Rusty Radiator Flushed Now Overheating

I just bought a 2.7 1996 Tacoma 4X4. I am very novice in auto care. I noticed the other day how much rust was in the coolant reservoir tank, an absolutely incredible amount. I decided to do a flush. I drained it and used Prestone Flush and filled it to the top with water. I took it for a short drive to cycle it through, as the instructions mentioned. It ran rough. I returned and used a hose to clear flush and rust until water was clear. I have gradually put in and ran engine to get the full amount of coolant mixture in (2.2 gallons). Got about 1.5 gallons in and took it for a drive. The temp fluctuated a lot during the short trip and often drastically as if the water pump was coming on and then turning off. By the time I returned it got very hot and steam was coming out of the cap and it was leaking. Any ideas?

 

Air trapped somewhere in the cooling system.

 

pull the thermostat to release the air pocket then refill.

trapped air can be a pain if you completely drain the system so always remember to pull the thermostat to "burp" out the air pocket

 

Thank you both for the quick responses. Where is the Thermostat? Sorry if that is a stupid question. Should I run the truck with the cap off until there are no more bubbles? I saw that in a video earlier. Thank you for your help.

 

here you go: http://www.youtube.com/watch?v=aZEYAkdyymg


wouldn't hurt to just put in a new thermostat while you are at it in case the old one is bad

if youi notice there is a little doo-dad (technical term) on the thermostats flat part (time stamp 1:22) where its supposed to allow air to bleed past and prevent trapped air but if there was a bunch of junk in the system this was probably blocked on yours and the reason you had trapped air issues.

also, its not mentioned in the video but this air bleed hole should be mounted at the top naturally so it can do its thing correctly

 

Good info above.
Not trying to convulute the issue but, It may be easier to remove the radiator cap and start the truck. When the thermostat opens and the truck reaches operating temp the fluid will drop.
At that point add fluid straight to the radiator until full. Cap and top of res.
GL.

 

Will pulling the thermostat off and putting it back on "burp" it enough that it could fix the over heating? I have ran the truck with the cap off while filling the coolant. Almost have the full 2.2 gallons in. I haven't ran it on the road since to see how the temp does but I will in the morning.

 

Are you squeezing the rad hoses going to and from the block?

Let it idle up to temp, have your heater on (full heat, full fan) and with the rad cap off squeeze the hoses. It doesn't hurt to bring up the idle while you're squeezing the hoses either, the faster the engine is turning the faster the waterpump is turning.

However, as stated by keakar, if you had a bunch of gunk/rust/ deposits of any sort you should probably take the thermostat out and make sure there isn't anything behind it. Thermostats aren't very "free flowing". What I mean is its a valve and it will restrict the flow, so any material that passes through the block freely might not pass through the thermostat.

I don't believe they're very expensive either, might as well replace it while you're in there. You should get a new gasket with a new thermostat so saves you from potential leaks, if you were going to reuse the old one!

 

Welcome and congrats on a great purchase. All the above feedback is great. But, you are just covering up the symptoms. Rust comes from an old radiator. Do it right and purchase a new radiator, prediluted red coolant (I always purchase this from the dealer) and thermostat. Not that expensive and pretty simple to replace, just time consuming. The thermostat is underneath the housing which is connected to the lower hose. There are pdf files stickied on here with repair manuals. Or just buy a chilton/haynes, its a wise investment.

 

There is long life and super long life. Ones darker.

 

bought a thermostat and gasket. About to get to it. Not sure if I mentioned this before but the reservoir tank filled up all the way to the top and hasn't gone down. I only put in 2 gallons, just shy of the 2.2 specification. Not sure if that says anything new.

 

Upon taking the old Therm out lots of old coolant came from behind it. Does that mean anything?

 

Are you sure it's rust? Are you aware that the factory coolant is reddish in color? Just checking the basics. Don't want you replacing anything the does not need to be replaced.

 

There were chunks and sediments of rust all through it. The reservoir was caked in rust. I replaced the therm and took it for a drive. The temp maintained very well and the truck ran well. However, the res was bubbling when I got back. It still hasn't taken the full 2 ish gallons.

 

Run the heater as well when you change it out so it circulates thru the system

 

The temp is maintaining continually but now the coolant is boiling in the reservoir tank. I found a possibly fantastic shop to take it to so I am thinking that is what I will do.

 

that's just the trapped air still escaping, (I assume you mean bubbling and not really boiling water) it will suck in water to replace the air as it cools so keep a close eye on the overflow so it stays filled unil it no longer bubbles then recheck your radiator level and after that your back to normal.

sounds like you got most of it out, but you had a lot of crud in there and im worried you didn't clean it all out which is why your not getting the right amount back in (its still full of sediments) if you still have sediments in there it could and likely will plug up your heater core and radiator in the future.

if it were me I would disconnect the radiator hoses remove the thermostat and run a hose under pressure through the engine block and heater core in both directions until you see nothing but clean water then do the same for the radiator to get any crud that went in there out and then finally reconnect and refill with antifreeze. think of your block as a dirty storm drain and you need to flush the buildup off the bottom of the pipe, it just takes time and patience (and getting your feet wet lol) so do your best to get it all out.

you have already done most of the work so no need to pay a mechanic to do a flush when you can and will do a better job yourself. when they do flushes they do a quicky flush and that's it they don't make sure to take the time to fully clear out everything. a trained monkey could do it so don't pay someone to do a job you will do better.

also when you are done remove the catch jug and clean it because the radiator sucks up water from there when its needed as it cools down so it needs to be clean in there.

 

Don't complete fill the expansion tank. Its there to catch the coolant when it gets hot and expands.

 

If you had that much rust & crappola inside..... you might have a blockage somewhere. Debris & lose crap clogging up the lines - and perhaps in the block itself. The fluid can't flow freely like it should.

When was the last time the water pump was changed? If the water pump is going bad (especially the bearings), it can't pump the fluids as good / and with enough pressure / to force out any blockages.

Just something to think about....

 

with that much crap in it its probably got worn seals in it anyway so being you had thermostat problems and found a lot of junk its worth the peace of mind and a very good idea to replace the water pump now before it goes out in 6-9 months from now, the water pump blades may also be worn from all that debris it had to push through it