I have an '02 Sequioa Limited. The check engine light (along with traction control lights, as I understand is normal) came on while I was driving, then the engine started knocking a couple of minutes later at highway speed My temp gauge went redline. I pulled over, let it cool for 30 minutes, checked fluids and restarted. My oil was at the appropriate level and coolant was not low.

Engine still knocked very slightly for about 1 mile, but temperature was fine. 1 mile later and no knocking or temp issue, but the same 3 lights were still on.

I was 30 miles from civilization, so I continued to drive with no issues (temp was normal, no knocking) except the same warning lights when my engine began to knock loudly, the radiator popped and sprayed coolant all over the front of the vehicle and my windshield. The temp gauge was still normal. I immediately shut it off, stopped there and had it towed the remaining 25 miles.

I'm nowhere near an import mechanic, any ideas or suggestions as to the cause of this? Even to move my car onto the road for the tow truck, it sounded fine with no knocking issue whatsoever.

. Check for codes--the information will be crucial.

. Read the links below:

https://www.askmehelpdesk.com/cars-t...tml#post235973

https://www.askmehelpdesk.com/cars-t...ml#post1365453

Phosphate scale can easily block passages, requiring the radiator to be changed. Only use a 50/50 mixture of Toyota recommended antifreeze and distilled water.

. kitch428 is our Toyota expert. He works for Toyota and will pounce on this thread, as soon as he gets home.

. To protect your car, in the future, only use full-synthetic engine oil. Toyota will soon be requiring it:

https://www.askmehelpdesk.com/cars-t...ml#post2059400

Synthetics have a higher coefficient of heat, which allows engines to run cooler. In emergency situations, you need all the protection you can get.

Cooling system problems are usually caused by a lack of proper preventive maintenance. Attention to details makes all the difference in the world on modern-day vehicles. My bet, from afar, is that minerals in the tap water formed phosphate scale, which blocked the radiator. It could be catastrophic water pump failure--however, I would be somewhat surprised. My father's Toyota Tacoma died due to head gasket failure. Keep us posted with the solution.

Definitely a cooling system malfunction. Water pumps go bad all the time. Especially when aftermarket parts are used. Could be as simple as a faulty thermostat, or something major such as a head gasket.
You will most likely have a temp related code(s) stored along with ABS/VSC Trac off lights (which is normal as you mentioned)
The shop should be able figure it out for you. It was a good thing you decided to tow it. Cheap insurance.
Well written post, hconnickjr. I wish all would post such useful information as you did. We will be glad to be of any help. Just chime in right here at this post.

Thanks for all of your prompt responses. What an awesome group this is! When I heard the knocking, I was pretty worried about the many things that could be wrong.

Here's the scoop. Kitch you were exactly right, it was simply a thermostat which caused the engine to overheat and, in turn, the knocking in my engine. I have no idea why the gauge showed a normal temp right before it popped, but they ended up repairing the hole in my radiator easily enough. I requested that they use the 50/50 Toyota recommended antifreeze as GreaseMonkey suggested and I will switch to full synthetic on my next oil change. The more that I researched it, after your comment, it makes sense and is a small price to pay for the extra protection.

I'm glad I got it towed either way. I really really appreciate your help and I will stay tuned to the posts on this site. I may not be a lot of help right now, but I'll learn and contribute all that I can.

Nice going. Thermostats often stick due to mineral build-up, too. Just make sure they use distilled water with the antifreeze. Change the coolant every 2 to 3 years or 30,000 miles, whichever comes first.

Your story had a happy ending, unlike many of them on this site. Towing likely saved you big bucks!

Great news! Here's the 'why' you saw the gauge showed normal right before it popped.
The engine coolant temp sensor must 'see, touch, feel' the coolant. If it's an air pocket, which you most likely had, then the accuracy of the gauge is not correct.
That should set you straight and possibly help others that come across this post.

Quote:

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Originally Posted by kitch428

Great news! Here's the 'why' you saw the gauge showed normal right before it popped.
The engine coolant temp sensor must 'see, touch, feel' the coolant. If it's an air pocket, which you most likely had, then the accuracy of the gauge is not correct.
That should set you straight and possibly help others that come across this post.

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Very good point again, Kitch!

Well I saw this post and was like. DID I post this. This happened to my 2005 SR5 Sequoia. I had the radiator, thermostat and hoses replace and it ran good for 1 month and now it's over heating again, to the point when I turned it on it was overheating within 5 minutes of idle. I had all the repairs done at Toyota Dealer and they said that the Water pump was fine. I don't think it is but what else could it be?

I'm sure others would agree, take it back!