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996 3.4

RC911

Well-known member
Joined
14 Feb 2014
Messages
74
hi guys any potential issues regarding the 3.4 block, things to look out for etc etc car is 87000 mile manual cab (year 2000)
 
Um... 3.4 has a lot going for it over other engines.

A very few cars had bad castings, leading to D chunked cylinders, out of round rear main seal (RMS) hole and cracked heads. This kick started the 996 engine reputation woes.

Any of those will have shown themselves by 87k miles.

You might have an RMS (rear main seal) leak, just forget about until the next clutch and then you can have the latest revision of RMS fitted (£20) and your IMS bearing cover re-sealed.

Talking of IMS, the early 3.4 had a stronger bearing than later cars. I just inspected mine after 134k miles and its smooth as butter.

Also the early 3.4 pistons have a more robust ferrous coating which Porsche phased out for the 3.6 for H+S reasons, this means the 3.4 does not suffer from premature bore score.

This being a 2000 might not have these "early" features, I'm not sure if you can even check by chassis number.

Ideally borrow a Durametric system (I have a chinese copy). This will interrogate the ECU and tell you if the engine has ever been "over revved" which can stress components. Also it will tell you the cam deviation figure which you can use to assess the integrity of the timing system and chain tensioners etc. - and can also indicate IMS bearing play (as above not generally a 3.4 problem).

Check the Exhaust manifold bolts - those are major PITA to drill out if they are just rusty blobs.

Fuel rails do rust away.

Check for corrosion at each end of the sills (not easy with plastic trims fitted), jacking points and the front subframe rearward mounting points.

These are the oldest of 996 and are starting to rot.
 
thanks for the reply he was initially thinking of the 3.6 but he thinks the 3.4 block is safer
 
3.4 is a much safer bet. 3.6 is prone to bore-scoring and has suffered a higher ims bearing failure.

123k miles on my 3.4 cab and drives like new.
 
RC911 said:
thanks for the reply he was initially thinking of the 3.6 but he thinks the 3.4 block is safer

Theres a million things that can go wrong with any engine at any time.... also the 3.4s are the oldest of 996 cars and age is a factor.

As far as I'm aware some of the last 3.4s got different combinations of piston coating and IMS bearings. Also I think warranty replacement 3.4s and new blocks came with single row IMS bearing and plastic coated pistons.

So I'm not 100% sure the 3.4 is the safest choice - that probably goes to a GT3 or turbo metzger engine, but then these have their own issues (coolant pipes on a turbo anyone?).

Just choose the nicest, best looked after car in price range and enjoy it.
 

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