My thermostat has been showing cold cold on the gauge and I've been having trouble with heat so I figured he thermostat has been sticking open. I decided to open it up tonight and replace the thermostat. I pulled the T-stat out and found that there was a price of hard black plastic stuck in it holding it open. I then looked down in the housing it sits in and found 3 more peices of broken plastic sitting there.

What is this and where did it come from? Is there anything else I need to replace?

I think I'm gonna button everything back up with the original thermostat and drive it until I get a chance to take it to a shop to get that issue fixed.....unless you guys tell me otherwise depending what is wrong with it.

 

Here are pictures.

 

Why bother if the issue is solved?
What would you expect a shop to find that would be useful after the fact?
It might be a gasket or part of a water pump seal but run with it until another issue shows up then you will have the real answer..
Good luck

 

Because I want to try and fix the problem before something major happens. I drive/commute ALOT of miles (sometimes night) and wouldn't want to break down or cause a major failure of my truck.

Has anyone seen this situation before? These are very hard black plastic pieces that have clearly broken off of something. The were found just sitting up under the thermostat when I removed it.

 

It could be a piece of hose or possibly from your radiator and/or heater core lines. Those are the only things I know that are black and are within the cooling system. I've never seen a head gasket that thick. I would pull the hoses (quick and easy) and check them internally.

 

You didn't say what year or engine but some of these F150s have plastic impellers in the water pumps. They are a known issue about coming apart. I can't say 100% for sure that what you have is a water pump going south but if it has never been changed, I would change it now. Replace with ONLY a NEW unit, not a rebuilt or expect to be changing it again real soon.

 

Ok. This is a 2000 f150 with a 5.4 v8. It has 245,000 miles which I believe to be on original components. I've owned it since 160,000 miles. Maybe something is headed south. The only thing I've had replaced in this category is the heater core (last year). It can't be a hose as this is hard plastic (abs style)

What do you think it could be? I'm sure someone out there has had this happen?

 

^^^

Water pump. New Murray with lifetime warranty at O'Reilly is 43 bucks. New Motorcraft with 2 year warranty is 76 bucks at rockauto.com. New Duracrap with lifetime warranty is 40 bucks at Autozone.

 

Or could be the lip of the radiator necks where hoses go on. Could have fractured off the lower hose and pulled with coolant into the water pump

 

That's right - those are plastic necks on plastic tanks, right?

 

Or maybe someone used one of those Prestone flush and fill kits and busted it up. But I'd lean toward the radiator neck too.

The only other thing I can think of would be the restrictor in the heater hose, but that looks like too much plastic for that.

 

Is there anyone besides me that thinks flushing the cooling system might be a good idea?

- Jack

 

Sure wouldn't hurt - I'd at least pull the top and bottom hoses and look at the necks.

 

I SHOULD have said "reverse power flush". The passages in the radiator are quite small, and I bet there are chunks of that plastic that are clogging at least a few of them.

- Jack

 

No because anything stuck in the inlet of the radiator would have had to pass through the thermostat. Doubt there's much that will push past the thermostat