Vmax540

1995 Truck with the 3.0 and 230K miles. Did not want to revive this old thread https://www.yotatech.com/forums/f116...m-help-261880/ but, I did follow most all the suggestions. The new (not O.E.M.) thermostat and a used Toyota will not open to allow circulation. Out of truck engine rebuild including heads milled/shaved all new seals, gaskets, water pump, timing belt, idlers, spark plugs & wires, filters and more. Engine appears to run like a clock.
Things (see below) I have tried to get circulation/thermostat to open while running the truck in my 60 degree garage for up to 30 minutes while idling with the cap on and also off.
-Raised front wheels 1.5 ft. off the garage floor and used a no spill funnel, full of fluid on the radiator cap while continually burping all the hoses including the small line that feeds the thermostat housing.
-Used two used different radiators one O.E.M. one aftermarket both will allow wide open flow of a garden hose. [B]Both radiators will show good flow with plain water and only if I remove either of the the thermostats.
[/B]-Thermostat in with stem/spring facing the engine block and the bypass hole at 12 o’clock.
-Pulled the bottom radiator hose off and it is always full of cold water.
-O.E.M. thermostat on the kitchen stove opens at ~80 degrees C and the new at 85 degrees.
- Truck blows hot heat in the garage or on the road.
-Truck shows at the maximum a temp gauge reading of 1/3 on the in dash dial in the garage or on the road.
-Gauge drops to where the needle is barely above the Cold mark when driving on the open road.
-Drove 13 miles this morning in 22 degree weather and the bottom hose AND also, the thermostat housing were cold and no flow thru the radiator. The engine was not showing any signs of overheating, no pinging of metal, no hot smells.
-I visually inspected the water passages when the heads were off and the head gaskets were marked right (pass.side) and Left (drivers side).
-Timing is at 10 degrees when jumped and idling.
-Tried a new radiator cap, a used Toyota cap and another used cap.
-Coolant is at -20 degrees F.
-Help……

Vmax540

Second day of running and does not overheat still, no circulation. Put a pressure tester on last night and it held 12psi.

Vmax540

After running for 2 weeks without circulation thru the radiator the heater core sprung a leak and the antifreeze blowing a mist out the vents prompted a replacement..... Upon refilling the antifreeze and with out all the special tricks on purging the system of air the truck now has good flow thru the radiator and low and behold the bottom hose actually gets hot.... Now someone please explain this to me.... Could it have something to do with the cold water bypass ? Thanks !

MudHippy

The cold water who? What are you talking about?

Vmax540

Sorry, should not of added Cold to the description.....


http://personal.utulsa.edu/~nathan-b...05descript.pdf
This engine is cooled by a pressurized water forced circulation cooling system equipped with a thermostatically controlled by – pass valve mounted on the inlet side.

Gamefreakgc

Hard to say... I'd just be happy it all is working well now!

MudHippy

No...you shouldn't have added the cold part. NOR the bypass part. Since what is being spoken of there is commonly refered to as a thermostat.

So...yeah. If you put the thermostat in backwards. I'd imagine you'd have some issues with coolant flow. Other than that possibility, nothing about what you're saying in this thread makes very much(if any) sense at all. Meaning, NO, bleeding the air from the system would NOT have that drastic of an effect on how well/not well the coolant was able to flow through it. And neither would a clogged heater core.

It's pretty hard for me to believe that you had the t-stat installed correctly the whole time. Are you sure you're not leaving out the part where you discovered that to be the case, and then reinstalled it correctly?

Vmax540

Wrong...... since, changing out the heater core did Not require removing the (correctly installed) thermostat. Having searched this forum for cooling/flow problems I found such issues to be fairly common and felt maybe just maybe this thread may help someone in the future. B.T.W. from now on if you're having such a bad day maybe just refrain from answering......

InToxicOne

Sounds like the best way to check this is by removing the new thermostat and putting a washer with a hole in it in its place. It may take a while for the truck to warm up but it will tell you if you have a lack of circulation to that part of the water system ie blockage. once you get it running make sure to try and pinpoint where the heat is stopping at with a laser heat gun. I got one from radio shack and trust me its a handy piece of equipment for cooling system issues.

Vmax540

InToxicOne Thanks for the reply, I have on other vehicles removed the stem and spring from a thermostat which allows using the original o-ring style sealing gasket and close to the same flow as a completely open stat. What I don't get is why the thermostat housing, lower hose and even the hose from the oil cooler was always cold to the touch therefore it would never come close to the temp needed to open.

Marc

The thermostat is controlled by the temperature of the fluid in the block, not the temperature of the lower rad hose.

InToxicOne

Well my question now is what percentage coolant to water are you using? I know it may be a stupid question but if you put too much coolant into the system it actually has the reverse effect and may not pull heat into the coolant properly. That would be the only other thing I could think of aside from flushing the bock and starting with fresh 50/50 coolant.

Gevo

Im curious as to how much toxicones idea of to much coolant would affect the system. Vmax, what have your coolant to water ratios been? How did you change it after new radiator.

Vmax540

From my first post. "Out of truck engine rebuild, I visually inspected the water passages when the heads were off, & Coolant is at -20 degrees F"


I hate to keep going back to where the thermostat housing never was more than luke warm to the touch but, how could the t-stat ever open if the surrounding water was not conducting enough heat to make the housing at least somewhat hot to the touch ? I guess I'll just move on and as Gamefreekgc said "Hard to say... I'd just be happy it all is working well now!"

Vmax540

I used all new antifreeze with bottled distilled water and a mixture that was close to 50/50 but, maybe a little more water than antifreeze. ~ -20 degrees

Gamefreakgc

You can run 60/40 coolant to water mix in extreme areas with no ill effects, some manufacturers even recommend it.

InToxicOne

Just seems odd that everything is new and no heat is getting through to your radiator. Well if the heater core works the only thing I could say is drive it but you will run into a rich fuel mixture as the temp sensor might not read your engine temp. I know on the 22rte that I have the coolant temp sensor sits right on the bypass.

Gevo: The only reason I asked that question was because if you start to go to too much coolant you actually loose heat transfer. That's why you have guys like me that run 75%coolant/25%water in CA. Coolant is great for preventing boiling of the water and freezing. That's basically its only job(minus the additives) but if you add too much or like some people have done mistakenly add the concentrated propylene glychol it actually will cause your engine to keep its heat without actually transferring it to the radiator.

Vmax540

Since, replacing the heater core (third post) I now have good flow thru the radiator..... thanks again. Being the heater core sits mostly above the radiator and engine I only drained ~ 1 gal before replacing so, it keeps coming back to me that maybe not draining all got rid of an air pocket ?

Gevo

I'm going to try to clean my old heater core and if it works sell it on ebay..

any suggestions on what kind of cleaning agent to use?

Vmax540

I had a good core out of the 89 parts truck and personally, with everything involved I went to Rock auto and spent ~ $70.00 for a new core.