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Jake
Jake, VW Technician
Category: VW
Satisfied Customers: 2399
Experience:  Over 30 years experience with VW, Audi, BMW. Factory trained, former Shop Foreman, Service Manager
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White smoke and engine tapping after timing belt/head gasket change?

Customer Question

White smoke and engine tapping after timing belt/head gasket change?
Submitted: 2 years ago.
Category: VW
Expert:  Tim's Auto Repair replied 2 years ago.
hi
why did you replace the timing belt?did it break?
did you replace the head gasket,or,did you check it,,if you checked it,please explain
do you ever need to add coolant?
please.tell me all you can
thanks
Customer: replied 2 years ago.
Hi, sorry for lack of detail. I thought I would have an opportunity to expound on it before it was submitted.

Anyway-I just bought this car, and assumed it needed a head gasket. Its got 160k on it. There was an obvious coolant leak (could see it drip on the passenger side of head), white smoke, and low compression. It also ran a bit rough, but the engine sounded strong (no knocking or anything).

I changed the head gasket and the coolant flange on the back of the head (where I think the visible drip was coming from). While I had the lock carrier in the service position, I figured I would swap the timing belt/water pump/tensioner, as well as the a/c and serpentine belt, just for maintenance sake.

I timed it by the factory marks, and spun the engine by hand about 20x (I was paranoid I'd mess it up). It consistently lined up on both the crank pulley and cam sprocket.

This morning I drained the green coolant (going to add G12), and started the car for the first time since the work I'd done to get the thermostat open. It fired right up, but had a loud tapping noise coming from (I think) the top of the engine. After a minute, white smoke started to come from under the turbo. I gave it a little bit of gas, and after a minute white smoke started coming out the back of the car.

On the advice of someone on a forum, I checked the oil pressure tonight at the sending unit port. I forgot to let it warm up (I can try it again tomorrow if it matters), but at start-up I had 35 lbs at idle and 60 lbs when I revved it to 2500 rpms. Oddly enough, the engine tapping stopped when I got above about 1500 rpms (that's a guess-I wasn't watching closely).

I was wondering if the top of the engine wasn't getting oil (causing the tapping) and the turbo was also not getting oil (causing the smoke). Is it possible to have good oil pressure at the sending unit and still have a blockage somewhere that prevents oil from getting everywhere?

Forgot to mention that I checked compression this morning. I had between 150 and 160 lbs on all 4 cylinders.

So yeah-I'm stumped. Thanks for your help!
Expert:  Tim's Auto Repair replied 2 years ago.
hi
did you machine the head[shave it] before you reinstalled the head?
how long did you let it run?
Customer: replied 2 years ago.
No, I didn't have it machined. It looked to be in good shape, so I just cleaned off the old gasket material and reinstalled it to the correct torque specs.

I've started it maybe 6-8 times. It's run for less than a minute each time-some of the times for only a few seconds. I've been scared to run it for longer, but the fact that the tapping goes away at higher rpms makes me think that the valves are ok.

Forgot to mention that compression before I pulled the head was between 110 and 130 lbs per cylinder, and now its between 150 and 160. There never was any mixing of coolant and oil.

