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  #11  
Old 02-09-2014, 02:51 PM
745 TurboGreasel 745 TurboGreasel is offline
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If you are not well equipped to deal with broken studs, don't remove the manifold unless you have to. If you must, use lots of penetrating oil first.
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  #12  
Old 08-18-2019, 06:50 PM
RedArrow RedArrow is offline
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Default Exhaust leak near turbo/egr area

Quote:
Originally Posted by 745 TurboGreasel View Post
Wherever steel plates about 2" long are sold.

or try no gasket and a little orange RTV
look in tascavolvo online catalogand see if you find anything
If not, maybe VW 038 131 547 A (ALH TDI EGR gasket manifold-tube) and 069 131 547 D(tube to valve)
I could see having to trim the bolt holes, but It seems like they'd be close enough to work.

Part #s are nice!!!

Similar issues here,
Visible leak and dark grey/black soot stains where the egr junk connects to the turbo area. High heat gasketmaker didnt work, red rtv etc didnt work.

If i decide to delete the mushroom egr , what else do i need to do besides blocking off the two ends?

THANK YOU
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  #13  
Old 08-18-2019, 07:44 PM
RedArrow RedArrow is offline
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Default Leak at egr

Leak showed up again at the egr .....high heat gasketmaker didnt work.
It leaks where the egr mushroom connects, at the lower end where the blockoff plate would/should be

So annoying! It used to leakat the downpipe ---turbo connection but now it is here. Egr----exhaust manifold connection
BTW IDK why so much pressure and why such dark soot.
I suddenly see that in my tailpipe too. Clogged(=worn) air filter can do that?? i think of the muffler or mufflers too. 1985 equipment i believe

Suggest me a good d24t muffler please with a link. Rear one too.
Or simply cut out the first one? Idk...i want nothing louder than stock sounds.
Ideas?
Imsure i cant just order a 740 gasser muffler.
Whatsbest to keep stock sounds without restricting the system??
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Last edited by RedArrow; 08-18-2019 at 07:50 PM.
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  #14  
Old 08-18-2019, 10:00 PM
ngoma ngoma is offline
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Quote:
Originally Posted by RedArrow View Post
Part #s are nice!!!

Similar issues here,
Visible leak and dark grey/black soot stains where the egr junk connects to the turbo area. High heat gasketmaker didnt work, red rtv etc didnt work.

If i decide to delete the mushroom egr , what else do i need to do besides blocking off the two ends?THANK YOU
That's right, two blockoff plates. Have extra bolts/studs/nuts on hand in case any get destroyed during disassembly. One of the nuts on the exhaust manifold flange is difficult access. Be careful with the inhex screws going into the intake manifold as the aluminum threads are easy to strip.

Last I checked those diamond-shaped gaskets were widely available on ebay for VWs.

Otherwise you can make your own gasket out of bulk exhaust manifold gasket sheet from your FLAPS.
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  #15  
Old 08-20-2019, 11:32 AM
v8volvo v8volvo is offline
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Excess backpressure from a restricted exhaust is one possibility, but these leaks also may be just old gaskets failing. These gaskets are 35 year old parts well outside of their life expectancy and they are exposed to constant thermal cycling. Having to renew them at this point would not be surprising.

Probably best to start by just cleaning up the surfaces very well and trying some new gaskets (not silicone, need to get the correct type stainless steel or fiber composition exhaust gasket which as ngoma noted is the same as VW parts and widely available). With any luck this will stop the leaks and you won't have to pursue exhaust changes. Plugged mufflers are not unheard of but usually they only occur as a result of a very poorly tuned engine that is emitting an enormous amount of smoke, and/or one that is never driven hard enough to get exhaust temperatures and velocities to the necessary levels to keep the system clear. If your engine is running correctly and you drive it on the highway from time to time, it would be unusual for a muffler to become restricted with soot.

On the other hand, if gaskets keep on failing in these locations even after you replace them, then you will want to investigate possible exhaust restriction. Any loss of power? Restricted exhaust would make a noticeable impact on performance, especially in terms of much slower turbo spool time (bad turbo lag), weak high RPM performance, and excessive visible exhaust smoke.

The soot marking around the leaks is normal, however, as long as there is not a large amount of smoke out of the tailpipe when driving.
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  #16  
Old 09-14-2021, 10:17 PM
RedArrow RedArrow is offline
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Default EGR area exhaust leak under the hood due to bad design or corrosion

Thank you for the reply.
I haven`t replied yet because I forgot to make the time to do this fix.

The original diamond shaped egr exhaust manifold gaskets (3 fixes ago) were in extremely bad shape or nearly nonexistent ... then I did the fix and car felt so great right after.
Then the problem came back after a multiple hr continuous highway drive at about 75-85mph.. but I bought new gasketS and did the fix twice again (this was in the past).

Manifold surface is probably too pitted from corrosion to create a good seal even with new gaskets. I also tried a 2-layer stainless version of the same gasket with not much luck. It held for a few months only.

Also, the manifold had a tiny vertical (tight) crack at the very low point at the very center below the mushroom pipe where the two sides of the exh manifold meet. It is on the lower lip of the surface where the gasket goes.

