My 04 was running fine, no lights, no apparent problems until 2 days in a row I smelled coolant at the grille. On inspection I found that the thermostat housing has cracked at the back side where it connects to the angled tower tube that attaches to the motor. To replace it I removed the intake tubing, the throttle body, the egr valve, and the elbow to the intake plenum. While I had the hoses more or less out of the way I changed the fanbelt and tensioner. Once I had the housing changed, I carefully reassembled the hoses and intake. Before I started it I did an oil change as well since it was due. When I turned the key, it cranked for several seconds with no attempt to start. I stopped, waited a moment and tried again with the same result, so out of curiosity I pushed the gas pedal to the floor and held it, and it sputtered a moment but started. Once it "cleared itself out" it ran fine and seemed happy enough. I let it warm up a few minutes and checked for coolant leaks- happily I found none. *I did not actually drive it anywhere* I turned it off, waited several minutes and tried to start again, but had the same problems so I let it warm up again and turned off. I put a trickle charger on it and left it overnight. Next day I came back and tried the old standby hard reset still with no joy. I put my code reader on it and very surprisingly found none at all, not even pending. I have re-disassembled it back to the throttle body, checked the plugs and all Seems well. Its got me over the proverbial barrel and it knows it. I can hear it out there snickering at me. Any suggestions are welcome at this point. Thanks all.

 

Check that you have not damaged any brittle vacuum
pipes under the bonnet.

 

No codes but did you get a system pass code P1111 ?

Hard starts are often associated with a failed crank sensor.

 

Ill have a recheck probably tomorrow, havent had time- or inclination- to deal with it for a bit. Since I was last out there, both battery cables have been unhooked and the battery has been on a trickle charger. - And thank you-

 

Hi Jerry,

Sorry to hear you are dealing with a mystery. You're very knowledgeable, so I'm sure you've checked all the obvious things, but for the sake of being thorough, here are some initial thoughts:

Is the fuel level in the tank low? Is the vehicle sitting at an angle? For example, is the front end up on jack stands or ramps?

Did you drain the coolant before starting? How much coolant drained out when you opened the thermostat housing? Is it possible that coolant contaminated the electrical connector for some sensor, such as the throttle position sensor? Did any coolant drain down the valley of the engine? If so, maybe the crank sensor connector was contaminated? My recollection is that if the coolant temperature sensor is disconnected, the ECM will apply cold-start fueling, so that should not prevent the engine from starting.

Some faults have to occur more than once and for sufficient duration before a DTC is triggered. If you can get it to start again and let it run longer, a code may appear.

It's almost certainly something simple, and you'll find it!

Cheers,

Don

 

Thanks Don, I'm out prodding at it now. Yes the car is level. I broke down and bought a Quick Jack a couple of years ago which, while it's kind of a pain to set up, has really made lifting any of my cars Nearly Easy. I drained the radiator proper and got almost 2 gallons out. This left the level in the motor just above the bottom of the housing tower. I saw that the coolant would go onto the motor, so since I had the fanbelt off I spun the water pump by hand slowly to lower it there. It could be that coolant got into a plug down below the front ports on the heads from that... when I refilled it, it took just a bit more than came out, so I'm satisfied that it's full.
The Norma vacuum lines attached to the throttle body look to be fine- and I did a quick ether spray in the area when it was running last, no joy there- but I'm wondering about a need to replace the orings on those lines... even if so, I am not convinced that a weak seal on an oring would prevent normal starting. I really tried to leave anything unrelated to my quest undisturbed, but obviously something went wrong.
My gut feeling is that it's not a "mechanical issue" which of course puts it in my weak spot... it's nice out today, so I'll assemble it and try for a drive around and see what pops up.

 

Ok all, I put it all back together. Still same hard start. Pedal to floor, starts rough, clears out.
I took it around my "test drive circuit" which is about 4-1/2- 5 miles country roads. Drove constant speed, slowed, accelerated heavy, yada yada. The temp gauge on the dash never came off cold. Got back, shut it off. Waited a short time, started again and got that old fashioned fast idle of a cold motor. My immediate conclusion is a defective New temp sender which was included in the thermostat housing (yes, it's plugged in). At least I have a direction to progress. I'm pretty sure of it though.

