I see on the Jag maintainence schedule for 1998 XK8's that the fluid for the top should be changed every 6 years by flushing the system and filling with "CHF synthetic fluid" to avoid jelling.

Okl, I'll bite, what kind of fluid is that?

My INDY says he can't find anything.

 

The old fluid in your '98 had a jelling problem. This is the newer fluid (http://www.amazon.com/Pentosin-CHF-1.../dp/B0006Q16YM). Once you flush the system and put this new fluid in, it is permanent and will not need further flushing.

 

White XKR;

How long did the jelling fluid for the tops go on?

Does this effect 2003's?

Is this for the locking mechanism along the leading edge of the top for the windshield?

I am assuming the motors that lift and lower the top are electric and not hydraulic, yes.

thanks, jamjax

 

I think the improved fluid started in 2000. With a 2003 you are fine. The new fluid is green, the old fluid is yellow.

The entire system is hydraulic (including the top latch and lifts) and is operated by an electric pump in the trunk.

 

I see that Pentosin CHF 11S comes in 1 liter units. how many would I need to flush the system and fill it?

Would a reg. Auto parts store carry this product?

 

One liter is more than enough for a fill. Maybe 2 if you are flushing.

I believe NAPA carries it.

 

Thanks Whitey;

Was this jelling fluid in the top system the cause of the dreaded hydraulic leak into the interior of the convertibles that plagued so many early XKs?

jamjax

 

These are different issues.

The jelling will eventually result in the pump being unable to generate enough pressure to operate the system.

The leak is primarily caused by hose failure at the top latch and effects all XK's ('97-'06). Actually some of the very earliest ones ('96 and '97 had a sturdier hose without this issue, but there were just a few of those made).

 

Yes the CHF 11S is the replacement fluid for the old y(j)ellow fluid. BMW dealers have it as well. I'm convinced that the newest Land Rover ACE/power steering fluid is the same with a different bottle. The jello was early cars but the hose leak is all of them. I believe (and I would like to hear others thoughts) that the darker colored cars had a higher percentage of failure. I rarely ever did a white car but it could also be related to production numbers, environment, etc.. I remember replacing a set in a 2005 under warranty. At the time Jag had a kit out to replace a section. The rep even told me not to mess with it as it was causing another leak! There even was a time that Jag engineers were convinced that the fluid was evaporating. The yellow fluid would somehow get low but there would not be any leaks. We didn't know at the dealer, but around the same time, the jelling was getting worse. The green CHF 11S fixed it all. Just my two cents.

 

Found this on the eBay: http://lsi-controls.com/JagKit.htm

A valve that is supposed to rduce the pressure on the hoses etc after closed to reduce hose & other component failure.

Any opinions?

You may have to copy and past on a search to get it to work, I just copied & pasted the address

 

Search the XK forum. There is TONS of discussion on this.

The valve is a good product.

 

Looks good to me. Some thoughts I had are cleared up with that write-up!

 

Big, welcome to the forum and the world of hydraulic failure in the top system. There are 1,000,000+ words on the subject. For basics, explore Gus' website...he and Walt collaborated on the valve. Others have tried different lower cost solutions to the problem. It's all here for you explore for the next few evenings; you can take sides (tastes great-less filling) or quietly make up your own mind. These top systems were poorly designed but the guys here have tried to fashion workable solutions. BTW, what year and model do you own?

 

I got the new fluid and the system was flushed and filled to proper levels.

The top seems slow to unlatch and start to go down and then slow to relatch.

Do I need to put the top up & down a few times to get rid of air?

I will be installing a pressure valve this week as well in hope to avoid the dreaded leak.

 

Correct, it should speed up a bit as it purges itself of air. Normal speed for the entire cycle is round 23-30 seconds. There is normally a significant pause at latch and unlatch.

 

I installed the pressure reduction valve on my 2000 XK8 after flushing the system and, like you, was hoping to avoid the leak. No such luck, it sprang a leak about a year later.

The upside is that with the new hoses (Colliflower - See Gus' website) new fluid (Pentosin from O'Reillys), Remote-Drop-The-Top from (WhiteXKR at this forum) and the pressure valve (LSI Controls) I have a dead on reliable and trick system.

Confidence restored, my top goes up and down more than a drunken cheerleader's these days.

 

I also got the Pentosin CHF11S hydraulic fluid @ O'Reilly's.

BMW uses it in their power steering systems.

 

Yes, BMW uses it and you can find it at NAPA parts stores as well. I got it from NAPA, cheaper.

 

is it possible to flush the lines to the latch by disconnecting at the pump and draining by gravity, suction or pressure. this seems easier than doing so much dismantling up front.

 

The hydraulic system at the top latch is a push-pull operation with no real fluid circulation. If you have the early fluid I would suggest that honey does not drain well and there is not a prescribed flush for the later green fluid.

There are only a few screws up top to remove; no big deal.