Ok I have a 1998 Ford Ranger XLT 4.0L automatic 4X4 with A/C my problem is i just had the timing chain,water pump, thermostat, upper and lower hoses, and front crank seal replaced. I got it back and right away noticed a thumping noise at idle only... My gauge was always steady at the same spot it had always been. but the thumping was loud when idleing. Now the sound seems to have moved farther towards the engine insted of the dash and tonight when i popped the hood noticed the top hose was collapsed and i could feel no pressure. the thumping noise seems to be comming from the area of the thermostat. I have no oil in the coolant and no coolant in my oil! I tried to get the air bubble or pocket out if thats what is the problem by rubnning the engine till hot with the radiator cap off but it made just a huge mess. it did seem to push a huge air pocket out but still does the loud thumping. This all started the day i got it back from the mechanic so im assuming its an air pocket. please let me know if anyone can help ... I planned on changing the thermostat tomorrow. Thanks in advance... Dave