I’ve got another problem (never ends).



I replaced the water pump and expansion tank (reservoir) after a giant coolant leak left me stranded.

https://www.jaguarforums.com/forum/xj-xj6-xj8-xjr-x350-x358-28/water-pump-pulley-stuck-please-help-249678/

I found a weird white sludge in some of the larger hoses, which I cleaned partially.




After running the car, there is a slightly white haze in the expansion tank’s coolant (it is a dark orange overall).



After replacing the water pump/expansion tank it looks like my XJ is not leaking coolant anymore, but I got a “restricted performance” message after idling for 30 minutes, and driving 10 minutes to a car wash and back.



I’m not sure if this is a leaking head gasket, or what? The restricted performance message seems related, but I can’t be certain.



Would anyone happen to know what next steps I should take to diagnose this “restricted performance” problem?

 

Did the car actually overheat? From what I understand, these cars do not like to be overheated, even once.

Do you have a check engine light or any codes associated with RP?

 

With Jaguar SDD (Symptom Driven Diagnostics) diagnosis, able to be serviced at Dealership, a Jaguar indi, or local member with software and interface (to ODBII port). Members in your area know who the indis are and who to recommend.

Then possibly, leakdown/compression check to tell you where leak is.
I wouldn't drive it if there is intermix of oil/water. You may see water in oil, and oil in water (already visible in your cooling system), or both. Oil analysis detects small amounts of coolant in the oil.

Ultimtely wil be clearing the codes, probably after checking the headgasket.

Best of luck.

 

I performed a combustion gas detection test ($25 from harbor freight) and it came back negative for combustion gases in the coolant reservoir.



I have driven 225 miles so far in warm temperatures since Wednesday, including idling, and it does not seem like coolant is leaking from beneath the car.



After resetting the CEL, my XJ8 ran for 60 miles trouble free, then through a CEL and “restricted performance” came on for a few minutes and went away.



As I left the highway and drove around town, restricted performance would come on for a few minutes and disappear randomly.



I will read the new codes and post again later tonight. As I drove 10 miles to work today, no “restricted performance” came on. The intermittent nature of this problem is frustrating.

 

I wanted to ask, what was that sludge like? This is actually the first time I have seen similar to what I had in my radiator. I had to replace my rad because it had some awful flow through it. I cut open some of the veins and some white sludge or whatever was clogging all the veins. I didn't bother taking apart the entire thing as I was replacing it, but I could never really figure out what it was.

So I hate to add another item on your list, but if you have some nasty sludge, it may be in your radiator. I tried all sorts of cleaning chemicals and could never get it cleaned. It would be something to look into at least. You can do temp scans with the car running so you don't actually have to take anything off.

 

The sludge was white and pasty. I’m really not sure what it was.

I have codes P0171,P0174, and P1000. These indicate the car is running lean. Perhaps a vacuum leak?

I visually inspected the airbox and hose, and could not find any obvious holes there.

I did find this random unconnected plug.

would anyone happen to know where it connects to? I had my air suspension replaced with coil springs years ago. Not sure if related.

 

Ok, so your Restricted Performance is due to the P0171/74 codes (lean - bank 1 and 2) you have a vacuum leak common to both banks, which is probably somewhere in your air intake.

The plug you show goes into the top of the air strut to control CATS. Since you converted to coil overs just tuck it away somewhere in the engine compartment.

Your cooling is probably fine. Need to find the vacuum leak.

Double check all clamps, connections and make sure your intake is good with no cracks in the plastic. I presume since you changed the tank and the water pump you disconnected/removed part or all the air intake.

You may also want to check your mass air flow sensor and clean it (MAF cleaner)

The P1000 means your readiness monitors are not complete and will not complete until you square away those lean codes.

 

I’m glad that the unplugged connector is irrelevant.

I did remove the intake (from air box to throttle body) to replace the water pump.

Before that, a few years ago, I had to replace the valley coolant hose and removed the whole intake manifold (with new gaskets on manifold and throttle body).

I had the same “bank 1 & 2 lean” problem and lived with the CEL since it did not put the car in “restricted performance” mode and did not seem to affect driving. Now it seems like whatever problem I had has become worse on account of the on/off restricted performance.

Is this most likely an issue stemming from the intake/air tube, or could the throttle body through manifold have an air leak?

Should I try to make a smoke machine using the various methods found online and diagnose that way, or try the propane bottle method?

