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Blown turbo? Maybe?

1131

New member
I apologize for jumping in with such a long first post but...

I have an 07 MKV GTI 140K BPY. Bone stock. No tune. It had been making a low, flute-like noise on acceleration for a few months, but other than that no other noticeable symptoms. Then a few weeks ago the whistling noise went away and was replaced by a metallic rattling sound that kind of goes away after the first few moments of the car running. The car was producing abundant smoke from the exhaust and the engine eventually cut out.I was unable to restart because of an EPC condition which I've since come to learn is due to the spark plugs being completely charred.

It's now demonstrating many of the "classic" symptoms of a failed PCV. There is oil pretty much everywhere. It's seeping out of both ends of the upstream (but not downstream) intercooler pipe. There is oil dripping down onto the drive axle. It's in the combustion cylinders fouling the spark plugs as previously noted.

Error codes pulled from the Torque app are the ones you would expect for misfiring spark plugs as well as boost leak (P0299), system too rich (P0171), as well as too lean (P0172). I also get intermittant P0506 and P0106 which I assume means my MAP sensor and throttle body need a good cleaning when this is all resolved. But they're not the main problem.

I replaced the DV with the latest revision which of course had no affect. The old plunger style DV I removed was perfectly fine other than the fact that it was covered in oil.

I replaced the PCV with the latest revision from Beck Arnley and it actually made the problem even worse. I even purchased a different PCV from Vaico just in case there was a defect in the first. Still worse than the original. So I've put the original PCV back on.

I changed the valve cover with a used one off ebay. No improvement. The valve cover came with yet another old style PCV. All four PCVs pass the "blow test." I feel resistance when blowing on the input end.

I've done an engine compression test and the result was 190 psi in all four cylinders. The engine should be good.

At this point, I've reluctantly decided that it's probably a blown turbo. With the engine cover removed, I can just barely reach back and under the turbo's exhaust manifold and feel the waste rod actuator arm. It seems to be firm. I'm thinking that the rattling noise on start is an important clue. Maybe part of the compressor has broken free. I have a no way to know without removing the turbo. And if you're removing the turbo, you may as well replace it.

The car is driveable. But barely. It struggles to make power. I can drive at low speeds for short distances. Any hard acceleration at all produces smoke and is liable to barbecue the spark plugs. I've gone through three sets already. They're cheap, but it starts to add up. I've also burned through a whole jug of nice 0W40 Pennzoil Euro. I've temporarily switched to Amazon Basics 0W40 Euro until I can get things sorted.

I've been reluctant to take it to a VW dealer because they'll take one look at the smoke coming out of the exhaust and say oh yeah, that's a blown turbo -- since that would be the most expensive (and potentially most lucrative) repair. My fear is that they will collect an easy $125 diagnostic fee without doing a lick of work.

So I've gone ahead and ordered a used, low mileage K03 turbo taken from another VW with a BPY engine. I'll find someone to install it, but before I do, I thought I'd quiz the forum members for anything I might have missed in either my thinking or analysis that should give me pause before pulling the trigger on the turbo replacement.

Indebted for any help provided.
 
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1131

New member
I find it interesting that installing the newer P revision of the PCV made things worse. It kind of lends credence to the claim that you should change the rear PCV to the latest revision (with the extra check valve) if you're going to update your front PCV.

I think my next trip should be straight to an installer, but if I should need to continue driving it, and if I understand how my car works, I'm thinking maybe it would be a good idea to disconnect the PCV breather tube and block off the path to the intake manifold. I could disconnect the rear PCV in the same way, collecting everything in a can. The crankcase would then be entirely VTA. Not good for the environment, but would probably leave me less liable to get pulled over by a cop for doing a bad impersonation of a Bond villain. It would still smoke though since the turbo still has its own oil lines.
 

vwengineer

Ready to race!
Location
Switzerland
It could be a blown turbo based on your symptoms, just know that these turbo leak oil "by design", therefore it's normal to find SOME oil in the intercooler piping. If the turbo is blown, before replacing it, be sure to find the cause of the failure, usually a lack of lubrication, I would check turbo oil hoses and see if they are clogged, as well as the oil pickup. Have you ever been low on engine oil? Is the electric water pump working correctly? Is the thermostat from the turbo to the radiator not stuck closed?
 

