2005 Audi 1.8T B6 cracked head

[willgibbs77]

Hello,

A few weeks ago I noticed I was getting no heat and car had a coolant smell. Nothing was leaking on the floor but can see the trans was wet with coolant. I found the coolant flange was leaking and also the bottom heater core hose looked like it was starting to tear. I replaced the hoses, coolant flange and temp sensor. Bled all the air out of the system with radiator bleeder funnel and upper rad air release in hose. The car seemed good for about 3 days then noticed no heat again.

This went on for about 2 weeks then the issue kept repeating but never overheated until recently. I overheated 2 times and the thermostat gauge went to 3/4s for about 5 seconds then back to normal once it spit out coolant from the overflow cap. This was done on tests just around the block and I stopped driving it after the second time it did a 5 second overheat. I thought maybe it was a bad cap which did the same thing after replacing with OEM. I did a head gasket test and showed positive blue to yellow so thought it was the headgasket went bad. So i was going to attempt it myself, upon taking the head off i noticed cracks in the intakes immediately then see cracks between the intakes and exhaust on 2-3.

Would overheating twice to 3/4ths on the temp gauge for 5 seconds cause the head to crack like that?

Intake 1
https://drive.google.com/file/d/1Sn3...ew?usp=sharing

Intake 2
https://drive.google.com/file/d/1Rs7...ew?usp=sharing

Intake 3
https://drive.google.com/file/d/1Ak7...ew?usp=sharing

Intake 4
https://drive.google.com/file/d/1mmD...ew?usp=sharing

Vid
https://drive.google.com/file/d/1AJy...ew?usp=sharing

Around 6 years at 130k I had a ton of work done to the car from Audi of Mt Vernon NY which royally ripped me off and never was right since -5k. (very bad experience if anyone is interested) Had timing belt, water pump, coolant flange, MAF, themostat, got the car back and over heated within 10min to full hot and brought the car immediately back to them. They kept the car for about 3 weeks and told me i needed a headgasket which i agreed to. After getting the car back for the second time after the head gasket was done the car seems to lack any power and Audi said they refuse to work on the car anymore and recommended me to rid of it. They offered me $500 trade in value after charging me 5k in repairs which made me furious. The car now has 160k seems like the repairs didnt last so they were right I guess. But whats wierd is i remember the head saying AEB but noticed it doesnt have any markings so Im wondering if they replaced the head back then when they did the head gasket and why it took them 3 weeks. Anyways was going to try and get a used head, attempt the job myself to make the car work again but not sure its worth it.

[Kevin C]

Those are casting marks, not cracks. Also, the crack that you would get are between the valves, and occasionally to the spark plug. I would pull the plugs and see what they look like as well as the piston tops. A combustion gas test for your coolant is also an option.

[egovreau]

What the head should have been stamped with is AMB. The AEB head was a large port head found on early B5 A4's and Passat. Unless your car had been modified with a big turbo, it most likely said AMB.

If there is no stamping now, then they definitely replaced it with a remanufactured head and didn't do a very good job of it if you continue to have problems.

I'm surprised they worked on it at all as these days Audi service doesn't want to mess with something that old.

Any cracks in the head will be most likely be visible on the piston side.

Second the exhaust gas check. You can generally buy them from a parts store.

Second checking the tops of the pistons...if one looks clean, like it's been being steam cleaned, you're definitely burning coolant which would account for the coolant smell and could cause overheating.

You could take your head to a machine shop to have it pressure tested, which is what I'd recommend also.

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[willgibbs77]

Thank you and appreciate the help and will bring it to machine shop to mill and pressure test.

[willgibbs77]

Im bringing the head to a machine shop, looking for advice on what may have happened. I checked the block and head with straight edge and feeler gauge amazingly no warp across jackets, cylinder and diagonal. Whats wierd was the head bolts came off with almost no effort noway seemed torque right. I removed them in the right order in 90 degree turns until all lose. 10 9 8 7 6 5 4 3 2 1,

I do not see any cracks between the exhaust valves or instake. I did notice on cylinder 2 it seems like both exhaust valves are open and the top middle intake seems to have a bit of play, on cylinder 3 the to right 2 intake valves seem to have a little play. Im just wondering why cylinder 2 valves would not be flush and timing marks are lined up on head top and also on the cams.

I also noticed the cylinder tops look like they have a slight exhaust valve mark, I think this may have happened from prior owner before i purchase the car and was in a front end accident but was told head was rebuilt. So im assuming i need a valve job too.

Block with no head gasket
https://drive.google.com/file/d/18Pm...ew?usp=sharing

Block with head gasket
https://drive.google.com/file/d/18OJ...ew?usp=sharing

valve top 1, 2, 3, 4
https://drive.google.com/file/d/18I1...ew?usp=sharing

Valves for Cylinder 1
https://drive.google.com/file/d/1870...ew?usp=sharing

Valves for Cylinder 2
https://drive.google.com/file/d/18F_...ew?usp=sharing

Valves for Cylinder 3
https://drive.google.com/file/d/18-u...ew?usp=sharing

Valves for Cylinder 4 (intake and exhaust look white)
https://drive.google.com/file/d/17yH...ew?usp=sharing

I also noticed the plastic line above the oil filter was cracked and looks like peanut butter from pcv piping to intake. But no other line and oil and head looked very clean inside. I noticed my turbo was leaky too and there is a bit of play. Just curious what people thought and would like to hear some advice. This is all new to me and learning. Im more familiar with 2 stroke and 4 stroke atvs

[Mike Tries]

If there are cracks, they can be very hard to see. Schmoo can fill them and make them a challenge to find, but I don't see any obvious cracks. Your machine shop will tell you for sure.

