mr2 86 overheating blues

rbutts9514 · 10-08-2009, 11:27 AM

I have had a 86 mr2 for several years and have been dealing with a overheating problem. I change engine and had some relief, but now the problem is back. I have taken the thermostat out to no avail. I have coolant running up the air bleeder valve hose to the recovery bottle and filling up completely. I took the hose off the recovery bottle and attach it directly to the host inlet on the radiator water filler cap. The car is not overheating with that change, (why is that?)even thou I know it is wrong, it gives me a little peace for running around the hood.
ps: things i have change
1. Head Gasket change on first engine
1. Radiator
2.thermostat
3. another engine

any help wound be welcome

dirocyn · 10-08-2009, 12:04 PM

Water is not supposed to come out through the air bleeder valve except when you're bleeding air out of the system. Probably air was getting in through that valve, an air bubble in the coolant lines will stop coolant from circulating. Now you've re-routed the hoses so air can't get in, so no more overheating.

My advice is put it back like it was, but with a new bleeder valve that seals up good. The radiator cap is a pressure relief valve, if you get too much pressure it lets coolant go into the overflow tank, and lets the system suck that water back in when it cools. The way you've got it now, that pressure's got nowhere to go, other than bust a coolant hose.

espguitarist33 · 10-08-2009, 12:08 PM

have you blurped the front 2 bleeder valves?

traintech86 · 10-08-2009, 12:26 PM

i am not sure you bleed right. you're sposed to hang the tubes up while bleeding. this allows the water to raise to be as high as the ass of the car. then air comes out of the system. there is info on it in the manual and thats floating around here

YellowJacket · 10-08-2009, 01:22 PM

Put the hoses back where they belong and put an OEM t-stat back in the tstat housing. Bleed the air from the cooling system the proper way using all three bleedcocks. Then make sure they are all closed. No coolant should run up the engine bleed cock into the reservoir while the bleed valve is closed. if you do not learn how to do this you will keep blowing headgaskets. Also make sure your reservoir CAP (not filler cap) is not cracked or broken and the hoses are connected to the reservoir cap PROPERLY. they have been known to get switched!

What symptoms are you experiencing that make you think the car is overheating?

Pilot · 10-08-2009, 08:42 PM

What is the litmus test to know the bleeding process need not be repeated? If you open the radiator cap when the car is cold and it is full to the top and the engine temperature gage goes to about 1/4 scale when it is fully warmed up, am I good to go or...?

traintech86 · 10-08-2009, 11:47 PM

it will look full even if it has air bubbles. try moving the pipe near the filler in the engine bay. you'll probly get some bubbles. here is the thing, if you attempt to bleed it again, its not like all your coolant goes lol. just set up the pipes, open the valves, have people sit on the front/jack the back up, and watch the bubbles come out.

i am not sure that it will be the problem if you have changed all that stuff you mentioned earlier, but imho, a free attempt is worth a paid solution

YellowJacket · 10-09-2009, 09:21 AM

Quote:

Originally Posted by Pilot

What is the litmus test to know the bleeding process need not be repeated? If you open the radiator cap when the car is cold and it is full to the top and the engine temperature gage goes to about 1/4 scale when it is fully warmed up, am I good to go or...?

If there is air in the cooling system of consequence you will usually experience a bouncing idle or erratic temp gauge as steam travels past the gauge sensor. Small amounts of air will not usually cause this to my understanding and still can cause problems, so the act of properly bleeding the system using the maint. hoses and topping off the filler neck (squeezing the hoses on either side of the filler neck as mentioned is a good idea) until car is warm and tstat opens and heater is on full hot (to allow heater valve to open) should show no air bubbles and require no more top offs... thats the best you can do.

if you check this after a while of driving on and off for a period of time and you find there is more air to bleed, then you have a small leak somewhere. I would think its likely that many people have small air leaks in their car.

If the system has a small leak, but its functioning properly, it should replenish this leak from the reservoir bottle and look full, but air will still be introduced into the system and you will see bubbles when you bleed again...

A perfect functioning cooling system would have no air leaks and the reservoir would remain 2/3 full on hot and about 1/3 to 1/2 full on cold and if you did a periodic bleeding procedure after multiple drives over a span of time you would eventually get to the point where you were so good at it, you would see NO bubbles coming out and be confident that the system was both free from air and had no leaks ....