Visually, I can’t find any gaping holes in the intake box or hoses.

 

The sludge could be from mixing types of antifreeze.european antifreeze does not mix well with US type. Especially if undiluted. The coolant can polymerize and make a solid. More like rubber.
Ran into this in work environment.used diesel to cut the “rubber”. Nasty stuff.

 

most universal antifreeze are copies of dexcool which is what this car uses.

that's not the problem here

 

I may or may not have frantically poured Poland Spring into the expansion tank on the side of the road that day.

There were no witnesses, so who’s to say what happened.

I removed and sprayed down the MAF sensor with appropriate cleaner, and still have my CEL.

 

With the SC 4.2L V-8 you might have the PB vacuum line leaking where it attaches to the rear intake elbow. Has a terrible design with an internal O-ring that gets old and hard then cracks. Causing a vacuum leak. One symptom is a check engine light if you let the engine idle but it goes off when you start driving the car. Depending on how bad it is the car might also go into restricted performance.

Do you have anyway to monitor fuel trims while the car is running? I only found this by spraying carb cleaner around the engine while monitoring the short term fuel trims. Could not find it otherwise.
I have a long post with pictures documenting the repair. Took a while to find this too!
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I have a n/a xj8, but there is a small vacuum line running from the intake hose to the top of the engine near the dipstick, which might be the one you are describing.

My CEL stays on when the car starts and has not gone away. I got “restricted performance” after a long 60 plus mile drive and a hot engine. It then came on and went off randomly as I drove, and went away all together when setting the cruise at ~ 70 mph on the highway.

If I can’t borrow someone’s vacuum smoke machine, I might buy one like this on Ebay:

https://www.ebay.com/itm/281805683189?_trkparms=ispr%3D1&hash=item419ced79f 5:g:7rgAAOSw8TBZcFX-&amdata=enc%3AAQAGAAACkPYe5NmHp%252B2JMhMi7yxGiTJk PrKr5t53CooMSQt2orsSwcmzw5CLtzTE60FqHcnq2M6zSEOADh K9JNbH9Rf3Ut85m0kGFos01cEBNaOQAbxnRmXK%252BrzYT%25 2FwGXdScQIWPmaxqmv8tYtmTBTMv9zqPW6iycOUMDKXHwOBtqt ycLhjQlNhiEywtQtgTvdXK4k8evtHdB5wCzLbUUGOq8A0o0Pky 5Ej7R1JFjLF0NsW1rySFh3wyjRsjrHdo4jKTd7zOIXZrRLA%25 2BwtDtFEjgNPprqSOU7i%252FuxKaWMkYz%252F%252BZLYa19 4IUciVJHDIWOnmVmgbxCxBPI4TB265U81WHMKIyVTAAM03%252 F6OUo3xzAIzMFVGcguo8WIMbaIaTObBWWSc1btI03cdrUBLgHF P23nYZ1AOHpMxciUiCXzxX1KcnIQ140P5c9LQsiX%252Fvr20J AjzLtTSvMD0pXGK0P3t%252BtsHaRd9W%252BNDwMOfCd1YYEu jvuWGbyQgcFxFH7HgWz9trUhU4hDG0asmk9dEv%252By%252FI wU%252FcS92%252B0hBL%252FGcmJ4Y8y8yElv9d%252FPM2WN bL8xHejY%252BWYqujPMwS0075SshBRd%252FQtRh0s7mHxZxu Zr2QV52UPgWj%252F4orhYdpuuhMygyJ79CkjlOf5IA%252FjR tunjr9WtNw2LZGXEvyL5y060T32f9bmgxO3%252FJgVrakeMmD yhWVtd1mg3MhQYCz3lQ%252BwHwvTI2vaOV4gnsYVbUnpr%252 FAvLw%252FH50cEr8wlr6JSx94M8t8ONcgyXU7FtPxATAGH7Cm fTyw%252FLEceGFwp4Cx9bMhN9VuJCOH54uSo74n8s%252BEMk QpfIDuemoAeNcOGrea4soaMxOXPir8sO2r3Kq6MZahWcsH9DIZ Ne3j8W%7Campid%3APL_CLK%7Cclp%3A2334524

I don’t have an OBD reader and can’t monitor fuel trims on my own.

 

Sorry my mistake you did not post the car details and you had XJR in your user name.
On the NA version this is not the same setup and does not cause all the problems that it does on the SC cars.
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