Need advice, Weird over heating issue , melted my Coolant Reservoir - Toyota Nation Forum : Toyota Car and Truck Forums

RMoore · 06-12-2011, 05:55 PM

Looking for advice to point me in the the right direction to diagnose this issue. My son calls me yesterday. His 1995 Toyota Avalon, 6 cylinder overheated while he was driving on the highway, luckily he was right by an exit and got off. The car stalled on the exit ramp with a check engine light on.
I went to take a look, It was still too hot to open the fill cap, but I did notice that the Coolant Reservoir still had antifreeze in it but the cap had melted and there were melted holes in the side. We waited a while and started it up. The temp gauge showed in the center so we though we may try to inch home. As soon as I put it in gear and went about 100 feet it started getting way too hot. I'm thinking waterpump? Thermostat?
We called a tow truck back to our house.

I go out this morning and take off the fill cap of the upper Radiator hose, I figure I'll start by checking the antifreeze level. It took almost two bottles of 50/50. I'm thinking maybe it just got low on antifreeze and over heated. I took it for a quick spin and the temp stayed right in the center and was normal. I'm thinking I lucked out, replace the reservoir and maybe the problem is fixed. WRONG.
As SOON as I pulled up and let it Idle I opened the hood to look things over. The reservoir was shooting out Antifreeze and started to boil. It took about a minute after I stopped for this to happen. I believe if I let it go it would have emptied all the antifreeze out of the engine. I'm thinking this is what happened the first time. I checked the oil and it looks good as far as I can tell, no water or milky oil. The check engine light is a P0115 code.
So now before going further I though I better check here on the forums for some guidence before going further. I appreciate any help or opinions.

Thanks
Ray

robcam13 · 06-12-2011, 10:30 PM

turn on the engine and the a/c and see if the fan kicks on. if it does then it could be a worn out radiator hose or thermostat.

RMoore · 06-13-2011, 06:20 AM

Thanks,

I will try that today and post results on the fan

RMoore · 06-13-2011, 06:25 AM

I am also wondering what is a test or how can you verify that the water pump is working?. With the cap off the fill spout I added water and let the car run. it did take water and antifreeze and then pull down when it was at the top of the spout.

Thanks
Ray

robcam13 · 06-13-2011, 08:07 PM

the water pump is driven by the timing belt. so if the engine will run then the water pump is working

robcam13 · 06-13-2011, 08:09 PM

and the check engine light is a coolant temp sensor code. probably due to it reading a high coolant temp.

RMoore · 06-15-2011, 06:56 AM

The fans are turning when the ac is on. If I let it set running the fans turn on. I can feel the pressure on the top hose once it warms up and then the bottom radiator get hot so I figure the Thermostat must be working.

I have a theory but need someone to run it by.

What if the Coolant reservoir hose from the fill cap broke off, which it was broken. If the radiator became low on water instead of pulling in Coolant it pulled in air, This caused the coolant to have air in the system and the coolant to boil instead of staying pressurized. Now when I am filling the radiator and running it there is air still in the system and the coolant is boiling,

Does this sound valid?

If so what is the proper procedure for filling and bleeding the air from the system, I seem to be in a loop, I can fill the system to the top, let it run and after a while it just spits it all back out the reservoir hose as steam.
I let it run with the radiator cap off for a while but still getting the same results.

I have a new coolant reservoir and cap on order from the Toyota dealer.

Thanks
Ray

Jack Deth · 06-16-2011, 11:06 AM

just taking a stab here... could a bad head gasket be blowing hot exhaust into the water jacket?

RMoore · 06-17-2011, 06:20 AM

Thanks for the reply

I thought about that but in trying to figure this thing out I tried removing the radiator cap and running the car with it filled to the top. I thought if there was a gasket blown on the exhaust side that water should geyser out of the fill cap while the engine is running due to the exhaust pressure. And possibly I should see some water vaper come out the exhaust when first starting but I have neither. Also if blown on the oil side I would have water in the oil, I checked and there is none.
Right now I am trying to replace the Theromstat as a start. Although mine is on the back of the engine ( 6 cyl) and it is crazy how complicated they made replacing a simple Thermostat. I am removing wiring harnesses out of the way, air cleaners, multiple hoses, and really worried I'll never get the three nuts back into place as I cannot hardly get my fingers to the bottom nut.

bob2 · 06-18-2011, 08:30 PM

you don't use your fingers. grease a socket and put the nut in it, then attach a short extension... i would buy a new rubber thingy, as well... the hole in the thermostat goes up... (so it will fill with coolant)

RMoore · 06-20-2011, 06:12 AM

That worked great!, Thanks for that tip. I have everything back together now and ran it for around 15 minutes and things seem OK, I will test drive again today and see how it goes, For a recap I have changed,

1. Change reservoir bottle and cap
2. Changed Temp sensor 1 and 2 ,( Fan controls on the thermostat housing)
3. Thermostat
4. Radiator cap
5. Flushed Radiator

SO far so good but today will tell when I drive into town.

Thanks
Ray