Hai. It's not necessary to take the engine out for replacing spark plugs on SLR Mclaren.
I've changed spark plugs on more than 5 SLR cars. Complete job gonna take 8-10 hours max. Steps as follows.
1. Disconnect ground cable from battery
2. Raise vehicle
3. Remove bottom engine compartment paneling.
4. Remove both side exhaust mufflers.
5. Remove both side charge air coolers (this is the difficult part of the job) To do that-
* First take out all the bolts (8 manifold & 2 mounting bolts- T30bolts) and disconnect hose clip at back.
* Gently pull cooler front and remove rear mounting bracket (E10 bolts)
* Gently take coolers out and keep on wheel arch. (For RHS cooler- Disconnect and block 2 bleeding hoses connecting to radiator expansion
tank). No need to remove any coolant hoses connecting to cooler. They are flexible and long enough to do the job.
6. Remove ignition coil with plug leads. (You have enough room to do it, no need to remove exhaust manifolds)
7. Replace spake plugs.
I've changed spark plugs on more than 5 SLR cars. Complete job gonna take 8-10 hours max. Steps as follows.
1. Disconnect ground cable from battery
2. Raise vehicle
3. Remove bottom engine compartment paneling.
4. Remove both side exhaust mufflers.
5. Remove both side charge air coolers (this is the difficult part of the job) To do that-
* First take out all the bolts (8 manifold & 2 mounting bolts- T30bolts) and disconnect hose clip at back.
* Gently pull cooler front and remove rear mounting bracket (E10 bolts)
* Gently take coolers out and keep on wheel arch. (For RHS cooler- Disconnect and block 2 bleeding hoses connecting to radiator expansion
tank). No need to remove any coolant hoses connecting to cooler. They are flexible and long enough to do the job.
6. Remove ignition coil with plug leads. (You have enough room to do it, no need to remove exhaust manifolds)
7. Replace spake plugs.