Hey Lads,

So I replaced the cam cover gaskets on the XJ a few weeks ago and while I had the cover off, I noticed that all the metal parts under there had basically a bronze appearance from the oil. I took some brake cleaner and a rag and the stuff will come off but obviously I am not going to brake clean my entire head.

So I was wondering if anyone know of an oil additive that over time will remove this from the metal parts. Its not sludge or anything, its just a light discoloration from many years of oil. Possibly some oil changes that should have been done a lot sooner.

Any input is appreciated

Bernie

 

Several rounds of short interval oil changes will help
matters.

The effect can be enhanced with the use of HDEO oils
like Shell Rotella. And it just so happens it comes in a
15W40 which is a pretty good pick for your engine and
climate.

Some people, including Brutal, like a quart of cheap ATF
dumped into the oil and the oil brought to temperature
by idling, no driving, just before doing an oil change
in these circumstances.

 

What harm do you think this discolouration/film is doing?

 

I've always run the Castrol recommended by Jaguar for our '93 XJ40 and have changed the oil regularly. The parts under the cam cover have achieved the same bronze color you describe and I think it's beautiful. :-)

Cheers,

Don

 

Beauty is indeed in the eye of the beholder! I agree.

 

I'm sorry, but I would **never** use brake cleaner on anything that is exposed to internal engine components.

I would not trust the residual by-product.

I hope I didn't start "an oil thread"

 

The whole point of brake cleaner is that it is very
volatile and leaves no residue.

 

OK, the brake cleaner leaves no residue, (it evaporates) but where does the stuff it is supposed to dissolve go?

 

Hey Lads,

First of all I never used brake cleaner in the manner you think. I put a bit on a rag and rubbed one of the cam caps just to see if the bronzing would come off. Like a quarter sized patch that's all.

Being used to building and racing motorcycles, I am used to seeing very clean parts in the head. Parts that look the way they did when they came from the factory and I know that the bronzing is doing nothing to the car. I was just curious if anyone uses an oil additive that works as a detergent to clean this sort of stuff up over time?

I am not going to go to any trouble to do it, I was just wondering if a bottle of this or that at the oil change may help to clean the parts over time since the bronzing does come off when I rubbed it with the rag.

I would also assume that bronzing like this is a predecessor to coking which is also something I would like to avoid.

Clean parts are happy parts IMO.

 

No, far from it.

 

After I pulled the dipstick tube adapter from the side of our XJ40's AJ6 and saw all the sludge that had accumulated in the block over 180K miles, despite regular oil & filter changes, I added two bottles of CD2 oil detergent when I refilled the crankcase with oil. I've had good luck with CD2 quieting noisy lifters in other engines, but it apparently did nothing to reduce the bronzing on the cams: the next time I replaced the cam cover gasket, all the metal parts were still that gorgeous bronze color.

Cheers,

Don

 

Wow!

You Nevada boys certainly take your Concours d'Elegance preparation VERY seriously.

Graham

 

So, assuming the much vaunted Restore oil treatment actually does anything, it does so by adding some magical substance, according to the manufacturer, per their documentation:
Quote:
RESTORE repairs worn out areas in the cylinder walls to improve the seal between piston rings and cylinder walls. It is the only product that contains the technologically advanced CSL formulation proven to fill in and seal microscopic leaks in the cylinder wall.
Endquote
Assuming Restore does really add something (notice the skepticism), and assuming some other magic does not limit the sealing to the cylinder walls themselves, then that something is probably not clear or aluminum color. So, maybe it is oil additives making the color.
In any case, I think it is a big stretch to think the patina is a precursor to coking or sludge.