For me, in the beginning, it was a confidence game... practice makes you the confident expert.... reading the forum just gives you the concept.

rbutts9514 · 10-09-2009, 10:03 AM

Hey YellowJacket
I must thank you and the others for the quick reply. After I had the engine change, it was working ok. Then it started overheating, going all the way over to the red line. I took it to a repair shop and the guy said I needed a head gasket. He put a thumb into the water filler cap and show me the pressure back up. Yes the water started boiling out, put I must admit I don't think it is the head gasket. I think the replacement of the bleeder value is a better start, plus I think it might be a good idea to replace the plastic hose in the recovery bottle.

YellowJacket · 10-09-2009, 02:03 PM

Quote:

Originally Posted by rbutts9514

He put a thumb into the water filler cap and show me the pressure back up. Yes the water started boiling out, .

Sorry, I dont understand this- What exactly did he do?

traintech86 · 10-09-2009, 03:04 PM

i think he is talking about when the coolant is hot and you block the filler, the water can't escape so it pressurises and forces its way up and out, but really i don't think thats a blown headghasket. if that were the case my 2 would be alot louder lol.

rbutts9514 · 10-09-2009, 11:10 PM

traintech86
Is right on what went down at the repair shop. I still don't think it show me that the headgasket was blown. I am new at this, but I see no water in the oil mix or alot of white smoke coming out the exhuast. But the car has been overheating bad. And if you look at the things i change. I am at a lost.

YellowJacket · 10-10-2009, 04:47 AM

I still dont understand that test, or even if its logical.

Have you checked the hoses on the reservoir cap like I mentioned earlier? Is the cap in good shape? The hose that comes OFF the filler neck should be connected to the cap and routed down the hose that goes into the reservoir in the coolant. the OTHER side of the cap hose that is the blow off hose should NOT be connected to that side of the cap. it vents the bottle. This is an easy mistake but a big one if they are switched incorrectly. Easy fix. TEST IT.

take the reservoir cap off with all hoses attached... use your finger to plug the hose that sits in the reservoir bottle in the coolant. blow air through each hose on the outside of the cap. you should NOT be able to blow through the hose that goes INTO the FILLER NECK with that reservoir hose plugged.... you should be able to blow through the other blow off hose while the hose that normally sits IN the reservoir bottle is plugged up. If this doesnt happen, switch the top two hoses.

Maybe your overheating got better when you plugged the engine bleedcock bleeder hose into the filler neck, because essentially you were stopping it up and if your reservoir cap hoses were connected improperly(reversed), you are sucking air into your cooling system instead of coolant. Just a theory....

Also.... just a story...

Mine just had a HG replaced. No white smoke, no oil in coolant, no coolant in oil... just overheated after long drives on highways at speed... could drive around city fine. Finally one day the water pump started leaking at the weep hole ... the overheating got worse.... then I couldnt even drive around the city for more than 30 minutes before temp spiked. Had to top off coolant after each drive to keep up with the loss of coolant. It was a BHG.

Not saying yours is, but just showing you that what you think are tell tale signs dont have to exist. The overheating could be other things. You have had some drastic measures to be still experiencing this.. a new HG? a NEW ENGINE?! Fire your mechanic.

You need to get your tstat back in there and all the hoses routed correctly.
When it overheats, is the front radiator hot? Are the front radiator hoses pressurized and hot? What are your symptoms when it does overheat? Boiling in the reservoir? Does it spew coolant?

rbutts9514 · 10-10-2009, 08:06 PM

I have taken off the air bleeder valve and will replace it and the reservoir cap next week. Once I put everything back together, I will bleed the system as recommended. I will let you know how I make out.

YellowJacket · 10-10-2009, 11:22 PM

keep us updated! Would be great to see you get to the bottom of your problems and resolve them. Dont give up....

traintech86 · 10-11-2009, 01:34 AM

Quote:

Originally Posted by YellowJacket

Dont give up....

