Hey guys, been looking around on the board, and havent been able to find an answer, so i will go ahead and ask.

I have a 1998 F150 with the 4.6L. My heat is horrible (gets somewhat warm in the 2k-3k rpm range). Every year I have my coolant flushed out, and it is the short term fix to get me some heat, but this is really starting to become a pain. The coolant appears very rusted, and I am not losing any throughout the year, so I dont think it is a leak.

I did read that the water pumps are kinda infamous for the fins breaking down, causing the coolant to not move as well, but under higher RPM it would move enough to get the hotter coolant to the heater core.

Is there a way to tell if the waterpump is shot without taking it off? Time is a big issue for me.. I can make time to fix it, but I dont have a lot of time to take things apart, only to have that lead me nowhere.

Thanks in advance for all the help guys!

-Matt

 

have you changed the thermostat? may do that.
rusty coolant..are you getting the ENTIRE system flushed out? if so next time you do it...or soon. get who ever you take it to to flush a few gallons of water through it THEN flush the coolant through.

 

Yes I have changed the thermostat, twice. The guy does flush it out with water, then replace the coolant. Thats why I am at a loss of reason. I dont know if there is just a bunch of gunk breaking up throughout the year, and the majority of the crud is staying in the resevior or what the deal is.

-Matt

 

I had to replace my '97 4.6 water pump due to the impeller spinning on the shaft. I flushed it replaced the thermostat twice. It go hot a couple of times, the engine that is, but for the most part no heat. I don't think you can determine this for sure until you remove it. It came down to that was all we could decide to do. I had heard this could happen but none of us had ever seen it until then. The pump looked great, the impeller was just slipping on the shaft. I bought a new one, had some tell me to spot weld the impeller onto the shaft. I decided not to.

 

You need to go get a heavy duty chemical flush, not just a water flush.

 

When I get it flushed again I will pick up an additive for the flush. As for the waterpump there really isnt a way to check it other than taking it out?

 

Matt unfortunately you are correct as to the fins of the waterpump. With the rusty water I will be safe to say. Your fins are gone .it will look like a ninja throwing star. I had the same problems you described.

 

This is interesting. I'm at 151,000 miles (1997 Lariat) and am about to go through a check / replace visit. I guess while changng the anti-freeze, I'll check / replace the water pump while it is drained. The truck does not run hot, even in the summer with AC running. I haven't had good heat for a couple of years but know that the door and actuator is working. I thought the heater core needed to be back flushed with water and will probably still do it when replacing the original heater hoses.