Aeration in Coolant Overflow Tank and Cool Radiator - Toyota Nation Forum : Toyota Car and Truck Forums

BlueFusion6851 · 09-12-2008, 10:11 PM

This issue has been coming and going for the past 7-8 months, and I've been doing the little 'band-aid' type repairs and being vigilant with checking fluid levels but this has started to really aggravate me, so just letting you all know in advance.

Anyways... so this is my issue: After I am driving on the highway or city for around 15-20 minutes and reach my destination, I'll shut off my car and I can hear the coolant in my overflow tank bubbling, like an aerator would in a fishtank.

My other issue, although it happens less is still perplexing... I'll be driving home from Minneapolis to Sartell, which is around 84 miles one way, and if I am on the road long enough, either due to rush hour or accidents, etc, my car will overheat, but after feeling the air going over the radiator, it's rather cool, almost as if there's NO coolant flow through the radiator.

Since this has occurred, we have replaced the radiator caps, thermostat, radiator, and flushed the coolant. I know the level of coolant is low due to the aeration, but there is no visible evidence of *large* amounts of coolant leaking out. I'm asking for your guys' help on this, I have searched, and poured over the pdf of the Factory Service Manual, and am really confused on what could be causing this.

-1993 V6 193,600mi
-No Sign of Coolant in oil
-No White Smoke

Any ideas or tips as to where I should turn?
Thanks!

***new echo owner*** · 09-12-2008, 10:14 PM

Are your cooling fans working on high speed? Have you had any other repair done on the car beside what you had mentioned?

N.E.O.

BlueFusion6851 · 09-12-2008, 10:17 PM

Yes, the hydraulic cooling fan is usually on high speed and its very noticible when I am driving at ~30-35 mph, it will cut in and out, and at idle it tends to run fast. Only scheduled maintenance has been performed.

Thanks for the quick response.

***new echo owner*** · 09-12-2008, 10:19 PM

Do the hoses feel warm or hot to touch, both upper and lower radiator hoses?

N.E.O.

***Eye8Pussies*** · 09-12-2008, 10:29 PM

^ what he said

and you mentioned replacing most of the cooling components...but have you had the rad itself pressure tested?

BlueFusion6851 · 09-12-2008, 10:51 PM

We did before replacing it, and it failed the test... but that is something that I can look at checking.
The upper hose was really taught and felt extremely hot, and I didn't check the lower one.

***new echo owner*** · 09-12-2008, 11:04 PM

Have to check the lower one as well, it will give you some idea on whether the coolant is flowing or not.

N.E.O.

jaybur_racing · 09-12-2008, 11:22 PM

I had a similar issue in my 99 4runner, but mine only overheated up hills, but it would do the bubbling in the overflow tank.

I tried coolant flush, water pump, thermostat, radiator cap, the only thing I didn't replace was the radiator , the radiator only had 14k on it, so I thought it can't be that!

took it to a shop to have them check it over, after driving it the tech said the radiator had hot spots on it, and cool spots. So he said he was pretty sure it was the radiator at fault.

I installed a new radiator, and all is well!

BlueFusion6851 · 09-13-2008, 01:24 AM

Did you replace the radiator with an aftermarket one? Because this is our third radiator in the car so far, and the last two were aftermarket due to being about 480 dollars cheaper.

***new echo owner*** · 09-13-2008, 01:40 AM

Have you ever had the water replace?

N.E.O.

xtremeskier97 · 09-13-2008, 08:09 AM

Quote:

Originally Posted by new echo owner

Have you ever had the water replace?

N.E.O.

Well, he said he flushed the system after replacing the radiator, so I would assume so.

Im watching this closely, as I get the EXACT same problems on my 93 V6 XLE in my sig.

Mine will over heat, bubbling like yours. After it cools down, Ill remove the caps and fill the coolant as much as I can, turn the engine on and keep cap off on the filler neck, but leave the cap on the radiator. I'll fill with coolant as its running to make sure all the bubbles get out and then put the cap back on. It'll run FINE for several weeks before it happens again.

***new echo owner*** · 09-13-2008, 09:50 AM

Well now, if I had just type up what I had actually meant to say, it would have make more sense.

I meant to ask if you ever had the water PUMP

replaced?

(Hey, finally got it right this time!)

N.E.O.

xtremeskier97 · 09-13-2008, 11:59 AM

Ah! Yeah..that makes more sense.

As for mine, im not sure, as Ive only had the car for a few months.

***new echo owner*** · 09-13-2008, 12:06 PM

Feel the hoses would help to see if the coolant is circulating; if there is a big difference between the upper and lower hose, you just might have circulation problem. The radiator will cool down the coolant but not to an extreme. An infrared temp gun would help too

N.E.O.

BlueFusion6851 · 09-13-2008, 02:21 PM

Hmmm yeah, I'm going to have my caps pressure tested this week at school, and I'll look into buying a infrared temperature gun. We did have the water pump replaced a couple years ago due to nonexistent impellar blades. I'll try and burp the system again like you did xtremeskier, and I'll test drive it again.

I also put my stock intake back on just to remove any anomolies, so we'll see where this takes us. I'll post later this afternoon!

Thanks again everyone for your input!