bleeding coolant system - is there a bleeder valve?

Hi, I'm new here. A little background info, I'm a fairly inexperienced mechanic, but have I worked my way through several repairs on a few different cars.

This is my basic question: Is there a bleeder valve for the coolant on my engine, 1995.5 2.7? Or is the radiator cap the "bleeder valve"?

What follows is a more thorough explanation of my situation.

So the heat in my truck is barely detectable. Here is what I'm up to:
Flushing the coolant/radiator.
Back-flushing the heater core.
Replacing the thermostat.

I've never flushed coolant before. While I was out working on the truck, my neighbors' adult son stopped by to check out what I was up to. I've never met him before, but it turns out he is part of a Land Cruiser club - he owns a diesel FJ45. So, he was very helpful with basic info on wrenching on Toyotas and cars in general. He didn't know my engine, but said some engines have a bleeder valve for the coolant. He said it's a more effective way to bleed a coolant system than just opening up the radiator cap. Is there a specific bleeder valve for the coolant on the 2.7 engine?

Also, any thoughts on my lack of heat? My blend door is a mechanical system and I hear/feel it moving when I slide the lever, and I feel like I'm addressing the remaining parts of the system, so hopefully I will have heat tomorrow.

 

If the blender valve is moving, the next likely cause is a plugged heater core. If your truck isn't overheating, flushing the coolant won't do much. Only real option then is to replace the core.

 

Backflush the core first, if the water flows freely your issue is elsewhere.

 

1995.5 - 2.7L

I flushed the radiator.
I back flushed the heater core, by removing the in and out hoses to the core and running water from a garden hose backwards through the core.
Tomorrow I will change the thermostat.

After I refill the coolant, is there a bleeder valve for the coolant system and if so, where can it be found ? I understand running the engine with the radiator cap off is an option for bleeding, but I'm wondering if there is a specific bleeder valve for this purpose.

After the system is refilled and bled, hopefully there will be heat. If not, it sounds as if a bad heater core is likely the problem.

 

There's not. With the stock setup you can park on an incline so the rad cap is the highest point and use it, or you can install a prestone flush T in the upper heater hose. It's the normal highest point, costs about $2 at walmart.

 

there is a plug in the block that can be removed to drain the water jackets in the block but I wouldn't mess with it. its not designed to be messed with for routine stuff and can get corroded and frozen in the block and may not seal again after its removed.

at the bottom of the radiator there is a drain plug there either on the bottom or in the bottom corner area somewhere.

when you ran the water hose through the heater core, did it flow in both directions? could you get an idea if the core was full or was there air in it?

if its not a blockage in the core, check the valve on the hose that sends water through it. make sure it opens and closes as it is supposed to.

it is also common for trapped air to fill the heater core so I tell people to completely fill the heater core using the heater hose held up high and pour coolant in until its full then pinch off the hose with locking pliers as you connect it to the block. this gets 95% of the trapped air out. air trapped in the heater core is very common because it is the highest point in the system and water doesn't flow that fast so its not easy for the air to get forced out unless you drive at fast highway speeds with the heater on which is the first thing I suggest you do to try fixing it by forcing out any trapped air then recheck radiator fluid levels.

 

I only ran water backwards through the heater core. I don't know how much, if any, air was in the core, because I attached the garden hose to the heater core hose by making a sleeve with a bike tire inner tube, then went to the house to turn on the water. I tried kinking the garden hose so the water wouldn't flow until I got back to the truck, but the the kink didn't hold. I'm about to get started here, so I don't know if I'll read any replies before I'm working, but:
Should I have run water both ways through the heater core (water was flowing unobstructed through the core backwards)? I will take your advice and try to refill the heater core with coolant independently before refilling the rest of the system.

I'm also replacing the thermostat. I don't know if it is necessary, but since I'm already invested in the project and a thermostat is only about $12, I'm just going to replace it.

Also, I was just reading a new coolant flushing thread that is on page 1 here in the forum. He spoke of flushing the system with distilled water and then accounting for the water residual water when refilling the system. I flushed my radiator with the garden hose, but at no point has the engine been running.

My questions:
Was is dumb to flush the radiator with a garden hose?
Did the water only flow through the radiator and not the engine, since the engine was never turned on?
Should I refill 50/50 with full strength coolant and distilled water, or is there water in the system that I should account for?
Or should I refill with distilled water, run the engine, flush, then refill with coolant?

The problem with the last option is I only have two gallons of distilled water and a truck that is not running. Thanks.

 

As long as water was flowing through the core easily, it's fine. It only won't work if its obstructed. Going backwards is the better way to break loose anything inside, the buildup is used to flow going the normal direction. I usually go back and forth for a few minutes to do my best and flushing it out. I've been driving for a couple decades, only needed to do this twice.

