first time doing a coolant flush

[Anon22]

im only 18 havent done alot of work on cars but i need to do a coolant flush+tstat replacement in my 4afe 1996 corolla. ive read the d.i.y on this site already and i had a quick read of my owners manual and noticed theres 2 drain plugs, radiator coolant and engine water. i really have no idea what engine water is LOL my guess is coolant that has passed the tstat and becomes trapped in the block when the car has cooled down? do i need to open and drain both of these? reading about doing this flush seems a bit confusing hopefully when i do it i will realize its not that hard.

thanks

[nitronate33]

one drain plug is at the bottom of the radiator and one is in the block somewhere. together, they will allow all the coolant to drain out of the system. i'm not sure what is referred to as "engine water", but that is just coolant in the block.

[wei]

A little bit comes spilling out of the t-stat housing if you don't drain the engine. It's not too bad though, because I only drained the radiator without realizing and ended up rushing to collect it all with a rag. I've read that you can pull the lower radiator hose to drain the engine block -- it should have the same effect as the engine drain plug but easier to get to.

[PatrickGSR94]

Originally Posted by wei

A little bit comes spilling out of the t-stat housing if you don't drain the engine. It's not too bad though, because I only drained the radiator without realizing and ended up rushing to collect it all with a rag. I've read that you can pull the lower radiator hose to drain the engine block -- it should have the same effect as the engine drain plug but easier to get to.

No, it won't. The lower radiator hose attaches up higher on the engine than where the block drain plug is. The block plug is on the front of the block, near the oil filter I believe (lower than the oil filter). Just go ahead and remove that to make sure you got ALL old coolant out, and then remove it again after flushing to make sure you get ALL the flush water out.

Just be careful and have a large drain pan handy, because buddy that stuff will come GUSHING out when you remove it.

[speedy25]

First get a cleaner and follow the directions on the bottle. The cleaner is VERY good at removing scale and other crud from the coolant passages. Then use a flush and fill kit so you can BACKFLUSH the system. Many times there are collections of crud that block passages that can only come out by reversing the flow direction.

Open the drain on the radiator like the directions say but you dont have to open anything on the block. Many times these are rusted to the block and you can break them off trying to remove them.

-SP

[PatrickGSR94]

Originally Posted by speedy25

First get a cleaner and follow the directions on the bottle. The cleaner is VERY good at removing scale and other crud from the coolant passages. Then use a flush and fill kit so you can BACKFLUSH the system. Many times there are collections of crud that block passages that can only come out by reversing the flow direction.

Open the drain on the radiator like the directions say but you dont have to open anything on the block. Many times these are rusted to the block and you can break them off trying to remove them.

-SP

But if you don't remove the block plug after doing that, you'll have some of the flush fluid and hose water mixture in the block. I NEVER recommend putting any type of water permanently in a cooling system other than distilled water. Water out of the hose can cause even more of the scale and corrosion that you just tried to remove with the flush.

I always recommend the following procedure:
1. Turn interior heater to full hot, drain radiator, and drain engine block.
2. Remove upper radiator hose from head, and lower hose from radiator.
3. Remove thermostat, then place thermo housing back on w/o the thermostat (finger tight bolts are fine).
4. Flush the system through the upper radiator hose and into the radiator with plain hose water until the stuff coming out the lower radiator hose runs clear.
5. Drain radiator and block again to get all the hose water out. Just remove the lower radiator hose from the radiator to drain it faster.
6. Put new thermostat in, close everything back up, and fill the radiator with a 50/50 mix of coolant and distilled water. I always use Prestone green coolant in both the Integra and Corolla, never had any issues. My current Integra radiator has at least 150K miles on it (303K miles on original engine and transmission).
7. Squeeze upper and lower hoses to expel as much air as you can, and fill with more coolant mixture to bring the level up to the base of the radiator neck.
8. Start and run the engine with the radiator cap off, heater still on full hot (no need to turn on the blower). Wait until the thermostat opens, both hoses get hot, and the radiator fans cut on. The coolant should go down a bit after this point so you'll need to add a bit more, then close it all up.
9. If the coolant in the radiator rises while the engine is running and heating up, that means there is still some air in the system. I would shut off the engine and squeeze the hoses some more until you can get that air out.

[Anon22]

uh-oh? the current coolant that im going to drain is red so i assumed id have to buy red coolant which i did. but im unsure now that you just said you use green coolant in your corolla............

[Kiwi-Corolla]

Originally Posted by Anon22

uh-oh? the current coolant that im going to drain is red so i assumed id have to buy red coolant which i did. but im unsure now that you just said you use green coolant in your corolla............

The red coolant is typically the long life stuff. It's perfectly fine to use and will last a lot longer than the green coolant.

[Anon22]

lol it took me 2hours to do the change! i feel like ive done a good job thanks to the advice and diy from these forums. heres a few pics of the old tstat im not sure where tstats open and close but it looks kinda obvious with this one as ive tried forcing that little gap closed and it just wont.



so yeah i finished up, put coolant in, took it for a test. the car stays at a constant warm temp now! even going 80km/h for a constant time doesnt drag down that temperature needle all the way down to C like it used to, pretty happy with that im hoping for better mileage. another thing i was looking out for was the heater, which didnt work before. when i put coolant in and let the car idle for 10mins the heater was on the whole time and it only blew cold air, drove it for 10mins and still cold air...after that 10mins a sudden gush of hot air just came out without touching anything. seems strange but its all good. so yeah only thing im a bit concerned about is that i let the car idle for 20mins when i was cleaning up etc and the overheating fan never came on once. oh well. i owe alot to toyotanation.com now =)

[PatrickGSR94]

The fan coming on doesn't mean it's overheating. The fan SHOULD come on after awhile with the car sitting and engine running, as that's what brings air through the radiator to PREVENT overheating. While driving there's already air rushing through so the fans aren't needed.

I always run the engine until the fans come on after filling the radiator, which in some cases can be 45 minutes to an hour.

[speedy25]

Perfect pic of a FAILED thermostat. AFter boiling it will be wide open and you can watch it close as it cools. The one in this pic will not move at all.

-SP

Originally Posted by Anon22

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