Drain some of the coolant.

 

I would not do that. Besides, the radiator cap will just allow more in from the expansion tank.

Out of curiousity- what blend of coolant are you running? 40/60, 50/50, 60/40?

Coolant does not release heat as effectively as water- the more coolant/less water, the hotter it will run. But too much coolant will not act as proper "anti-freeze". You might try doing 80% anti-freeze and 20% water.

Some good information- http://hellafunctional.com/?p=629 and http://www.engineeringtoolbox.com/bo...ter-d_926.html

http://docs.engineeringtoolbox.com/d...emperature.pdf

atmospheric air is about 14 PSIA, which is what a raw data of your MAP sensor will give you with key on/engine off. Pure water boils at 212F at 14PSIA and 246F at 28 PSIA. Pure anti-freeze freezes at 10 degrees F and boils at 350F at 14PSIA. Because of the specific heat properties, the industry has settled on 40/60 to 60/40 for acceptable combination ranges.

Now keep in mind that most of our trucks come with 195F thermostats....

 

LOL! I hear ya man! This is freaking bizarre!

Ive owned over 100 cars/trucks/bikes of the past 37 years and have never seen anything like this.

I'll give another update after I change out that sensor and flush out the heater core.

 

I honestly don't know. It tested down to -35 degrees IIRC.

I know there was WAY too much water in it when I bought it. I did recently (several weeks ago) take it to a local (reputable) garage and had them do a Flush-n-Fill.

I was hoping it would flush some crap out of the system and get it squared away. As you can see where I'm at at this point, it did NOTHING except make my wallet lighter.

 

We do our own coolant mixing. Being in Texas, a deep freeze for us is the 20's, sometimes single digits. So we run a high pure antifreeze ratio and top it off with the water hose once the antifreeze fills to where we can see it in the radiator or stove pipe.

Racecars run 100% water, gentleman's agreement. Antifreeze has to be boiled off the track with a blowtorch, water and most fuels evaporate real quickly.

 

Oh Lord.... TX and freezing weather brings back some bad memories for me. LOL. I was stationed in San Antonio 84-86. My wife Managed a 180 unit Apt complex at the time down there. We got a real cold spell (single digits) for a few days. They had 90.. 1/2 the apts in the complex got BUSTED water pipes! No joke! Ya'll don't believe in insulation down there and insist on placing the clothes washer/dryer in the OUTSIDE closets. Oh yea! Much fun those days were! LOL!

Oh! And then there was the MASSIVE snow storm that hit San Antonio for (2) days straight! Did NOT hit ya'll up North in Dallas/Ft.Worth nor did it hit down South in Houston/Galvaston.

San Antonio got 13" INCHES on SNOW in those (2) days ! 13" freakin INCHES! Now mind your I'm a Damn Yankee (grew up outside Pittsburgh) and learned to drive on snow/ice on STEEP hilly, skinny roads. So for me driving on flat snow covered roads was nothing. BUT! You shoulda seen the massive ciaos on Loop 410! IIRC, there were around 450 "Reported" accidents in a 24 hour span. 450!

It was unfugginbelievable to see! I'm driving 30-35 MPH fastest I felt safe and people were FLYING past me like the were still driving on DRY pavement! There were cars littering the roadside ditches, up on guardrails and all !

I got a pic somewhere.... Let me go find it.....

 

Timbers Edge Apartment Complex San Antonio, TX December 1985.

This was the first day. 6" on the ground. 7" more came the next day! Total 13" !

 

yep, that's texas. We don't know how to drive on dry roads and nothing changes on wet ones.

 

Hey Kat,
Just rethinking this a bit. Is your engine truly running cold? Or are you saying you have no heat? Two different things entirely.

It sounds like you have an accurate coolant temp gauge and you have tested the Tstat to make sure it's opening when it should. And you can verify the lower radiator hose is definitely cooler than the top hose. I'd conclude from this information that the system is cooling as designed, especially since your truck is not overheating. The heat's got to go somewhere afterall, and it is.

Assuming the above is all correct, then the question is why so little heat in the cab? Plugged heater core could be the case. Apparently that is an issue with some of these trucks. I'll offer my theory but that is all it is.

I think you could well have some heater core issues, but it seems to me on these trucks the radiator may be a one size fits all, designed with enough capacity to cover all the engines offered from 4-cylinders to 8. So it may work so well on a 3.9 that the lower hose is always cool. My guess is the heater cores may be on the small side, perhaps just barely large enough to heat the cab. I've noticed in really cold weather the heat in my 3.9 is tepid, because that little heater core is trying to warm up some 20-30 degree air. When it's 50 outside, the heater will run you out of the cab.

I intend to flush my heater core soon to see if the heater temp improves. But I'll try to check my own lower radiator hose to see if it stays cool or not. We might both learn something here.

Keep us posted!

 

My coolant readings are consistently between 175 and 185 on the 3.9 and the heater is enough to make me sweat.