Overflow tank causing overheating? - Page 2

Maticuno · 08-18-2008, 01:43 PM

Is there supposed to be a tube that runs from the thermostat housing bleed screw to the coolant tank?

nitrate · 08-19-2008, 01:32 AM

Quote:

Originally Posted by Maticuno

Is there supposed to be a tube that runs from the thermostat housing bleed screw to the coolant tank?

yes and hooks to the side of the tank abought 1/2 way down. it lets the air out and coolant in when you blead the system. it should be a clear plastic hose so you can see the air bubbles comeing out

Maticuno · 08-19-2008, 01:34 PM

I replaced the coolant tank and routed the hoses the best I could. The one from the thermostat housing goes into a port on the bottom of the tank and the overflow line runs through the cap and sits on the bottom of the tank. The cap seals tightly and I siliconed the hose running through the cap to seal that off. The car isn't overheating, but it still won't suck coolant back into the system from the tank. The tank fills up when it gets hot, but it never draws back down when the engine cools off which leaves the system low on coolant. Any ideas?

nitrate · 08-20-2008, 02:35 AM

you will never see it suck it back in to the system. its is a every small amout of coolant that is pushed out of the system as it expands. so every time you run the car. you loos a little more coolant. if there is no way for the car to recover the little amount every time the cars ran.and tube going in to the coolant condenses the hot coolant so it does not keep evaperating/ leting steam out.

tjmr2 · 08-21-2008, 12:49 AM

Use only a stock Toyota thermostat, the MR2 will suck a cheapo open every time you open the throttle, doesn't cause overheating, but your engine will lose all heat.

Bleed it properly, it's imperative that you get the radiator and heater bleed screws open and get all the air out of the system.

Any overflow bottle will work, the important part is that the tube from your filler cap goes to a line that always stays below coolant level. As coolant heats up and expands it will pressurize the system to more than the filler cap is rated for and the excess coolant will flow into the bottle. As it cools it contracts and must be able to suck coolant only back into the system. Thus maintaining a system that has no air in it.

Your filler bottle level will drop over time as the hot fluid running in and out will evaporate out of the vent, however it should take months before you drop enough to need to add more coolant.

I used a Harbor Freight brake line vacuum bleed kit with an old one quart water bottle set up in front of it as a fluid reservoir (set up the in and out lines just like the brake bleed kit, in to the bottom, out at the top of the cap) and bled the heater core and radiator until I didn't get any air. Took about four quarts for each, just poured the bled quart back into the system at the filler.

If you still overheat (and or lose coolant) after bleeding a "Leak down test" is in order as you might have a head gasket problem.

Maticuno · 08-25-2008, 01:38 AM

At 213K miles, would it be possible that the water pump blades are so worn that it isn't flowing properly and possibly even cavitating?

nitrate · 08-25-2008, 03:09 AM

Quote:

Originally Posted by Maticuno

At 213K miles, would it be possible that the water pump blades are so worn that it isn't flowing properly and possibly even cavitating?

no way. only thing that can happen is that they rust a way. try flushing out the radiator ?

Maticuno · 08-25-2008, 01:28 PM

Replaced the radiator and during the flush a TON of rust came out. I didn't get it all unfortunately because I couldn't get to the engine drain. I'm tired of trying to figure this one out so I'm hopefully taking it in to a shop tomorrow.

nitrate · 08-25-2008, 01:39 PM

i hate to tell you ods are its full of rust again. you might even have the cooling tuds half packed with rust sediment.

amzoun · 11-18-2009, 02:27 AM

I read in another web site according to the manual , the car should be leveled before bleeding? I cheked the site with the pictures you mentioned that the car need to be put on ramps? why?
thanks

Quote:

Originally Posted by feral4mr2

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.

