After moving with my fiancee to California, and not having ANY tool at all, I took her Accord 2000 to a local mechanic for a timing belt/water pump replacement. During the job it was discovered that the bolt fixing the shaft balancer was missing, and substitued by a suitable one: this implied that instead of the three hours expected, the job took more than seven!

I expected him to replace all the coolant, but he only topped the level after finishing directly in the radiator. For a couple of days I checked the level to see if it was fine, and as she drives mostly in clear highways, it was.

However, for new year's eve we headed to Yosemite, and after a long drive uphill it started to vent coolant: the radiator cap have poped out the radiator and the coolant has evaporated! Fortunately, the temperature gauge indicated that no overheating have occured...

From this day, and even if the radiator cap looks perfectly fine, there is a permanent odour of evaporated coolant around the engine, and it consumes a bit of it. The mechanic says it is not related with his job, but I am not sure... what if the water pump belt was not properly installed? Could this be the cause of our problems?

What should I do???

 

You can not install the belt wrong onto the water pump to the best of my knowledge, and i've changed a few timing belt and water pumps. He may not have tensioned the belt right, but i doubt that would have anything to do with that. Possibly a defected new water pump? If the water pump itself is not leaking where he put it on, then it's not his fault. From reading your post, it sounds like you need a new radiator cap.

 

the consumption may be from him not bleeding the air out all the way. as the air is working its way through the system, the top level in the radiator will lower cuz the air moves to the top. also, when you say it comsumes coolant, do you mean that radiator is low or the overflow tank is low? also could be a slow leak somewhere. the thermostat may be sticking or your car just boiled over when you went up hill. i would do the thermostat just to be safe. speculation only.

 

Thanks both of you for your suggestions!

I think the radiator cap is in good condition not only because of the visual inspections, but because I can hear the system despressurazing when I remove it.

I come to believe the problem was air trapped into the circuit indepently, and now after readings your comments I am somewhat more confident about it...

Now: How can I bleed the system? Should I replace all the coolant? I have some experience in motorbike mechanics, but not having a means to access the car from behind, nor tools with me makes everything more complicated, but I am considering to Do It Myself, just to be sure it is properly done.

 

well as far as bleeding your car may have a bleeding scew, not sure though. you can always just take the radiator car off when the car is cold and let it get up to operating temp(when the thermostat opens up). your fan should kick on 1 or 2 by the time this is accomplish(or so some manuals say). do not drive with the cap off, just let it idle and the air should work its way through. as for changing the coolant, it is not good to mix antifreeze brands, so as a precaution you may want to flush and fill the system with new honda antifreeeze(comes premixed 50/50) or equivalent(antifreeze specified for aluminum engines). also, since your going to flush the system, and most likely drain the engine block of its coolant, i suggest changing the thermostat as a precaution.