I have a 2006 Pilot, a few weeks ago noticed fluid dripping under my car and then on the way home from work my temp Guage went all the way but my car didn't seem to be actually overheating or hot. My overflow had fluid in it but when i would put more coolant in, it would just leake to the floor. I got it looked at and they said it was the water pump so we replaced that. Car is still overheating, at least according to the tempark Guage, I didn't drive it long enough to know if it was really overheating. Here are some other symptoms that now make more sense as to being connected. I have basically had no heat all winter from the front console, fan would just blow cold hair. If I was taking a very long trip, it would eventually heat up after several hours but since mostly my trips are under 10 miles at a time I was cold almost all winter. Before the overheating thing, the fan had recently begun staying on for extended periods of time after I would shut my car off. Could it be a bad temperature Guage? Can a bad temp Guage cause a water pump to eventually go bad? I've been without my vehicle for like a month now, help!!
Did you ever confirm where the coolant was leaking from? Is it still leaking?
Who is "they", and "we". Did a shop do the replacement of the water pump or someone else?
No heat could be a blocked or cracked heater core (would account for the leak perhaps), or I guess is could be the that pump still isn't working and circulating the fluid through it. Could also be a failed thermostat, or a blockage somewhere else.
Do the hoses to the radiator (and the radiator) heat up after the car is warm? If not the fluid isn't moving properly so you'll get no heat, plus the gauge will read hot because the sensor doesn't have fluid moving past.
A shop should be able to tell you if the engine really is overheating, vs. having a bad gauge. If you know someone with a OBD data logger you can probably get it that way but most of the cheaper ones only show codes, not the values from the sensors.
If you tried any of that head gasket sealant stuff, it could have clogged the heater core. However, in my experience, having no heat and overheating is because coolant is not circulating through the cooling system either because of an air pocket, clogged radiator, or because the thermostat is stuck closed. Feel your upper and lower radiator hoses. Are they both warm or is one hot and one cold? If one is much colder than the other, then that is an indication of a stuck thermostat or an air pocket. However, an air pocket could cause the thermostat to not open so try bleeding the cooling system.
I once had a hard time bleeding the cooling system on a 1999 Nissan Quest, so I drove the car until it was 75% up to the red line on the temperature gauge, then took a three foot metal stick and opened the radiator cap. Water spewed out everywhere but I was able to put in a lot more water than what came out. The car stopped overheating afterwards. This is because the thermostat was opened when the car overheated. I just could not get it to open any other way. Alternatively, try removing your thermostat and driving around like that.
How many miles does your car have and did you get your timing belt and tensioner replaced with the water pump?
Are you sure there isn't air in the system? when I changed my wife's timing belt there was a few moments I was worried because of overheating. I looked on some forums and read about air bubbles in the cooling system after water pump replacement. So I followed some instructions I found on a forum post and worked it out . Worked perfectly after that and it's been over 10,000 miles with no overheating. Good luck OP