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Coolant leaking from radiator cap + car taking longer to start
Hello all,
My XJL started doing this suddenly just today:
- Taking much longer to start (many more crank turns). It goes on for approx 3-4 seconds before it finally starts.
- After turning ignition off, I notice that radiator fan stays on for approx 30 sec. Also, bubbling sound coming off from some tubes (can't see any leaks on them).
- Coolant leak from radiator cap.
Engine temperature guage in dash is at normal level. No loss in performance either. I am allowing the car to cool completely down to check for change in coolant level.
The sympthons point to a head gasket. I dont recommend to use the car before repair, because the cylinder block are made by compacted graphire iron and hot escaping flowing exhaust gasses can make pernament unrepaireble damage.
...- Car taking much longer to start due to some other reason.
Is you oil level full & do you have it (& filter of course) changed often (8k kms more or less)?
A lot of things can impact how an engine starts - spark plugs/gaps, battery strength, starter motor health, fuel (both gas & air intake).
Then there are things like compression that are very likely (and hopefully) not your problem as they're more in-depth & serious.
But as you & others recognize the cooling system needs urgent attention too.
You don't mention how many miles but with a 2015 your due for a good amount of maintenance. Has the water pump been changed? How about the failure prone plastic cooling pipes? Coolant is good for 10 years and your there. Plugs are 100K miles but again lack of car information will always limit any useful suggestions.
As posted above how old is the battery?
What is the resting voltage of the car after it has sat all night?
If concerned about head gaskets as Vasara posted above (Note the SC V-6 is alloy and not an iron block) you can use a test fluid to check for combustion gases in your coolant. It's a quick and easy test too. Most any auto parts store will sell this kit.
Be aware that the dash temperature gauge is more properly called an indicator as it's NOT a gauge and has been damped to read in the middle position over a fairly wide range of coolant temperatures. Some of us use aftermarket scanners that do read the actual coolant temperature in degree's as added insurance.
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You don't mention how many miles but with a 2015 your due for a good amount of maintenance. Has the water pump been changed? How about the failure prone plastic cooling pipes? Coolant is good for 10 years and your there. Plugs are 100K miles but again lack of car information will always limit any useful suggestions.
As posted above how old is the battery?
What is the resting voltage of the car after it has sat all night?
If concerned about head gaskets as Vasara posted above (Note the SC V-6 is alloy and not an iron block) you can use a test fluid to check for combustion gases in your coolant. It's a quick and easy test too. Most any auto parts store will sell this kit.
Be aware that the dash temperature gauge is more properly called an indicator as it's NOT a gauge and has been damped to read in the middle position over a fairly wide range of coolant temperatures. Some of us use aftermarket scanners that do read the actual coolant temperature in degree's as added insurance.
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The car currently has 147,000 km on it. The oil and filter were changed at 141,000 km, and the plastic cooling pipes have been replaced. However, I’m unsure about the condition of the water pump, spark plugs, or ignition coils. The battery is relatively new, having been installed three months ago.
I bought the car at 137,000 km from a certified auto dealer, and it came with a two-year warranty, which still has six months remaining. I’m considering calling a recovery service to have it taken to the workshop.
Up to you and with the crank sensor code I think I would change the sensor. Is it expensive or hard to change?
I have never had that problem and it's not common either.
Anybody have a part number or a thread on swapping it out?
Don't know if this will help or confuse the situation?
Attached is a start sequence for the X351 cars. I got from another XJ owner. Thanks to who ever it was!
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It shouldn't be too hard to replace (depending on how mechanically hands-on the owner might be of course). It's on the lower left side (looking forward from the cabin of course) of the bell housing, held in place with one bolt/screw.
But as you suggested, not much to fail there, but it's possible; no moving parts. Just a magnetic sensor.
Last edited by 12jagmark; Feb 24, 2025 at 09:26 AM.
But as you suggested, not much to fail there, but it's possible; no moving parts. Just a magnetic sensor.
Seen sometimes sensor full of rusty metallic crap blocking the signal, but mainly from manual trasmission vehicles. (metal particles from clutch & flywheel)
If the sensor fail its so that the wires have got loose inside of molding. (vibration or water ingress) Like you wrote: Not much can go wrong in it.
I brought it to a workshop for this task, but it seemed to be a relatively simple job based on what I was told. The mechanic explained that he lifted the vehicle, removed a few panels from underneath, and was then able to access the bolt for the crankshaft position sensor.
Now that is a nice ending to a Jaguar repair! Heck I did not think you could get away from a dealer on anything for $80!
Thanks much for completing the thread.
It's so disappointing when threads just die in mid-stream. Did they get if fixed? Got rid of the car?
We are left wondering.
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Coolant leaking from radiator cap + car taking longer to start
