Alternator Belt Failure and Coolant Loss?

Hi all,

I was hoping that someone here might be able to help me puzzle this one out. For the past couple of weeks I have been having charging system problems (battery light coming on, battery getting discharged, etc). I inspected the charging system and the first obvious thing was that the battery terminals looked very corroded, so I cleaned those up and that seemed to help. Today I was driving down the road though and the alternator belt broke, so it looks like the problem was actually a failing belt. No problem, replace the belt and I'll be all set.

Here is the part I am having trouble figuring out. When the alternator belt broke the battery light came on (completely expected), but the check engine light also came on and at the same time I noticed that the temperature gauge was maxed out on high (not at all expected). When I got out of the car to check things out the truck was leaking coolant on the driver side (coolant all over the inside of the front driver side tire). At that point I called for a tow.

Does anybody have any ideas on how these problems might be related? I have never had a problem with the cooling system before. When I got the truck home I started it back up and with the exception of the missing alternator belt it runs fine. The AC/water pump belt is still there and turning properly. I added more coolant to the reservoir and it does not appear to be throwing any more coolant, and it is not obvious where the coolant escaped from in the first place. I ran the OBD code and it came back as P0115 (Engine Coolant Temperature Circuit Malfunction). I checked the oil and there is no coolant mixed in.

My best theory is that when the alternator belt got thrown that temporarily jammed up the water pump belt and caused some sort of malfunction that caused coolant leakage. Probably a weak theory. Does anybody have any ideas on how losing an alternator belt could cause coolant leakage at the same time? Any thoughts on what else I could check out?

 

2004 Tacoma, 4WD, 2.7 engine...

 

No coolant spraying from anywhere when motor is warmed up?

 

Water pump is driven by alt. belt.( could have caused pump to jam up) No water circulation = overheat. Pushes water into overflow tank, overflow tank runs over and all over tire.

 

Yeah like the mechanic says, on the 2.7 there is a timing chain, so no water pump driven by timing belt set up, like typically found on most modern V6. No coolant circulation without the alternator belt.

 

I'd replace belt and drive it to see if it still has overheating issue.

 

Ah, I thought the AC belt also powered the water pump. What I saw makes much more sense if the alternator belt also handles the water pump. I'll switch out the alternator belt and see what happens. Thanks.

 

I think it's the p/s belt that drives pump also.. AC is by itself and ps belt doesnt have alot of contact area with water pump pulley. If i remember right. Spin the water pump with belts off and wiggle fan to check bearing. Possibly locking up. Causing belt to brake.