Lubricating new head bolts? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Lubricating new head bolts? by wil892 on 19 Apr, 2009 13:46
• What are the requirements for lubrication of the head bolts? I've just torqued up my head to the stage just before warming it up i.e. 180 degrees done in two stages.
  
  To lubricate the bolts I rubbed some synthetic 5w40 oil on the threads and put some anti seize copper on the underside of the thick washers.
  
  The bently says nothing about lubricating them but I didnt want to put them in dry. Now I'm wondering if I should have put more oil on them or some anti seize on the actual threads.
  I'm a bit wary of the next stages of torqueing if they are not properly lubricated.
• #1 by lovinthedeez on 19 Apr, 2009 14:24
• best way that makes sense to me is to dip your bolts threaded part in oil, then let them sit on some cardboard or a rag for a little bit for the excess to drip off
• #2 by burn_your_money on 19 Apr, 2009 14:44
• Lots of people put them in dry so I wouldn't worry about it. I've personally seen it done both ways with success.
• #3 by gigaz2 on 19 Apr, 2009 15:38
• I've put mine dry, the important part about bolting the head is that the holes must be pristine.
  there can be nothing in there, as clean as possible!
  
  I have a cracked block to prove that
• #4 by wil892 on 19 Apr, 2009 15:51
• thanks thats put my mind at rest. I made sure there was no liquid in the holes and I ran a bolt tap through them to clear any debris from the threads. There may have been a couple of specs of carbon at the bottom of some of them but nothing bad.
  I will see how the tightening goes tomorow when I get it running hopefully. I assume that they have to be tightened when the engine is still hot? To get the car hot can it be driven or should I just idle it up to temp?
• #5 by theman53 on 19 Apr, 2009 19:39
• Idle with coolant cap off and if I remember you are supposed to let it cool. I could be wrong on the cool part, but the other 2 I know are good. Let it idle until the thermostat opens/fans come on.
• #6 by Quantum TD on 20 Apr, 2009 09:37
• I strongly recommend that you DO NOT use synthetic oil to lubricate your threads. It effectiively reduces surface tension, making the torque reading on your wrench mush higher than it ought to be (i.e. the final torque values will be too high).
  
  I found out the hard way. I lubes some bolts with 5w/40 synthetic oil when installing a head on a 98 TDI. On the final pass (1/2 turn), 3 out of 10 bolts gave up the ghost on the beginning of the turn and started to stretch out. I had to pull the whole head off and redo it.
  
  The bolts do need to be lubricated. Reinz headgaskets come with an instruction manual that insists that the bolts be lubricated. Sadly, they do not specify what lubricant to use. Most bolts come pre-lubed, but if not, then use some WD40 and let any excess run off.
  
  There are a couple threads here about torque values and lube. Do  a search.
  
  In the meantime, if your bolts have not stretched on any of the passes in the torquing process, then you're probably ok.
• #7 by wil892 on 20 Apr, 2009 11:02
• Hi quantum
  
  the oil I used was only a group 3 oil and I did not dip the bolts in the oil, simply rubbed my fingers on them which I had just dipped in a cap of the oil. Do you think this poses a problem, removing the head again would be a real pain.
  I've only torqued the bolts to the stage before the first warmup, when tightening them they all felt pretty much the same in terms of effort to turn them, one was possibly a little easier but that may have just been the angle I was turning it from.
• #8 by DCC on 20 Apr, 2009 11:20
• I've always used copper grease. Just a little ammount on the threads and it's done. All VW head gasket kits I've bought (head gasket and bolts) come with a little bag of copper grease. That includes Febi, Elring and Ajusa.
• #9 by Quantum TD on 20 Apr, 2009 23:26
• Quote from: "wil892"

  Hi quantum
  
  the oil I used was only a group 3 oil and I did not dip the bolts in the oil, simply rubbed my fingers on them which I had just dipped in a cap of the oil. Do you think this poses a problem, removing the head again would be a real pain.
  I've only torqued the bolts to the stage before the first warmup, when tightening them they all felt pretty much the same in terms of effort to turn them, one was possibly a little easier but that may have just been the angle I was turning it from.

  
  
  Do the final torque and see. The TDI sequence is the same as the IDI, except you don't do the warm up or the 1000k retorque, as the gasket is multi-layer-steel (MLS). You should have the composite (fiber) gasket which will give more. In my case, there was no where for the metal to go, so when the yield value for the bolt was met, it stretched out.
  
  As a failsafe, set your torque click wrench to 118 ft/lbs and do the final torque (warm-up). Be sure to note how the bolts feel when you do the last turn, and when/if the torque wrench clicks when you turn the bolt. The 118 ft/lbs is about what the bolts should finish at on a 1.6 diesel after the full sequence, based on my experience. 125-135 ft-lbs is about the max the bolts can handle before they'll give up.
  
  I think/hope you'll be ok, but if you start to feel the bolts give, then stop turning. You've reached their limit. You can try to run the gasket and see how it goes. The 1000k re-torque is only really necessary if you notice weeping (coolant seeping out of the sides of the gasket).
  
  Not trying to scare you. Anything's possible. My experience was my first time on a TDI head job. I followed all the precautions, but I was delivered dry bolts. I had some synthetic laying around and tried it. I found out the hard way.
  
  If just the edges (and not the valleys) of your bolts were lubed, then you should be ok.
• #10 by wil892 on 23 Apr, 2009 02:56
• Thanks, im getting the timing set up properly today by a diesel shop. Then I'll run it up and do the next sequence.
  
  Do the bolts have to be tightened when the car is still hot or do I let it go cold?
  
  ps yes I pretty much just lubed the edges, possibly a tiny bit in the valleys but hardly anything. I'll just have to wait and see.
• #11 by dieselweasel on 23 Apr, 2009 21:55
• FWIW, I use Caterpillar branded moly paste on head bolts (threads and washers).  The molybdenum disulphide reduces friction.  It's what Cat specifies on most of their engine's head bolts.
  
  I see nothing wrong with using a light coating of engine oil though.