Sorry if this has been addressed previously, I tried searching but wasn't exactly sure how to word it so i got little results. My car has been running fairly well. I have had a stumble at idle while in gear, but figured it was the taped up hose running from the oil filler neck to the air intake piping. I found one in the local junkyard that looked brand new (I like to be cheap when replacing stuff like this, buying new only when I've isolated the problem), and they gave it to me for free. When i took my old one off it was almost completely packed with white sludge. I looked down the filler neck and it was coated in it, but not too bad. I naturally check my dipstick and it's got clean, light caramel-colored oil, no sign of moisture. I figured maybe it was that hose, pulling moisture from the air (we've had a lot of snow/rain lately), but my stumble is back and the oil filler neck has some white in it again. I DO get an intermittent Fuel Fault code (FF1 I think), but it's so random I haven't pinpointed a cause. Am I missing something else here? Could I be drawing moisture from the air intake itself? I don't imagine there's any sort of vacuum there, since it seems to be more of a crankcase breather than anything. Could i have a more serious issue (head gasket) that's starting to manifest itself? Any help would be greatly appreciated!

Car is an '89 VDP with a stock 3.6L, I also cleaned out the white sludge the first time, carefully, so I'm not just seeing the same stuff from before. Also, my stumble is only like say 50 RPM difference (based on the gauge), and it's not very bad, just noticeable.

 

White sludge is usually an indication of water/coolant in the oil.

Since oil floats on water your dipstick may not pick it up.

Are you losing coolant at all?

Any excessive moisture coming out the exhaust?

Any excessive pressure in the cooling system?

 

I haven't noticed a drop in coolant level, no white smoke, no sweet smell. I have a coolant issue with my 03 Navigator so I'm pretty good at noticing that stuff. Maybe I'll do an oil change this weekend and get a good look at my oil. It's due for one soon anyway. All things considered it runs and drives pretty dang good. If it's a serious issue it would be nice to catch it early because I'm starting to enjoy this car a lot. Thanks for your help, and I'll keep you updated!

Edit: Also no noticeable increase in cooling system pressure, but honestly it's not something I watch. I haven't seen any bubbles in the tank with it running, but again, I don't often check, so maybe I'll do that at lunch this afternoon.

 

This is perfectly normal on an XJ40 - we all get some of that sludge, basically it's condensate buildup and by the sound of it yours has probably not been attended to in some time.
Myself, I do an annual cleanup in the spring, buildup usually occurs after cold winter starts and short runs. Lumpy idle is one symptom of a muck-filled intake.

The entire intake system including the breather hoses and corrugated bellows (where you will find a great deal of sludge) should be removed and washed out. You might as well clean off the carbon and check the clearance of the throttle butterfly at the same time.

There are several threads on this process in the archive, this one is my car which gets a regular intake cleanout ...so not so much white as a neglected intake, but still an annual chore for a daily driver.

Larry

https://www.jaguarforums.com/forum/x...tumble-196826/

 

 

Maybe a compression test of the cylinders.

 

I ran Alfa Romeos before I drove Jaguars and this condensation was normal in the Alfas in cool/cold weather.
Short runs with the engines not getting hot enough to burn off normal condensation was the cause.

 

Dry compression numbers were all right at 124-125 psi. I also did a leak down test and got, from front to back (cyl 1-6) 30,30,40,30,45,40. Those 40s and 45 obviously aren't great, but not terrible I guess. I couldn't really hear any noise when any were being tested, except maybe from the oil filler neck (I took the cap off). Would that sound just be the air passing through the rings into the crankcase? If my bubbles in the coolant were exhaust getting into the coolant, would I have numbers like these? Thanks everyone for all the help so far!

 

The compression numbers look good and do not indicate a blown headgasket.

Have you checked your EGR valve? Make sure it is not blocked.

Bubbles in the coolant when running cold is I think "unusual". Do not check when hot!

 

The condensate is pretty NORMAL for engines UP TO engine number 179541 (with the long filler tube to block)
The filler was moved to the cam cover from engine 179542 onward. That seems to have cured the issue.

bob

 

Check your pcv

 

Hi Terrance,

There is no PCV valve on an XJ40/AJ6 - were you thinking of some other component? Crankcase breathing is managed by a series of pipes, hoses and restrictors which are designed to maintain a slightly negative air pressure in the crankcase under varying running conditions. I believe the info is in the Engine Management System manual:

AJ6 4.0L Engine Management System/OBDI Diagnostic Guide

Cheers,

Don

 

 

 

Thanks for the continues responses. It helped put my mind at ease a bit driving this thing around. I haven't used it a whole lot for short trips recently, especially as it's been pretty cold and wet out. My commute is about half an hour one way, a lot of which is freeway so I'm sure it's helped keep too much from building up in there. No drive-ability issues and no smoke or coolant loss, so I'm going to go with what Brewtech said about the t-stat.