Thread: Restricted performance

If the hoses haven't already been replaced, it's likely to be leaking at one or more of the 4 short hoses that connect the air distributor to the intake manifolds. Cut up a piece of 70mm (IIRC) silicone hose to make replacements.

If not the hoses then the secondary inlet air valve could be sticky if the valve is the original style. The valve is seen looking directly down between the left half (right half when facing the engine) of the radiator and the engine.

12987AA2-2B56-41FD-9886-9C3E71B46D45.jpgThese ones graeme
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The 4 in the first picture. The rear 2 are half covered by the cabin air intake which is easily removed by removing 1 nut each side and pulling the whole assembly forwards and upwards, leaving easy access to the back half of the engine.

I can't see the hoses well enough to determine if they are the original with bellows in the centre or straight hoses. If straight and you can't see any blackness around them then they could be OK.

The change-over valve is directly ahead of and a little below the air conditioner pulley. If the pivot pin for the connection of the arm of the vacuum chamber has a nut when looking down at it then the pivot is the early version. A vacuum chamber and linkage update kit is available to convert the valve to the later model, rather than have to replace the whole valve. If your valve is the early version then clean the pivot with WD40 or similar.

Just took these Graeme

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I expect those hoses to be genuine replacements with the line-up marks for the clamps as they certainly aren't the originals. Time to check the air change-over valve and lubricate the pivot if it has a nut.

Tried a few things no good, took it down to my mechanic he put it on his scanner, he checked the vacuum chamber and pivot point was working fine, did a smoke test for all the hoses, he worked for over an hour on it rang another guy that works on RR and checked everything he suggested, he tried one last thing he checked a sensor underneath the motor pulled the lead off and it was coated in oil, cleaned it all up couldn’t find where oil was coming from, test drove took a lot longer to come on, thought he had fixed it until last burst before arriving back and fault came up, damn he didn’t charge me for the work it’s a big shop well known in town. Nice guy. He thinks it’s just something simple, it’s just a case of finding it, Suggested I go out to the guy he rang Wade Brothers auto so I’ll head out in the morning, have a couple of jobs on this arvo.

It's not a common occurrence but the solenoid that controls the air flow to the change-over valve can fail, but there is a test for the solenoid/valve operation so no need to start throwing parts at it. The solenoid is only available with all vacuum tubes so won't be cheap.

Clean the MAP sensor (in the top of the air distributor) because if it's clogged with oily soot then it can give a false reading. Only use a spray cleaner - don't poke anything into it.

The oil may be from leaking o-rings on the turbo oil feed pipe at the back of the oil cooler and/or the oil cooler gaskets as the gaskets harden. The 2 o-rings are easily replaced but fit Viton - BS611 size.