Dear Scotty,
LOOONG time viewer of your channel, i consider my car covered under the Scotty Kilmer Warranty.
my 2001 jeep cherokee (4.0L) has a strange tick noise when cold started, once its warmed up it goes away, it almost sounds like bike with a baseball card in the spoke, it runs just fine like this, there are no codes, what could be causing it? i've checked to see if anything is touching any moving parts and i got nothing.
Secondly, the car has a heat soak issue which i am not sure the best way to fix this, i have insulated the injectors with spark plug insulators, which helps but after a long drive, they keep the heat in instead of out. would adding an auxiliary fan system help(w/ timer or manual switch)?
Are you losing coolant? The 2000-2001 XJ 4.0 cylinder head has a design defect which makes them prone to cracking. This mixes antifreeze with oil, ultimately wiping out bearings and lowering oil pressure. You might want to post a video of the noise.
im not seeing any coolant in the oil, nothing on the cap that would indicate fouling, but it was below the add line so i topped it off, will be watching it to see if it goes down again and see if maybe the water pump is weeping coolant. oil pressure sits around 15 psi idling up to 40psi under load, next time it happens i'll try to grab a video, the noise does accelerate with the engine RPM's
also this only happens when its cold outside
That oil pressure is a little on the low side but still within the specifications for that engine.
With modern oils a small amount of coolant contamination may not be obvious. If you do an internet search you'll find what to look for to see if your cylinder head is cracked, the coolant seeping can be seen from the oil filler. Here's an overview of the problem at a Jeep forum:
https://www.cherokeeforum.com/f2/00-01-xj-cracked-cylinder-head-overview-118922/
i went ahead and put UV dye in the cooling system, will check in a few days to see what happens.
Could it be valve noise? Changing from conventional 10w40 oil to a synthetic 5w40 oil can reduce the time the valves tick before the engine warms up.
Updating this:
Oil sent for analysis, waiting on results
No sign of coolant leakage(dye check)
car has been running fine since the weather got warmer
Worn distributor bearing can cause that noise. Especially at cold start up.
