Engine support mount thread stripped when doing TB

I was doing a timing belt last night on a car that was on its third change. Well just the last step before I could take off the Harbor Freight engine support, the bolt acted weird.

Here is what happened. I put the top engine bracket piece in and installed all 4 engine mount bolts. All four were torqued. I was going to do the +1/4 turn on each of them. First 3 went without trouble. The fourth bolt stripped the threads in the engine support piece. I just barely started doing the + 1/4 turn. I will use degrees to make it clear. A 1/4 turn is 90 degrees. So as I turned about 20-30 degrees, the bolt suddenly felt loose. I continued to make the 90 degree turn and it was way to easy. So I knew something was up. I took the bolt out and it didn't have any signs that the bolt was twisted or stripped. Then I put it back in using a socket wrench and try to tighten it. It never got tight. I can turn forever. (It reminds me of that oil pan drain plug I had two years ago, which I end up replacing the pan.)

It was something I had thought about this issue like 10 timing belts ago. I just never got around to post this concern until it happened. Especially now is a great time with the issue on Lemforder tensioners.

The replacement part number for the engine support is 038 199 207 H. It is called "support" on the ETKA. At vwparts.com, it is $78.04. I figure dealership cost around $90-100.

That engine support is made of aluminum and you use steel bolts to tighten it. It may be alright on the first timing belt change. But after that, it starts to bring up wear and tear on the threads inside the engine support. Torque to 44 ft/lbs plus a 1/4 turn is more than it could handle on repeated timing belt changes.

The concern with Lemforder tensioners now is that even thought most of us have our first or second timing belt done. Doing the tensioner replacement will make it 2nd or 3rd on such a low mileage.

What I want to know is that is there another solution to the problem without possible of stripping the threads in the engine support? There has to be another way or something. One thought I had was not to turn 90 degrees but to 60-70 degrees. Will it still hold?

The owner told me that it is really stupid of VW to do that and as a timing belt changer, I should carry a few spares on hand so that if it happens again, I could sell my piece so that we can get the person back on road instead of being stranded. I thought it was a nice idea especially if you are doing timing belts on a Sunday or after hours.

Howdy "DeafBug"

This is a great topic.
I have in my garage an assortment of failed components ..one of which is an A-4 eng. support (038 199 207 H).

Here is the interesting part:
This support came out of a TDI on its first timing Belt replacement.
Details:
Engine was supported from the engine hoist...The engine mount bolts were removed from the mount/ fender ( there are the 2 / 16MM mount bolts).

At this point the engine is supported by the hoist..no engine weight is on the mount. Then I removed the rear mount bolt (18MM)..and then I started to remove the front mount bolt (18 MM)..as I was turning the bolt out from the engine support...I watched as threads of metal shavings came out along with the bolt.

The only way that this could have happened was the bolt was cross threaded during assembly at the factory,or the support itself was not correctly tapped during the machining process.
No one had touched this bolt befor ..because the "tamper" marks were all intact BEFOR I put a wrench to the bolts.

But you make a valid point...how many times can this aluminum threaded engine support...take the stress of torquing a steel bolt befor the threads fail from normal fatigue / stress loads?

I think I posted photos of this ...some time ago..I'll have to see if they are still on the server.

It happened to us on my TBG last June. I don't know about safety, relibilty, etc. but when I put the new one back on I just turned it 1/8 of a turn to be safe and I check it every once in a while. Maybe the part needs to be aluminum but if they are just concerned with weight then I would just as soon have a steel part there.

Any chance there was a problem with the stretch bolts? My understanding is that the extra 1/4 turn is to set the stretch tension after you reach the threshold torque value. If the bolt is too stiff and doesn't stretch (or was already stretched), it will apply too much tension to the threads and they'll strip out.