ROH ECHT

K04 PLAY
Location
PDX OR
Ride
2007 MKV GTI
There are problems with aftermarket PCV's. A local guy came to me to help discover why his made no boost. Could've been many reasons of course, but the first thing I saw was that the PCV he had just installed was "aftermarket". I disconnected the corrugated tubing to it from the intake manifold and blew into it. It leaked even though it was new. Inside the PCV is a "check/anti-return" valve that should close when boost is present in the intake manifold. The whistling noise could be anywhere along the boost system between the intake to the throttle-body. Could be a failed DV, cracked N75 boost control valve, both are mounted on the turbo. Could be a cracked PCV tubing, that one I mentioned...or even a cracked intake manifold. A smoke test may help if you get to a point where you have done all you can in visually inspecting it all.
 

1131

New member
It could be a blown turbo based on your symptoms, just know that these turbo leak oil "by design", therefore it's normal to find SOME oil in the intercooler piping. If the turbo is blown, before replacing it, be sure to find the cause of the failure, usually a lack of lubrication, I would check turbo oil hoses and see if they are clogged, as well as the oil pickup. Have you ever been low on engine oil? Is the electric water pump working correctly? Is the thermostat from the turbo to the radiator not stuck closed?
Thanks for the response. I understand that some blowby oil collects in the intercooler hoses, but this is WAY more than should be normal. Is it possible to check the turbo hoses with it still on the vehicle? I put it up on stands, and the only part of the turbo I can reach from under the car without removing a whole bunch of other stuff would be DV. If I have to remove the turbo just to inspect it, I think I should replace while I'm there.

And if it were the coolant or oil lines, that wouldn't really explain the noises I heard, does it? Whistling before. Rattling now. Something done physically broke sounds to me.

The only time I'm been low on oil is AFTER the incident -- now that it's blowing smoke at a prodigious rate. I've seen the oil pressure low light a couple of times and have pulled over to add oil each time. In fact, that has been one of the frustrating things about this whole event -- that there was such little warning in terms of CELs. Most of the DTCs are effects, not causes. ie the dirty plugs, MAP, and TB are a result of the incident causing large amounts of oil to be burned in the turbo. The only code that's believably upstream of the others is P0299 -- boost leak.

I assume the water pump is working correctly or there would a slew of other warning lights. There have been none.

I'm not sure of the location of the temperature sensor between the turbo and the radiator. Does it have a part number I can look up? Is it easy to reach and swap? Again, wouldn't that throw a whole bunch of other codes?
 

1131

New member
There are problems with aftermarket PCV's. A local guy came to me to help discover why his made no boost. Could've been many reasons of course, but the first thing I saw was that the PCV he had just installed was "aftermarket". I disconnected the corrugated tubing to it from the intake manifold and blew into it. It leaked even though it was new. Inside the PCV is a "check/anti-return" valve that should close when boost is present in the intake manifold. The whistling noise could be anywhere along the boost system between the intake to the throttle-body. Could be a failed DV, cracked N75 boost control valve, both are mounted on the turbo. Could be a cracked PCV tubing, that one I mentioned...or even a cracked intake manifold. A smoke test may help if you get to a point where you have done all you can in visually inspecting it all.
Thanks for your response as well. But is it possible that all four of the PCVs that I've tried are bad? All four pass the blow test. The whistling noise is exactly what lead me to suspect the PCV and try replacing it more than once.

Cracked N75 sounds intriguing. I have the same response as I had to vwengineer. It's very very hard to reach any part of the turbo other than the DV. (With great effort I was able to reach the waste gate actuator arm by feeling around blindly under the heat shield from the top of the car. No significant play.) I think I'd have to pull the turbo out to even look at it. What are the ways that an N75 can fail? Wastegate stuck open? Stuck closed? Could either condition lead to large amounts of smoke out the exhaust?

A smoke test might not be a bad idea. Ebay just sent me a $15 off $75 Q so now might be the right time to get a little smoke machine. But what would I use as the input port for the smoke? The PCV coupler hose? The valve cover breather hose?

In any case I still have some time to work on the problem since I still need to solicit bids for the new(er) turbo installation and then actually raise some funds to get it done. I really should have set aside some money for things like this. I mean, 140K really is an impressive run for a turbo, I think. I'm not even mad if that's what it is.
 

vwengineer

Ready to race!
Location
Switzerland
I am not sure if you can easily get to the turbo oil feed lines, but in the process of replacing the turbo I would do a complete diagnostic.

The electric water pump only circulate coolant in the turbo after you switch off the engine, to prevent the oil from cooking in the hot turbo (which in turn leads to lubrication problems). It is not essential for the engine to work but I think you are right that it would register an error if it is not working.
 

