ago.

After I complete this job I imagine a couple months from now the bottom end will next to explode. Older cars and especially Audi's are something you have to care about I guess otherwise mine would be in the dump.

Yes the poly drive should remove your bolts.

Auddii
02-11-2013, 06:34 PM
With stated above, you will need o-ring for the rear coolant flange. With the TB, read DIYs and you will be fine. Mark the gears with belt before removal and you will be fine.

http://www.audiworld.com/tech/eng35.shtml

The diy is pretty entailed, but I would mark it different. Use white out to mark both the gears and the belt. Then simply match the white out upon reinstallation and you will be fine. I assume you will be wanting to place on a new belt at this time (do it, along with water pump and tensioner). Same thing applies with the white out. Place the old belt that would have the white out on it against the new belt and place white out onto the new belt. Count the amount of teeth between them to make sure you marked it correct and it will go on perfect the first time you place it on (unless it was already off).

When I got the car I had an invoice from the PO that had the timing belt and water pump replaced at around 100k from what I can remember off hand. I'm at 125k now. Is it still recommended to replace the water pump and tensioner? I've seen a couple of places where guys will re-compress the tensioner and reuse it. I can see how that might not be the best idea.

Auddii
02-11-2013, 06:40 PM
http://www.audizine.com/forum/showthread.php/190393-DIY-B5-B6-A4-1-8T-Head-Removal-and-Install

In this DIY it looks to me like he just removed the tensioner and took the belt off the cam gear. I would think you would do this and mark the belt as well.

contrldsub
02-12-2013, 05:59 AM
http://www.audizine.com/forum/showthread.php/190393-DIY-B5-B6-A4-1-8T-Head-Removal-and-Install

In this DIY it looks to me like he just removed the tensioner and took the belt off the cam gear. I would think you would do this and mark the belt as well.

marking the belt isnt nessecary, turn the motor til both the cam and crank lines up with the timing marks, the crank mark can be hard to see but its there just left of tdc on the pully. i would recommend doing the timing belt and water pump while your here. as long as your timing marks are lined up when you put tension back on your belt all is fine. if not take it off and do it again. its got to be perfect or you will throw a cam sensor code and go into limp mode. not to mention if its too far off time you will bend valves and such.

i just did this job 3 weeks ago on my 01. i bought a felpro gasket set as ive used them alot and my machinist gets them for me cheap, 140 i think before taxes it was. timing belt set was about 220 for the belt, dampener, idler pulley, water pump. if you have a machinist straight edge and some feeler guages you can check your head for warpage yourself, the tolerance is like .004 - .010. if you dont have a machinist edge take it to the machinist.

clean your surfaces, use new bolts (thats the correct way) and it relieves alot of stress while your torqueing the head down not worrying about breaking bolts.

98A4TurboAWD
02-12-2013, 06:13 AM
marking the belt isnt nessecary, turn the motor til both the cam and crank lines up with the timing marks, the crank mark can be hard to see but its there just left of tdc on the pully. i would recommend doing the timing belt and water pump while your here. as long as your timing marks are lined up when you put tension back on your belt all is fine. if not take it off and do it again. its got to be perfect or you will throw a cam sensor code and go into limp mode. not to mention if its too far off time you will bend valves and such.

i just did this job 3 weeks ago on my 01. i bought a felpro gasket set as ive used them alot and my machinist gets them for me cheap, 140 i think before taxes it was. timing belt set was about 220 for the belt, dampener, idler pulley, water pump. if you have a machinist straight edge and some feeler guages you can check your head for warpage yourself, the tolerance is like .004 - .010. if you dont have a machinist edge take it to the machinist.

clean your surfaces, use new bolts (thats the correct way) and it relieves alot of stress while your torqueing the head down not worrying about breaking bolts.

I'm with you, I didn't mark anything.

However, I do not go by the marks on the crank. The pulley has play in it and is not exact. I took an extendable magnet and stuck it through the #1 spark plug hole. When the magnet reached it's highest point before moving back down, that was what I used for TDC, which was not exact with what the crank said, but it is more accurate because as I mentioned, there is a good amount of play in that pulley.

Auddii
02-12-2013, 02:26 PM
Thanks for the input guys. I think I'm going to replace the belt, tensioner and tensioner pulley and call it a day. The water pump was just replaced 20k back so I'm not really concerned.

This should be a learning experience to say the least but I am ready to get this mofo back on the road.

98A4TurboAWD
02-12-2013, 02:31 PM
Thanks for the input guys. I think I'm going to replace the belt, tensioner and tensioner pulley and call it a day. The water pump was just replaced 20k back so I'm not really concerned.

This should be a learning experience to say the least but I am ready to get this mofo back on the road.

If the water pump was replaced with another water pump with the plastic impeller then I would replace it. Otherwise it is probably fine. I would also buy the tensioner roller for the tensioner just for the hell of it. I think it's like 7 dollars.

Auddii
02-12-2013, 02:43 PM
The all of the tensioners I've seen come with the rollers installed so I've got that covered.

98A4TurboAWD
02-12-2013, 02:47 PM
The all of the tensioners I've seen come with the rollers installed so I've got that covered.


Oh ok, that must be an AWM thing. The AEB tensioners do not come with it. Almost makes up for the fact that your parts are 2-15x the price of the AEB!! [:p]