Blue_petersen77

Ok fellas I just had a VERY strange and unexplained thing happen with the truck.
About 3 months ago my rad gave up the ghost by splitting across the top. I put in a new rad and thermo right after flushing the system. Everything was going great with the new parts. It was holding perfectly at operating temp and the needle never wavered.... Until last week.
All of a sudden, out of nowhere the truck temp digs past the redline and starts blowing coolant out of the overflow! I just happened to be picking up my daughter and was in front of the truck and noticed the green waterfall at the driver front.
Luckily I was only 5 minutes from the house and got back fast as I could. While driving, I noticed that even though the engine must have been baking, it responded like normal. Not how the truck used to act before the new rad when it was overheating.
So it takes me a full half hour to depressurise the system and let out enough steam to pop the cap.when I got it off I noticed the overflow was almost empty but the radiator was just a little low. Not anywhere near as low as I would have thought giving the half hour steam bath.
I checked everything out and couldn't find anything leaking or broken or any sort of problem at all. So I decided to just top everything off with water (took a little less than a gallon for the rad and overflow) and run it to double check for leaks... Nothin doin!
So for the past 2 weeks now she's been running perfect again with no problems at all and the temp needle stays put exactly where it shoul and doesn't move when at OT.
It's just troubling me cuz she sees a lot of interstate time and don't want a repeat of this while I'm halfway to Nashville.

Anyone else ever have a similar one time issue like this or know what happened?

Btw: I know it's going to be asked, but I haven't done anthing to the truck lately with the exception of a new 6ga power supply wire (about a month ago) and Lucas oil stop leak in the power steering (the day of the mysterious incident)

Any info, suggestions, stories or comments are welcome

thanks guys

Blue_petersen77

I don't think the power steering could affect any thing with the coolant sytem unless it seized up, which it hasn't and if it did I'd have a whole new set of problems =)

bugs1961

If you're not burning antifreeze, you may have gotten lucky on the HG. The only thing that comes to mind is a sticking thermostat. If you used an aftermarket thermostat of any brand, I'd put in a Toyota one. They are much better and tend to be trouble free for the five years or so they are in use between timing belt/water pump changes.

Kiroshu

Yea A piece of trash prob flaoted by the the thermo stat and got it stuck for a sec causing the rushing hot pressurized coolant the water pump was pumping to go nowhere but out! Into the overflow. THats what its there for. So you may be fine for now. Just when ever the truck is running red hot like that "NEVER" drive it. Cut it off. And try to fix there or call a tow truck. Especailly the 3VZ. I would just keep driving it. The only thing i can tell you to do to be perfectly safe. Is to flush the cooling system out and put in a new thermo stat.

Blue_petersen77

Stuck thermo was the first thing that popped into my head too. It is an aftermarket one so I guess I'll pic up a toyota one at the stealership.
I just thought since it had been running fine and I had just flushed the system a few months ago there shouldn't be any trash in the system... But I have been known to be wrong before =)

another question: do they make a cooler running thermo and if so, would there be any benefits or drawbacks?

Kiroshu

Well the thermo opening to soon would cause over cooling and some premature engine wear and longer warm-up period. Its best to get one thats "OEM"

Blue_petersen77

I guess I'm just thinking cooler is better for most parts because warmer temps tend to make metal more pliable and therefore more susceptible to bending or warping. It just seems strange that colder air intakes make your engine run better but a cooler engine temp would cause more damage. I'd think it would be the opposite... Guess I'm missing something lol

That's a good idea for a thread lol. I'm sure someone here has all the answers =)

betelnut

Metal starts to weaken significantly only after reaching a certain temperature. Engines are designed to stay well below that temperature.

Cool air is denser than warm air, so if you can draw cool air into your engine, you can also draw proportionately more fuel, resulting in more power.

The theoretically optimal engine temperature is way, way higher than metals can stand, but at that temp the air/fuel mixture burns most completely, resulting in further efficiency. Think about how your car doesn't run as well when the engine's cold. Automotive engineers choose thermostats to compromise between the engine running cool enough under a variety of loads and conditions, but hot enough to gain some of the efficiency.

Blue_petersen77

Thanks betelnut! That explains a lot for me. Guess I'm gonna stick with the regulation tstat.

Blurr

another thought, could it be your fan clutch? if it isn't spinning when the temperature increases then your radiator isn't doing a lot of good.