1131

New member
I think I'm going to forgo the smoke test. It turns out ebay sent out the $15/$75 Q's in error. Plus. I kind of sort of already have a smoke test built into the system. The turbo is already generating such a large amount that it comes billowing out if I remove the oil filler cap or the dipstick. Any other leaks would be immediately obvious. If there is a leak in the system it would have to be a vacuum leak. Is there a kind of vacuum leak that would lead to large amounts of smoke in the exhaust?

I think the symptom that has me the most baffled is the fouled spark plugs. I've been removing them and wiping them off periodically. I've even tried cleaning them with a brass brush -- but I don't really recommend that as anything other than the desperate measure that it is. You're liable to do just as much harm as good. I did notice a large amount of motor oil pooling in the #2 cylinder. So much that it covers the end of the coilpack and drips off the spark plug socket. How can there be a leak in the #2 cylinder if the compression is still 190psi? My decision to try and save the car is predicated on the engine and transmission still being good. As much as I love my car, if either of those systems is also faulty then it might be time to consider letting her go. I went ahead and ordered a new valve cover gasket just in case I pinched mine while swapping the valve cover. It's such a cheap part. Why not. But my ECM swears it's the #1 spark plug that misfires the most frequently -- and all four spark plugs look charred. There is something pumping motor oil into the combustion chamber -- or dripping it down into it.

And the other two important clues are the sounds. Whistling before. Rattling now. Oh, and it does smoke immediately even from a cold start. There's only one thing in our cars that's capable of producing smoke as soon as you turn the key -- and that's the turbo. I would estimate that it is consuming about a quart of oil every seven miles or so. I know I know. Stop driving it.

I've priced out turbo replacement from two dealers and two independent shops. One dealer quoted $3600 and refused to do the replacement with a used turbo. Keep in mind that the blue book value on my car (if it weren't smoking) would be around $2K. The other dealer quoted $2600 or $1300 labor only -- but strongly advised against swapping in a used turbo. The independent shops were only slightly less unreasonable. $900 and $650.

My greatest fear is that after spending so much to replace the turbo, it still might not fix the problem. So I'm looking over this DIY on Pelican and am thinking about doing the job myself.


I have all the tools including the oddball triple squares. Still, it will be the most ambitious project I've ever done. If I fail, the fallback would be to push it into one of the independent shops and have them take over. I'm now just waiting for the FSI gasket kit to come in. There are very few places that sell a complete FSI/TFSI gasket set. ECS is out of stock. USP Motorsports website says it's in stock, but you get a popup telling you it's out of stock when you click to complete the order. But your PayPal still gets charged. You then get an e-mail telling you that the gasket kit will be ready to ship -- 8 days BEFORE you placed the order. I e-mailed them and they reassured me that it was just a system glitch, that they do have it in stock, and that it will be out to me shortly. So if I can get it by Friday (which I'm kind of doubting) I'll have this entire weekend ruined trying to do the swap. The one thing that bothers me about this kit is that it doesn't appear to include the mounting bolts for the turbo. I thought those were single use?

I'm visualizing doing the swap successfully and what a feeling of accomplishment I'll have when it's done.
 

vwengineer

Ready to race!
Location
Switzerland
I don't understand how you get oil on the coils if it's not coming from the valve cover gasket? As for the compression test, if you have that much oil in the cylinders I am not sure if it's relevant since oil will act as a seal and allow the compression to be higher than when "dry". But the most obvious thing is that if the turbo is dumping so much oil in the air intake, then the oil in the cylinder comes from the intake valves and not from the crankcase.

When installing the turbo, the most important thing is to fill the turbo with oil before installing it, be sure no dirt gets inside and check your oil lines. Before starting then, disconnect all the coils so that the engine but doesn't start as you will want to build oil pressure before spooling the turbo. Then when you start the engine, let it run a minute or two before reving it.

By the way, if you don't want a used turbo, you can buy an aftermarket one on aliexpress, I am not sure what is the best solution but I heard they work on some French forum (and chances are you just need the CHRA, not a complete turbo if the wheel did not contact the housing). That's about 100$ on aliexpress, or 400-500$ for OEM.
 

vwengineer

Ready to race!
Location
Switzerland
Also if you lose that much oil, don't drive the car because that leak lowers the oil pressure globally and you might ruin the engine without being low on oil
 

1131

New member
I don't understand how you get oil on the coils if it's not coming from the valve cover gasket? As for the compression test, if you have that much oil in the cylinders I am not sure if it's relevant since oil will act as a seal and allow the compression to be higher than when "dry". But the most obvious thing is that if the turbo is dumping so much oil in the air intake, then the oil in the cylinder comes from the intake valves and not from the crankcase.
Right. I'm like, 90% sure the oil is coming from the VC gasket. I just received a new one and will be installing it while replacing the turbo.

