Hello, I've been an owner of a beat up 1998 XJ8L with 180,000 miles on it since last August. She's my first ever car. I don't drive her far, or even very frequently (I opt to walk whenever I can), but I'd like to get some opinions on some miscellaneous issues that have stacked up since my last visit to a Jaguar Independent repair shop. If possible, I'd like to make the needed repairs myself, but I have no automotive maintenance experience. I'll start with a brief maintenance history.

Bought in August 2017, 177,000 miles. Not sure about maintenance history before then, but I can probably find it with the papers I got with it. Got the car cheap so I took it to a Jaguar Independent Service in the area for an inspection. They gave me a checklist of recommended mechanical and cosmetic repairs with price breakdowns.

Nov 2017: Full inspection. Replaced oil pan gasket and filter, renewed oil. Replaced broken low beam headlamp. Renewed air filter. Broken hood cable and latch fixed.

Jan 2018: Transmission service. Flush of incorrect engine coolant and correct coolant replacement. Broken door handle fixed.

March 2018: I personally did a hard reset of the battery following a guide on this forum to fix a problem I had with the windows and sun roof closing automatically.

I've driven her since then with no glaring faults, but little things have popped up and I want to make sure they aren't indicators of something catastrophic.

1. Car usually (>90% of the time) starts in 'Failsafe Engine Mode' on the first startup of the day, but there's no impact on engine performance. Doesn't start in Failsafe when starting the car when it's warm. (I've experimented with various things to see if I can get it to start up without Failsafe, and in the four or five times I've tried it since discovering it last week, starting the car for the first time of the day with the Sports mode switch in the ON position seems to negate this issue; could be coincidence.)

2. On rare occasions braking normally will produce a 'Bulb Fail Rear' warning.

3. Braking and making normal turns sometimes (~50% of the time) produces a 'Low Oil Pressure' warning. I never see this warning for more than a second. This behavior makes me think it has something to with the sensors rather than the oil pressure itself. The oil isn't low.

4. A loud rattling sound accompanies acceleration every once in a while but I think it goes away when the car switches to a higher gear.

5. Recently acquired a 'Check Engine' light.

As a final note, I use regular gas even though it's recommended to use premium. None of the previous owners seem to have any issues with it, I've never had any issues with it, and I can't afford premium gas anyway. I'm not using it to race or anything so I'm not too worried about it.

Like I said I drive pretty lightly, and these warnings seems innocuous, but I'm going to get her another checkup at the local Jag Indy service anyway, and I'd also like to hear some thoughts on these indicators. If it would help I can get an audio recording of the rattles.

Thanks much.

 

On the bulb warning, I would have a friend apply the brakes while you're behind the vehicle. I think you may have a faulty bulb or brake switch and the system is just doing it's job to inform you.Rattling noise? possible pinging from using regular or an exhaust rattle. The check engine light diagnosis should lead you to the failsafe issue. A faulty brake light switch could be the cause of the whole issue with the failsafe and bulb warning. Try turning off the cruise control master switch next to the SPORT switch and see if the failsafe issue goes away..

 

I'd start w/ a fresh properly sized battery & see what errors & issues disappear.

 

How might I go about replacing the battery, and what battery would I need? Is there a guide around on this forum somewhere?

 

Any good auto parts store can fit the battery for you (but test it before burning money). Check the tightness of the battery cable and all grounds (google it). Brake Light bulb or corroded terminal most likely issue with brake lights (but do test to see if it occurs with or without the cruise control being on -- then it is the brake light switch), might also be the SLCM (security and locking control module). Issue of engine light when turning implies low oil level, or worse, low oil pressure. Starting issue when cold might be a bad temperature sensor (it is in the crossover cooling pipe and has wires running to the MAF sensor in the air cleaner box).

A good tuneup is in order: new plugs, new MAF, clean the throttle bore and plate, check for vacuum leaks, get the OBDII sensor readout for check-engine-light codes (do that same time you have the battery check). Report back to this thread for forum guidance once you know more.

AND, most importantly, go through that pile of papers in the trunk or glove compartment and record what work was done and when. You are specifically looking for renewal of the secondary tensioners (TO QUOTE JOE BIDEN: "THIS IS A BIG ****ING DEAL!" If you have the original plastic parts, and they break, your engine is toast!). If you can't find repair receipts to say they were replaced, you will have to pull the cam covers and check (good time to also change the worn gaskets that are leaking oil).

And I would hazard a guess you need new radiator hoses, water pump, thermostat, maybe drive belts, brake pads, fuel filter, grease of rear axle grease fittings -- but these can wait until you ascertain cause of more pressing issues. All the same: it is an easy car to work on and learn (although parts may prove expensive and occasionally, hard to find). Pay somebody, you won't learn much but burn a lot of money. And every new driver/car owner needs to learn the basics sooner or later: this is a good car with a great forum from which to learn.

end RANT.

 

If you can't afford premium grade fuel I don't see how you are going to be able to come up with the funds that would make this a reliable car. The items that Jim has listed will cost a couple of thousand if you do all the work yourself, and he didn't mention rubber suspension parts.

 

And that loud rattling sound when accelerating (without hearing it I can only guess at what you are describing) may in fact be the engine pinging from too low octane fuel. I've accidentally filled with 87 octane and got real bad pinging when the engine was under a load. A bottle of octane boost and grandmotherly driving got it through to the next tank. Had a Lexus LS400 before the XJ8 and it did the same exact thing if you put less than the recommended octane. I know people who swear they get away with using the cheaper gas. We even have a local automotive radio talk show host who tells people all the time that its OK. On many newer modern cars, the computer reads all the sensors and makes adjustments for octane level, but you're probably at least getting less than optimal performance. However, when a car gets old and has a lot of miles on it, the operating parameters change. The pistons and valves may be all coated with carbon deposits, the spark plugs may be well worn, all the various sensors may not have accuracy throughout their whole range anymore and particularly the knock sensors may be worn but not so worn that the computer registers an error. Plus an old car may not have had the capability to adjust itself for low octane in the first place. Next tank go to a top tier gasoline station like a Chevron and put in a full tank of 93 octane and see if it helps. Since you say you don't drive it much, the additives used by the top tier stations will also help keep the gasoline fresh longer. Especially with ethanol, gasoline starts going bad in six months to a year.

Another thing about not driving far or frequently is that is hard on batteries. If the car doesn't have a chance to fully recharge the battery after each start cycle, then it will "sulfate", meaning that deposits form on the plates and reduce the capacity to recharge next time. A fresh battery could be recharged to 100% after a half hour or so of driving, but if you only drive it for 10 minutes then you may get it back to 85% or so. Do that over and over again, and over a couple of years, now you've got a battery that could only ever get to 85% even if you drove it nonstop for hours. And we know Jaguar electronics are sensitive to having a bad battery, throwing all sorts of meaningless random error messages like a Windows computer. If you put in a fresh battery, your situation calls for a CTEK battery maintainer. You can read many threads on this forum about CTEK. Alternatively, if you know you're not going to drive the car again for like a week or more, maybe try to prolong your last drive to more than 30 minutes to be sure that its as fully charged as can be before you put the car away. Also, be sure to lock the doors even if its in your own garage as that signals all the computer modules to fully shut down. If the doors remain unlocked then its kind of like leaving your laptop computer in "sleep" mode and that too reduces the life of the battery.