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Discussion Starter #1
I've got a 2003 and I'm replacing the exhaust manifold gasket. Got the old studs out, ordered a new set of studs from www.eeuroparts.com. The new studs are loose as they screw in. Even all the way threaded is still wiggle/move. Obviously the wrong size. Why?

visually the old stud thread and new stud thread look the same. But screwing on a nut you can tell that they are different. The self-locking nuts from the old studs pass right over the new studs without much effort, so... What's going on?
 

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Discussion Starter #3
Part# 21347280

unless I'm missing something, I have double checked and this seems to be the right part when every website I visit. It definitely appeared to be the right parts when I opened it up.
 

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That's the right kit for cars in this forum, but I just noticed you have a 2003. Is it a convertible or a hardtop? If you have a hardtop, then you're in the wrong place, and probably bought the wrong hardware kit. If it's a convertible, then I'd start to wonder if someone drilled out the head for larger exhaust studs.
 

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Ignore me. :) I was thinking of the 9-3. That should definitely be the right kit for any 2003 9-5. I really do wonder if someone drilled out the holes in your cylinder head. Did the old studs you took out look odd in any way? Were the same length as the new ones?
 

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Discussion Starter #6
It was rebuilt in the past, got 183 k on it now. Guess I'll take a new bolt and an old bolt down to the shop and see what we need to get the right bolts :) nothing about the old ones look weird.
 

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Discussion Starter #7
So I went down and grabbed some M8 1.25 nuts. They fit both new & old manifold studs...but the new studs are loose and the old studs are SOLID - no wiggle room yet screw on smooth with no binding.

So are the new bolts just cut with lots of slop? This doesn't seem right. With a couple of the stud-spots in the head the new bolts are extra loose. Even the new M8 1.25 generic bolts from the hardware store have slop compared to the old studs. Not as much as the new studs...but still a little.

So why are my old studs so perfectly fit to the engine...do they make an oversized stud? something with a slightly larger size?

Not sure what to do now. Suggestions?
 

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That's really odd. The bolts are M8x1.25 and pretty much standard. If the head is worn you would expect all of the bolts to be loose.
 

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Discussion Starter #9
That's really odd. The bolts are M8x1.25 and pretty much standard. If the head is worn you would expect all of the bolts to be loose.
Yep - really strange. Someone local suggested that the threads might have stretched...but it doesn't make sense to me that the old studs and head would stretch to match...I just don't think that is possible.

I've ordered another set of studs to see if it was a bad batch. I'll have them tomorrow and will update. Hoping I just got a bad set :(

PS has anyone tapped the head to cut new threads? Is there enough room to
 

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Discussion Starter #10
Received a new set or ProParts studs and they are the same - loose. Went and purchased some M8 1.25 All Thread to test and it is still not as tight as the old studs but a much better fit than the new ProParts studs.

Thinking I'm going to source some GM or universal studs of similar length to work with.
 

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Discussion Starter #12
Maybe someone tapped them to a non metric thread.
hmm....hadn't thought of that as the new M8 stud fit (almost) and the olds stud fit M8 nuts perfectly....but maybe.

What size would be that close to M8 to nearly fit? I'll start googling for a conversion chart...
 

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If they were tapped to a non-metric thread the bolts would not screw in more than a turn or so. The issue is not the diameter but the thread pitch.

Those studs have been a bit loose on most of my cars, it's remarkable how easy it's been to get an ez-out to take out teh ones that have broken off when I needed to. I've even been lucky enough to use a small drill to make a "slot" in the top of a couple and used a flat screwdriver to take the studs out. But wiggling around? not that much.

I't take it to a machine shop and ask for their opinion. But tell them to be careful if they drill out the holes for a helix-coil or something like that since if they drill too deep they can drill into the water jacket in a couple of spots. (yes, I know someone that had that happen. I have one of his exhaust valves from that head sitting in front of me right now on my desk being used a a paperweight)
 

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Discussion Starter #15
one word answers your problem Proparts Chinese stuff class c threads or just wrong Buy gm studs problem solved
Thread Class - didn't know that was a thing until now. So as I have an old stud with the correct fit, how do I measure it so that I can identify & source the correct replacement?
 

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Alternately try Genuine SAAB (Taliaferro Imports) for a set of studs - not as cheap, but they have $$ and $$$ priced stainless stud kits. I used their moderately priced stainless kit, and I was pleased. Their $$$ product is ARP stainless, which was nicer than I wanted to afford.
 

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Discussion Starter #19
While I have not snugged anything down yet, the ARP studs are a world of difference! They thread in with almost zero play and should completely solve this issue :)

Question: Do you torque the studs in the head or only the nuts on the studs? I was thinking I would just hand tighten the studs & torque the nuts to 18ft/lb

I'll report back when the car is assembled and running again - hopefully this weekend!
 

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Check the ARP instructions - from what I have seen, they sometimes have unique and specific instructions on use of thread locker and / or lubes when installing their products (head studs especially). You could even call them and ask.

I used Genuine SAAB's less expensive stainless studs, and I installed them with 18 lb/ft of torque using thread locker. I used thread locker because I read a post from one SAAB 9-5 owner who complained that his stainless studs loosened over time. I then used the same 18 lb/ft torque to install the nuts. The car on which I installed these has been fine to date - over 5K miles ago - but this is just a description of what I did, not guarantee that this is the right or best way to do it.

Hope this offers perspective.
 
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