The thermostat is an easy replacement, when you're already drained is a good time regardless of if its bad or not. There is a small hole in the thermostat if memory serves, it needs to be in the right position. I don't remember which it is but a search will show you.

The garden hose is fine. People make entirely too much of having nothing but distilled water touch their engine. The water stops being distilled the moment it touches anything, unless you have seriously hard water it will never hurt anything to have some in the engine. Most vehicles on the road have some tap water in them. If you want to flush most of the engine as well you'll need to remove the thermostat and reinstall the housing, then flush, then remove the housing and install the thermostat. Refill with a 50/50 mix, buy a $2 fluid tester anywhere and make sure the mix give the freeze protection you need. If its off, adjust.

 

no, you fill the whole system first then the leftover air is trapped in the heater core because it is the highest point in the system, then when you fill the heater core through the disconnected hose you get "all" the air out of the system. if you fill the core first any leftover trapped air will go right back up into the core so you will be trying to, and need to, fill the entire block through the heater hose.

these trucks are famous for having heat issues because the heater core is so hard to get the air out completely and only running high rpms with the blender valve wide open is all the air able to be forced out normally

 

Alright, so yesterday I refilled the heater core first and then refilled the radiator and guess what, I have no heat. Before undergoing this endeavor I had a just a little heat and now it is straight up cold air. Based on your last post, I did it backwards and I have the cold air to prove it.

How should I proceed at this point?
Will a thorough bleeding at the radiator cap clear the air, or should I be working on the heater core from the firewall junctions, or something else... ?

Today I'll be working in 20º weather, so my progress can be slow with breaks to warm up the fingers. I've been removing the heater core hoses right at the firewall, and I have a few of extra feet of hose I can hook up to those connectors if needed while I'm working on this. Ideally, I don't want to unhook any junctions that I haven't already worked on - breaking things free for the first time can be real time consuming.
Thanks.

 

see my post #9 above, what you did was add more trapped air in the heater core, that's why you have no heat at all now, it has nothing but air in it. you also probably forgot to make sure the blender valve was open so it let all the air from the block to escape through the heater core hose.

to make things easier you can install one of these: http://shop.advanceautoparts.com/p/dorman-help-radiator-flush-tee-1-2-in.-47151/21299842-p?cm_mmc=ACQ-_-Google-_-GPLA-_-21299842&ci_src=17588969&ci_sku=21299842&ci_gpa=pla_with_promotion&ci_kw=&iv_=__iv_p_1_g_12425515822_x_pla_with_promotion_y_6201684_f_online_o_21299842_z_US_i_en_j_73681971262_s__n_g_t__d_c_v__vi__&gclid=CLfV_K64lsICFUVk7AodgGcAKQ#utm_source=acq&utm_medium=google&utm_campaign=gpla&utm_content=21299842

with truck running and warmed up (thermostat open) with heater core valve open, remove the cap (installed facing upwards on the exit side of heater core hose close to firewall) and it lets all the air out. when coolant starts coming out, then you put the cap on it and all the air is bleed out of the system. but I don't like to use these things because the caps can often start leaking on you so if you get one look there first if you suspect coolant leaks.

 

I read your #9 post, and it seems like I do have a heater core full of air.

So moving forward, I should just bleed the system from the radiator cap, or are there any additional steps?

Sorry for asking for clarification, I just don't want to make any assumptions - assumptions have left me with an air-locked heater core.

Thanks again.

 

no you bleed out the air and refill the heater core from the heater hose but you fill the block FIRST before you do it, then try and pinch off or hold thumb over the end of the hose and reattach quickly without letting too much air back in. any remaining air will pass out through the radiator cap. or if you still cant get it, use the fitting I linked to. its not hard to do but it needs to be done in the right order.

 

from the radiator cap or the heater core outlet?

fill the block from the heater core inlet hose with radiator cap open?

Sorry, I hope you are not pulling your hair out. There is just multiple point of entry and exit for both the coolant and air.

You know when Clinton said "it depends on what your definition of 'is' is"? I feel like I'm caught up in that scenario. I just want to make sure I'm defining/interpreting your words correctly.

 

with engine running and fully warmed up with heater valve open and heat on full, fill the radiator to the top and put the cap on.

turn off engine and let cool down so water isn't hot enough to burn you then disconnect the outlet hose from the heater core where it enters the engine block.

fill heater core with coolant by filling up the heater hose and hold your thumb over the end of the hose when its full and then reconnect without spilling too much out.

there will still always be "some" air trapped in the lines but if you do it right it will not be much.

start engine and run with radiator cap removed and after the engine is fully warmed up, rev the engine to around 2500 rpms for a minute or so then let idle and top off the radiator and replace cap. this "burps" that last little bubble of air out of the lines.

everything should work fine now.

 

Thank you for the elaboration, hopefully this will leave me with little opportunity to bungle matters now.