I noticed the same kind of exhaust manifold crack on another d24t engine too, perhaps it is a common thing to ignore such as hairline crack between the valves?
I have no idea but I started to see dark black stains again where the current gasket is not sealing well. And the car doesnt really pick up speed and has a weird high rpm performance... this developed slowly and gradually and no other fixes were done so i am sure it is this exh manifold seal tricking me.

I doubt I have restricted exhaust but I do have high rpm power loss and a very slow turbo spool action. I also noticed that the little square blockoff plate under the turbo has a very seriously corroded tiny set of screws and plate. I bet there`s no gasket inside there anymore, either....that humpy shaped Mercedes Benz Garrett turbo gasket... hard to find btw.

You suggested trying other type of gaskets to see if that would solve it...
For the leaky manifold surface I tried various types of gasket materials, stainless steel and composite too.
Eventually they let the hot fume make its way through. Prior to the 2020/21 Weird Virus Winter I did this fix successfully (messing with broken studs and the typical exhaust pipe joint stud issues as well) and thought (=hoped) I will be happy with it for a good couple of yrs. Wrong.
I was lucky to have time for 15 skiing daytrips to a far away PA ski resort that added about 3500-4000 highway mountain miles and on the last one I felt the car really losing power due to this leak... Left it like that but i`m annoyed a lot by it. First I thought it was all the heavy gear and five passengers, mtn elevation etc but it wasnt that...

Thinking of JB Welding it and simply use my fingers to apply it after wire wheeling that crap instead of removing so many parts and/or dealing with rusty bolts or broken studs again.
The benefit was to be able to add new intake gasket and exhaust manifold gaskets and check on the rear hose behind the head and clean the starter area as well. Other than that, I really want this issue to end. I would be happy if egr hole got welded shut.
I am considering to get another d24t manifold welded shut then `simply` add that right after I get the current one off. But still, it is not my fav project. If jb weld fixed it, i would be ok with the looks.
Hey it worked on diesel injectors before and they are still holding. Hot and transfering diesel fuel, jb weld is holding there strongly (fuel nipples of the injector came loose/out)

Would it be a realistic idea to jb weld under (and between) the gasket and exh manifold surfaces? I think my manifold surface is too badly pitted to create the best seal even if i keep throwing various new gaskets at it. And you also risk killing the stud every time. Especially if you think all it needs is tightening.
I am really into this because it is so damn annoying to drive it like that since even a well set d24t is kind of slow.

Last edited by RedArrow; 09-17-2021 at 08:50 PM.
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  #17  
Old 09-15-2021, 10:02 AM
ngoma ngoma is offline
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Quote:
Originally Posted by RedArrow View Post
Would it be a realistic idea to jb weld under (and between) the gasket and exh manifold surfaces? I think my manifold surface is too badly pitted to create the best seal even if i keep throwing various new gaskets at it.
Might be realistic, have you checked the JB Weld temperature range? IIRC, the EGTs can get up into the 1,000 degF range.

Could you resurface the sealing face with a belt sander?
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  #18  
Old 09-15-2021, 08:36 PM
RedArrow RedArrow is offline
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Quote:
Originally Posted by ngoma View Post
have you checked the JB Weld temperature range? IIRC, the EGTs can get up into the 1,000 degF range.

Could you resurface the sealing face with a belt sander?
There`s a paste version of JB Weld that is said to withstand higher temps than their other products.
https://www.walmart.com/ip/J-B-Weld-...te-3/112083744
(I am not sure how it handles vibration though and how clean the surfaces need to be to apply it efficiently. There`s no good access to this part of the engine...)

Plan B would be (as you suggested) sanding/resurfacing then to reassemble it all again using new gaskets (and maybe(?) a thin layer of some sort of good sealer or JB.

One of my many past attempts were fixing it with new gaskets and using a high heat red sealant between mating surfaces, but it didn`t hold longer than a few months.
The engine power is not pimped up in any way, my pump is not turned up and I don`t race/abuse the car; so I doubt that I have `higher than healthy` exhaust temperatures.

Thanks for the reply Ngoma.
I need to take it apart again and touch up that pitted surface really well. Fingers crossed about the studs...
I bought copper nuts to be kind with the studs that are worn a little, especially the one on the right/front. I think I also bought about six VW diesel exhaust studs on FCP but ruined like two of them by the time I got one in. I should be able to find two more in some toolbox and do this project soon.
(I remember fighting two exhaust studs out but I can`t recall which engine it was. I am hoping it was done for this car but I am not sure.)
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  #19  
Old 09-16-2021, 11:55 AM
ngoma ngoma is offline
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Maybe the hairline crack you mentioned is expanding at operating temp.?

As long as you are struggling with this, disassembling/reassembling, etc., why not do this:

EGR Blockoff Plates
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  #20  
Old 09-17-2021, 08:29 PM
RedArrow RedArrow is offline
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Default Tried exhaust cement this time... lets see how it holds.