When installing the turbo, the most important thing is to fill the turbo with oil before installing it, be sure no dirt gets inside and check your oil lines. Before starting then, disconnect all the coils so that the engine but doesn't start as you will want to build oil pressure before spooling the turbo. Then when you start the engine, let it run a minute or two before reving it.
Thanks. I have seen warnings to that affect on other turbo replacement threads. Always good to be reminded.

By the way, if you don't want a used turbo, you can buy an aftermarket one on aliexpress, I am not sure what is the best solution but I heard they work on some French forum (and chances are you just need the CHRA, not a complete turbo if the wheel did not contact the housing). That's about 100$ on aliexpress, or 400-500$ for OEM.
I've been cautioned against buying Chinese turbos. Something about the wastegate duty cycle being just different enough that it requires a tune to smooth (plus, allegedly higher failure rates.) When you add the cost of a flash to the cost of the Chinese turbo, you don't really come out ahead. I decided that it's better to buy a used , relatively low mileage OEM turbo from a car with the same engine code. The one I got appears to have been made in Hungary. I understand what you're saying -- that the faulty part sounds like it will be the compressor wheel, and a cartridge swap might have been sufficient, but 90% of the "cost" of a turbo swap is in labor. I have no idea what I'm gonna find .So if I'm deep in there, I may as well replace the whole thing.

In any case, and in full defiance of Murphy's Law, the gasket kit came in. So I have all night tonight to cram and mentally prepare before I go at it tomorrow and Sunday. It shouldn't take more than two days even if everything goes wrong. I hope? I have a feeling I'm going to learn a lot about my car this weekend.
 

1131

New member
Also if you lose that much oil, don't drive the car because that leak lowers the oil pressure globally and you might ruin the engine without being low on oil
Right again. I was mostly curious about using oil consumption as a possible diagnostic tool. My feeling is that a bad PCV or VC should produce only a little bit of smoke and some oil consumption. A quart per 7 miles is an alarming rate of consumption. I'm pretty certain there is something more serious going on, and I'm about to find out what.
 

1131

New member
So. Just for gits and shiggles, I did a test. I hit the turbo with a pry bar with striking cap several times near the mounting bolts -- where the compressor and waste gate live. The smoking has stopped. I still can't boost worth shit, but at least I can see the cars behind me now as they change lanes to pass me on the tiniest hill. Was the compressor wheel rubbing the housing and now temporarily freed? Or did I kill the compressor altogether with my love taps? I guess I'll find out in the next few days. But I'm more certain than ever that I'm on the right track.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Ride
2007 MKV GTI
Thanks for your response as well. But is it possible that all four of the PCVs that I've tried are bad? All four pass the blow test. The whistling noise is exactly what lead me to suspect the PCV and try replacing it more than once.

Cracked N75 sounds intriguing. I have the same response as I had to vwengineer. It's very very hard to reach any part of the turbo other than the DV. (With great effort I was able to reach the waste gate actuator arm by feeling around blindly under the heat shield from the top of the car. No significant play.) I think I'd have to pull the turbo out to even look at it. What are the ways that an N75 can fail? Wastegate stuck open? Stuck closed? Could either condition lead to large amounts of smoke out the exhaust?

A smoke test might not be a bad idea. Ebay just sent me a $15 off $75 Q so now might be the right time to get a little smoke machine. But what would I use as the input port for the smoke? The PCV coupler hose? The valve cover breather hose?

In any case I still have some time to work on the problem since I still need to solicit bids for the new(er) turbo installation and then actually raise some funds to get it done. I really should have set aside some money for things like this. I mean, 140K really is an impressive run for a turbo, I think. I'm not even mad if that's what it is.
Yes, it may not be the PCV, I only mentioned it because it should be checked.
The N75 can crack or fail and drop its resistance. To access it, you need to remove the right side inner wheel liner. I do not believe any of those you mentioned would be the cause of exhaust smoke. For smoke testing, you can begin at the air intake or disconnect the PCV tube or IAT sensor at the intake manifold while the air intake is plugged. Just wanting to test the boost plumbing, or all, between the turbo inlet to intake manifold. Does yours have the EVAP canister in front? Check that for cracks as well.
 