Damn. Who would have thunk it. Great to know that this is something to "stayalert" for.....Interesting part for me was that when I started up the car this morning to go return from an "out to lunch" outing I suddenly heard a athroaty exhaust note from the front end where none had previously been. The sound stops when I blip the throttle and I havn't looked into it yet bt I'm thinking/hoping a loose exhaust connection or support..........I don't think I have any engine mount woes (1 TB change performed by a qualified (understatement) mechanic) but will certainly take a look see whne I get to raising the hood to prepare to drive home later.....Rob M
Concord, MA

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Great to know that this is something to "stayalert" for.....Interesting part for me was that when I started up the car this morning to go return from an "out to lunch" outing I suddenly heard a athroaty exhaust note from the front end where none had previously been. The sound stops when I blip the throttle and I havn't looked into it yet bt I'm thinking/hoping a loose exhaust connection or support..........I don't think I have any engine mount woes (1 TB change performed by a qualified (understatement) mechanic) but will certainly take a look see whne I get to raising the hood to prepare to drive home later.....Rob M
Concord, MA

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BEWARE!! BE FOREWARNED!! I recently had to have an "emergency" TB replacement, about 2000 miles after the 2nd belt change at 120K. The same 'throaty exhaust note" was noticable for a week, before the two new long stretch bolts broke and the engine dropped away from the mount. I commute 150 miles a day. Luckily, I had just pulled off the highway and more luck, was about 6 miles from a dealer. Ruined the new TB, new Tensioner, TB cover, something called the 'dogbone, and my credit card. /images/graemlins/crazy.gif

This brings up a question I've had since I did my 1st belt in January.

When the procedure called for an extra 1/4 turn I didn't want to do it. Intuition said to avoid overtorqueing and possibly stripping out the holes on the engine mount. It doesn't make sense to have hard steel bolts tighten into softer aluminum.

I torqued them a little extra turn with the wrench but was freaked out with the idea of tightening 1/4 turn beyond 30 ft-lbs. Why don't they just recommend 40 ft-lbs to include that extra 1/4 turn instead of saying 30 + 1/4 turn?

I wonder what the risk factor is for undertorqueing these bolts?

I had this very same thing happen to me a few months back. I torqued the bolt as specified, then gave it the extra 90 degrees. At about 60 degrees or so, if I remember right, there was a strange snap sound, and something didn't feel right. Although the bolt was tight, I decided it would be best to remove it and examine the situation. Well, when I pulled it out, all of the aluminum threads came along with it. Being it was Saturday evening, and the dealer was already closed, (and probably didn't have the part in stock anyway), we came up with an alternate fix. I am not saying anyone else should do this, nor do I recommend it, but it worked, and is still working, so no need to start a flaming war.
What we did to fix it was go to the local hardware store, and purchased a 1/2 inch, 13 thread tap, and a 1/2"-13 bolt with similar length to the original but was grade 8. We then tapped out the hole, and used the standard thread bolt along with a washer, and torqued it to about 50 ft/lbs. (The owner is aware of this and wanted to try this before dealing with the hassle of getting a new mount and installing it. He also keeps an eye on it.)
The 1/2" bolt is thicker than the original, but the hole on the body part of the mount is large enough for it to fit through.
There has been 20,000+ miles put on this car since then, and no sign of failure yet. At the next TB change (200,000 miles), we plan on putting in a new mount.

I agree that this is a terrible design by VW. Why would anyone design an engine mount that hangs the engine from weak bolts that are over-tightened into a too weak aluminum piece? Wouldn't a person logically think it would be better to have the motor part of the mount sit on top instead of the bottom, so in case of fastener failure, the motor wouldn't just fall to the ground? Instead it would just move around in the mount.
This design sounds like a lawsuit waiting to happen...

Now, while I don't know anything about the configuration of these mountings here's a thought. Could the bolts be replaced by studs yet allow the bracket clearance for removal? I don't think there's any issue with a steel bolt going into alloy as long as proper procedures are used for it's fitment, but obviously the fewer cycles the thread has to undergo the better...
My wife's Citroen diesel has a r/h mounting that bridges over the t/b and bolts to the head. Has to be removed for access to belt, tensioner, for head removal, etc. The engine hangs from the threads of it's fixings in a similar manner the the A4 by the sound of it. But PSA use studs rather than bolts, and there's no issue...

Sounds like VW should be putting HeliCoils in the motor mount to prevent this from happening. I'm going to look into the feasability of rebuilding these mounts with HeliCoils to provide a safely reusable mount.

I did my timing belt about 6 weeks ago. What is this 'torque' you guys are talking about?

