Headbolt or stud question

[mystery3]

Is there a definitive way to tell if an engine has 11 or 12mm headbolts without pulling the head and measuring? I'd like to order some arp studs and have read a lot of conflicting info regarding triple-square and allen head bolts and when the switchover was made etc.

I have triple-square bolts, my truck is an 81, it's had a few owners and I don't really have any history from the first 28 years of it's existence. Should I go ahead and order 12mm? How is the shipping speed from headbolts.com?

[Thezorn]

some if not all 1.6's have 11mm and all the 1.9's have 12mm. Im not sure if all 1.6s have 11mm, I sorta remember reading some came with 12mm? And as for older 1.5s Im not sure.
Hope that helps a bit. haha

[ffgb]

I forget what month in 1981 was the cutoff when VW made the switch from 11mm to 12mm headbolts.  I thought I saw that the month was august of 1981 manufacture, but don't quote me on that!

[RabbitJockey]

no u need to find out what u actually have because 1981 was the year they used both size head bolts.  i am almost certain that if you have an 17mm bolt holding the crank sprocket on that u have 11mm head bolts, and 19mm crank bolt is a 12mm engine

[rabbitman]

My rabbit has a 17mm crank bolt and 12mm head bolts.

AFAIK the 1.5 was always 11mm.

IIRC you can tell by pulling the VC and looking at the bolt heads.

The search function works pretty good sometimes .

[truckinwagen]

problem is that not all 11mm bolts have the allen head.
some had the triple square head just like 12mm bolts.

the only real way is to pull them and compare to an 11 or 12mm bolt...

-Owen

[rabbitman]

Maybe it works to pull one and look at it and then replace it without disturbing the HG.

[Wayland]

Maybe it works to pull one and look at it and then replace it without disturbing the HG.

I tried this for the very same reason, and noticed a bit of coolant seeping out between the gasket and head next to where I pulled the bolt out. I put it back in and retorqued it, but haven't tried running it. My guess is that I'll have to replace headbolts and gasket.

[8v-of-fury]

My ETKA shows that if the truck shows an 81 build date... everything leading up to VIN serial # 176 338 should have 11x98 head bolts. Every VIN serial # 176 339 and up should be the 12x115 bolt



HOWEVER! Upon further digging...

They show the same picture for an 84 cylinder head as well.. and they also show a hydro head and cam cover on both.. I cant see this being accurate in the least bit.. They also show the 11mm head-bolt for an 84 engine.. even though im almost dead certain the 12mm would have been in full swing by then..



WTH ETKA lol

[mystery3]

I was reading your message thinking "wow, this is super helpful, I'll go check my vin" only to get further down and realize that I still can't find any concise data on these damned heads...

[maxfax]

1.5's All had 11mm bolts..

1.6's had 11 mm bolts till mid 1981 officially, however some of the Westmoreland built cars had them on early '82 model year cars... My guess was since the engines were built in Germany and shipped over that they had a few leftover and stuck em in some '82 cars..

For diesel head bolts the 11mm were allen heads, 12mm were triple square..  However 8v gasser bolts are 11mm with a triple square head, and some people used these in their diesel..

Unfortunately IIRC, the 11mm gasser bolts, and the 12mm diesel bolts both use the 12mm tripple square socket..

The best way for you to determine which head bolts you have could be to get the code from the block.. (this can be found stamped into a flat spot under the upper hose on the engine block, kind of a pain to see).. 

[stomperz71]

OK, So I'm in the process of replacing my HG. By the way I'm working on a '81 VW Caddy. I know I have 11mm bolts, but the head of the bolts that I am removing are the triple square. I assumed these were stretch bolts so I ordered a new set along with the gaskets I needed from Parts Place. They told me that the 11mm bolts are only avaliable in the triple square anymore?? So my question is how do I treat these bolts when I torque them? Are they really stetch bolts?

[vanagonturbo]

The triple square bolts are all stretch bolts. The allen bolts are not stretch bolts. That is correct that 11mm triple square bolts are the only ones available now for an 11mm application.

[BillyWillicker]

isnt another way to tell by looking at the back of the block and where it is cast D, 16D 1.6D a tell-tale too??  Like D means 1.5, 16D means 11mm 1.6 and 1.6D means 12mm 1.6?  I seem to remember reading that here.

[stomperz71]

So I should do the 30 ft lbs, 44 ft lbs, 55 ft lbs and then 1/2 turn with breaker bar? Then another 1/4 turn after first warm up? I think that's what the Bently SM said for 12mm stretch bolts. That seems like a crap load of torque on them bolts. That's another 3/4 turn after the 55 ft lbs. That would probably be up around 80 ft lbs total???