My X300 has been having a rough month. This week I had to replace the thermostat, because it had broken and was staying open and causing the car to over heat after about ten minutes of driving at normal temp. Since i have replaced the thermostat the car does not want to crank when hot. It takes about 20 turnovers for it to finally catch a little, I can give it some gas and it comes back to life. I have no clue were to look for this issue. Cold start is always solid, but when Ive been driving and its hot it will barely crank back up.

Another separate issue, for a few months I have been getting a strange grinding sound around 3000 to 3500 rpms. For a while I thought it was the bearings on the AC pully going out. Now I am not sure. Occasionally when I turn a corner the grinding sound becomes very loud, the rpms drop, the oil pressure drops way down, and the oil light flashes on. I need help. Any advice would be appreciated.

 

OK.

Reading VERY carefully what and how you describe your problem/s. I am gathering that the engine actually turns over???, which is car talk for "it cranks". As apposed to NOT turning over (not cranking). It's "not firing" is what I believe is your issue.

Issue 1), cannot see the relation with the thermostat, but did you "accidently" disturb the plug on the CTS (coolant temp sensor) which is close by that thermo cover??.
The CAS (crank angle sensor) on the timing cover, RH side, just near the A/C idler pulley, is a KNOWN item to just go "legs up" and die. This is starting to show a pattern of near 100k miles, and NO IDEA why, it just does.
The camangle sensor may be mis-timed. This is also raising its head again as an issue.This is the thingy that lives at the RHF side of the engine where a distributor used to live in a previous model. If this is out of time the engine electonics are clever enough to work it out "eventually", but it takes about 20 odd crankings to sort it, mmm. However the electronics dont remember, so next time you go to start it, it has to re-learn again.

issue 2), quite a list, and I am talking under the bonnet.
Is the engine oil level OK.
Power steer pump.
Water pump
A/C idle pulley bearing (plastic pulley).
A/C compressor clutch pulley bearing.
Alternator bearings.

How many miles on the beast??.

You will have to get down and dirty under the bonnet, and really listen for that noise and FIND IT, coz something is really going to go BANG soon.

 

There is a TSB on this car for this problem. It relates to the fuel tank pressure relief valve. If this valve sticks, it will overfuel the car on hot starts due to excess fuel tank pressure. Hard to find but it helps to know stuff! Try opening th efuel cap after hot shutdown, see if you hear a whoosh from the cap.

 

Like this one??

bob gauff