"In this new Special Series named “S85-002”, I earn a badge of honour: I blew up my V10.
I document the service history of my original S85 engine and diagnose its failure. I go through the process to source, refresh, cam and refit the replacement V10 into the E60.
In this entry, I touch on the maintenance regime it went through, how it failed and the probable causes."
It had been my daily driver.
My M5 V10 had been my not-exactly-reliable daily driver since picking it up in the Summer of 2021. Sitting at around 20,000km, I put on over 40,000km since in every other conditions imaginable.
Everywhere I wanted to go, it went - all the way North to the chalet.
It saw -40C all the way up to +40C. This is Quebec weather.
It had seen its share of dirt roads to reach mountains out in the wild.
Maintained to high standards.
The car underwent a PPI before being purchased in 2021. The car had the benefit on an extended warranty that was used and abused to great effect by the previous owners and its service shop. It had recently been fitted with new brakes, suspension arms and SMG accumulator pump.
I had extensive records of the work totalling over 10,000$ in 2 years.
[...] and more.
Still, I experienced every other non-catastrophic failure in the books while doing every preventive maintenance required. This is the M5 V10 life - for better or for worse.
The car was fitted with a higher temperature thermostat. It ran Redline 5W50 in the Winter and Motul 300V 10W60 in the Summer.
The rod bearings had been replaced just in time with ACL custom sets.
Both Idle Control Actuators had been replaced.
The oil cooler evidently leaked. I first replaced it with an OEM replacement unit and then upgraded to the Radtec performance cooler.
The voltage regulator got replaced.
All 10x injectors were replaced.
The fuel pump and filter were replaced.
Even the gas cap was!
The 4x VANOS solenoids were also replaced due to failure. I lost time, and a lot of money trying to find aftermarket units only for them to fail VANOS bleeding adaptations. OEM units went in and worked without a hitch
I blew out the SMG3's 6th gear actuator casing a dowel pins off the OEM clutch. This was self inflicted due to mis-positioning the clutch discs during the lightweight flywheel's installation.
Beat that! A rarely seen problem on SMGs. The cast casings were designed with indents as preventive failure points to avoid damaging other components of the transmission. We transfered every accessories and pumps to a new casing.
I'm not even touching on trims wearing out - but notably, I broke 2x hood latch handles.
A few PCV valves were replaced.
The passenger side thigh extender gear broke.
The power steering pump failed and reservoir leaked. Both were replaced.
It also suffered an auxiliary main radiator fan failure - this is an event that will be important to remember.
It's the Mustang's fault!
On a sunny late afternoon, May 29th 2023, I was taking the long road home to clear my mind and stretch the V10 legs. I came across a supercharged, Coyote powered 6spd Mustang - making 750 crank hp, these are no slouch.
The first 100-200kph run on a closed road was interesting, the V10 wasn't getting left behind at all. Its high speed gearing and the FBO V10's top end once more showing its prowess.
The 2nd run didn't go so well: it evaporated from my sight. The gas pedal wouldn't give anything, anymore.
I started hearing engine rattling noises and my biased mind went straight to bolt failure on the CSL plenum on which I had just re-installed the lid recently.
No - the rattling rapidly turned into metallic rattling noises, then the red sign of death dong'ed the dash: main oil pressure lost.
I called up Phil @ InnovAuto with the news, and my insurance's emergency tow line. Phil had hope it could be a VANOS pump failure, and the engine could still be saved considering the block hadn't been blown through.
The engine died rolling into this construction lot. There was no visible oil spill.
We all react differently to situations: I just smiled. I knew it was over and the future of the V10 would be unpredictable.
I sat by, breathed in and out, and pulled out the Kodak. If I was going to keep the V10 adventure going, this would make a great story.
A reel? Why not.
Preliminary thoughts on culprits.
The 2005 produced S85B50 engines had every other issues in the book. There are various differences with 07+ engines, amongst many, the infamous VANOS high pressure oil pump had its sprocket revised in 2006 produced engines and up.
This was the only component we had no yet serviced on this engine.
VANOS high pressure oil pump.
The VANOS pump sits in the oil pan and drives the main engine oil pump straight off the crankshaft's gears. Considering the oil pressure error code, our hopes were the VANOS pump had failed and I had managed to shut off the engine in time to avoid oil starvation.
We briefly inspected the engine by dropping the oil pan, and we eliminated this as probable cause.
Coolant system failure.
The engine bent the cylinder 7's rod and fused the crankshaft to the rods, burning through the rod bearings. The pan was filled with engine coolant. On the day prior, the car had burnt through a gallon of engine coolant.
We had been chasing a slow leak for the entire Winter, having to top up the expansion tank a few times over the Winter months.
The block was dry. The leak appeared internal. Our next step was to inspect the thermostat housing and replaced seals.
So, do I double down or ditch the V10 adventure?
You already know.
Up next: I chat about the rationale, my experiences sourcing a replacement engine and the plans for it.