Overheating nightmare

I have a 2006 Toyota Tacoma that the motor was replaced with a 2014 motor after the first one blew from a head gasket repair that I was unaware of when I bought the truck. Current problem is the truck will sit at idle in park and not overheat it stays temperature. No problem nothing happens. I can move it out of my driveway. Just fine as many times I want it won’t overheat if I drive anywhere at 55 or below it doesn’t heat up very quickly it just gets to operating temperature and kind of stays there once it gets any speed over 55. It starts to heat up no matter If started at 55 and above it gets hot quicker but what happens is if it starts to get hot and I throw it in neutral normally would start to cool off because the motor is not working hard when I put it in park it cools off for the most part. If it’s not too hot, it doesn’t lose coolant and it doesn’t have a thermostat in it and I rerouted the heater core so it’s out of the equation as well if I am at a stoplight and put it in neutral it still doesn’t cool off only if I put it in park is it cool off? If it’s not too late it’s already way too hot why? Could it be a issue with trans temp ? I replaced my trans filter and put fluid in like it said in the temp trans Check mode I just had it running for 45 min in park no temp change all good went for short 4 mile drive and 4 of the 6 cylinder misfired and limped it some carefully but made it no water in oil no stern or smoke fr tail pipe and still had coolant let it cool for a few days and put code reader on it no codes and started right up no issues!!!im SO CONFUSED

 

First off you need a thermostat installed for the cooling system to work properly so I'd start with getting the proper thermostat installed.

If that doesn't solve it I'd be looking at the radiator to see if it's restricted internally.

 

Yup, without a thermostat the coolant doesn’t hang out in the radiator and get cooled off. Don’t run straight water either or you’ll eat the water pump bearing. You didn’t say you were running straight water, but that’s a common mistake in hot climates.

 

Correct the thermostat does need to be installed to work properly. I agree but the cooling off issue was a part of why I pulled the thermostat to get it constantly cooling but if you guys think that it’s supposed to be installed no matter what then I’ll put it back in as far as coolant I don’t have all coolant I have maybe 4060 30,70 as far as coolant to water because it’s so expensive to buy and just keep replacing when it’s just getting drained in and dropped in and pulled out again so I agree I’ll put Coolant back in it again also i’m not in a hot environment I mean Oregon so the temperature does rise somewhat during the day but it’s not a hot temperature area where I live Also, if I sound like I’m being a jerk or rude I don’t mean to. It’s just how I am. I guess how I speak so please disregard any sort of thought that maybe I’m being a jerk if that’s thought at all, I get it a lot in person so. I am grateful immensely for any help I get in this overheating nightmare I’m having

 

One other thing I have flush the radiator two or three times and sent straight water through just to get it cleaned out and I’ve been told a few times. Maybe it is a plug somewhere I’m still trying to find said plug if there is one any thoughts on what good radiator flush material would be good as far as liquid I mean, is there any specific ones that you guys really stand by or stay away from?

 

Oh and finally I am in it now. I just drove it may be 15 miles and no overheating. It didn’t have any codes. It ran just fine. It still had water in it. I’ll put some coolant in it but I’ll get more but it seemed to run fine. I have a heater cause I hooked my heater core back up And so far it hasn’t gotten hot I don’t understand I’m so confused so I’ll do another update when I drive it home here in about an hour but I stayed under 55 or 55 max and it seem to drive just fine. I’ll post an update when I’m back at home.

 

Typically you want to be running a 50/50 mix of coolant and distilled water, too much coolant hurts heat transfer and too much water degrades the lubrication, corrosion inhibiting, and antifreeze/boiling point properties of the coolant. You can always drain it in a clean container should you need to drain it to replace something and reuse it if it's in good condition.

Also what are the actual temps we're talking here? The gauge is not a good indicator of actual temp, need some kind of scan tool or scangauge to see what actual coolant temp is. Operating temp should be in the 180-200F range, wouldn't want to go much past 220-230.

There's not really a good way to flush a radiator if it's full of crap, best to just replace it. Sometimes if you have a thermal camera you can see how well it's transferring heat and if there are any cold spots which would indicate a restriction but if the radiator is in doubt I would replace it, they aren't terribly expensive.

Why did you have your heater core unhooked?

 

Hottest engine temps I've witnessed on my 4L is 218F while driving in 119F ambient temps (126F intake temps) and that was on a long grade coming out of Death Valley with the AC on full blast. I thought there was a problem with the gauge because it never moves once the motor is warmed up but the OBD readings confirmed that it keeps the temps pretty consistent, the engine runs at 184~186F 99% of the time.

 

Is all of the air out of the system? Air pockets will disturb coolant flow and cause your engine to run hot.

 

Something I’ve done in the past is wash the radiator externally. I did it with the radiator removed but it could be done mounted. There’s a couple special tools I’ve seen to do it with air or water. Wash from the rear towards the front. I was surprised how much dirt came out, it didn’t look dirty at all.