Coolant flush?

[CoElkFreak]

A little back story. 2004 4Runner 4.7. Replaced timing belt and water pump last summer. Everything been fine as son drove to college and back over the last 10 months. He got home Monday and I noticed it was a little low on coolant…I poured maybe 2 quarts into it so not too bad. For some reason when we bought it had orange coolant so when I replaced water pumped I used orange again. I used Zerex originally but when I topped off Tuesday I used Peak Orange OAT.

He was driving to Denver today and after about 30 miles he called me and the check engine light came on and then steam coming out of the overflow tank. I headed to him. When I look at the over flow tank it is gray in color and the radiator was obviously low on coolant. Not sure what happened I topped it off with some distilled water and a small amount of coolant hoping I could limp it home. I made it five miles and it started to get hot and then the steam showed up. Pulled over and had it towed home.

I’ve decided to replace radiator, thermostat, hoses and radiator cap. So I don’t really need to flush the radiator but I would like to flush the engine block and replace with the proper Toyota coolant.

Any body have an easy method for doing so? Also what about the heater core? Or any ideas on what could have went wrong. Truck has been so faithful so has me confused.

Sorry for the long winded post….

Thanks, Marty

 

[Hungryhawk]

There are test kits to look for combustion gases in coolant. Not sure about recommended coolant chemistry and color. But seems like the grey color could be oil/combustion by-products from leaky headgasket. Any weird oil color or pressure in crankcase?

 

[CoElkFreak]

There are test kits to look for combustion gases in coolant. Not sure about recommended coolant chemistry and color. But seems like the grey color could be oil/combustion by-products from leaky headgasket. Any weird oil color or pressure in crankcase?

Yeah the oil looked good. I did not see what looked like coolant in the oil.

 

[rdruss]

Yeah the oil looked good. I did not see what looked like coolant in the oil.

I have an '03 V8 and it originally had the orange coolant, but Toyota told me to switch to the pink when I asked for coolant, which I did several years ago, not that the orange is your problem, you have a mechanical issue and need to test for blown head gasket. Check your trans too as the trans cooler is built into the radiator.

 

[maxdef]

Good choice on swapping to OEM coolant- this an an area I believe is worth the price of exact spec fluid (I have a 2005 v6, so potential ticking bomb here). The heater core can be flushed by disconnecting the two clamped hoses going into the firewall next to the master brake cylinder. Low pressure is all you need, and stick to distilled water for any flushing you do.

Some stop leak products are grey, but as far as I know they wouldn't mix in with coolant enough to change its color; rather the glittery junk might collect at the bottom of the overflow reservoir. Do not use any stop leak- I am merely exploring possible causes, and that is definitely not a solution.

This video should help you identify the drain spots on either side of the 2UZ-FE block: https://www.youtube.com/watch?v=OyVJxgqDko4

Determining any potential head gasket issue is priority as "improper cooling" is the most obvious symptom at this point. Good luck and keep us updated!

 

[CoElkFreak]

Good choice on swapping to OEM coolant- this an an area I believe is worth the price of exact spec fluid (I have a 2005 v6, so potential ticking bomb here). The heater core can be flushed by disconnecting the two clamped hoses going into the firewall next to the master brake cylinder. Low pressure is all you need, and stick to distilled water for any flushing you do.

Some stop leak products are grey, but as far as I know they wouldn't mix in with coolant enough to change its color; rather the glittery junk might collect at the bottom of the overflow reservoir. Do not use any stop leak- I am merely exploring possible causes, and that is definitely not a solution.

This video should help you identify the drain spots on either side of the 2UZ-FE block: https://www.youtube.com/watch?v=OyVJxgqDko4

Determining any potential head gasket issue is priority as "improper cooling" is the most obvious symptom at this point. Good luck and keep us updated!

I doo not see what looks like antifreeze (white milky) on the dipstick but I plan on draining the oil her so to have a better look.

 

[CoElkFreak]

So I did a block test today. The appears to NO exhaust gases in the cooling system…so that a good thing.

 

[Voltan73]

So I did a block test today. The appears to NO exhaust gases in the cooling system…so that a good thing.

I'm not surprised by this good news; the 4.7 is not known for popping head gaskets. I've worked the technician's parts counter at a Toyota dealer for 24 years now;
I'd bet your radiator is the culprit. It would be a very good idea to stick with the Toyota SLLC2 coolant as well. Good luck, hope it all works out.

 

[CoElkFreak]

I'm not surprised by this good news; the 4.7 is not known for popping head gaskets. I've worked the technician's parts counter at a Toyota dealer for 24 years now;
I'd bet your radiator is the culprit. It would be a very good idea to stick with the Toyota SLLC2 coolant as well. Good luck, hope it all works out.

I was happy about the test. I’m replacing radiator, thermostat. Is the Toyota brand the best or would the Xerox Red be the same?

 

[T4R2014]

Do all your heater hoses and throttle body hoses. I guarantee this will be an issue on all these trucks as they begin to age.

 

[Voltan73]

I was happy about the test. I’m replacing radiator, thermostat. Is the Toyota brand the best or would the Xerox Red be the same?

I only use Genuine Toyota, but considering where I've worked for 24 years plus employee discounts, what would you expect, lol. I'd stick with the Toyota stuff.