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BMW Head Bolt Thread Problems

2003_bmw_3-series_sedan_330i_fq_oem_1_300There is a run of 6 cylinder BMW engines causing mechanics and owners all sorts of grief when it comes to repairing cylinder heads and replacing head gaskets.

The 6 cylinder BMW engines affected include the M50, M52 and M54 that come out in various models from the early 1990’s through to about 2007.  3,5 and 7 series vehicles as well as the  Z3, Z4, X3 and X5 are all at risk.

Now the problem is simple….the aluminium blocks are stripping the head bolt threads when you try to torque down the cylinder head after gasket replacement, even if the engine hasn’t been overheated.  bmw-engineYour options are to source a second hand motor of unknown condition and take your chances with it, or have the threads repaired.

Southside Cylinder Heads and Engine Reconditioning Australia have a thread repair kit available to do the job.  This kit is suitable for both flush threads and recessed threads.  Its available as a rental with security deposit and you can fit them yourself, or we can come to you and supply and fit the thread inserts on site and in car.   $POA

                                     Please contact us for pricing phone 07 3343 5899

Thread Repair Kit BMW

Thread Repair Kit BMW

 

New Ultrasonic Cleaning Technology

Over the Christmas break we were spoilt here at Southside Cylinder Heads as we too received Christmas presents! We were lucky enough to get a BRAND NEW ULTRASONIC CLEANING MACHINE!

This machine has enough power to clean even the most stubborn Carbon build ups on Diesel and Petrol Cylinder heads/Blocks/Rocker gears and Timing cases.  Especially handy for late model turbo diesel inlet manifolds, which tend to become heavily carboned up and nearly totally blocked  resulting in loss in power and increased fuel consumption.  Dont forget we have a pick and delivery service available 🙂

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Warning on the use of Hylomar!

Most of the head gasket designs available for aftermarket use can be classified into two general categories – Composite and Steel (MLS).  Typically composite head gaskets have a steel core, usually perforated, with softer facing materials (graphite or aramid fiber) bonded on each side.  Until recently steel head gaskets consisted of four to six layers of steel bound together by a variety of mechanical methods however the trend now is for fewer layers with three or two layers not uncommon and even a single layer now in use on some applications.  Also common to these head gaskets is an impervious silicone coating or viton rubber sealant bonded to the outer layers, a key characteristic in the ability of the gasket to “cold seal”.

Gasket

 Generally speaking, almost all aftermarket head gaskets (both composite and MLS) are designed to be used without additional chemical sealants (i.e. hylomar).  The use of an additional chemical sealant on gaskets not designed for it will actually do more harm than good and affect the gaskets ability to seal.

The use of additional chemical sealants such as hylomar can affect the head gaskets ability to:

  • Cold-seal, the ability of the gasket to seal coolant until the engine is first started.
  • Cold Flow, the characteristics of the coating material to creep as the gasket is loaded (clamped), to seal small scratches and imperfections on the head and block surfaces.
  • Reduce the shearing forces that are applied to gasket sealing surfaces by thermal expansion of the cylinder head and block
  • The added thickness of an applied sealant on a head gasket can cause uneven loading and or a loss of torque retension.
  • The use of an additional sealer may also cause relaxation when temperature is introduced

Some chemical sealants may also react with the gaskets silicone coating, causing the gasket to deteriorate, and in some cases can cause the deterioration of the chemical sealer itself.

The vast majority of gaskets supplied by Southside Cylinder Heads will not require any additional sealants and the use of such products is not recommended, and may void the head gasket’s warranty.  Please read the gasket fitting instructions before fitting your next head gasket, or simply give us a call if you are unsure if your head gasket requires an additional sealant.