Friday 15 May 2020

Head off

The head is coming off hopefully just to replace the gasket but that depends if everything is still within spec.

Why am I doing this

The failure I believe is due to overheat caused by a failing temp sensor and lack of fan cooling when the car was stationary. i.e. I believe I have identified the root cause before this attempted fix.

Disconnecting ancillaries

Step one is dismantling, the head is coming off but to release it there are a number of steps.

Intake side: Injection rail, cam position sensor, plenum - inc accelerator cable and air temp sensor, alternator brackets x2
Exhaust side: Water rail, exhaust manifold.

First look under the cam cover and some tale-tale white on the bolt tops - coolant in the oil, corroborates the CO2 detection kit so she definitely had to come apart.

Cam shafts and followers

Water pump pulley to release the cam belt cover and cam belt, cam shafts out..

Cam followers all labelled to go back in the same place.

Parts table and boxes to try and stay organised.

Head bolts, nothing particularly noteworthy - they're not going back in.

Head

The head lifts off - a surprisingly delicate component for a heavy block of aluminium - oil and coolant channels everywhere and the valves smaller than you might expect packed together in each cylinder. A really impressive piece of engineering - no less impressive that they were built in the tens of thousands to the same standard.

Block

Cylinders carboned up after best part of 30k miles. Pictured with the old gasket in place and removed and liberal oil soak to clean.

First stage done.

It's all had a soak of WD40 and will sit overnight under a rag to help with cleaning and measuring up to see if everything is still flat. The operational spec on the head is max out of flat by 0.1mm!

The bigger challenge is can I put it back together and get it operational?
Worst case this will become an engine rebuild job for an engineering firm.


Update - Received knowledge (thank you) - WD40 is less than ideal for this job - it cleans, but it also strips any other lubricant or surface coating which can induce surface rust. I've since cleaned up and made sure the parts that matter have an engine oil soak/coating to ensure lubrication is maintained.

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