+1

and i really doubt its a blown ghasket. i am pretty sure there would be some sort of other issues if thats what it was.

as for the test, when i overheated on the side of the road(due to no fault other then my own) i put some water in the system and it was still to hot so it was steaming out. i tried to put the cap on and it cause alot of extra pressure to come up. needless to say i couldn't get the lid on till later. i don't think that sort of a test proves anything except that hot stuff expands... don't let these shops sucker you into buyin **** you don't need! get a second and even a third opinion! GL man!

randomxzero · 10-11-2009, 03:59 AM

sorry to hear bout your overheating problems.... how many times can you overheat before the HG blows?

if you really wanna test if your HG is bad just get the oil in coolant tester at your local auto parts store... its around 30 bucks last time i saw it.. it tests if you have any gases or oil in your coolant to ensure you have a bad HG or not..

muffinman · 10-12-2009, 12:16 PM

Quote:

Originally Posted by rbutts9514

I am new at this, but I see no water in the oil mix or alot of white smoke coming out the exhuast.

Are you sure it's smoke and not steam? My old Toyota truck started blowing what looked like white smoke but it turned out to be steam from a blown HG. If it dissipates quickly it may be steam and not smoke. If that's what's happening then you wont find water in your oil you will just slowly lose coolant.

traintech86 · 10-12-2009, 11:06 PM

i think he means there is no smoke sir :P

jimmer411 · 10-13-2009, 05:13 PM

Ok so your on a completely different engine and the car still over heats? How long after you start the car does it overheat? 10 mins? 30 mins? Few hours? Did you replace the waterpump when you put the new engine in?

Since you removed the Tstat and it still overheated, we can rule out Tstat stuck closed. Air in the system is still the most likely culprit, especially since the majority of mechanics dont know squat about our cars cooling systems.

Remove your alt belt and spin your waterpump by hand, it should spin smoothly. If its hard to turn by hand, chances are the belt just slides across it when your driving.

I wouldn't rely on the smoke and oil tests, since you usually don't catch a BHG early using either of those methods.

I don't know If I'm understanding this right, but it sounds like your getting excess pressure in the coolant system? Have you done a combustion leak test? Lisle Corp LIS 75500 - Combustion Leak Detector

You could have a break in the headgasket that is pushing exhaust directly into a coolant jacket, it will pressurize your coolant system and push everything into your overflow bottle. It starts small, then boom.

And I dont know what your doing with your bleed valves, but it shouldn't be hooked up to the radiator cap. If its leaking when closed it needs replaced asap.

10-08-2009, 11:27 AM	#1 (permalink)
rbutts9514 SilverRunner Join Date: May 2007 Location: NewYork Posts: 4 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	mr2 86 overheating blues I have had a 86 mr2 for several years and have been dealing with a overheating problem. I change engine and had some relief, but now the problem is back. I have taken the thermostat out to no avail. I have coolant running up the air bleeder valve hose to the recovery bottle and filling up completely. I took the hose off the recovery bottle and attach it directly to the host inlet on the radiator water filler cap. The car is not overheating with that change, (why is that?)even thou I know it is wrong, it gives me a little peace for running around the hood. ps: things i have change 1. Head Gasket change on first engine 1. Radiator 2.thermostat 3. another engine any help wound be welcome

