Overflow tank causing overheating?

Jr.Two · 02-27-2008, 09:14 PM

Hey guys

As you can see this is my first post here

So...

Hello everyone!

I got my aw11 a few months ago and it is my first car

A few days after I bought it it overheated...

We had it towed to a mechanic and he thought it was a blown head gasket...

I read a little bit about overheating issues in aw11s and I began to think that it was misdiagnosed..

I took it to the local Toyota dealership and they told me to replace the radiator

So I did...

And of course, that didn't fix anything...

I thought I might as well try replacing the thermostat...

And the old one was very corroded looking

But that wasn't the whole problem apparently..

I took it to Toyota once again and they replaced the filler cap pipe thing saying that is was not sealing correctly or something...

Once again not the problem as it still overheats

It seems to be losing coolant

If I keep it filled up it is just fine

When it does overheat I see a good deal of steam coming out of the overflow tank cap and it seems to have some sort of leak in it because I've seen coolant come out from it in a way that it shouldn't...

Could this be the problem?

Could replacing the overflow tank with it's tube and cap fix my overheating issues?

Thanks for your help guys, sorry for making you read such a long post but I thought I'd give ya the full story

I love my AW11 but I can't afford to buy 2 or 3 gallons of coolant a week

canadam · 02-27-2008, 09:16 PM

Have you made sure the coolant system was bled properly? If not done right, an airlock can be a read headache with MR2s.

tymr287 · 02-27-2008, 09:23 PM

Yes it can cause overheating problems. Check your cap on the overflow bottle, make sure it is not cracked or the tube going down into the bottle isn't sucking any air. Always make sure the is coolant in the jug. If the system isn't bled properly it'll cause a bouncing idle.

Jr.Two · 02-27-2008, 09:24 PM

Quote:

Originally Posted by canadam

Have you made sure the coolant system was bled properly? If not done right, an airlock can be a read headache with MR2s.

I've bled it the best I could through the radiator bleeder cock

The other bleeder cock in the frunk is stuck and I couldn't find the engine bleeder (although I think I saw a post explaining where it is somewhere so I'll try that)

I'll try that then the next chance I get

Don't you think Toyota would have done that?

Because it overheated a day or so after I got it back from them

And would not bleeding the air properly cause me to lose coolant?

tymr287 · 02-27-2008, 09:28 PM

There is a bleed port on the block by the oil filter, real pita to get to. I use the bleed port on the radiator, heater core, and the one by the t-stat housing to get the air out.

Jr.Two · 02-27-2008, 09:33 PM

Quote:

Originally Posted by tymr287

There is a bleed port on the block by the oil filter, real pita to get to. I use the bleed port on the radiator, heater core, and the one by the t-stat housing to get the air out.

Ah, okay, I'll use those and see if that does the trick

I never have time during the week to properly bleed it, so it'll have to wait..

I hear a water flowing wishy washy sort of sound coming from behind the dash sometimes..

Do you think that could be due to air in the pipes ?

Around the heater core ?

Or something else ?

tymr287 · 02-27-2008, 09:38 PM

Yeah sounds like air in the heater core. Try putting something on it to soak to break the bleeder loose like some PB Blaster or similiar lubricant.

tjmr2 · 02-28-2008, 02:08 AM

Make sure the coolant system is bled according to the BGB, and check your timing. If the timing is too far advanced the car will overheat.

Jr.Two · 03-02-2008, 03:35 PM

All right, thank for all your help guys, no more over heating it seems!

I feel stupid for never bleeding it enough until now, but I'm glad it works

Thanks again guys!

55mr2 · 03-02-2008, 04:01 PM

Quote:

Originally Posted by Jr.Two

I've bled it the best I could through the radiator bleeder cock

The other bleeder cock in the frunk is stuck and I couldn't find the engine bleeder (although I think I saw a post explaining where it is somewhere so I'll try that)

I'll try that then the next chance I get

Don't you think Toyota would have done that?

Obviously the dealership didn't bother to bleed the heater cause the bleeder cock wouldn't have been stuck if they had opened it up to bleed the system properly. I'd go back and give them some grief. Just because it's an old Toyota, it is still a Toyota and they should know these things.

feral4mr2 · 03-09-2008, 09:30 AM

here's how i bleed the coolant. i dont bother with the one on the block, as long as you get the radiator, heater matrix and thermastat housing bled all will be fine.
The simple way to change your MR2 coolant.

also make sure the new cap on the overflow is hooked up the correct way, if the pipes are on back to front the cooling system cannot 'suck' any expelled coolant back in giving you more air in the system.

mr220v · 03-09-2008, 11:51 AM

A crack in the valve on the top of the overflow cap can cause the motor to over-heat. This happened to me once. It cracked on the plastic connection about 3mm before the hose. I just grabbed one off of a celica, and cut the in-tank tube to fit.

There was a good bit of steam coming from the area of the overflow cap while it was overheating.

NHinNC · 03-11-2008, 07:18 PM

I have also seen posts about the hose being on the wrong pipe on the top of the overflow tank causing problems

katrina664 · 03-21-2008, 03:47 PM

The bleeder screw that is on the thermostat housing has been melted and jammed into the hole. This kicks fluid into the overflow tank.