Quote:
Originally Posted by ngoma View Post
Maybe the hairline crack you mentioned is expanding at operating temp.?
As long as you are struggling with this, disassembling/reassembling, etc., why not do this:
EGR Blockoff Plates
Hi Ngoma,
your link shows a nice repair that I also did, approximately a year and a half ago, that was the actual `egr delete job` when that mushroom shaped pipe got cut off and removed then I fought the two studs out of the manifold.

I installed new VW studs in there and I made two aluminium plates to block the two holes. That time I used the high heat version of some red/orange color gasket maker and hoped for a good seal. I roughly cleaned mating surfaces (manifold was very pitted), added a new composite gasket for the upper hole at the intake and used a stainless steel double layer gasket for the hole at the manifold.

The upper one held fine until now and only once had a tiny leak that showed a dark dot of stain.. One of the nuts was later found being a little loose.
I think that happened because I was too concerned about the intake manifold threads (at time of initial installation...). Tightening it a few months later worked well and it has not leaked since.

The `lower` plate, at the exhaust manifold, started showing leaks after those multiple highway high RPM trips. I was afraid to overtighten the nuts so I left it as is but the car really felt that leak (of smoke) and lost quite some `power`. `Roadside` tightening did not help it actually.
One of my new exhaust manifold studs lost some good thread at the time of installation, so I did not want to force tightening nuts too much. At home I shimmed it up using larger washers to use the outermost part of the threads.

The cause of the leak (obviously) is heat itself... it managed to warp the plate I made. I know now, that it was too thin of an aluminum piece to be used for this purpose... its thickness is only about 1/4inch (6mm).




Today I removed the block-off plate from the exhaust manifold
and started cleaning its deeply pitted surface.

Corrosion made its way down into the cast iron really well. The old metal gasket also left the mark of its own shape `carved` into the surface of the manifold.
I used sandpaper to try removing as much materaial as possible, in a mad attempt to recreate a flat surface as much as it was possible, without taking stuff apart, without removing the manifold(s), without power tools, without making the car non-drivable tomorrow.

I also noticed that the plate I removed had a curve or was slightly bent, it was not completely flat anymore so I had to get it cleaned and make/sand it more flat.
I decided to do it the quick way, just to get it done without being involved too much.

The double layer metal gasket was found in fully reusable condition but in the end I decided to use no gasket at all. This may be a mistake, I`ll hear your opinion about it.
It seemed that that gasket had a `bumpy ring` on its surface (at center) and that ring would be working against the totally flat seal of the surfaces.


We`ll see. So I cleaned it all off and used `exhaust cement` between the manifold and the blockoff plate. I think it is rated for 950F (*only).
I regret not buying the high heat JB WELD 2400F manifold paste because that would have been a better choice, I`m sure.



Do you think the exhaust cement can cause problems IF tiny particles end up going in/falling in?

Looking back at my repair today, I recall that I used the cement on the entire surface of the inside of the blockoff plate so there will be a layer of cement where the `hole` is.
If that cement falls off, or burns off and falls, can that be an issue there or anywhere?

If you say yes, I will not use the car like this and I will go ahead and will buy the 2400F paste... and not cover with adhesive the entire block off plate surface on the inside.

The cement sealed really well, protruded when I tightened the nuts and `dried` in 30 mins then I ran the car to warm it all up to sped the rest of the curing up a lot (we had a rainstorm after i took car apart).

Ngoma your plates look very thick, they are double the thickness of my choice... If today`s repair won`t hold, I`ll get thick plates and the Extreme Heat JB WELD sealant. DID YOU USE ANY GASKETS IN YOUR FIX (at the manifold)??



About the crack.
I have this crack on the very bottom of the exhaust manifold where the two sides meet, right in the exact center (lower lip).

As you suggested, it is highly likely that the crack is able to expand although it is super thick material there and the shape of the design hopefully wouldn`t let major expansion happen. Also, it sits really well on its base and four large nuts hold it all together from the bottom.

Are these manifolds easy to weld? I may grab it from the other engine and get it welded (also cracked at the same spot) then get it refinished to completely flat then I could forget this issue for a while. But I am totally not ready to do removals of both manifolds on both engines then assemble them both, twice.



Main news, lol:

I ran a check on how tight my 12 exhaust manifold nuts were.
We all know that there is one at a bad spot AND it`s a bad angle, AND there are 2 more nuts at an even worse spot and an even worse angle...

So, all 3 of those were not exactly as tight as you would want them to be. I tightened them. This I think will help with the power loss symptoms I was experiencing while driving, IDK yet. (Finding them was just the benefit of dealing with the block-off plate issue)
I think the 3 nuts were not tight enough because at the time of torquing the 12 nuts these were the 3 spots where the torque wrench did not fit, so I had to tighten them to specs by `feel`... I probably was overly concerned of overtightening Also the exhaust manifold was installed with brand new gaskets at the time, that could be a factor.

Test drive tomorrow...
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File Type: jpg Screenshot_20210918-011427.jpg (28.8 KB, 7 views)
File Type: jpg Screenshot_20210918-011529.jpg (7.0 KB, 4 views)

Last edited by RedArrow; 09-18-2021 at 06:20 PM.
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