10-10-2009, 04:47 AM	#13 (permalink)
YellowJacket 1985 N/A 6-Speed Join Date: Sep 2008 Location: Nashville, TN Posts: 262 Thanks: 8 Thanked 17 Times in 13 Posts iTrader Rating: (1/100% )	I still dont understand that test, or even if its logical. Have you checked the hoses on the reservoir cap like I mentioned earlier? Is the cap in good shape? The hose that comes OFF the filler neck should be connected to the cap and routed down the hose that goes into the reservoir in the coolant. the OTHER side of the cap hose that is the blow off hose should NOT be connected to that side of the cap. it vents the bottle. This is an easy mistake but a big one if they are switched incorrectly. Easy fix. TEST IT. take the reservoir cap off with all hoses attached... use your finger to plug the hose that sits in the reservoir bottle in the coolant. blow air through each hose on the outside of the cap. you should NOT be able to blow through the hose that goes INTO the FILLER NECK with that reservoir hose plugged.... you should be able to blow through the other blow off hose while the hose that normally sits IN the reservoir bottle is plugged up. If this doesnt happen, switch the top two hoses. Maybe your overheating got better when you plugged the engine bleedcock bleeder hose into the filler neck, because essentially you were stopping it up and if your reservoir cap hoses were connected improperly(reversed), you are sucking air into your cooling system instead of coolant. Just a theory.... Also.... just a story... Mine just had a HG replaced. No white smoke, no oil in coolant, no coolant in oil... just overheated after long drives on highways at speed... could drive around city fine. Finally one day the water pump started leaking at the weep hole ... the overheating got worse.... then I couldnt even drive around the city for more than 30 minutes before temp spiked. Had to top off coolant after each drive to keep up with the loss of coolant. It was a BHG. Not saying yours is, but just showing you that what you think are tell tale signs dont have to exist. The overheating could be other things. You have had some drastic measures to be still experiencing this.. a new HG? a NEW ENGINE?! Fire your mechanic. You need to get your tstat back in there and all the hoses routed correctly. When it overheats, is the front radiator hot? Are the front radiator hoses pressurized and hot? What are your symptoms when it does overheat? Boiling in the reservoir? Does it spew coolant? Last edited by YellowJacket; 10-10-2009 at 11:20 PM.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

10-08-2009, 12:04 PM	#2 (permalink)
dirocyn Cage Fighter Join Date: Mar 2009 Posts: 133 Thanks: 6 Thanked 12 Times in 12 Posts iTrader Rating: (0/0% )	Water is not supposed to come out through the air bleeder valve except when you're bleeding air out of the system. Probably air was getting in through that valve, an air bubble in the coolant lines will stop coolant from circulating. Now you've re-routed the hoses so air can't get in, so no more overheating. My advice is put it back like it was, but with a new bleeder valve that seals up good. The radiator cap is a pressure relief valve, if you get too much pressure it lets coolant go into the overflow tank, and lets the system suck that water back in when it cools. The way you've got it now, that pressure's got nowhere to go, other than bust a coolant hose.

10-08-2009, 12:08 PM	#3 (permalink)
espguitarist33 Cage Fighter Join Date: Nov 2008 Location: west chester PA Posts: 415 Thanks: 4 Thanked 5 Times in 5 Posts iTrader Rating: (2/100% )	have you blurped the front 2 bleeder valves?

10-08-2009, 12:26 PM	#4 (permalink)
traintech86 Traintech86 on all im's Join Date: May 2009 Location: Norfolk VA Posts: 913 Thanks: 13 Thanked 25 Times in 24 Posts My Google Map iTrader Rating: (2/100% )	i am not sure you bleed right. you're sposed to hang the tubes up while bleeding. this allows the water to raise to be as high as the ass of the car. then air comes out of the system. there is info on it in the manual and thats floating around here

10-08-2009, 01:22 PM	#5 (permalink)
YellowJacket 1985 N/A 6-Speed Join Date: Sep 2008 Location: Nashville, TN Posts: 262 Thanks: 8 Thanked 17 Times in 13 Posts iTrader Rating: (1/100% )	Put the hoses back where they belong and put an OEM t-stat back in the tstat housing. Bleed the air from the cooling system the proper way using all three bleedcocks. Then make sure they are all closed. No coolant should run up the engine bleed cock into the reservoir while the bleed valve is closed. if you do not learn how to do this you will keep blowing headgaskets. Also make sure your reservoir CAP (not filler cap) is not cracked or broken and the hoses are connected to the reservoir cap PROPERLY. they have been known to get switched! What symptoms are you experiencing that make you think the car is overheating?

10-08-2009, 08:42 PM	#6 (permalink)
Pilot Master MotorcycleMechanic Join Date: Oct 2009 Posts: 73 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	What is the litmus test to know the bleeding process need not be repeated? If you open the radiator cap when the car is cold and it is full to the top and the engine temperature gage goes to about 1/4 scale when it is fully warmed up, am I good to go or...?