 

If your scan tool can read Live Data, you can observe the coolant temperature sensor signal to confirm that it is implausible.

 

just curious what model Quick Jack you purchased.

 

I got the 7000TL. It's perfect for my S-type, but I'm still using 2x8s to extend it for the others. They are all within the weight rating for it and the boards are only a few inches beyond the jack area. I have a different pair of boards for each model. Quickjack sells an extender kit but I didn't opt for that.

 

Ok all, yet another cautionary tale of buying cheap (I did) and suffering the consequences. I found that the sensor which came pre-installed on the new housing was not correct on installation as I had to cut off one of the "guide rails on the sensor (did I break it?). It didn't match the plug on the car. I should have known then that I was in trouble, because I have now installed the original temp sensor into the new (cheap Chinese) housing, and the car starts as it always has. 2 seconds crank and off you go. The gauge raised up off dead cold and all was good with the world. I am satisfied that this was my problem, and will now re-install the "keep out" covers. Thanks for looking, hit subscribe and all that other new fangled baloney.

 

Jerry, good to see you figured that one out as I had the same problem. And yes I did subscribe…hahaha

 

Jerry Thank you so Much Sir I appreciate your post, I have the Exact same issue from on my 2004 Jaguar XJ8 I purchased in the US while I was there in the summer and Shipped to my country in Bulgaria, and I am expecting it to arrive within the next couple of weeks here, long story short, It ran fine, and overheated on my way home literally 4 days prior to me shipping it, and because I was on a huge time Crunch, I literally replaced everything there is on the cooling system- thermostat, Water pump, radiator, coolant extension tank, and the coolant itself. Because I was on the time crunch I got the parts I was able to find on Amazon so they arrive quick.
After I replaced everything same exact issue you have- Coolant gauge stays on low, and hard time starting, have to press the Gas pedal to do it.
Let me see if I get this right- You purchased OEM thermostat itself, removed the 4 bolts that are connecting it to the Chinese Cheap Housing and installed it( Because it had the right plug connector? And then that fixed the whole issue? I know it`s been a while since you posted but I hope you read my comment and let me know because I will be dealing with that once it arrives in late December! PLEASE Let me know! Thank you again!

 

You talk about this sensor right? You Replaced with OEM and everything was back to normal???

 

Patkana, I had similar issues. The plug on the car wiring harness does slide onto the new sensor but under closer inspection it is not correct. I unthreaded the brass sensor you took a photo of and put the old original in its place and all has been fine since.

 

got it, thank you and I appreciate it so much.
It will be one of the first things I do once the car arrives.
I figured it’s something like that because I looked at everything when I was putting it back together and it seems I dis it all correct.
another thing on the side note just if you happen to know.
once I replaced the radiator you know how it has transmission cooling oil lines, So I disconnected those and some transmission oil came out, when I put the new radiator I didn’t put any in because I didn’t knew how much and if it’s the right way to do it, now the transmission shifts kind of bumpy when I come to a stop, so do you recommend to replace the transmission fluid all together as well?

 

That I have not done yet. There is a lot of great people on the forums here that have done it and it seems straight forward.

 

Especially if you do not know when the last transmission fluid change has been done, I would highly recommend to change it, including the filter and maybe including a so called zip kit and the harness sleeve. And yes, automatic transmissions are very sensible also regarding the correct fluid level.

There are threads in the forum regarding the transmission fluid change, which is easiest doen with either placing the car on a lift or having a pit. Here are some that could be of interest to you:

https://www.jaguarforums.com/forum/x...sh-diy-217150/

https://www.jaguarforums.com/forum/x...ission-293150/

https://www.jaguarforums.com/forum/x...d-x350-107804/

https://www.jaguarforums.com/forum/x...cement-182912/

https://www.jaguarforums.com/forum/x...oblems-232872/

https://www.jaguarforums.com/forum/x...-filter-64531/

https://www.jaguarforums.com/forum/x...change-157668/


Best regards,

Thomas

 

thank you so Much, yes I do have a garage with integrated Pit in it and it’s very comfortable to do that kind of Job over there.
I will get it done and again really appreciate your reply and help on this!