amzoun · 11-18-2009, 02:38 AM

I would like to get some help, the mechanic in my town scared my yesterday he said my 85 MR2 has the Head Gasket Symptoms!!
I started over heat after 30 to 40 min drive, random idel fluctuation( its gone when I push the rpm to 4000 to 5000 ). I hear running water sound under the dashboard like washing like pouring water in a tube. also I never heard my side fan runing( in the engine compartement).some time have no heater it blows only room or cold air,
I think my car need to be bleed and its not the head gasket.
I think I have air trapped on the heater core under the dash board, do you think I blowed the engine? the car drive nice, has lot of power.
I dont know where is the bleeding valves under the car?
is any one have the bleeding steps on the mR2 manual? if so I would love to see the location.
thanks all Its great site, first time here.
I am from california and I own a nice MR2 85 with 150, 000 miles and I love it,

amzoun · 11-18-2009, 02:49 AM

hello, I am amzoun , I am from California, I have the exact symptoms on my 85 Mr2, please tell me exactely what you have done step by step, My car is over heating after 30 to 40 min of drive not always I hear the sound of water under the dash board, idel fluctuation , steams comming for the cap, and there is air coming bubbling in the plastic bottle.
I would really appreciate your help
a mechanis scared me yesterday telling me it may be the headgasket, he wats to charge me $70 just to runa test to determine if I blow my engine. I think I need to bleed my cooling system.

YellowJacket · 11-22-2009, 02:39 PM

amzoun (and probably the OP):

the engine bay cooling fan pertains to engine bay ambient temp only and comes on when the temp sensor in there reaches about 159 degrees. It has nothing to do with the cooling system.

Sorry to say your headgasket is blown. You are describing my car exactly prior to getting the headgasket replaced. Now that it has been fixed, there are no more exhaust gases being forced into the cooling system via the blown HG, no more loss of coolant, no more gurgling sounds in the heater core in the dash, no more idle fluctuation (bouncing idle), no more overheating after long drives, no more boiling/bubbling in the reservoir... no more frustration. I had every symptom you described perfectly.

I spend many hours in denial and not believing it, and constantly bled the car of air everytime and had to top off coolant regularly but couldnt understand why I would never seem to get air all out. Finally one day my water pump started weeping and I had coolant on the ground... once it got in the shop, it was finally confirmed and the HG was blown near #4 internally.

You will NEVER get the air out of the system with a blown headgasket because as soon as you start the car the exhaust gases are being pumped right back into it. Its only going to get worse quickly and can cause more block warpage and damage so just get it fixed or dump the car.

Save your $70 and put it towards an OEM headgasket. Its just time to admit it and get it fixed. Make sure you replace the water pump and tstat at the same time with OEM parts. While you are in there its recommended to refresh the timing belt (60k maint. item) if you dont know how old it is.

Odds are this will cost more than you paid for the car but if its done right it will last you another 150k or more miles. MR2's are scrapped or sold because of a blown HG all too often.

11-18-2009, 02:38 AM	#31 (permalink)
amzoun No Skills Join Date: Nov 2009 Posts: 4 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	engine overheat, sound of runing water under dashboard idle fluctuation I would like to get some help, the mechanic in my town scared my yesterday he said my 85 MR2 has the Head Gasket Symptoms!! I started over heat after 30 to 40 min drive, random idel fluctuation( its gone when I push the rpm to 4000 to 5000 ). I hear running water sound under the dashboard like washing like pouring water in a tube. also I never heard my side fan runing( in the engine compartement).some time have no heater it blows only room or cold air, I think my car need to be bleed and its not the head gasket. I think I have air trapped on the heater core under the dash board, do you think I blowed the engine? the car drive nice, has lot of power. I dont know where is the bleeding valves under the car? is any one have the bleeding steps on the mR2 manual? if so I would love to see the location. thanks all Its great site, first time here. I am from california and I own a nice MR2 85 with 150, 000 miles and I love it,

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08-18-2008, 01:43 PM	#21 (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% )	Is there supposed to be a tube that runs from the thermostat housing bleed screw to the coolant tank?

08-19-2008, 01:34 PM	#23 (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 replaced the coolant tank and routed the hoses the best I could. The one from the thermostat housing goes into a port on the bottom of the tank and the overflow line runs through the cap and sits on the bottom of the tank. The cap seals tightly and I siliconed the hose running through the cap to seal that off. The car isn't overheating, but it still won't suck coolant back into the system from the tank. The tank fills up when it gets hot, but it never draws back down when the engine cools off which leaves the system low on coolant. Any ideas?

08-20-2008, 02:35 AM	#24 (permalink)
nitrate All the skills Join Date: Nov 2007 Posts: 439 Thanks: 0 Thanked 6 Times in 4 Posts iTrader Rating: (0/0% )	you will never see it suck it back in to the system. its is a every small amout of coolant that is pushed out of the system as it expands. so every time you run the car. you loos a little more coolant. if there is no way for the car to recover the little amount every time the cars ran.and tube going in to the coolant condenses the hot coolant so it does not keep evaperating/ leting steam out.