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Sounds like VW should be putting HeliCoils in the motor mount to prevent this from happening. I'm going to look into the feasability of rebuilding these mounts with HeliCoils to provide a safely reusable mount.

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My motormount failed about a month ago, but in a different way (another story). But upon looking at the mount, I saw that one of the holes was stripped. I obviously did not want to reuse it, so I bought another one. It was from a 20k car, so one would assume it would be good. It also had one stripped hole. Perhaps they are being assembled to quickly at the factory & not enough care is taken during assembly? I explored the idea of drilling, tapping & inserting a heli-coil, but the casting of the mount does not allow much tolerance. The 'web' design of the mount does not provide a lot of 'meat' where the bolts attach. In my case, I bought a new mount and was done with it, but as mentioned before, it might be feasable to just go slightly oversize & tap out the hole to the next larger imperial size? That should suffice for a temporary fix till the next scheduled TB change when the mount can be replaced. With a bit of blue thradlock, I can't see why the bolts can't be just tourqued to 35 or so? It won't vibrate out with the threadlock in there.

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Sounds like VW should be putting HeliCoils in the motor mount to prevent this from happening. I'm going to look into the feasability of rebuilding these mounts with HeliCoils to provide a safely reusable mount.

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This is what I've been thinking about... My back bolt threads on my mount are not great. Very touchy getting them in... and I've never gone the full range with the tightening... just going until its tight...

I'd like to see a full length sleeve type helicoil in those mounts...

So anyone wanna whip up a batch of modified thread motor mounts?

I like the stud ideas... thread lock a stud in there and use a big monster nut on the top... the only issue I could think with that is getting the mount in and out...

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So anyone wanna whip up a batch of modified thread motor mounts?

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I'll give it a go, I just have to find some used mounts to work with. I won't be needing a TB till closer to 2005.

I have one I could send you to try out. But as I mentioned before, not much meat around the existing hole to work with. The webing under the surface does not allow for a much larger hole. It would have to be a pretty thin Heli-coil so the hole drilled to tap for it doesn't get close to the edge. I still think tapping the hole for the next largest bolt oversize is a better solution. Maybe a coarser thread so there is more for the bolt to grab?

Looking at the mount, I'd say you could go up to the next bolt size. Alternately, you could drill out the bottom, tap all the way thru, and use longer bolts.

btw, I still have a 038-199-207-H mount that I was trying to unload last May Link
It came off the motor I used for my TDI Rabbit.

If anyone is interested, just let me know.

-Dave

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I have one I could send you to try out. But as I mentioned before, not much meat around the existing hole to work with. The webing under the surface does not allow for a much larger hole. It would have to be a pretty thin Heli-coil so the hole drilled to tap for it doesn't get close to the edge. I still think tapping the hole for the next largest bolt oversize is a better solution. Maybe a coarser thread so there is more for the bolt to grab?

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I would like to give it a try, at least have a look at one out of the car to see the options. Send me a PM with details.

My throaty exhaust note has not been reproducable. I'm thinking ice or something was inbetween the exhaust and body...Visually my motor mounts look fine and I just drove 550 or so miles without troubles (except for front pad worn warning)
Rob M Concord MA

After hearing a clunk after VW replaced my motor, I found that one of my bolt was stripped. I went to Ace Hardware and bought the next size larger SAE bolt and screwed it in. That was at 28,000 now after one TB and 54,000 miles later it still holding strong.

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So as I turned about 20-30 degrees, the bolt suddenly felt loose. I continued to make the 90 degree turn and it was way to easy. So I knew something was up. I took the bolt out and it didn't have any signs that the bolt was twisted or stripped. Then I put it back in using a socket wrench and try to tighten it. It never got tight. I can turn forever.

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Okay, here is the picture of the bolt. I finally got around to take a picture and uploaded to a server.



Now recently I have done two timing belts and one of the was good for a picture of the engine mount. After removing the 4 bolts and removing the top engine mount, this is what I saw. Notice the metal shavings, the little white specs.

If there are some who remember the old air cooled engines; steel coil and inserts were part of a rebuild. Poor design to have a load bearing part made of aluminum without steel threads of some sort. I know on my next TB relacement it will be a point of interest and action. /images/graemlins/wink.gif

Re: Engine support mount thread stripped when doin

TTT so I can bookmark this page.