I have the new screw and working on getting help with removing the old one without trashing the housing, putting a new thermostat in while I'm at it.

Here's the trouble, I bought the flex cap for the overflow tank as it was badly needed and low and behold now the poor thing can suck fluid out of the overflow when necessary BUT the guy helping me says this is not because of the cap but rather because he:

left some old tubing on that engine bleeder outlet and capped it. Then he capped the new tubing coming from the flex cap so there is no longer flow.

I would assume this is right, but it scares me that he insisted on modifying it and besides that I bought the new flex cap for a reason, not to have the system interrupted.

I hope someone on here knows, I have to drive it 30 miles to his shop in the morning to put that thermostat in (must be ordered to the month of manufacture from toyota by the way).

Does anyone know?

Also, guy who keeps overheating, you probably have an airlock because it is a closed system. If you can drain it and refill it according to directions you can find on links here, that may help.

Same guy who capped my engine bleeder valve refused to fill it according to those specs and left it capped so I am having more trouble now than before.

I have always loved toyota, but MR2s are a real bitch!

Maticuno · 08-16-2008, 01:01 PM

I can't seem to find an overflow tank specific to the MR2. Will a universal aftermarket one work as long as it has the lower return hose?

Gairloch · 08-16-2008, 09:16 PM

Quote:

Originally Posted by katrina664

Does anyone know?

I have always loved toyota, but MR2s are a real bitch!

I'm not quite sure what your question is here. Can you clarify?

Sounds like the problem you're running into is the tech, not the car

Quote:

Originally Posted by Maticuno

I can't seem to find an overflow tank specific to the MR2. Will a universal aftermarket one work as long as it has the lower return hose?

As long as you have it plumbed in correctly it should be fine. If you do some digging I bet you can find the correct one though. Car-Part.com--Used Auto Parts Market

Maticuno · 08-16-2008, 11:55 PM

Quote:

Originally Posted by Gairloch

As long as you have it plumbed in correctly it should be fine.

What does "plumbed correctly" look like. The one that is on now is aftermarket and it is already broken. I know where the bottom hose goes, but does the overflow line need to be all the way to the bottom of the tank or can it just pour into the top?

Maticuno · 08-17-2008, 03:33 PM

If someone could post a picture of their stock coolant tank setup that would help me a lot to be able to tell what I should be trying to reproduce. Thanks!

Maticuno · 08-18-2008, 01:41 AM

Seriously guys...I need some help.

nitrate · 08-18-2008, 01:48 AM

yes you need the tube go go down in the collant. so when the car cools down it can draw coolant back in to the system.

02-27-2008, 09:14 PM	#1 (permalink)
Jr.Two No Skills Join Date: Jan 2008 Posts: 12 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Overflow tank causing overheating? Hey guys As you can see this is my first post here So... Hello everyone! I got my aw11 a few months ago and it is my first car A few days after I bought it it overheated... We had it towed to a mechanic and he thought it was a blown head gasket... I read a little bit about overheating issues in aw11s and I began to think that it was misdiagnosed.. I took it to the local Toyota dealership and they told me to replace the radiator So I did... And of course, that didn't fix anything... I thought I might as well try replacing the thermostat... And the old one was very corroded looking But that wasn't the whole problem apparently.. I took it to Toyota once again and they replaced the filler cap pipe thing saying that is was not sealing correctly or something... Once again not the problem as it still overheats It seems to be losing coolant If I keep it filled up it is just fine When it does overheat I see a good deal of steam coming out of the overflow tank cap and it seems to have some sort of leak in it because I've seen coolant come out from it in a way that it shouldn't... Could this be the problem? Could replacing the overflow tank with it's tube and cap fix my overheating issues? Thanks for your help guys, sorry for making you read such a long post but I thought I'd give ya the full story I love my AW11 but I can't afford to buy 2 or 3 gallons of coolant a week

03-21-2008, 03:47 PM	#14 (permalink)
katrina664 No Skills Join Date: Mar 2008 Posts: 11 Thanks: 4 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Related, but need help with engine bleeeder screw The bleeder screw that is on the thermostat housing has been melted and jammed into the hole. This kicks fluid into the overflow tank. I have the new screw and working on getting help with removing the old one without trashing the housing, putting a new thermostat in while I'm at it. Here's the trouble, I bought the flex cap for the overflow tank as it was badly needed and low and behold now the poor thing can suck fluid out of the overflow when necessary BUT the guy helping me says this is not because of the cap but rather because he: left some old tubing on that engine bleeder outlet and capped it. Then he capped the new tubing coming from the flex cap so there is no longer flow. I would assume this is right, but it scares me that he insisted on modifying it and besides that I bought the new flex cap for a reason, not to have the system interrupted. I hope someone on here knows, I have to drive it 30 miles to his shop in the morning to put that thermostat in (must be ordered to the month of manufacture from toyota by the way). Does anyone know? Also, guy who keeps overheating, you probably have an airlock because it is a closed system. If you can drain it and refill it according to directions you can find on links here, that may help. Same guy who capped my engine bleeder valve refused to fill it according to those specs and left it capped so I am having more trouble now than before. I have always loved toyota, but MR2s are a real bitch!

