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LiamSG Samba Member
Joined: May 22, 2018 Posts: 12 Location: Canada
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Posted: Sat Jul 14, 2018 4:19 pm Post subject: TSII seized - can it be drilled? |
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In the process of trying to install a new head temp sensor on my 77 bay, I have discovered that the old sensor is completely seized. So seized, that even after liberally dousing it in penetrating oil over the course of 48 hours, I managed to snap the bolt head off of it, leaving the threads inside the cylinder head.
I am hoping that someone who knows their engine a bit more intimately than me can confirm this - when looking through the hole in the tin above the #3 spark plug, it appears that the hole for the sensor is open on the back. I am hoping to drill out the sensor casing enough to use a bolt extractor to get it out, but want to make sure I am drilling into an open hole, and not going to damage my cylinder head.
Alternatively, I don't suppose anyone has any creative ideas for alternate sensor mounting locations? Really hoping to avoid dropping my engine and replacing the cylinder head if at all possible. |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Jul 14, 2018 4:38 pm Post subject: Re: TSII seized - can it be drilled? |
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yes it is open on the back. Use tape on the drill to set a depth stop. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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LiamSG Samba Member
Joined: May 22, 2018 Posts: 12 Location: Canada
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Posted: Sat Jul 14, 2018 8:22 pm Post subject: Re: TSII seized - can it be drilled? |
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Excellent. Thank you for confirming that I'm not about to ruin my cylinder head |
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furgo Samba Member
Joined: September 06, 2016 Posts: 944 Location: Southern Germany
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Posted: Sun Jul 15, 2018 2:51 am Post subject: Re: TSII seized - can it be drilled? |
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Same exact thing happened to me a while ago. In my case, it was so badly stuck that even after drilling it, it wouldn't easily come out.
Yes, the hole is not a blind one and the sensor can be drilled. IIRC you have about 7-9 mm after the exit hole before you hit the cylinder head. Other than the method SGKent has already posted, a car vacuum cleaner with a hose attached to its noozle also works wonders to remove the metal filings.
A couple of notes from that miserable experience:
• Drop the engine to do the job. If you possibly can, that is. I did it with the engine in place and a right angle drill (I didn't have a driveway to drop the engine), but it was an absolute pain I would not wish to anyone else.
• Be careful with bolt extractors. I'm of the opinion that they might work well for steel-bolt-to-steel-thread applications, but I've seen them crush the softer aluminum in steel-bolt-to-aluminum-thread configurations such as the TS-II. For what it's worth, I tried them with my stuck sensor and they didn't work at all for me.
• Consider removing the intake runner. if against advice you're doing it with the engine in, and if your intake runner or boot needs to be restored/replaced anyway, remove it to get quite some more manouver room. Stuff the cylinder head intake ports with paper while you're doing the job. Replace that cracked intake boot if necessary.
• Dremel is your friend. One option is to drill/machine off the sensor until it's just a few mills off the thread, enough to pick off its remains and save the original thread. If you go for this approach, and unless you are using a drill press which you can center to drill with precision, a dremel with a diamond drill/grinding bit is easier to operate in there.
• Use anti-seize. After claiming victory, use a good quality, high-temp anti-seize on the new sensor thread sparingly, to not ever ever have to do this again.
After the initial drilling, what I ended up doing was to use a combination of a metal file and then Dremel with the diamond bit to carve a slot on two opposite sides of the seized bolt. The plan was to use a big flat screwdriver to do the rotating/unscrewing motion.
That actually didn't work either. The bolt part of the sensor was truly stuck and I actually ended up with a big fat screwdriver twisted. But I ended up carving so near to the thread, that I could separate the bolt in two segments and use the screwdriver and a dental pick as a lever to ultimately pop off each segment. Fun times. _________________ '79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Sun Jul 15, 2018 6:45 am Post subject: Re: TSII seized - can it be drilled? |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50255
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Posted: Sun Jul 15, 2018 7:57 am Post subject: Re: TSII seized - can it be drilled? |
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Drill and tap the equivalent hole on the #4 cylinder, you can cut out the tin with a 5/8 hole saw if need be. It takes longer to gather the tools than to do the job. |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50255
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Posted: Sun Jul 15, 2018 8:39 am Post subject: Re: TSII seized - can it be drilled? |
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Somewhere there is a post about someone buying a thermistor to make their own TSII sensor. It is likely possible to buy the correct thermistor and just JB Weld it into the broken off TSII sensor base in situ. |
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airkooledchris Samba Member
Joined: January 25, 2005 Posts: 2700
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Posted: Mon Jul 16, 2018 9:31 am Post subject: Re: TSII seized - can it be drilled? |
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Keep in mind that if you have replacement heads from AMC - they put that sensor port on all the heads they make, so you could just use the one on the #1/2 side instead. |
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LiamSG Samba Member
Joined: May 22, 2018 Posts: 12 Location: Canada
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Posted: Tue Jul 17, 2018 11:04 am Post subject: Re: TSII seized - can it be drilled? |
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Furgo, your story sounds like exactly the hell I am going through. I too am having no luck with a bolt extractor and am considering creative ways to just drill the whole thing out as you ended up doing. And unfortunately, I am currently in an apartment so dropping the engine is not an option until next spring when my house is built - I am already pushing my luck doing as much work on the bus here as I do.
The more time I spend swearing with my head in the engine bay, the more I am convinced that drilling and tapping over cylinder #4, as Wildthings suggested, is definitely the way to go. There is already a hole in the correct location and it is even open through the tin (not sure if a bolt was meant to be in there at some point in the past?). I just removed a couple hoses, etc and access looks really good.
