Head Bolt Question

[thekingof7]

Long time no see!
After posting this thread, http://www.audizine.com/forum/showth...-Bad-Reservoir
I have had the head tested with no leaks or cracks found. What I am thinking is that I either scratched some material off of the head gasket or I torqued the bolts down incorrectly.
I am aware of the factory procedure for setting torque, but I was wondering if anyone had any tips for getting these bolts set properly.
Should there be any lubricant or thread compound on the bolts? If so what kind?
Should I be using an angle gauge, or does someone have a torque value that is approximate to the 90 degree turn?

Last, if you look at my old thread you will see a post referring to a "17704 - Error in Mapped Cooling System (usually temp Sensor or Thermostat) P1296 - 008 - Implausible Signal" code. Since I have the head off and I'm near the thermostat is there any sort of test I should perform? Has anyone resolved this by replaceing a particular coolant temp sensor?

Sorry for the barrage of questions, but this car needs to move out of the driveway.

-Nice to be back.

[SaabtoAudi]

Long time no see!
After posting this thread, http://www.audizine.com/forum/showth...-Bad-Reservoir
I have had the head tested with no leaks or cracks found. What I am thinking is that I either scratched some material off of the head gasket or I torqued the bolts down incorrectly.
I am aware of the factory procedure for setting torque, but I was wondering if anyone had any tips for getting these bolts set properly.
Should there be any lubricant or thread compound on the bolts? If so what kind?
Should I be using an angle gauge, or does someone have a torque value that is approximate to the 90 degree turn?

Last, if you look at my old thread you will see a post referring to a "17704 - Error in Mapped Cooling System (usually temp Sensor or Thermostat) P1296 - 008 - Implausible Signal" code. Since I have the head off and I'm near the thermostat is there any sort of test I should perform? Has anyone resolved this by replaceing a particular coolant temp sensor?

Sorry for the barrage of questions, but this car needs to move out of the driveway.

-Nice to be back.

I can get you the 90* turn part, but the rest of the question I don't have any answers for. I would mark the bolt with a grease marker/pen and the head in the same spot, then you can rotate the bolt until it's 90* away from that mark.

[MikTip]

Long time no see!
After posting this thread, http://www.audizine.com/forum/showth...-Bad-Reservoir
I have had the head tested with no leaks or cracks found. What I am thinking is that I either scratched some material off of the head gasket or I torqued the bolts down incorrectly.
I am aware of the factory procedure for setting torque, but I was wondering if anyone had any tips for getting these bolts set properly.
Should there be any lubricant or thread compound on the bolts? If so what kind?
Should I be using an angle gauge, or does someone have a torque value that is approximate to the 90 degree turn?

This is where having a manual like the Haynes or Bentley comes in handy:

Insert cylinder head bolts and hand-tighten.
Tighten cylinder head bolts in two stages in sequence shown as follows:
Tighten using torque wrench:
Step 1: 40 Nm
Tighten with normal fixed wrench:
Step 2: 180 degree (1/2 turn) further (2 x 90 degree turns permissible)
Note:
It is not necessary to re-tighten cylinder head bolts after repairs have been performed.

A 90 degree is just that, no torque value, just turn the bolt 90 degrees. Ya can mark it with a magic marker if needed...

[Charles.waite]

Pull the thermostat off, and submerge it in hot water. With a set of tongs and a thermometer, try to ascertain when the thermostat is opening. It should begin to allow water to pass through the mechanism around 80ºC. If it waits longer that 90ºC then its broken and should be replaced. If it allows water through before 70ºC then its broken and should be replaced.

[Seerlah]

Use assembly lube on the bolts (ARP preferred).

http://www.summitracing.com/parts/arp-100-9909 (seems they made their old assembly lube better)

And use a quality torque wrench. If it looks like the one sold at Autozone, don't use it. I don't care what brand it says on it and where it is sold at. Preferably a digital one should be used. Cheapest quality digital ones are Craftsman, IMO (what I have and built my engine with).

[MikTip]

I have used Craftsman torque wrenchs for many years on various Audi's!

[thekingof7]

Appreciate the advice guys.
I was using some no name torque wrench from the mid 90s . Guess it should be kept for setting wheel bearings and lugnuts. I'll go check out the local sears and see if they have any craftsman products that fit the bill.

As far as lubricant, I am not using ARP head studs $$$, but rather some OEM or Felpro. Does this lube work with stretch bolts as well? Also is there a similar product that wont need to be special ordered? I was hoping to get this started over the weekend and would rather just pop into a NAPA or similar place.
-Thanks

[DiertyEuroSpec]

I over tightened a head bolt once and.....it snapped LOL Well at the time I shit my pants but I was able to grab hold of it as it was JUST sticking out above the block otherwise I would've been screwed. Someone had posted "when you get the stock head bolts to the right torque after the sequence they come out to about 90 lbs" Whatta joke go by manuals as Miktip posted.

[thekingof7]

So, lubricant on OEM stretch bolts? Yes or no?
I've seen all kinds of debate on the net over this so it would be nice to see what people have done for the a4.

[PreciseD]

Head bolts are spec'd for Dry Torque. There is a big difference in values between Wet and Dry Torque. If you Wet Torque you need to decrease the SET Value by roughly 20% to 30% or you will over tighten them.

EDIT:

Sample

DRY - 100 ft lbs / 1.00 = 100 ft Lbs of Rotational TQ

WET - 100 ft lbs / 0.70 = 143 ft lbs of Rotational TQ

[customa4]

No. Torque the bolts in three stages and the correct sequence.

This picture shows the head bolt removal sequence.



The head bolts should be torqued in three stages.

I – Tighten with torque wrench to 40 Nm.

II – Turn 90° (1/4 turn) further using a rigid wrench.

III – Turn 90° (1/4 turn) further using a rigid wrench.

This picture shows the head bolt install sequence.