Also-I checked the codes 3 times this afternoon. I didn't clear them in between readings, nor did I run the car for very long-so I have no idea how accurate they are. The first time it gave me 0354, 0353, 0351, 0302, 0300, 0352, and 0102. The second time it only gave me 0302, 0300, 0352, and 0102. The last time it gave me the same as the second read, but it added 0301.
Expert:  Tim's Auto Repair replied 2 years ago.
ok
you should always shave the head when replacing a head gasket on an aluminum head engine,,the head will always be warped when removed,,,
with that
you need to start it up and let it run,,,,,,bleed the air from the cooling syatem...it is common for the engine do blow white smoke when repairing a head,,,,,this is steam from maybe some coolant in the exhaust and condincation,,,,,let it warm up,,it is also common to get a tapping sound after the head has be removed and reinstalled,,,because of the hydrolic tappets have bled off and needs to build up.........
you will need to let it run,,,,im not thrilled about the head not being shaved,,though,you may be lucky
thanks
Customer: replied 2 years ago.
ok. I'd be surprised if the head is warped just because of the compression difference between the before and after of the gasket replacement. If i had to do it over again I would get it machined, but I doubt that's the problem. that makes sense about the tapping. do you think i need to check the oil pressure again? also-that doesn't explain why white smoke was coming from the bottom of the turbo. I'm wondering if this is a separate issue, though, like maybe seals going bad in the turbo. how long should I let it run for?
also forgot to mention-after running for about 20 seconds the turbo was hot to the touch.
Expert:  Tim's Auto Repair replied 2 years ago.
well
you could check the pressure again.if it worries you..the turbo will get hot,it has exhast going through it...the whie smoke is steam,,,again,it may just be from dampness inside the exhaust pipe..you need to let it run long enough to get the exhaust hot and the engine is at tempeture..it is possible for you to have a leak in the turbo,,but,if it didnt do this before,,it should be fine now
thanks
Customer: replied 2 years ago.
how long do you think i should let it run for?
Expert:  Tim's Auto Repair replied 2 years ago.
well
you need to let it get hot,,maybe 20-30 minute,,just keepyour eyes and ears on it
thanks
Customer: replied 2 years ago.
Relist: Incomplete answer.
Questions not answered thoroughly. Not sure this expert has much experience with volkswagen.
Expert:  vwtech0405 replied 2 years ago.
Welcome to Just Answer!!!

Ok am here to help you i work on these cars 6 days a week so i know whats going on , the smoke was there before the head gasket replacement? ever since you bought it right ??
Customer: replied 2 years ago.
Right, exactly. It smoked a bit from the back (and I THINK) from the turbo area, but I assumed that was from the bad head gasket and the turbo area smoke was from coolant splashing on hot metal (maybe the exhaust manifold).

Good head gasket now, though, and no coolant splashing yet there is still lots of smoke, not to mention the tapping.
Expert:  vwtech0405 replied 2 years ago.
Ok these engines are very common to have oil sludge issues there are so many cases like your more then likely the engine was starved from oil pressure before you even received the vehicle i can bet you that the oil pump pick up tube is clogged and not supplying the upper cylinder head of the engine enough oil and your lifters and the cam chain tensioner are making the noise you are hearing and hopefully the turbo is not shot because of lack of oil pressure where the turbo seals are leaking oil into the exhaust and causing the smoking issue. I recommend you remove the cam caps and check for abnormal wear on the cam bearings if those check out you will need to drop the oil pan and replace the clogged oil pick up tube and retest everything hopefully its not too lat and you will need a new turbo if the smoking does not stop . I hope this helps.

Feedback and bonuses are appreciated this is the only way i get compensated for my time and knowledge thank you !!
Customer: replied 2 years ago.
ok, that makes a lot more sense and correlates to what I thought.

1) what sort of wear amount is normal on the cam bearings? what should it look like if things in the top of the engine are starting to fail?

2) I did an oil pressure test today and it checked out good (though I didn't wait for it to come up to temp because of the tapping). Is it possible to have good oil pressure at the sending unit and still have a plugged pickup tube? should I also replace the oil filter?

when i bought it the engine sounded strong, so i doubt much damage (if any) had occurred at that point. the turbo might be another story, though.
Expert:  vwtech0405 replied 2 years ago.
1) If the cam bearings are severly scored then thats not good , if you see the cam chain tensioner guide worn down or broken this is a sign of wear due to low oil pressure.

2)Usually oil pressure checks out when checking it and still have the oil pick up tube clogged its a very common issue in the 1.8 turbo engine .

I hope this helps.


