Is it safe to crack open the coolant drains on the engine block on a 23 yr old truck?

About to attempt a coolant flush for the first time, and since im trying to completely rid the system of the universal yellow to replace with zerex red, I want to get every last drop out. But during my research ive notice a few people warn against cracking those drain valves open because they could snap, does anyone have experience with this one way or another? Since I live in a rust free state, my truck is completely free of rust, so I feel like maybe this issue only applies to the rust belt? I obviously don’t want to create a major issue with simple maintenance. So I come to you good people for advice.

Would love to hear any advice, tips, or suggestions.

 

I only cracked the passenger side when I did mine, but I got a least a half gallon more once I disconnected the oil cooler line for the timing belt job. So even cracking both sides wouldn’t get rid of all the coolant

 

Mine broke off in the third year of ownership back in 2005. Rust isn’t necessarily a factor. YMMV

 

In the process of loosening should I be able to “feel” it if it’s about to break? And how detrimental is it if it does indeed break?

 

Mine just broke off the tip but didn’t leak. To be careful, you need to visually see what your wrenching and slowly loosen and tighten in small increments until it’s loose enough to take off altogether. Kind of hard unless you’ve got a borescope set up.

It’s possible mine was just defective and prematurely broke. The problem is that every dealership I’ve asked (at least 3 here) what they do, and they specifically told me they don’t touch the drain cocks when they change fluid.

To play it safe I just drain the radiator twice and replace the fluid with 1000 miles in between the two changes until I need to do it again in 30k miles.

 

Personally I would apply principles of Risk Management here. If the vehicle is your daily driver don't fuck with it and do what Jack posted.

 

My problem is that there is a mix of universal yellow & red in my radiator and I want to completely purge the system to rid it of the yellow, but it’s sounding like the only way to possibly do that is to drain the block. I would flush the heater core but I don’t have a Garden hose and Spicket

 

You can certainly dilute it enough until it appears clear by just draining and filling the radiator frequently with distilled water.

If you’re adamant about getting those drain cocks open maybe you can spray those cocks with rust penetrant like Kroil for a week and then give it a shot one morning when the engine block is cold.

 

For something like this, I always like to have a spare part at the ready just in case it snaps. Example would be I keep a spare OEM oil filter housing just in case I crack the one I have on my truck. Especially since I don't have a 2nd vehicle so I always make sure I have every tool and/or spare part available before I tackle a job.

 

Thats a good idea to spray them down with my PB blaster. Hopefully those cocks dont get the best of me. I’d hate to break my cock off. Sounds like I’ll have to be real gentle with them

 

If it does snap off or break, how easy would it be to put a new one on?

 

Hawk tuah that thang with PB blaster

 

I recall seeing a post about that recently. Even listed the part # you need. Lemme see if I can find it

Edit: Found it..
https://www.tundras.com/threads/block-coolant-drain-cock-assembly-part-number.153861/

Though I'm not sure if new gen cocks are the same as old gen cocks

 

Heat them up with inductive bolt heater before touching.

 

If I decide against touching them. Would it be a good idea to instead, drain as much as it’ll let me from the radiator, and then refill with distilled water, drive around like that for a full day or two. Then drain again, fill with the distilled water, drive again another day or so. (Repeating about 2 more times) and then on the final drain refill with my coolant.

I guess to put it simply, is it safe to drive with nothing but distilled water/very diluted coolant in my system? Or is that risky?

 

If the temperature doesn’t drop below freezing then yes.

 

Also, I’d like to add you shouldn’t be overstressing the engine using just water as coolant since the boiling temp is 212F and coolant is around 225-250F.

 

Im not worried about it freezing. I live in the south and spring is in full bloom. Im more worried about my truck over heating. During the day time the temps are getting up to 85° F

But it sounds like that won’t be an issue, will it?

 

I opened all four bleeders on two different engine blocks about 2 years ago. I think you'll be fine. Just don't use a 3/4'' drive cheater bar on the things. Being that they're made out of brass, i can't imagine them ever getting rusty...even if you drove the truck in the ocean. Sprits it with some penetrating oil first, then slowly loosen with a wrench (maybe it's a 10mm wrench?).

 

Ambient background temp does factor into it. If you want to keep it as cool as possible:

1. Don’t tow anything
2. Avoid stop and go traffic as much as possible
3. Drive at slow speeds
4. Use overdrive
5. Crank the heater to draw away heat from the engine

Maybe one of these guys using Scanguage all the time can tell you definitively? They’re on top of that stuff.

 

Wait there’s 4? I thought there was only 2 on this engine?

 

two different trucks i was working on. Two bleeders on each block. They are located towards the rear of the block.

 

Drain it, fill with tap water, warm it up, drain again. Repeat as many times as needed to be clear. Then distilled water, drain, distilled water again, then finally drain and fill with coolant.

 

Thanks for the info. But just trying to figure this one out… if it does snap/break on me, how easy of a job is it to remove and replace w/ a new one? I only have a basic set of tools.

 

If they somehow break off, then no big deal. Only the plug head could break off, which would still leave the rest of the plug body sealed up tight inside the block. I really believe you're over thinking it.

 

Shouldn’t I be driving in overdrive anyways? I’ve never turned off overdrive in any of my cars. (There’s a light on the dash that comes on that says OD off, that light is never lite up in my car, am I doing something wrong here with driving with OD on at all times?)

 

Never had to replace one myself but looking at the image of the part in that link I posted, it looks fairly simple to replace. Might be a tight fit to get your hands and tools in there but maybe just try fitting a wrench in there to see what your looking at in case it snaps. Post a pic of what yours looks like, you say your not in the rust belt so I'm pretty sure you'll be fine. Just be gentle opening it and don't over tighten it when closing.

 

Run the heater while doing preflush. Leave heater on while draining coolant. Run the hose into the top rad hose. Fill with water, run for a minute or two, then drain again. Blow air into top rad hose, till most comes out. Button up and fill with coolant

 

Just replace radiator, don’t wanna risk the strawberrie milkshake.

 

ahem…strawberry blowpop milkshake