Hi, all!

I recently bought an S-Type with only 30K miles in December. Been driving it to work (my commute is only about 5 miles) and around where I live problem free. But I went to lunch about 45 miles away in early February and had an issue upon getting home. Car showed zero signs of issues on the way to lunch. Car showed zero signs of issues on the way back. But when I got home, I wanted to swap places in the driveway with my wife. So I turned off the car, came in the house and got my wife, and went to start the Jag back up. It started. Then immediately died. Tried three more times. Died. Died. Died. Waited about 1.5 hours and the car started backup with no issue at all. ALMOST happened another time, a couple weeks later, after driving locally. Made a few stops, driving around maybe a total of 20 minutes and had the same situaton when I got home -- needed to swap places with my wife. Car started up immediately and then started sputtering. Didn't die this time. But almost did.

I will note that when I returned from that lunch that day that I smelled coolant and two mechanics have confirmed I do need to replace the coolant reservoir.

Other facts:

- Took it to the dealership I bought it. They couldn't replicate or diagnose the issue.

- Took it to another mechanic. They couldn't replicate or diagnose the issue. And they said they drove it "a lot". Only confirmed the reservoir issue.

- Maybe unrelated but the screen in my center console wouldn't come on until the car was heated up one freezing night here. And another die (also cold temps), the screen was very dim. Sucked when the screen wouldn't come on at all because I couldn't even activate the heater or defrost.

- I did have the second mechanic test the battery and they said it was good and saw no jumps/falls with the voltage.

- I haven't been able to recreate stall issue either but I just don't drive "long" distances.

- Never saw any sign of the car overheating. Temp gage was normal.



So questions:

- Any ideas why the stalls might be happening?

- Could it be related to the reservoir? Seeing as the cooldown period help, I'm thinking .... maybe???

- How difficult is the reservoir replacement? Seems like I can get the part for between $50-$100 but these mechanics want to charge me $500. Seems like it's two bolts and two hoses. The second mechanic said I could do it but that the hose connections could be tricky and aren't like the Chevy Spark hose clamps, which they noted because I just had done a Spark reservoir replacement myself. He said there is some sort of pressure connection or something. IDK. They said they'd do the work for $120ish if I got the part. I expect really it would be more because that didn't include new coolant, which they said there upcharge on was minimal.

Thanks, all.

Matt

 

Big question: which engine?

If 4.0, could be bore wash.

Any (petrol/gas) engine, maybe a faulty temperature sensor / fuel injector / air leak. Use OBD to check sensors & fuel trims.

 

@mattbuc16, use a smart phone with the Torque app to connect with the vehicle's PCM via the OBD port using a Bluetooth interface to see what the fuel pressure is.

With the ignition in the ON position, without engaging the starter motor, there should be around 300 kPa of fuel pressure. If not, the fuel pump is likely about to fail.

One other check you can perform if there is no fuel pressure is to swap the relay for the fuel module to rule out a faulty relay.

On rare occasions, the CKP is faulty and causes the PCM to shut down the fuel pump.

 

Thanks all for the responses so far.

FYI. It's a 4.2 v8.

 

Essentially, use OBD.

Keep in mind reasons for a stall.

E.g. not enough fuel, sudden extra air (air leak).

 

Will look into OBD. I'm a total newb and nowhere near even a shade tree mechanic so I have no clue but I'll research it.

As to not enough fuel or sudden extra air, what after the car being hot would lead to that? You mentioned faulty temp sensor ... but would that not be reflected on the dash? Or are you saying maybe the dash is wrong and the car really IS way too hot? And could the what-would-seem-minor (as I see no leak) reservoir leak be severe enough to cause a stall issue like this?

I've driven the car probably 150 times since owning it. It's only done this a couple times -- both after relatively longer drives.

 

Not sure if the S-type has a similar Evap system to the X-type, but you might try momentarily releasing your fuel filler cap next time you experience that starvation effect.

If the cap is faulty or done up too tight, you might be getting a substantial vacuum in the fuel tank from the car's evaporation management operation, which might be causing your fuel pump to struggle to deliver correct line pressure.
I believe Evap will only cycle briefly once car warms up to consume tank fumes and condensates in the charcoal filter, so might explain why you don't get issue when car is cold and why when it has sat after a run it might resume normal running if the vacuum dissipates over time.
I could be totally wrong, but it is a 30 second test to eliminate one possible cause.
Tip: When refitting your fuel cap, just do it up to 3 clicks.

 

Do I need any additional hardware to do this? Or do I just download an app (which one is best?) for my phone and I'm good to go?

 

Cheapest is an elm327. With Android, can use bluetooth. Apple, need wifi.