Feedback and bonuses are appreciated this is the only way i get compensated for my time and knowledge thank you!!
Customer: replied 2 years ago.
ok sounds good. do you mind if i wait until tomorrow before accepting so I can check this stuff out? thanks!
Expert:  vwtech0405 replied 2 years ago.
You can accept now or tomorrow whatever you choose i can still help you after the accept on this issue
Customer: replied 2 years ago.
great, thanks. I'll accept tomorrow after I check into those things.

One more thing if you get a chance-my oil pressure warning light is not on, at least not in the few minutes that I've run it. Does that undermine the lack of oil argument? And why did the tapping stop at higher rpms?

thanks a lot!
Expert:  vwtech0405 replied 2 years ago.
The oil light usually comes on when the car is hot and after a couple of minutes of test driving the vehicle . Check the cam chain tensioner that may be your tapping noise .
Customer: replied 2 years ago.
Ok, I pulled the valve cover this morning. Everything seems fine-no sign of damage or abnormal wear. I still need to check cam bearings though since I wasn't sure what to look for. I'll do that shortly. I have 16 rollers between the cams, and the timing marks seem to line up (they're both within the square mark, though they aren't exactly the same). I cranked the engine by hand and the valves and cams all seemed ok to me.

However, the cam chain tensioner seemed a little odd. It make some strange noises as I cranked the engine, and it seemed to have a bit of play. At certain points in the rotation the chain was more slack than at other times. How do I diagnose a bad cam chain tensioner? Is it possible that it would start working again if I had an oil delivery problem that was fixed?

Also, is there any other way to diagnose a plugged oil pickup tube without dropping the pan? Everything I've read on this motor makes it sound like dropping the pan is nothing short of awful. It looks like the pan has been dropped before, since there is red silicone smeared all over the place.

Expert:  vwtech0405 replied 2 years ago.
The adjuster will have play check the guides on it, remove the cam caps this will show wear if you have any . There's no way to test the screen the pan will need to be dropped to physically check the screen . The adjuster works off oil pressure hard to test when without hearing it, Yes it can work again because more then likely the oil pressure is low but may be damaged due to low oil pressure . I hope this helps .

Feedback and bonuses are greatly appreciated thank you
Customer: replied 2 years ago.
Checked cam bearings-they all look good with no grooves at all.

However, on closer inspection I found a broken plastic piece of the lower guide on the cam chain tensioner lying down behind the chain. Would this prevent it from working correctly?

The fact that the pan has obviously been pulled before makes me wonder if the screen was cleaned or replaced already. I'd really like to try to check oil pressure some other way...could I unhook the supply line to the turbo and check it there or something?

Right now I'm thinking that one of two things are happening/have happened.

1) cam tensioner broken from normal wear and tear, smoke from turbo a separate turbo issue. oil pressure good.

2) low oil pressure made the tensioner break and is causing turbo smoke/failure.

I don't really understand how I can have good oil pressure at the sending unit if the pickup tube is plugged. Every time I've run low on oil I've seen the pressure drop (I had a truck with an oil leak :)) Can you explain how this could happen?


I'm happy to accept but I need to be sure that I can continue the conversation. thanks!
Customer: replied 2 years ago.
Relist: Other.
expert was good and we were in the middle of figuring out my problem. I was ready to accept, then he vanished and the status changed to "finished." Except we're not finished.
Expert:  Jake replied 2 years ago.
Hello,

I have reviewed your questions and I think I can help you better understand and get your questions answered.

Let me start with a brief description of what's going on with the "oil sludge" problem.

A common issue on all 1998 - 2005 1.8T motors (AEB, ATW,AWM, AUG) in all VW and Audi models is commonly referred to as “the sludge issue”. I believe some confusion lies is in the term “sludge”. I have always taken issue with the use of this term to describe the condition. I think this is translation error from German to English. The issue is oil deposits, in the way of black flakey particulates, building up on the inside walls of the crankcase and crankcase ventilation system. If you remove the oil filler cap and look at the underside you will likely see the buildup of these deposits. Over time these particulates flake off and work there way down into the oil pan eventually plugging the oil pick-up screen. This restriction in turn restricts the passage of oil to the point where oil pump can no longer supply the specified quantity of pressurized oil to the system. The oil pressure warning system, picks up on this lack of pressure, illuminates the light and sounds the warning.

