No need for thermostat? (2 Viewers)

[MarkM]

Hi everyone,

A couple of months ago I bought a 96 80 series. It sat for a few months Before I bought it, and I am slowly addressing some of the issues and base lining for reliability. I will be building the truck for camping and fishing excursions, as well as a winter 4x4.

Today I drained and refilled the coolant with Toyota red. I drained from the lower hose, and filled with water to circulate once the engine came up to temperature. I left the cap off, and waiting for the thermostat to open and see a sudden drop in the uncapped radiator, it never happened. Even after running for 25 minutes, the thermostat housing, lower hose, and water in the tank never got over 160 degrees. So I replaced ththe thermostat and gasket, drained the water, and being short on time refilled with a 50/50 mix (after draining the overflow of whatever s*** was in there).

I drover for 50 total miles, checking several times along the way to see if I needed to refill the overflow. I grabbed the lower hose each time, and it never got hot to the touch.

We have temperatures in the low 40s right now. Is it normal for the thermostat to not open due to the coolant not getting hot enough in the engine at this air temperature? I just don't want to do anything to harm the engine. My gauge sat at halfway the whole trip.

 

[LFD2037]

It's set to open @ 185* (that's what my Toyota t-stat opened @ when I tested it). Only downside is the heater may not blow as hot. You'll be fine. Did you happen to test t-stat before installing?

 

[MarkM]

It's set to open @ 185* (that's what my Toyota t-stat opened @ when I tested it). Only downside is the heater may not blow as hot. You'll be fine. Did you happen to test t-stat before installing?

I didn't test it with water, just matched it up with the old one to make sure it was the right size. The new one is a 180 degree Stant, which I have never had an issue with. And my heater works fine.

We took a laser thermometer and were using it on various surfaces to see what was going on. The block on that side hit 215, the heater line above the thermostat hit about 210, the thermostat housing no more than 161 degrees, and the water in the radiator with the cap off only came up to 163 with the engine revving at 2500 rpms.

 

[LS1FJ40]

Sounds like it isn't working. Pull the thermostat and boil water. See if it opens at 185. I'm going to guess that it doesn't.

Is it a Toyota OEM thermostat?

 

[LFD2037]

Agree w/above. Sounds like it's not opening.It's just 3 nuts, take it out & test it real quick.

Also, there's a specific way the t-stat is to be installed, w/the jiggle ball thingy @ the top. It can be up to 15* to either the left or right. Not that that would cause what you're describing, just saying.

 

[MarkM]

I'll have to pull it out and take a look. But wouldn't it be odd that the same thing happened with the thermostat that was in there and the brand new replacement? To me that would be a statistical improbability.

I was wondering if there might be an air bubble somewhere? But wouldn't the heat working well lead you to believe that is not the case?

Weird, I've been working on my own cars for 25+ years and haven't seen this on back to back thermostats.

 

[LFD2037]

Could be something blocking in the system, be it air or something else. Take t-stat out, park on incline nose up, turn on front & rear heater (if applicable) on high, remove rad. cap then let it run for 20 minutes. If there's any air in it, it'll come out. Test t-stat while it's out. I agree it'd be really odd they both s*** the bed but hell, stranger things have happened!

 

[MarkM]

LFD, next time I run to my brothers, which is an hour away, I will do as you suggest. When I filled with water after the first drain, I turned on both front and rear heaters and let it run, and didn't get much in the way of bubbling.

We had it on a lift to drain, and lowered it to the floor to refill.

Hence, why I am so puzzled.

 

[bloc]

If your heater is on, with the ac using fresh air, your heater core is acting as a radiator. The flow of water through the heater circuit bypasses the thermostat.. this way you can still get heat even when the thermostat is closed. Also, a properly working thermostat should find a balance of being slightly cracked open during steady state driving (thermal load) so that the water flowing over it stays at whatever the tstat is rated for. It doesn't necessarily go wide open, then close, then open, then close.

i can imagine a situation where between your heater core acting as a small radiator, and the main radiator only needing to deal with the heat in excess of that, your lower hose wouldn't get very hot. Try turning your heat off and see if the lower hose gets any hotter.

Besides.. if your gauge is staying in the middle, the tstat HAS to be working. I've had two toyota tstats fail and they are well designed.. they fail open. So I couldn't get the trucks to heat up.

 

[LS1FJ40]

I know it seems strange but I've heard of multiple starters being dead out the box from Toyota. And a handful of thermostats as well.

I've also heard of multiple people insisting they had the air out of their cooling system and then didn't. If there is air in the system you can still get heat.

Careful running it on a long trip without the cooling system functioning properly. The 1FZ-FE does not like to be overheated.

Also, have you replace the radiator cap with a new OEM one? Not related but I recommend everyone replace them every 4-5 years. And always buy OEM. It is set to release at 12 psi and works well. Aftermarket or old ones don't.