1131

New member
Yes, it may not be the PCV, I only mentioned it because it should be checked.
The N75 can crack or fail and drop its resistance. To access it, you need to remove the right side inner wheel liner. I do not believe any of those you mentioned would be the cause of exhaust smoke. For smoke testing, you can begin at the air intake or disconnect the PCV tube or IAT sensor at the intake manifold while the air intake is plugged. Just wanting to test the boost plumbing, or all, between the turbo inlet to intake manifold. Does yours have the EVAP canister in front? Check that for cracks as well.

Well. It's not any of those things unfortunately. It is... drumroll please... indeed a blown turbo. Even without fully removing it, just separating it from the cat, I could reach in and feel the compressor wheel rattling around, completely free. So that's the bad news. The even worse news is that I am now stuck in the middle of the job because I rounded the head off one of the exhaust manifold bracket support bolts (figures 30 and 31 in the Pelican guide). Worse still, I don't know the replacement part number. I just know that it has a 13mm head, is about 8mm thick and 40mm long. I called a local VW dealer and they gave me two part numbers: N90292903 and N9090352, but a google search shows those aren't the right parts at all. Those bolts look like they are for attaching the black support that goes underneath the silver turbo bracket.

There is not much room to work to liberate the stuck bolt. Bolt extractors haven't worked. There's no room to drill a hole in the middle for a screw-type extractor. There's no room to swing a hammer and attach a smaller socket. I thought about dremeling a slot into the bolt and then maybe use a flathead screwdriver sideways but it would have to be a short handle screwdriver. My alligator nose channel lock keeps slipping off.

My current plan of attack is to saw the turbo bracket in half. The problem with this approach is that there is (allegedly) only one VW dealer in the whole of the US who has it in stock, and it's a $66 part. Apparently, it's not considered a high-failure part which is why they don't stock it. So I ordered one off ebay. While I wait for it, I can keep trying to remove the bolt with a gator grip, knock 'er loose, and a small butane torch (I know, it's not hot enough, but it's all I've got) applied to the welded nut end of the stuck bolt.

I guess I could also try and remove the passenger side CV axle, and then drop the turbo down instead of pulling it up. (I would just need to remove the two 6mm Allens on the black support that the VW dealer erroneously tried to sell me bolts for). But the problem here is that it's a two person job. You need to have one person with their foot on the brake while the other goes at it with an m10 triple square. And I'd probably have to go out and buy a gigantic socket to fit the CV axle bolt.

It was not a good weekend.
 

1131

New member
I totally guessed about needing a new turbo and ordered one without confirming the need. If I had it to do over again, I would put together an inspection procedure that's basically just the Pelican guide steps 21-26. (Note that those are actually 13mm bolts in step 24).
 

vwengineer

Ready to race!
Location
Switzerland
Sorry to hear that, did you found a way to get the bolt out? You can remove the CV axle without stepping on the brakes, you just need to jam a screw driver in the vents of the brake disc to prevent the axle from turning. You could also put the car in gear, it's just much faster being two.
 

1131

New member
Sorry to hear that, did you found a way to get the bolt out? You can remove the CV axle without stepping on the brakes, you just need to jam a screw driver in the vents of the brake disc to prevent the axle from turning. You could also put the car in gear, it's just much faster being two.
Appreciate the tip. I'd have to go out and buy a 27mm socket. And I would still need to remove the stuck bolt to move the support bracket to the "new" turbo. But removing the CV axle and dropping the turbo would give me more room to work on the stuck bolt. I'll keep trying to remove the bolt in situ, but if I can't get it within the next day or two, I'll try removing the CV axle.
 

1131

New member
Sorry to hear that, did you found a way to get the bolt out? You can remove the CV axle without stepping on the brakes, you just need to jam a screw driver in the vents of the brake disc to prevent the axle from turning. You could also put the car in gear, it's just much faster being two.
Before running out to buy that 27mm socket, I decided to try your suggestions. Neither jamming a screwdriver in the brake disc vents (even a very long one) nor putting the car in "D" arrests the CV axle. It looks to be a two-person job for sure with one person standing on the brakes. It's also looking more and more like cutting the bracket is my only option.
 
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vwengineer

Ready to race!
Location
Switzerland
The idea is to jam the screw driver in the brake caliper so that it prevents the disc from turning, never did it myself but as I have to replace the CV boot that's what I found. As for the gear, D will not work but P should prevent the wheel from turning (but I would get a second advice if it's OK to do it with an auto, on a manual it's fine at least). Note that without an impact you should crack the axle bolt with the wheel on the ground (remove the center cap)
 
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