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02-27-2008, 09:16 PM	#2 (permalink)
canadam MidshipExpress Join Date: Feb 2005 Location: Beautiful British Columbia Posts: 10,399 Thanks: 120 Thanked 142 Times in 121 Posts My Google Map iTrader Rating: (34/100% )	Have you made sure the coolant system was bled properly? If not done right, an airlock can be a read headache with MR2s.

02-27-2008, 09:23 PM	#3 (permalink)
tymr287 Some Skills Join Date: Jan 2008 Location: New Orleans Posts: 74 Thanks: 0 Thanked 7 Times in 5 Posts iTrader Rating: (0/0% )	Yes it can cause overheating problems. Check your cap on the overflow bottle, make sure it is not cracked or the tube going down into the bottle isn't sucking any air. Always make sure the is coolant in the jug. If the system isn't bled properly it'll cause a bouncing idle.

02-27-2008, 09:28 PM	#5 (permalink)
tymr287 Some Skills Join Date: Jan 2008 Location: New Orleans Posts: 74 Thanks: 0 Thanked 7 Times in 5 Posts iTrader Rating: (0/0% )	There is a bleed port on the block by the oil filter, real pita to get to. I use the bleed port on the radiator, heater core, and the one by the t-stat housing to get the air out.

02-27-2008, 09:38 PM	#7 (permalink)
tymr287 Some Skills Join Date: Jan 2008 Location: New Orleans Posts: 74 Thanks: 0 Thanked 7 Times in 5 Posts iTrader Rating: (0/0% )	Yeah sounds like air in the heater core. Try putting something on it to soak to break the bleeder loose like some PB Blaster or similiar lubricant.

02-28-2008, 02:08 AM	#8 (permalink)
tjmr2 Cage Fighter Join Date: Jan 2008 Location: Colorado Posts: 410 Thanks: 0 Thanked 62 Times in 59 Posts My Google Map iTrader Rating: (0/0% )	Make sure the coolant system is bled according to the BGB, and check your timing. If the timing is too far advanced the car will overheat.

03-02-2008, 03:35 PM	#9 (permalink)
Jr.Two No Skills Join Date: Jan 2008 Posts: 12 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	All right, thank for all your help guys, no more over heating it seems! I feel stupid for never bleeding it enough until now, but I'm glad it works Thanks again guys!

03-09-2008, 09:30 AM	#11 (permalink)
feral4mr2 ghetto modder Join Date: Sep 2006 Location: Western Australia Posts: 130 Thanks: 0 Thanked 11 Times in 10 Posts iTrader Rating: (1/100% )	here's how i bleed the coolant. i dont bother with the one on the block, as long as you get the radiator, heater matrix and thermastat housing bled all will be fine. The simple way to change your MR2 coolant. also make sure the new cap on the overflow is hooked up the correct way, if the pipes are on back to front the cooling system cannot 'suck' any expelled coolant back in giving you more air in the system.

03-09-2008, 11:51 AM	#12 (permalink)
mr220v Beams Owners Group Join Date: Mar 2006 Posts: 2,529 Thanks: 13 Thanked 176 Times in 147 Posts iTrader Rating: (11/100% )	A crack in the valve on the top of the overflow cap can cause the motor to over-heat. This happened to me once. It cracked on the plastic connection about 3mm before the hose. I just grabbed one off of a celica, and cut the in-tank tube to fit. There was a good bit of steam coming from the area of the overflow cap while it was overheating.

03-11-2008, 07:18 PM	#13 (permalink)
NHinNC No Skills Join Date: Mar 2008 Location: Greensboro NC Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	I have also seen posts about the hose being on the wrong pipe on the top of the overflow tank causing problems

08-16-2008, 01:01 PM	#15 (permalink)
Maticuno Park Ranging Join Date: Aug 2008 Location: California Deserts Posts: 313 Thanks: 15 Thanked 25 Times in 17 Posts iTrader Rating: (2/100% )	I can't seem to find an overflow tank specific to the MR2. Will a universal aftermarket one work as long as it has the lower return hose?

08-17-2008, 03:33 PM	#18 (permalink)
Maticuno Park Ranging Join Date: Aug 2008 Location: California Deserts Posts: 313 Thanks: 15 Thanked 25 Times in 17 Posts iTrader Rating: (2/100% )	If someone could post a picture of their stock coolant tank setup that would help me a lot to be able to tell what I should be trying to reproduce. Thanks!

08-18-2008, 01:41 AM	#19 (permalink)
Maticuno Park Ranging Join Date: Aug 2008 Location: California Deserts Posts: 313 Thanks: 15 Thanked 25 Times in 17 Posts iTrader Rating: (2/100% )	Seriously guys...I need some help.

08-18-2008, 01:48 AM	#20 (permalink)
nitrate All the skills Join Date: Nov 2007 Posts: 439 Thanks: 0 Thanked 6 Times in 4 Posts iTrader Rating: (0/0% )	yes you need the tube go go down in the collant. so when the car cools down it can draw coolant back in to the system.