After confirming that there is an oil pressure issue the extent of damage to the engine, if any, is determined by inspecting the camshaft journals (bearing surface) for any signs of lubrication failure. This is the first component to get damaged if oil starvation was excessive. If the journals are OK repairs would consist of cleaning the crankcase, replacing the oil pickup tube with strainer or pump/strainer assembly, replace oil feed line of the turbocharger, replacing ALL crankcase ventilation system hoses, pipes and pressure regulating valve as described in the service bulletin. Then a special engine flushing system would be hooked up to the lubrication system and flushing procedures would ensue. After which the vehicle would be restored to running condition. Only synthetic oil with the VW 502 00 grade standard should be used.

This complete cleaning of all deposits and replacement of the oil pickup screen/tube is essential! This complete cleaning of all deposits and replacement of the oil pickup screen/tube is essential! (this was not a "typo")

I this particular case the turbo is likely failed and will require replacement, as well as the oil supply line going to the turbo. Do not do this unless you have done the complete cleaning. You can confirm the failed turbo by inspecting the charge pipe between the turbo and intake manifold. If there is oil puddled in the low spots, the turbo is failed. Also, if this is the condition do not idle the engine for extended periods as the "pooled" oil can be picked up when accelerating and "hydrolock" the engine. If you would like you can wait until after the complete cleaning to replace it as the damage is done.

Now to answer your last questions;

Right now I'm thinking that one of two things are happening/have happened.

1) cam tensioner broken from normal wear and tear, smoke from turbo a separate turbo issue. oil pressure good.

2) low oil pressure made the tensioner break and is causing turbo smoke/failure.


OK, 1) would be correct. This is likely a separate issue.

I don't really understand how I can have good oil pressure at the sending unit if the pickup tube is plugged. Every time I've run low on oil I've seen the pressure drop (I had a truck with an oil leak :)) Can you explain how this could happen?

When you remove the pan and the pickup tube you will see the screen that filters the oil before it is drawn into the pump. Out of maybe 500 holes made by the mesh of the screen, you might have all but a dozen that are open. The rest will be plugged. So at idle or low speeds there is enough area for the oil to pass through and the pump puts out sufficent pressure. When the vehicle is driven, and the speed increases the volume of oil required is increased. The volume available through the restricted screen is insufficient and the pump "starves" for oil and the light comes on. Sometimes this only happens after extensive driving, as more particles are picked up from the bottom of the pan and further restrict the screen. This is VERY COMMON I would not even consider proceeding without removing the pan to replace the pickup tube and doing an intensive cleaning. VW and Audi even recommended after ALL recommended replacement of crankcase components and cleaning, that after driving the vehicle for awhile, remove the pan once again and clean the screen. This step was eliminated when they introduced their engine flushing system.

Should you have further questions on this matter, please do not hesitate to ask. I want you to be 100% satisfied with my answer.

Positive feedback, referrals and bonuses are always APPRECIATED! If you accept MY answer please don't forget to leave feedback.

Thank You!
Jake “The VW Doctor”







Jake, VW Technician
Category: VW
Satisfied Customers: 2399
Experience: Over 30 years experience with VW, Audi, BMW. Factory trained, former Shop Foreman, Service Manager
Jake and other VW Specialists are ready to help you
Customer: replied 2 years ago.
Ok, awesome, thanks for your explanation. I'll start with dropping the pan and inspecting the screen. I'll also see what I can see on the turbo.

I'm wondering about the tensioner. If the triangular piece on the end of the lower guide is broken, does that mean the tensioner is no good? Should I try to get the oil issue fixed first and see how it does, or should I just bite the bullet and replace the tensioner?

