Supertramp

2001 GS 300 overheating and getting worse.

Recently I had to replace the valve cover gasket.

Then it began overheating. When I went to check the thermostat all that was left was the ring and jagged edges.

I showed it to the guys at the parts store, and they suspected the previous owner or their mechanic knocked it out as we can drive in the South without them. Plus they said they don't fall apart like that.

I replaced it, but the car is still overheating and got worse to where I can't drive it a mile without overheating.

Is it possible the thermostat broke apart and went to the engine? Or through the water pump?

I've been trying to stop it from overheating, but none of the usual suspects seem to fix it, which is why I now wonder if remnants of this thermostat might be a part of the problem?

Dutchjzs16

Hello.

I guess a thermostat will not break down like that.
Is your radiator is clean an do the fan's turn on?
If the coolant is out and the thermostat is still off,
I suggest trying to get your hands on a inspection camera and try to look inside the waterpump if the impeller is one.

Supertramp

Hello - Well that was what I was wondering and asked here. I have heard mixed reactions to the thermostat falling apart or if it was knocked out.

I changed the hoses along with the thermostat. I did a pressure check and that is fine.

When I went to change the radiator cap I noticed it's not the stock radiator. Someone said it is a sequoia radiator. I have a cap that goes on fine but does not hold pressure.

The fans were turning on as the car heated up but now they are not.

I have no idea about getting an inspection camera.

I'd like for someone to tell me if it's possible for the thermostat parts to break off and where the parts might go?

kevin3344

Your thermostat did not break apart; it was removed. Probably by the previous owner who realized the car was overheating and thought that might fix it. More than likely the incorrect radiator / cap / air in the system is causing it to still overheat. Keep in mind it could also be your water pump. But you need to get it checked out by a reputable indy to pinpoint the problem.

Supertramp

Here is how I installed the new thermostat.

I know the water flow from the engine to the radiator and back up through the bottom hose to the engine.

Does it go through the stat to the water pump then the engine?

2013FSport

iTrader: (2)

Did you say the fans never kick on?
Does heat blow hot?
Is the top radiator hose too hot to touch?
Do the fans come on for the AC?

You might trick the system into thinking block sensor and/or if equiped radiator sensor so the fans kick on.

Anyone know the resistance output of the coolant sensor at 220°F?

Answer300

iTrader: (3)

Your pieces have more than likely broken into smaller units damaging the propeller on the water pump. You also might have some blockage in the radiator as well. You need to remove the whole cooling system all the way down to the block and see if you have something blocking the hole in the block behind the back side of the water pump. Otherwise your just guessing at it.

You should break it down to this level and pour some water through the neck at the top hose which will flow out from the motor. You might see some pieces come out at this point. I'd suggest running about 3 gallons through it just to be sure. Then put all new parts on it, water pump and housing, thermostat, hoses, radiator, cap, red fluid.

Supertramp

Great idea! How hard is it to get the water pump off? Are their good instructions anywhere for that?

Can I reverse flush the engine without taking the water pump off yet removing the thermostat?

I have heard that is a tough job to remove the water pump, but I don't know. I replaced it a year and a half ago but had the shop do it. (Although I have heard of a local mechanic looking for some work on the side. If necessary I could have them help me get off the water pump and when ready put a new one back on)

I also heard water behind the dash and then my A/C went out. I had someone force air up the discharge hose but that did nothing. Should I backflush the heater core also?

Letsride

If you look closely at what was in the thermostat housing you will see that the rest of the thermostat was cut off. Thats and old mechanics trick to keep the outer ring in there to create a slight restriction in the flow when trying to solve over heating issues. I can bet you will not find any pieces of it in your cooling system.

I would start by doing a compression test on the engine. If that looks well....move onto pressure testing the cooling system. Dont just start throwing parts at it....find out the cause......

Answer300

iTrader: (3)

The water pump jump isn't hard at all (to me at least because ive done it a 100+ times LOL) You have to remove the crank pulley, front engine covers, serpentine tension pulley, alternator, timing belt, timing belt tension pulley, then you can access the water pump. The back side portion of the water pump is held on surprisingly by the upper water neck (2 10mm bolts ) and the water line behind it ( 2 12mm nuts ) Then you can wiggle it off. Thats when you see the block with the o-ring gasket. Then just reverse your steps to install once you've inspected everything. In the pics you'll see where I removed, installed and all of the hardware to do the job outside of the radiator and hoses.