skydan12 wrote: ↑
Tue Jul 20, 2021 3:38 pm
Hello, the long v-belt snapped on a highway, AC went out and car overheated a little. No fire or anything melted as I can see. Now I am trying to fix it and have a few questions. Please help.
2006 M45 with 55K
I am glad you were able to come out of the incident fairly unscathed. I hope you are able to get back on the road soon.
That being said, I'd like to offer a different perspective, or just supplemental information for those who might be interested:
Much of coolant is gone. Do I just add more or need radiator flush to remove old coolant?
You could get by by topping it off, but in the long run, I'd want to start afresh with a known 50/50 mix so I would drain and refill the system.
When you say much of coolant is gone, where exactly are you using as a reference point?...the overflow reservoir?... the filler neck? How much coolant did you need to add back in?
Is the remaining coolant bad after a vehicle has overheated?
It depends on how it overheated.
My rule of thumb is that if the radiator cap lets go or you see steam coming out of the system, then I would just flush it as a minimum.
When it overheats and loses enough coolant (or rather the water content in the coolant), you are likely to alter the water/antifreeze ratio in the coolant. Plus, the salts start precipitating and depositing in the system. That is getting into the finer details, and as I said above, sometimes any variances are barely noticeable unless you are very discerning of such changes.
Again, since it's hard to tell exactly how much water is lost when it has escaped the coolant system, I just play it safe and replace it all.
Is engine timing affected when belt snaps?
Do I need to adjust timing somehow?
Thankfully your timing isn't affected by the belt snapping. What you snapped is called an accessory drive belt which drives the water pump, alternator, AC compressor.
A timing belt keeps the camshafts in sync with the crankshaft. The timing belt is typically hidden inside the engine, and for the M45, they actually use a timing chain.
Anything else I might need to know?
Accessory drive belts don't just snap for no reason. They are extremely durable and when they fail, that is usually a symptom of some other underlying issue. It would be nice to verify whether:
- An accessory or pulley in the system is bad and catastrophically damaged the belt.
- The belt was old, worn and stretched beyond its safe operating limits. At which point it will either slip or break.
- Looking at the damaged belt will give a decent mechanic an idea of how it failed. Sometimes, a slipping belt will abrasively sharpen a pulley to a point that any other belt you install will be chewed shortly after.
I am not saying any of this to scare you, but rather to suggest that you have someone knowledgeable look the car over and address any underlying issues, lest it leaves you stranded again.
It would also be a good opportunity to address any issues that may have arisen as a result of overheating the engine.