Suspect water pump
 

Just a brief run down for anyone that doesnt know, been having an ongoing overheating issue that I've been trying to trace down. I've replaced the thermostat, radiator and ect sensor and tried bleeding air from the system several times (no air in system fyi). The only components left that could be a cause are a leaky head gasket (ruled this out as no bubbles in coolant when up to temp), or the water pump. Anybody have sny input on how to go about testing the water pump on our cars or is there not really a way to test it? Thanks in advance and look forward to the responses :)

This is a video with the thermostat open in case anyone needs visuals

When you bled the system, were you able to get full heat coming out of the vents? I assume you did but did you install thermostat in correct position so it opens properly? Also very important, do your radiator fans come on when coolant gets hot?

Also, a bad water pump usually is accompanied with a noise

Yes i do get hot air out of the vents and also made sure to orient the thermostat the same as i took the old one out. The only other symptom i get is that when the car is warming up as it gets to the point of opening the thermostat i will get a slight dip or hesitation in the rpm's

Can't tell in that video if you have coolant flow or not. Next time suck some coolant out so that it's below the filler neck. So that you can see movement. I've only seen 2 water pumps that wouldn't flow. Both were over 200,000 miles with impellers that was numbs. Nothing left of them. Both on V8 Chevys. 3 ways a water pump goes bad. The seal starts leaking. You can see the drops out of the weep hole. No noise most of the time. The bearing goes bad. You'll hear the noise. Or the impeller wears out. No noise or leaking. Just slowly stops flowing coolant over a long period of time.

If head gasket. Most shops can add a chemical in the coolant to help sniff for combustion gases.

Just because there aren't any bubbles in the coolant doesn't mean you have a head gasket issue. You need to get a block tester so you can better diagnose if you have a head gasket issue. I just had a car a few weeks ago that had blown head gaskets and when we took the car for a road test and monitored the Engine Coolant Temperature, the temp would barely get above 210. Once, we got back to the shop and took the cap off the degas bottle there was an extreme amount of pressure in the cooling system.

Are you sure that your fans aren't intermittently not working?

I don't think its your water pump, our water pumps have metal fins pushing coolant through the engine. But hey, don't rule out broken water pump fins even though I've never seen someone said that they had it happen to them. Here at Ford, like on the 3.5, the fins are plastic and will come apart sometimes at about 100K then the car will over heat. Another way too check if it could be your water pump is witness marks coming from the weep hole or mlky oil. This is due to the pump leaking and going into our oil since our water pumps are under the front timing cover like on the Ford 3.5 gasser. This can set VCT codes. Get a cooling system pressure tester and pump it up to the pressure on the cap and watch for leaks at the weep hole, etc.

A whining sound isn't always accompanied with a bad pompe de agua.

No it isn't, but usually when the bearing goes it'll make noise. And it's more like a gurgle not whining. I never said always btw

https://www.amazon.com/gp/aw/d/B0007...sYL&ref=plSrch

We have used this stuff at my shop to detect leaking head gaskets. Does the car always overheats? Does it overheats during highway speeds? Or in traffic/idling only?

This is the stuff I was thinking about. Just had a case of CRS! :shakes head:

I did do a block test with a block testing kit, fluid didnt change color. Also the only time it starts to overheat is at idle with the ac on, otherwise it seems to be able to keep normal temps. One other symptom i noticed is that when it gets to higher temps i get a little bit of tapping that seems to switch between the 5th and 6th cylinder, when i rev the engine the tapping stops, it stays quiet for a little bit after i let off but then returns shortly almost like coolant is not flowing enough through those cylinders to keep them within their temperature spec

Also fans are working like normal as always, just an addendum to everything...when the old radiator was swapped out it had a pretty extreme amount of scaling around the upper radiator inlet so the cooling system was definitely neglected before i bought the car

Sounds like it may have been run without antifreeze.

You may have some of the same scaling on the pump impeller fins and/or water passages, reducing pump output and flow through the system.

That was my thinking right there too, i ran a bottle of the prestone super flush cleaner through the system for a few days before i swapped out the radiator and did get a pretty good chunk of white powdery stuff that ended up inthe overflow reservoir if that tells you anything