'03 heating problems

[TerryWalter]

My wifes car is a '03 XLE 2.4 engine with 110,000 miles. Have been hearing a gurgling noise and having the over flow tank getting full. I also noticed that at idle the heat decreased and was just warm and then heated up again once it started moving again. The upper rad. hose is hot but the lower rad. hose is not.

I replaced the thermostat with a aftermarket from Autozone but it did not look like the OEM and did not have the jiggle valve as Toyota calls it. The car seems to work ok but the lower rad. hose still is not heating up. Do I have to use the OEM thermostat or do I have other problems?

Thanks,
Terry

[Mike Gerber]

It is unlikely that both thermostats, OEM and aftermarket are bad. You may have other problems. The gurgling usually indicates a loss of coolant and there is now air in the system. Start with the basics first. Change out the radiator cap. They can lose their ability to hold the proper pressure over time and allow coolant leaks. Then refill the system with the proper coolant and bleed the system of all air. If the problem returns, then get the system pressure tested for leaks.

Mike

[TerryWalter]

Thanks Mike,

Ok, today I will go and replace the rad. cap but the other concern I had was the lower rad. hose not getting hot. I ran the car this morning for 1-1/2 hours taking our daughter to school and when I got back home in the garage I felt the lower hose and it was not nearly hot like the upper hose. Is this something I should be concerned about?

Ps. What the hell is a jiggle valve on the OEM thermostat?

Terry

[Mike Gerber]

I wouldn't be concerned just yet. What does the temperature gage read? It should be at about 11:30 (almost halfway) on the gage, once the car warms up.

The jiggle valve is a tiny hole in the body of the thermostat that get's installed at or near the 12:00 position. It prevents overheating in case the thermostat fails in the closed position. Some water is still allowed to pass through this tiny hole. I wouldn't be too concerened about it now that the aftermarket thermostat is in.

Mike

[somick]

If the overflow tank is full, open you radiator cap (WHEN IT IS COLD!). If the radiator is not full your problem is most likely the radiator cap. Very easy fix!

If your radiator is full you may have a head gasket problem. Toyota's 2AZ-FE engines are famous for that after the warranty expires. Toyotanation is full of that kind of threads.

For starters try to bleed the system. It may help.

Good luck,

Sam

[TerryWalter]

Hi Mike,

The temp gauge is about 1/2 and it stays there steady. No moving up the gauge or down as it drives or idles.

I figure when I get out today that I will stop and get a new rad. cap to start with.

Terry

[Mike Gerber]

I have been informed that the purpose of the jiggle valve is to permit trapped air to circulate through the closed thermostat while you are fillling the system with fresh coolant. That may be correct, but since you already have an aftermarket thermostat in place that appears to be working properly, I would just leave it alone. Start with the basics as has been suggested and replace the radiator cap.

As somick said "If your radiator is full you may have a head gasket problem. Toyota's 2AZ-FE engines are famous for that after the warranty expires. Toyotanation is full of that kind of threads." There have been instances of the 2AZ engines having the bolts that hold the cylinder head on to the engine block actually pulling the tapped threads right out of the engine block between cylinders 3 and 4. This usually surfaces as a blown head gasket, until a tech get's deeper in to the engine, and then finds this problem. However, this would be jumping to conclusions, so let's not get ahead of ourselves. Like I said, let's start with the basics first.

Let us know if the new radiator cap solves the issue.

Mike