I did something I shouldn't have.

I planned on doing a super flush of my cooling system before winter and while doing that I wanted to remove as much of the "green" Prestone antifreeze, then replace it with the Toyota equivalent "pink" antifreeze - Zerex Asian.

I read in my Haynes manual to do a proper flush the thermostat is removed, then idled 10 minutes. I decided to drain the antifreeze, remove the thermostat, add Prestone cleaner/flush with deionized water and instead of just idling it for 10 minutes, I drove it for about 80 miles over 3 days.

I didn't realize without the thermostat it would run rich, causing carbon build up, with the unburned gas. I did notice black residue inside the end of my tail pipe and I just changed my oil before removing the thermostat.

Should I change my oil again, incase unburned gas is in my oil and is there anything else I should do? I had planned to change my spark plugs Monday before this happened anyway.

 

Just keep driving it, it will clean out within a few miles!!!

 

OK, should I be worried about the oil being diluted with gas and would it be worth changing it out just incase?

 

Next time you fill up take the premium and give it a good ride should be fine then

 

If your oil gets up to temperature the gas will evaporate

 

OK, lesson learned about the proper way to do a coolant flush for next time.

 

Why do you think without the thermostat it will run lean, and why then would there be unburned gas and carbon buildup. Either way lean or rich, 80 miles is nothing, your oil is fine.

 

My father ran a few old trucks without thermostat because they causing problems back in the days and it didn't cause any problem with gas in oil. It is not like you would have drown it like and old skidoo or atv lol should be fine. Like @homesteader said, it will evaporate.

 

OK, I didn't realize it would burn off and not cause wear.

 

I would be more worried about your catalytic converters. You have been sending unburnt fuel thru those cats for the duration that your were running rich.

Get that thermostat changed and run the truck normally. It should clean out those cats just fine.

 

It probably ran cold on open loop...
I always thought engines ran hotter with out the thermostat, not enough saturation time in the engine or the radiator

 

Straight, but true!

 

Without the thermostat it runs in an "open loop", as it never reaches operating temperature.

When the engine is first started the system goes into open loop operation. In open loop, the ECM calculates the Air/Fuel ratio based on inputs from the coolant and MAF sensors. The system remains in open-loop until the following three conditions are met:

• Coolant temperature above 105°F.
• Oxygen sensor has varying output voltage (indicating it is hot enough to operate properly).
• A specific amount of time (preprogrammed into the MEM-CAL) has elapsed.

 

I agree, and it has been flushed with the thermostat replaced = lesson learned.

 

No kidding, but with no thermostat it will reach 105F. You are way overthinking this.

 

If your worried about carbon or gas on your oil, personally I would change it. Carbon puts a ton of wear on your crank bearings and honestly what's an oil change gonna hurt

 

I agree, but new trucks have an ECU That control fuel output.

 

Change the oil. Pay a technician to do it next time. There nothing like a trained person for the job, not saying you can't do it.

 

Yeah, but I get satisfaction doing it myself, when it's done right and this taught me what not to do next time.

 

Yeah, it may be worth doing it just for peace of mind, after doing a smell test and check the viscosity.