Re: Engine support mount thread stripped when doin

I recently had something similiar happen. I had some issues with the three mount bolts that attach the mount to the engine. To get to these bolts you have to take out the rest of the motor mount & lift up the engine a few inches. When I took out the rearmost bolt that goes down into the aluminum mount it came out with some aluminum shavings on the threads of the bolt. Uh-oh.

When I went to reinstall new bolts I knew to be careful with the threads in the aluminum mount. I blew out the mount holes with compressed air & then hand threaded the new bolts down in & out of the mount several times. Then blew the little aluminum chips out of the holes again. I installed the bolts & brought them up to the torque value a little at a time.. 20 ft lbs on one.. then 20 on the other..30 ft lbs on one... then 30 on the other.. etc. I finished with the book torque value but DID NOT do the 90 degree turn. I know its a stretch bolt but when you have a steel bolt going into aluminum it makes no sense to me to do something like that. It's pretty clear the aluminum threads are the weak spot & they will give way before the steel bolt stretches. I have been keeping my eye on the bolts since then & they are holding fine.

I hate to say it but with the bolts going in & out of the aluminum housing at every belt change that mount almost seems like a part thats going to require replacement at some point. It only takes doing it wrong once to ruin it. What I would like to see is a hole right through the mount & then a flat spot machined on the bottom side of the hole. Then you could use a longer bolt & a washer & locknut & capture the mount so stripping out the hole wouldn't be an issue.

If I was taking the bolts out again I would loosen them a little at a time. Break one loose & then the other. & then loosen them both up. In other applications I've seen where its best to break all the bolts loose before you remove any of them to keep them from binding up as you try to back them out.

tdiflyer nailed it.

Link for Helicoil.

Similar thread posted here

Not sure if anyone is following this thread anymore, but I found doing some searching. I am looking for an alternative to HeliCoils and wonder if a mount can be repaired with Loctite's Form-A-Thread Product. This would work best if used when the first indication of metal shavings starts. I've started a new thread here...

http://forums.tdiclub.com/showthread.php?t=274147

I would love ya'lls input based on 4-5 years of experience since this thread was started and if anyone has better determined why the threads are stripping. I think the feeling was that it was related to the TTY being too stiff or overtorqued.

Reviving an old thread...
well at 350k miles, I figured it was time to change the engine mounts. The M12 bolts (18mm) on the TB side mount didn't like to be removed for the 4th time and both stripped out. I drilled and tapped the holes to use M14 bolts. 5k miles later, still holding torqued to 74 ft/lbs.

pepper10 said:

Reviving an old thread...
well at 350k miles, I figured it was time to change the engine mounts. The M12 bolts (18mm) on the TB side mount didn't like to be removed for the 4th time and both stripped out. I drilled and tapped the holes to use M14 bolts. 5k miles later, still holding torqued to 74 ft/lbs.

Click to expand...

Just curious as to how many miles you have on the bolts now - I think I need to do this to my car. One stripped out on me and I used JB weld to get it back in there. I'm currently not driving the car and wont be for the next couple weeks so, I'm looking for alternative repair solutions.

Wow this is an ancient thread and DeafBug is no longer in this world. The tried and true fix that Wingnut developed:

http://forums.tdiclub.com/showthread.php?t=369932&highlight=timesert+motor

Since this just happened to me with with the threads stripping out I thought I would toss out this solution that worked for me. This support bracket (038199207H) is used on 1.8T and 2.0 Beetles, Golfs and Jettas for a number of years. I went down to the local Pick-n-Pull yard and pulled one off one of the cars there. It cost me around $10 and about an hour of my time. Just be sure to support the engine when the bolts are removed so the threads aren't damaged in the removal. Take a good look at it to make sure the threads are in good shape. If not just find another donor car. Generally the U pull it yards have several there.

I was looking a drilling and tapping the old support and using a helicoil or time sert when I realized there was an easier solution. Chances are the Gassers haven't gone through the multiple timing belt changes like the diesels do. The bracket I pulled worked out perfectly.

Just my 2 cents.