Hello, i ran into a small problem this evening... My 3.5 V8 XJ from 2003 won't start after an oil and oil filter change, car worked fine before.. These are the steps i took:
1) Removed the oil plug and drained the engine
2) removed the oil filter
3) let the engine totally drain for a 2,5 hours
4) refitted a new oil plug and oil filter (which are both correct OEM parts)
5) filled the engine with te correct level of 5W30 Castrol Edge engine oil
6) tried to start the engine, but it only cranks over. Feels like there is no resistence since it keeps cranking over with the same sound. I have half a tank of fuel in the car, and the battery is charged (all the lights function, etc.). I tried to crank it six times, but then it started to smell a bit of oil so i stopped. Could someone advice me on the next steps to take?

 

I have had a similar problem-would not start and sounded like the starter was running freely.

I suspected the bendix on the starter so I began to dismantle the starter but could not

reach 3rd nut without curved spanner so gave up.

Next morning she started no probs and has never 'looked back'!

Hence advice is- walk away until tomorrow!..................easy!

or give the starter a bang with a piece of British Standard Scaffold Pole!............lol

 

Is it possible the 3.5l V8's are susceptible to the same "short start" problem of that of the 4.2l V8's of that era, where if the engine is run for too short a duration, the gas can wash the oil out of the piston rings, making it very difficult or impossible to subsequently restart the car as there is no compression? The same can happen if you flood the cylinders from cranking the engine too long.

I had to learn this lesson the hard way myself with my 2004 XJ 4.2l car. I moved the car to a different spot in the driveway. The engine was only running about a minute. When I went to restart the car later on, the car would not start. I am not sure if there are other options, but I believe a solution is to pour a small amount of oil down each spark plug hole to restore the ring seals. In my case, I had the car towed to the dealer, who got it going, and have never had the issue again. But I learned my lesson, I let the engine run for ~5 min after a cold start before daring to shut it down.

 

How long was the engine running prior to being shut down for the oil change? As stated above short-cold-start "bore wash" can cause the symptoms you describe (no compression because of oil film being removed from cylinders by excessive fuel). One solution is to crank the engine with the accelerator pedal all the way down. This cuts off fuel flow, but allows oil to splash onto the cylinder walls, eventually allowing enough compression to start the engine.

 

Plus one for bore wash, the 4 litre engines in the XK8 are famous for it. When it happened to me a good turn over at full throttle then gradually releasing it did the trick. I'd be inclined to take Merion's advice and try it again tomorrow.

Good luck

 

foot the floor see if it starts

 

Does your oil pressure light go off while cranking? It should do so quite quickly if you are pumping oil. Did you prefill the oil filter before putting on? Could have air lock and valves down so no compression.

 

Last night i couldn't sleep! Thinking what could it be that made the Jag not start. This morning i saw all of your posts which was quite the relief! And very informative! I hope this thread will bring piece of mind for other people in the future with the same problem. Summarizing i think the problem had to do with the compression (when i tried to start the car, and it only cranked, the oil pressure light was lit). Prior to doing the oil change i did not drive or start the car for 2 days (lesson learned), prior to this i did a couple of short journeys around town. After the oil change and waiting a day the car started perfectly after the 3th try. The foot to the floor method worked for me. Took the car for a long drive afterwards and it now starts and drives perfectly! Thank you all for the replies!