3.9L V8 sticking valve?

[CSK]

Hi,

I took my Range Rover 3.9L V8 into the LR specialist after having an intermittant miss when warm. I replaced the plugs, leads, cap and rotor before going in and didnt improve the situation.

They did all these auto logic and gas analyser tests and reset mixtures, it was running quite lean they said. As a result the RR goes waaay better, really hauls arse!

The intermittant miss is still there occasionally, they said it could be a slight sticking valve and recommended some upper cylinder lube.

Is a sticky valve a major? Has anyone else encountered this?


Cheers.

[Scouse]

Sticky valves are quite common on 3.9 D1s, mostly city cars that are babied around instead of being given a good thrashing :).
I can't say I've seen a RR with the fault hough but they are the same engine.

Upper cylinder lubricant & some enthusiastic driving will help if it's an occasional problem.

[big guy]

Put the boot in.
I had that on my D1 3.9.
After a long drive through the hills and always running PULP, it did clear.
My mechanic also recommended upper cyl lube but I never got around to doing that.
Make sure the cooling system is good.
Last thing you want is a cooked motor.

[CSK]

Make sure the cooling system is good.
Last thing you want is a cooked motor.


Thanks for the info, I was a bit worried for a moment.


When you say cooling system is good, you mean fresh coolant etc or is there a bit more to it?

I only bought the car a few months ago, coolant is still green, I'm planning on doing a few full system flushes with with radiatior cleaner. And maybe get the radiatior profssionally flushed?

[PhilipA]

The only real way to fix a sticking valve is to pull the heads off and clean them as it is the exhaust valves that stick, so any lubricant etc is burned before it gets to it, so it is a relative biggie. It is most likely to happen under heavy load like going up a mountain pass.

With regard to the cooling sytem, even professional flushes are unlikely to clear a blocked radiator. The best solution is a detank and rod, particularly if it still has the Rover OE core (unlikely at that age) as they have very fine tubes .

Regards Philip A

[Utemad]

Rodding out the radiator will only cost you around $110 if you remove it. I just had mine done and it is good piece of mind to have had it done. It is the only way to ensure that all the gunk is out.

[Grumbles]

PhilipA and Utemad are on the money. And perhaps also don't forget the condition of the cooling fan viscous hub.

[CSK]

Thanks for the replies.

I will get it rodded when I do the waterpump.

[Utemad]

Removing the tanks to clean a radiator out is called rodding as they push a rod down through the water ways to push the gunk out. So your brother is talking about the same thing as we are.