08-21-2008, 12:49 AM	#25 (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% )	Use only a stock Toyota thermostat, the MR2 will suck a cheapo open every time you open the throttle, doesn't cause overheating, but your engine will lose all heat. Bleed it properly, it's imperative that you get the radiator and heater bleed screws open and get all the air out of the system. Any overflow bottle will work, the important part is that the tube from your filler cap goes to a line that always stays below coolant level. As coolant heats up and expands it will pressurize the system to more than the filler cap is rated for and the excess coolant will flow into the bottle. As it cools it contracts and must be able to suck coolant only back into the system. Thus maintaining a system that has no air in it. Your filler bottle level will drop over time as the hot fluid running in and out will evaporate out of the vent, however it should take months before you drop enough to need to add more coolant. I used a Harbor Freight brake line vacuum bleed kit with an old one quart water bottle set up in front of it as a fluid reservoir (set up the in and out lines just like the brake bleed kit, in to the bottom, out at the top of the cap) and bled the heater core and radiator until I didn't get any air. Took about four quarts for each, just poured the bled quart back into the system at the filler. If you still overheat (and or lose coolant) after bleeding a "Leak down test" is in order as you might have a head gasket problem.

08-25-2008, 01:38 AM	#26 (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% )	At 213K miles, would it be possible that the water pump blades are so worn that it isn't flowing properly and possibly even cavitating?

08-25-2008, 01:28 PM	#28 (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% )	Replaced the radiator and during the flush a TON of rust came out. I didn't get it all unfortunately because I couldn't get to the engine drain. I'm tired of trying to figure this one out so I'm hopefully taking it in to a shop tomorrow.

08-25-2008, 01:39 PM	#29 (permalink)
nitrate All the skills Join Date: Nov 2007 Posts: 439 Thanks: 0 Thanked 6 Times in 4 Posts iTrader Rating: (0/0% )	i hate to tell you ods are its full of rust again. you might even have the cooling tuds half packed with rust sediment.

11-18-2009, 02:49 AM	#32 (permalink)
amzoun No Skills Join Date: Nov 2009 Posts: 4 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	hello, I am amzoun , I am from California, I have the exact symptoms on my 85 Mr2, please tell me exactely what you have done step by step, My car is over heating after 30 to 40 min of drive not always I hear the sound of water under the dash board, idel fluctuation , steams comming for the cap, and there is air coming bubbling in the plastic bottle. I would really appreciate your help a mechanis scared me yesterday telling me it may be the headgasket, he wats to charge me $70 just to runa test to determine if I blow my engine. I think I need to bleed my cooling system.

11-22-2009, 02:39 PM	#33 (permalink)
YellowJacket 1985 16v NA 6-speed Join Date: Sep 2008 Location: Nashville, TN Posts: 415 Thanks: 8 Thanked 31 Times in 24 Posts iTrader Rating: (1/100% )	amzoun (and probably the OP): the engine bay cooling fan pertains to engine bay ambient temp only and comes on when the temp sensor in there reaches about 159 degrees. It has nothing to do with the cooling system. Sorry to say your headgasket is blown. You are describing my car exactly prior to getting the headgasket replaced. Now that it has been fixed, there are no more exhaust gases being forced into the cooling system via the blown HG, no more loss of coolant, no more gurgling sounds in the heater core in the dash, no more idle fluctuation (bouncing idle), no more overheating after long drives, no more boiling/bubbling in the reservoir... no more frustration. I had every symptom you described perfectly. I spend many hours in denial and not believing it, and constantly bled the car of air everytime and had to top off coolant regularly but couldnt understand why I would never seem to get air all out. Finally one day my water pump started weeping and I had coolant on the ground... once it got in the shop, it was finally confirmed and the HG was blown near #4 internally. You will NEVER get the air out of the system with a blown headgasket because as soon as you start the car the exhaust gases are being pumped right back into it. Its only going to get worse quickly and can cause more block warpage and damage so just get it fixed or dump the car. Save your $70 and put it towards an OEM headgasket. Its just time to admit it and get it fixed. Make sure you replace the water pump and tstat at the same time with OEM parts. While you are in there its recommended to refresh the timing belt (60k maint. item) if you dont know how old it is. Odds are this will cost more than you paid for the car but if its done right it will last you another 150k or more miles. MR2's are scrapped or sold because of a blown HG all too often.