Author: John Thorne

We first came across some issues with the power steering pump 2 years ago, an owner commented on issues he was having with multiple canbus failure due to water ingress into the front compartment but as we never saw the car nor inspected the issue we put in in the ‘keep an eye our for it’ section for Mclaren and moved on, but this week we had two 12c Coupes both recovered/limped in with multiple ECU faults and on both cars a complete electrical break down.

First car was reported as complete electrical failure, multiple ECU faults, power steering, ABS, traction, suspension you name it, every light was on and the car was stuck – pretty much screams canbus failure and the fact it happened in the pouring rain meant we assumed water ingress of some kind. Initial inspection confirmed this, water in the footwell and carpet area so we started the process of chasing down the fault ECU by ECU. Having the full Mclaren wiring diagrams and diagnostic kit was essential and we eventually tracked it down to three ECU’s all in the front of the car, the main dash ECU, power steering ECU and suspension ECU.

After taking apart the whole front end section we found the issue – the power steering pump was heavily corroded and the lower case seal had failed allowing water into the pump unit itself causing it to ground out and as its part of the main canbus system caused a multiple cascade affect of ECU failures (think of it as a weak link in a chain, if the link goes the whole chain does).

 

In UK spec cars the power steering pump is ‘protected’ by a plastic cover, which is designed to keep the noise in the cabin down from the pump.

The problem is that this plastic cover (despite costing £85!) is a bit crap and it has split allowing water into the foam which acts like a sponge resulting in the power steering pump sitting in a pool of water, this has corroded the casing causing water ingress and ultimately the pump to fail.

We can dry out the pump easily enough but if enough water has penetrated the mechanism it means the pump motor will fail so needs replacing at a cost of £1300 plus VAT. A lot of this water ingress comes from the washer pipes which split quite regularly resulting in washer fluid leaking directly onto the power steering pump cover which leads to the question of whether this is something that should be covered under warranty?

The answer is probably no, the water ingress is caused by a split pipe (wear and tear) but after that its a split in the cover that makes it worse (trim) and then corrosion on the pump itself, all of which one could argue is a design fault with the car though. For us, we will cover it as a goodwill issue for cars with our warranty but we dont imagine anyone else will for the above reasons. To help prevent the issue happening to your car – check your washer pipes regularly – they do split, often, but we are adding this to our list of checks to cars for warranty and purchase inspections. If you want to know you have an issue just try your windscreen washers, if its not on the screen from both arms then its going somewhere and is most likely going over your power steering pump.

Whilst its disappointing that a supercar has such an issue at least it is fixable.

Just a few shots of the recent Mclaren Owners club meet at Salon Prive.

Great had by all, 36 cars in total so a great display. Strongly recommend owners join up as its great value at £50 and has a mass of meets, events and deals on offer as well as 10% discount on our labour rate!

For details see here: Mclaren Owners Club UK

 

Another great Greystone track day, this time at Goodwood where we again provide full technical support for everyone attending. As well as the Mclarens (12c, 720, 570, 650s) we also looked after a couple of Aston Matins, AMG mercs and a lovely 911 GT3RS.

 

Great time had again with the UK Mclaren owners club, 81 cars this time (second largest group of Mclarens together since our record breaking 100+ at Silverstone two years ago) and a great mix of new owners as well as long term owners still enjoying their cars.

Thanks must go to Jeff and the team at the Mclaren owners club, growing all the time and a real support network for Mclaren owners everywhere.

The Mclaren range all uses the same base engine known as the M838T. The 3800cc twin turbo charged engine was originally developed for Indy car racing and after work from a variety of operations including Mclaren, Walkinshaw and Ricardo is now the staple engine for every Mclaren road model from P1 to 12c.

 

Over the models a variety of changes have taken place mainly to the head from 12c to 650 and 675LT and more changes to the Sports series and then the 720 where the capacity was increased by 200cc by stroke with new pistons and crank. The engine is nothing short of an engineering master piece having won awards since inception but being dry sump it does have one achilles heel – oil level.

IT IS CRUCIAL TO ENSURE THE ENGINE HAS THE CORRECT OIL LEVEL AND IS NOT REVVED HARD WHEN COLD.

Yes, thats in caps, it needs to be as I’m afraid we are starting to see cars with top end engine wear due to either insuffucient oil or being revved hard when cold (which is essentially the same thing – lack of oil pressure to the top end as the oil is cold).

Now of course no one with any mechanical sympathy will want to run a car hard when cold or run the car with low oil, indeed we and any other engineer would consider it abuse and hence not covered by any warranty but sadly it does happen and potentially could happen when the car was not in your control (if you’re the second or third owner) so it is important to understand the importance.

Lack of oil, ie a lack of lubrication to moving parts is easy to identify; excess wear on the rockers, followers and cams which can be seen by scoring and marking on the surfaces.

Given time the rockers can wear so thin that they snap which is as bad as it sounds – lots of bits of metal floating round the engine which can result in even more internal damage.

So, without opening up the engine what are you looking for?

The answer is a ticking noise, when the engine is warm and running it should be relatively silent, any loud tick which runs in time with engine rpm is something to be concerned about. Its important to note that this is only an indication of engine wear when the engine is warm, ticking when the engine is cold is perfectly acceptable, the dry sump oil system and unique rotation of the cams means it can take some time for the oil to get to pressure and lubricate the top end of the engine hence the secondary advice of not to run the car hard when cold so some top end ticking on start up is not something to be overly worried about – only when the engine oil is up to temperature is any noise an indicator of a potential issue.

If you go to a Mclaren dealer they only have one solution – a new head(s) which at £4600 plus VAT each for a 650 and a whopping £7600 plus VAT each for a 12c (just fit a 650 head, they fit the same) plus 10 hours of labour timing and 30 hours labour removing and installing the engine means a ticking engine for a 12c if repaired by a dealer could equate to a £30,000 bill.

However we are now able to offer a full engine rebuild service, working with the same people who designed and engineered the engines for Mclaren Automotive and using the same suppliers for engine parts we can now offer a complete turn key engine build service. For a comparison, a full rebuilt head with coated rockers, followers and cam regrinds can be as low as £4000 with labour to remove and install the engine for £3500.

However the point of this message is avoid all that by simply by checking your engine oil regularly (once a week and before and after any track work) and when the next door neighbours kid comes out and tells you ‘rev it mister’ ignore the little scrote, 30 seconds of his entertainment could cost you thousands of £££.

If you’re unsure how to check your oil level watch this short video how to for a 12c/650 (its the same process for all the models and we will update our Youtube site with those as and when we can.