I will give this a try and report back, as soon as I can get a crusty hose clamp off and remove a piece of fuel line (don't worry - a full fuel line replacement is up high on my to-do list).
I don't suppose anyone knows off hand the correct tap for this sensor? |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Tue Jul 17, 2018 11:22 am Post subject: Re: TSII seized - can it be drilled? |
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There is one 10mm screw holding down the tin on the 3/4 side. That is the original place VW placed these senders on early FI T4 engines. Although the temperature range is different on those original senders you might be able to put the TS2 there until a time when you have a better place to work on it. I have never tried this so someone else may overrule me and say it doesn't work well there.
Good Luck _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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LiamSG Samba Member
Joined: May 22, 2018 Posts: 12 Location: Canada
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Posted: Tue Jul 17, 2018 11:55 am Post subject: Re: TSII seized - can it be drilled? |
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SGKent, is this (Green circle) the bolt you are referring to?
For reference, blue circle is the location above cylinder 4 I am looking at drilling/tapping. |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Tue Jul 17, 2018 12:27 pm Post subject: Re: TSII seized - can it be drilled? |
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there are two screws that hold the tin on that side - one is over #4 and one is over #3. It is the one over #3. It will either fit or not but quite a few cases have the proper size for a TS2 there. Below is a quote of someone who was wondering what went there. VW has a special tin screw that fits. It is larger than all the rest. Same thread and pitch usually as the TS2. You can see the foam seal and the embossed #3 by the spark plug in his photo. When you take that screw out compare it to the TS2 and you'll know right away. You should be able to look straight down on it with the hatch cover off.
Beagledog1 wrote: |
After I rebuilt by 2.0 liter type 4 engine a year ago, I haven't been able to figure out what goes in this hole (center of photo). I would think it would just be an engine tin screw, but its too big for a standard engine tin screw. As the photo shows, it's near the #3 plug but it's not for the Temp Sensor 2, as far as I can tell. My Temp sensor 2 is further down and screws into the head, not the block. Any ideas?
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_________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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furgo Samba Member
Joined: September 06, 2016 Posts: 944 Location: Southern Germany
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Posted: Tue Jul 17, 2018 3:11 pm Post subject: Re: TSII seized - can it be drilled? |
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LiamSG wrote: |
Furgo, your story sounds like exactly the hell I am going through. I too am having no luck with a bolt extractor and am considering creative ways to just drill the whole thing out as you ended up doing. And unfortunately, I am currently in an apartment so dropping the engine is not an option until next spring when my house is built - I am already pushing my luck doing as much work on the bus here as I do. |
Ok, I hear you. You're in exactly the same situation I was in, so I won't question not dropping the engine. I'm hoping yours does not end up being such a miserable experience as mine. Good news is, I finally claimed victory
I'd still suggest trying to use the original location on cylinder #3 and saving the original thread. This summarizes my thoughts on this:
https://www.thesamba.com/vw/forum/viewtopic.php?p=8820358#8820358
https://www.thesamba.com/vw/forum/viewtopic.php?p=8820934#8820934
Others may have other opinions and that's fine. Hopefully you have enough info to make an informed decision on your approach. Whichever one it is, let us know how it goes and we'll try to give a hand.
Some notes:
• Thread size for the TS2 sensor is metric M10x1
If you choose to go for the #4 location:
• The hole in the blue circle on your picture is the one you want.
• You are lucky the screw is no longer in there. They tend to seize in that location, just as your TS2 did, so you'll be spared another world of pain by not having to remove it first.
• You'll need to make the hole in the tin bigger
• Don't drill too deep. 15 mm max. Use a stopper on your drill bit.
• If you do drill too deep, don't despair. The head is not ruined, you've just drilled through a fin. Ouch. Not the end of the world, though.
Some "X-ray" pictures of what's behind the cylinder tin should help you. I.e. what you'll be drilling. Both sides (cylinder #3 or cylinder #4) look the same, other than being mirrored. These are for #4. Please ignore the remains of the seized screw. This is an extra cylinder head I used for a mockup.
This simply shows the hole going through
This shows the room you have before you hit the next fin with your drill. Don't drill deeper than 15 mm
View from the front. Please ignore the remains of the seized screw.
Good luck! _________________ '79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
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LiamSG Samba Member
Joined: May 22, 2018 Posts: 12 Location: Canada
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Posted: Sun Jul 29, 2018 8:51 pm Post subject: Re: TSII seized - can it be drilled? |
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Update:
It took a while to find the right tools and help, but I finally have the sensor mounted! I didn't have any luck finding an appropriate tool to drill out the original threads, so I did end up drilling and tapping over cylinder #4.
If anyone else chooses to try this in the future, I would say that while this certainly was the easier option, without dropping the engine it still was quite challenging. A drill JUST fits at the right angle against the tin, and is difficult to hold steady while drilling out the hole. A tap wrench doesn't fit and the tap socket I had was too long to keep the tap at the right angle, so we ended up having to hold the tap by hand while turning it with an open-end wrench. Not the best technique by any means but I was lucky and it worked.
In any case, the engine now starts much easier and runs great. Now I can relax a little before setting off on a ~900km trip on Saturday. Thank you all! |
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furgo Samba Member
Joined: September 06, 2016 Posts: 944 Location: Southern Germany
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Posted: Mon Jul 30, 2018 3:37 am Post subject: Re: TSII seized - can it be drilled? |
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Nice one, glad it worked. Thanks for updating everyone with the progress!
Time to enjoy the bus now. _________________ '79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
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