[unmesh]

MY2006 has begun to exhibit a surging sound while idling or moving at very slow speeds in stop and go traffic. It is like the speed of something is going up and coming down again. It is not the engine RPM and the engine temperature does not seem to be flutuating, at least as per the temperature gauge.

My independent mechanic has taken the week off and I was wondering if there was something I could look at in the interim

Thanks

 

[sixto]

Radiator fans?

The engine temp gauge is garbage.

Sixto
‘04 LE FWD 206K miles

 

[unmesh]

I will look at the fans with the engine running while in park. We rarely use this vehicle and my adding of coolant several weeks ago may have caused a problem.

I have an OBD reader and Torque app. Might the temperature readings in it be more reliable than the gauge?

Thanks

 

[unmesh]

Popped the radiator cap to check coolant levels and found my first problem ...

 

[bencahill]

Popped the radiator cap to check coolant levels and found my first problem ...

I had the same broken cap in my 2009. Only issue it caused was that at high altitude (Denver) some of the coolant boiled out. I replaced it with OEM since price was about the same.

Does it happen in Park or only in gear? Could you post a video of the sound?

 

[sixto]

The gauge isn’t linear. Actual engine temp can vary from 180 to 220F with little gauge movement. A scanner reading through the OBD port will give you the same numeric temp value the ECU sees which is more accurate than the gauge.

Losing coolant could indicate cracks developing in the radiator end tanks. Hard to see because much of the radiator ends are hidden. Borrow a cooling system pressure tester.

Sixto
‘04 LE FWD 20K miles

 

[unmesh]

So I borrowed a loaner cooling system pressure tester from a nearby auto store but there isn't enough clearance above the radiator opening to accomodate it and its converter/adapter for the Sienna. I have changed the radiator cap and added some coolant to both the radiator and the reservoir (which was empty!) and took the van for a drive to get it to operating temperature. The previous symptom did not reappear but the operating conditions were not exactly the same.

I will stop by a different auto store to see if they have a lower profile pressure tester. And I will watch more closely for symptoms.

Also, how do I know there is enough coolant?

 

[sixto]

I don’t think a 3.3 has a bleed port so professionals use a funnel over the fill port with excess coolant in the funnel then run the engine until the thermostat opens. There are offset adapters since the fill port is blocked by the cowl. If you don’t have such a funnel, keep driving and filling through the fill port (cold engine!) until it takes no more. Mind the level in the reservoir. The cooling system naturally draws coolant from the reservoir as necessary as the engine cools, but that process isn’t efficient at purging air.

Sixto
‘04 LE FWD 206K miles

 

[unmesh]

I chickened out and took it to a repair shop which found a leak in one of the bottom corners of the radiator itself. I will be out $500 to get it replaced :-(

 

[jseyfert3]

That’s unfortunate, but seems like a reasonable price to me for a radiator replacement.

Think on the bright side. You found the issue before you overheated your engine and potentially caused a lot of damage.

 

[unmesh]

All fixed now though it cost $600. The shop had given me a verbal quote of $500 but the OEM radiator cost them more than the service writer had estimated off the top of his head.

I've been using them for decades and will give them the benefit of any doubt.

 

[paul r]

The online price of the radiator from the dealer runs about 350 bucks so the 600 bucks seems reasonable for this job.