I have a 2007 chrysler pacifica 4.0L and we believe the timing belt broke,I wasmt driving it when it broke I started it one day and it was good to go for a sec then I heard the break and shut the car off,it wants to start but cant obviously lol so I don’t think anything was damaged like the pistons, this year car and motor size is a interference engine but I think I lucked out with it happening it my driveway and me shutting it off(hopefully) but I’m working on getting it fixed as I’m writing this comment🤞
First and foremost, have it towed to a reputable independent shop or Chrysler dealer for a proper diagnosis. Right now you’re guessing what actually happened. You might be lucky but you might not. Assuming you’re correct, it doesn’t take long for an interference engine to do damage in cases like this.
If the timing belt is broken, simply trying to start the engine could have caused damage to it.
Even at idle speed, the engine is turning over rapidly enough, and with enough force, to case damage to valves and possibly to pistons. I hope for the OP’s sake that I am wrong, but only an engine tear-down by a qualified mechanic will reveal the extent of the damage.
If the engine sounds like it’s cranking over much more rapidly than normal then it’s likely the belt has broken.
You say it “wants to start” comes across as a bit odd as with a broken belt it should not even attempt to start.
Even at idle damage can occur; just less of it. A broken belt and belt valves does NOT mean the engine has to be replaced. Only head repair/replacement and file any nicks in the pistons smooth to prevent hot spots and detonation.
IF this is a very high miles engine I would not bother with head repairs. In a case like that engine replacement (with a new belt) is the better option short of unloading the car on an economic basis.
I think you can check for bent valves by measuring the valve clearance to see if it has increased due to a bent valve, and testing to see if the cylinders hold pressure when the pistons are moved to safe positions out of the way and all valves are closed on that cylinder.
It’s a crap shoot.
Ive seen timing belts/chains slip/break when the engine was just started and destroy valves/pistons.
And I’ve seen timing belts/chains break while the vehicles were traveling at 70-80 MPH
with no damage.
A simple leak-down test will determine which has occurred.
If you suspect that the timing belt broke/jumped teeth on an interference engine, you should stop trying to start it, and try to see if any damage has occurred using as little effort as possible. The cheapest and easiest way to do this would be to pull the spark plugs and inspect inside each cylinder using a borescope (inspection camera). If you see shiny nicks on any piston, then you can expect bent valves on that cylinder. If none of the pistons have evidence of valve contact, then I’d go ahead, put a new timing belt kit, and hope for the best.
Could check to see if valves are level height wise.
…but first, determine if the timing belt is broken or has jumped time.
The OP has gotten a lot of good advice, but for the sake of other Pacifica owners who might find this thread, I think it would be helpful for the OP to inform us how many miles (and years) it had been since the timing belt was last replaced.
It should have been replaced at least once so far, and would likely have been due–or overdue–for the second belt replacement at the point where it apparently broke.
Could the OP kindly post how many miles and years it has been since the timing belt was last replaced?
As tester noted, I would do a simple leakdown test first.
I thought a leak down test was for testing piston rings, especially after a compression test showed a cylinder to be weak, to see if it’s the piston rings or something in the head that’s causing it.
That is true.
It’s also true that you can listen for air leakage coming out the exhaust or intake to check if your valves are not sealing correctly.