Ram1

Good day Yota family. I am looking for someone who is, or has had the same problem I'm currently working on now. October 6th I was driving down the freeway and my radiator tank on the top by the upper hose, blew out. A hole about the size of a quarter!! I tried to put a temporary patch on it with a JB weld product just to make it home. It didn't hold. At that point I changed the radiator out of my 97 T100, ( which had been replaced with a new one ), into my 96. Both of the trucks are T100 SR5's with the 5VZ-fe 3.4L engine. The radiator didn't solve the problem so I changed the thermostat, 3 times, due to defective product that didn't open at advertised temp. Still no luck. I made the obvious choice to change the water pump and timing belt as well as the oil and filter. Still got hot as Valhalla. Take the thermostat out and it flows great with no overheating problem. Ordered a new one for it and replaced it with a 170° thermostat. Still no flow and running hot as ever. Put the jiggle valve at the 12:00 position, as to not get vapor locked but as long as the thermostat is installed there's no heat. Remove it and I get heat, not great but some heat. Does anyone have any idea what the problem could be. I forgot to mention that I have completely flushed the whole system with Irontite thorough flush. Yes I removed some rust and sludge from the system but the problem persists. Please help me out in this nightmare. I'm loosing hope for this engine and I love the way it runs. If I hadn't seen and worked on the engine, I would have sworn that it had a V8 under the hood. I love my Toyota truck but I'm not sure where to go from here and I'm afraid that it may be a lost cause. Any advice will be appreciated if given, I am ready to try just about anything at this point.

Tims86Toy

Have you checked your radiator fan and fan shroud? If you have a fan clutch you should have replaced it with your new water pump. If it's an electric fan make sure the fan is coming on and your fan shroud is not allowing air to bypass the radiator.

Is it possible to install the thermostat upside down? The spring assembly should go down into the intake.

Have you tried to burp the system for air?

Is there a head gasket leak?