Cylinder head bolt tightening sequence

Cylinder head bolt tightening sequence for the ET3 and TU3 C3 petrol engines


Stretch bolts are used in the ET3 and TU3 engines fitted to the C3 and they can be re-used if they are still within spec.




Spec for ET3 J4 (KFU) 1.4 16v X = 119mm maximum

Spec for TU3 (KFV) 1.4 8v X = 175.5mm maximum



The head bolt tightening torque for ET3 J4 (KFU) 1.4 16v is

A pre-tightening of 1.5 ± 0.2 (m.daN)
Then a tightening of 2.5 ± 0.2 (m.daN)
And a final angular tightening of 200° ± 5°



While the tightening torque for the 8v 1.4 TU3 (KFV) head bolts are

A pre-tightening of 2 ± 0. 2 m.daN
With a final angular tightening of 140° ± 5°


Note 0.1 Deca Newton Meter (daN·m) is 1 Newton Meter (N·m)


Tips for re-using head gasket stretch bolts

Insert a tap in the threads of the holes in the cylinder block receiving the cylinder head bolts to clean the threads.
Wire brush the threads of the cylinder head bolts.
Coat the head and under the under the head flange with Molykote G-Rapid Plus.


If the bolts are out of spec (stretched), look suspect or show any signs of surface corrosion, get a new set of Citroen C3 head bolt sets from here to avoid problems later.

I don't recommend reusing torque-to-yeld (stretch) bolts but that's my personal opinion.

The user must be aware of the potential to snap the bolt on re-installation and the consequences.

I understand that stretch bolts can be reused but the person reusing the bolts needs to understand and accept the risks.

Also, you won't know if a bolt is stretched beyond it's limits until you have pulled it out. If you are reliant on your car for transport (to get new head bolts)...well...it's a bit late after you have pulled the head bolt out.