I can't tell from your images, but if your cams are installed, then some valves may well be open a bit. I think that's fine. Rotate the cams and see if the valves close. If your cams are not installed, then your valves could be bent. Loose valves can be a sign of valve guide wear, but that is something a machine shop can address for you (and even fix).

I wonder if the Audi service tech didn't torque the heads after running them down? They should make a very satisfying cracking sound when you loosen them, and that should take a reasonable amount of effort. It won't be hard, because they are not going to be rusty, but it'll require some effort. If the head wasn't torqued, then you'd have all sorts of issues with sealing the thing. I've never seen this, so I can't comment on what problems you'd have, but the engine running super, duper weak could easily be one of them. In fact, I'd bet money that if I installed a head and didn't torque the bolts properly, I'd lose horsepower if the engine ran at all.

Cylinder 1's spark plug looks.... crusty. What's up with that? You should take that one out and have a gander at it. It looks rusty and corroded.

The pipe coming out of the oil filter housing thingy being broken is pretty common, if that's what you're referring to. Just get a new one. Some members here may have some input on whether there's a good upgrade that will last longer.

Turbos will have a measurable amount of axial shaft play. Fore/aft, that is. They should not wobble all about though. And, the measurable amount of play should be measured with precision instruments because we're talking a few thou. You can feel it move, but it shouldn't move much.

Gang, do these head gaskets ever fail by themselves? I think a head gasket failure is extremely uncommon. They're steel. They'll leak if the head warps or if the surfaces aren't flat enough, but the gasket itself failing? I don't think that's a common thing. It definitely shouldn't happen twice on the same engine all by itself.

Having a service department tell you to buy a new car because the engine that they just assembled for you is all crappy is super shady. Do you have another car you can rely on, and do you like this one enough to put some time into it? If the answer is yes, pull that engine out and refresh the thing. You've already got the head off, so a good deal of one-time-use-only parts have already been committed to the dumpster (all the timing stuff, head bolts, gaskets, etc.). You'll be able to put fresh bearings in it, new rings, get the block freshened up, etc. If you're having trouble sealing the thing, maybe the block has a pit in it around one of the oil or coolant channels (my head had this, actually). You'll be spending some money, but it's not horrendous. I probably spent as much on tools as I did parts when I did mine. Plus, it was fun. But I'm not you. If you really just need to get the thing going again, getting the head inspected and machined may work just fine.

Good luck!

[Puddin Tane]

Those OE hard plastic PCV bits above the oil filter bracket go brittle with age and shatter like glass. It sounds like you need to rehab all that. While the head is off is the perfect time, plus thermostat and J-plug. Billet aluminum for that last. When you **try** to remove the hard plastic PCV elbow from the oil filter bracket you may discover all sorts of fun down inside (hundreds of tiny plastic shards that used to be the elbow). I had my fun a year ago, replaced the entire PCV system with silicone and billet aluminum pieces from 034 Motorsport. The silicone hoses do sweat oil but no worries about brittleness, ever. Having a sound PCV system again has made a noticeable difference.

[egovreau]

If you're noticing the intake valves are not flush then they're in the midst of an open or close stroke and if you take a close look at the intake cam lines, you'll notice that they're not all level. It's by design that the outer valves open and close slightly off from the middle...it's by design. As to why, I'm not sure.

Same goes for as to why the exhaust valves are open. The exhaust cam is just at that point.

If you pull the cams from both sides, the valve springs should pull all valves closed. If you still have valves open with cams removed, it's likely the valve guides are bent for those valves.

It's not usually a big issue if there's indication of valve strikes in the piston crowns, so long as you can verify the connecting rods aren't bent (the pistons will end up being lower than they should be at the top of their stroke).

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[Kevin C]

Nice photos. Typically the cracks are very obvious by the time they hit water. Things to check are that the head is flat. As far as the turbo goes, some axial and radial play is normal since its a floating bearing. A dry bearing feels worse. A good indicator of an issue is if the wheels have hit the housing. On a severe overheat the heads expansion can increase the strain on the head bolts so that they yield. The head cools off and the reduced clamping force allows it to leak. My experience on the valves is that all three intakes are timed the same. The cam lobe on the center looks like it in a different spot, but the lifter buck is also displaced. That's because the valves are in different location in the head.

You can confirm the valves by rotating or removing the cams and pouring fluid into the chamber. If you have a bent valve the leak will be obvious. There is a spec for the amount of play in the valves. It's typical that the exhaust guides are out of spec. The intakes seem to hold up quite well.

[willgibbs77]

Thank you for all the help and replies. The head was milled and pressure tested by machine shop. It Passed pressure tests and was ok. I was told there was a good amount of warp between the middle two valves which i noticed too when checking with flat edge. Finally got everything together and so far knock on wood everything has been working well. This was my first attempt at a head gasket, timing belt, waterpump, thermostat, did a aluminum coolant flange and jplug this time and took me like 20hrs :) Also had to replace a bunch of cracked plastic elbows, and noticed some lines had tears and small rips. I cleaned out all the lines with the peanut buttery looking sludge (oil/condensationmix) that looked like peanut butter. which was only in the line from back of intake to the pcv. Nothing was in intake, head or pcv and looked clean.