Thanks again! XXXXX accept your answer, can I still ask you a few questions as the process goes along?
Expert:  Jake replied 2 years ago.
Ok, awesome, thanks for your explanation. I'll start with dropping the pan and inspecting the screen. I'll also see what I can see on the turbo.

Your welcome, glad to do it!

I'm wondering about the tensioner. If the triangular piece on the end of the lower guide is broken, does that mean the tensioner is no good? Should I try to get the oil issue fixed first and see how it does, or should I just bite the bullet and replace the tensioner?

If you are going to keep the vehicle you are going to have to "bite the bullet" and do it all eventually. But, before you proceed BE SURE that the cam journals are not damaged. Typically the journals on either end are damaged first.

Thanks again! XXXXX accept your answer, can I still ask you a few questions as the process goes along?

Yes, you can accept now and still ask me questions at anytime in the future as you always have, just so long as you do not manually "close" the question it will remain open.

Thank You and Best of luck! Check back with me at any time.

Jake "THE VW DOCTOR"
Customer: replied 2 years ago.
Yup, checked cam journals and they seem fine. no grooves or anything.

i'll go ahead and drop the pan and try to clean the sludge out as you suggested, and see if that fixes the tensioner and turbo. if not, i'll replace those.

thanks again!
Expert:  Jake replied 2 years ago.
Your very welcome!

Good thing on the journals. Seriously consider doing MORE than simply cleaning the sludge out. If you see evidence of the "flakey" deposits, ALL the crankcase hoses should be replaced (can you see it caked in the elbow hose on the back of the valve cover?). Also, the oil separator under the intake manifold typically has a lot of deposits.

Thank You!
Jake
Customer: replied 2 years ago.
When I pulled the head I had to obviously pull a lot of hoses. I saw little to no evidence of deposits in the hoses. The underside of the valve cover has some, but not nearly as much as some pictures I've seen online.

The top half of my dipstick tube is broken off (got another one coming), plus the rtv used when the last guy pulled the oil pan is kind of messily applied. There may well be deposits on the screen, but I wonder if there are plastic pieces from the dipstick tube and/or chucks of rtv that are causing all or some of the problem.

I'm also going to replace the oil filter while I'm at it...I think the one on there now is the smaller sized filter.
Expert:  Jake replied 2 years ago.
Hope for the best and inspect it. I have seen large amounts of RTV block the screen. Be aware of where the RTV seals the pan on the right rear corner (by the starter) when it goes back together. Get a SMALL bead of sealant along the entire pan and around each bolt. Don't over do it.

Thanks!
Jake
Customer: replied 2 years ago.
Quick question for you- today I started to pull the oil pan, but first I pulled that big sensor out of the bottom and looked inside with a flashlight. It seems very clean-some deposits but not much. I think someone has pulled it before to clean the sludge, although it might be clogged again.

However, when I drained the oil, it was NASTY. Black and mixed with coolant from (i assume) the head gasket problem. I could easily see that thick coolant mixture clogging the filter and/or pickup tube.

I'm wondering about filling it up with some cheap oil and maybe some sort of additive, replacing the filter, and trying to run it.

Have you ever seen coolant/oil mixes cause clogged pickup screens? If I pull the pan and the screen is good is there anywhere else that might be causing low oil pressure to the head?
Expert:  Jake replied 2 years ago.

I realize it's tempting not to pull the pan... But DO IT. Often times the pan looks clean, just the holes in the screen are plugged as it free floating contaminants in a apparently clean pan that plug the screen.

DO NOT USE ANY TYPE OF A CRANKCASE FLUSHING ADDITIVE! This breaks free the debris and... You know where it ends up?

I suspect when you remove the pick up tube and you shine a flashlight through it you won't see many open holes. I have done it too many times to believe this one won't be plugged. And you won't know, until you know. Do you want to risk a $ 1,000 worth of turbo charger on it?

Jake

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