 

[MarkM]

If your heater is on, with the ac using fresh air, your heater core is acting as a radiator. The flow of water through the heater circuit bypasses the thermostat.. this way you can still get heat even when the thermostat is closed. Also, a properly working thermostat should find a balance of being slightly cracked open during steady state driving (thermal load) so that the water flowing over it stays at whatever the tstat is rated for. It doesn't necessarily go wide open, then close, then open, then close.

i can imagine a situation where between your heater core acting as a small radiator, and the main radiator only needing to deal with the heat in excess of that, your lower hose wouldn't get very hot. Try turning your heat off and see if the lower hose gets any hotter.

Besides.. if your gauge is staying in the middle, the tstat HAS to be working. I've had two toyota tstats fail and they are well designed.. they fail open. So I couldn't get the trucks to heat up.

Thanks bloc, I'll have to take a look. I get how the thermostat functions, which is what really puzzles me. I just had the heaters on to circulate the coolant, and then turned them off to get the thermostat to open. It's entirely possible that I messed this up. But it was cold enough on the way home that I needed the heat to stay warm, so I turned it on and it kept me warm.

I had some hills to climb on the drive, so I expected the coolant temp to rise high enough to open the thermostat but it never happened.

 

[MarkM]

I know it seems strange but I've heard of multiple starters being dead out the box from Toyota. And a handful of thermostats as well.

I've also heard of multiple people insisting they had the air out of their cooling system and then didn't. If there is air in the system you can still get heat.

Careful running it on a long trip without the cooling system functioning properly. The 1FZ-FE does not like to be overheated.

Also, have you replace the radiator cap with a new OEM one? Not related but I recommend everyone replace them every 4-5 years. And always buy OEM. It is set to release at 12 psi and works well. Aftermarket or old ones don't.

I'll check it out. I'll replace the cap just to be safe.

I kept an eye on the gauge the whole ride, it never went above halfway with an only warm to the touch lower hose. Had the temp gone up I would have pulled over and investigated.

Thanks

 

[LFD2037]

It is set to release at 13 psi and works well. Aftermarket or old ones don't.

FIFY!

 

[LFD2037]

I'll check it out. I'll replace the cap just to be safe.

I kept an eye on the gauge the whole ride, it never went above halfway with an only warm to the touch lower hose. Had the temp gone up I would have pulled over and investigated.

Thanks

The gauge is very vague. It'll be in the middle for a large range of heat. It won't go past middle till it's too late!

 

[LS1FJ40]

I'll check it out. I'll replace the cap just to be safe.

I kept an eye on the gauge the whole ride, it never went above halfway with an only warm to the touch lower hose. Had the temp gone up I would have pulled over and investigated.

Thanks

Good luck. Keep us posted.

FIFY!

You're forcing me to say it! F&%$ Texas!

 

[LFD2037]

Good luck. Keep us posted.



You're forcing me to say it! I LOVE Texas!

Fixed that mistake for you, too!

 

[Landseer]

This sounds like perfectly normal operation to me. After draining the coolant if you fill the radiator all the way up the coolant will flow into the engine block through the top right (US drivers side) radiator hose (reverse direction of normal flow). If you keep adding coolant to the radiator you will completely fill the system, or come very close, and there will be no/minimal drop in the coolant level after operating the engine.

 

[MarkM]

This sounds like perfectly normal operation to me. After draining the coolant if you fill the radiator all the way up the coolant will flow into the engine block through the top right (US drivers side) radiator hose (reverse direction of normal flow). If you keep adding coolant to the radiator you will completely fill the system, or come very close, and there will be no/minimal drop in the coolant level after operating the engine.

The problem is that the engine ran for a combined total of about 2 hours, and the lower hose never got hot and the thermostat did not open no did it need to. That is certainly not normal. But, as you described, I did add enough coolant to flow back into the block through the radiator. We watched the flow of the coolant towards the upper hose in between filling the radiator.

Next time I work on it I will pull the block drain and open the radiator while the front of the vehicle is elevated. Hopefully this allows the air to escape and get the system running as it should.

 

[ChaseTruck]

I'll have to pull it out and take a look. But wouldn't it be odd that the same thing happened with the thermostat that was in there and the brand new replacement? To me that would be a statistical improbability.
...

I've had that happen on my K5 this summer - 12y old t-stat malfunctions, and same with the first replacement. And yet another one didn't open as spec'd, either (that one on the stovetop in a pot of water...).

Of course, Toyota stuff is much betterererer, so it won't happen

 

[MarkM]

I've had that happen on my K5 this summer - 12y old t-stat malfunctions, and same with the first replacement. And yet another one didn't open as spec'd, either (that one on the stovetop in a pot of water...).

Of course, Toyota stuff is much betterererer, so it won't happen

I guess weirderererer things have happened