Mystery overheating

[mk378]

"I can't afford to fix the leak right now" is nothing compared to "I can't afford to have the engine completely burn up."

 

[Japanese]

I know and all your advice is spot on, but unfortunately I have no choice. So fingers crossed.

If you don't use the van for work, meaning you don't have any tools and equipment in it, it's better to use Uber (or a friend's car) until you fix it.
Unless you want to make things worse.

 

[Dinoburner]

Have had success testing a water pump by removing the fan belt and moving the pump shaft in different detections. any play is a potential problem . Problems like the OP is having could be temperature related. A pressure gauge set to 15 lbs. at the radiator is an inexpensive test.

 

[CleanSump]

He says in the first post he has big leaks. A pressure test is a waste of time until the leaks are fixed.

 

[maduroman]

Heater core plugged up

 

[Auto tech]

Fix leaks first. RE check for leaks. ensure fan is operating. ensure thermostat is working correctly. test cooling system for exhaust gases, if gasses are present and replacing the head gasket is not in the cards for you try this next: bars leak head gasket sealant. Add this to a warm system and drive.

 

[MichaelRS]

Have you checked any Toyota or Sienna owners' forums? This overheating problem may have been diagnosed and/or remedied there. Good luck, John

Good point. I'll try that

 

[MichaelRS]

I had another thought...could coolant types have been mixed at some point and caused a "sludging" condition in your cooling system? Once your leak is sorted you might want to try a coolant system flush. Do some research, Cascade may be an option.

No, I am meticulous about that. Had a flush done when I first got the car used 12 years ago. Since then I've run the same type brand of coolant in it. Would have it drained and refilled every two years with the same stuff.
Also had a new radiator a year and a half ago.
Thank you for the thought

 

[MichaelRS]

Heater core plugged up

could be. Although I'm leaning to some damage have been done by having to run the excessively hot, though not redlining, coolant through the heater core to cool the coolant down.
At this point I should know something in 2 days.
But ****, I hope it's not the core itself

 

[MichaelRS]

If you don't use the van for work, meaning you don't have any tools and equipment in it, it's better to use Uber (or a friend's car) until you fix it.
Unless you want to make things worse.ou're totally right. But my circumstances is such that that is not of option.

If you don't use the van for work, meaning you don't have any tools and equipment in it, it's better to use Uber (or a friend's car) until you fix it.
Unless you want to make things worse.

You are totally right. But my circumstances are such that that's not an option.

 

[Donald]

I would definitely replace the thermostat. Ride a bike or walk. Don't drive it until the leaks are fixed.