10-08-2009, 11:47 PM	#7 (permalink)
traintech86 Traintech86 on all im's Join Date: May 2009 Location: Norfolk VA Posts: 913 Thanks: 13 Thanked 25 Times in 24 Posts My Google Map iTrader Rating: (2/100% )	it will look full even if it has air bubbles. try moving the pipe near the filler in the engine bay. you'll probly get some bubbles. here is the thing, if you attempt to bleed it again, its not like all your coolant goes lol. just set up the pipes, open the valves, have people sit on the front/jack the back up, and watch the bubbles come out. i am not sure that it will be the problem if you have changed all that stuff you mentioned earlier, but imho, a free attempt is worth a paid solution

10-09-2009, 10:03 AM	#9 (permalink)
rbutts9514 SilverRunner Join Date: May 2007 Location: NewYork Posts: 4 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Hey YellowJacket I must thank you and the others for the quick reply. After I had the engine change, it was working ok. Then it started overheating, going all the way over to the red line. I took it to a repair shop and the guy said I needed a head gasket. He put a thumb into the water filler cap and show me the pressure back up. Yes the water started boiling out, put I must admit I don't think it is the head gasket. I think the replacement of the bleeder value is a better start, plus I think it might be a good idea to replace the plastic hose in the recovery bottle.

10-09-2009, 03:04 PM	#11 (permalink)
traintech86 Traintech86 on all im's Join Date: May 2009 Location: Norfolk VA Posts: 913 Thanks: 13 Thanked 25 Times in 24 Posts My Google Map iTrader Rating: (2/100% )	i think he is talking about when the coolant is hot and you block the filler, the water can't escape so it pressurises and forces its way up and out, but really i don't think thats a blown headghasket. if that were the case my 2 would be alot louder lol.

10-09-2009, 11:10 PM	#12 (permalink)
rbutts9514 SilverRunner Join Date: May 2007 Location: NewYork Posts: 4 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	traintech86 Is right on what went down at the repair shop. I still don't think it show me that the headgasket was blown. I am new at this, but I see no water in the oil mix or alot of white smoke coming out the exhuast. But the car has been overheating bad. And if you look at the things i change. I am at a lost.

10-10-2009, 08:06 PM	#14 (permalink)
rbutts9514 SilverRunner Join Date: May 2007 Location: NewYork Posts: 4 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	I have taken off the air bleeder valve and will replace it and the reservoir cap next week. Once I put everything back together, I will bleed the system as recommended. I will let you know how I make out.

10-10-2009, 11:22 PM	#15 (permalink)
YellowJacket 1985 N/A 6-Speed Join Date: Sep 2008 Location: Nashville, TN Posts: 262 Thanks: 8 Thanked 17 Times in 13 Posts iTrader Rating: (1/100% )	keep us updated! Would be great to see you get to the bottom of your problems and resolve them. Dont give up....

10-11-2009, 03:59 AM	#17 (permalink)
randomxzero Downshift to Reverse! Join Date: Sep 2008 Location: 562 Posts: 1,032 Thanks: 10 Thanked 5 Times in 5 Posts iTrader Rating: (0/0% )	sorry to hear bout your overheating problems.... how many times can you overheat before the HG blows? if you really wanna test if your HG is bad just get the oil in coolant tester at your local auto parts store... its around 30 bucks last time i saw it.. it tests if you have any gases or oil in your coolant to ensure you have a bad HG or not..

10-12-2009, 11:06 PM	#19 (permalink)
traintech86 Traintech86 on all im's Join Date: May 2009 Location: Norfolk VA Posts: 913 Thanks: 13 Thanked 25 Times in 24 Posts My Google Map iTrader Rating: (2/100% )	i think he means there is no smoke sir :P

10-13-2009, 05:13 PM	#20 (permalink)
jimmer411 NA > Boost Join Date: Mar 2008 Location: Enumclaw, WA Posts: 70 Thanks: 1 Thanked 1 Time in 1 Post My Google Map iTrader Rating: (0/0% )	Ok so your on a completely different engine and the car still over heats? How long after you start the car does it overheat? 10 mins? 30 mins? Few hours? Did you replace the waterpump when you put the new engine in? Since you removed the Tstat and it still overheated, we can rule out Tstat stuck closed. Air in the system is still the most likely culprit, especially since the majority of mechanics dont know squat about our cars cooling systems. Remove your alt belt and spin your waterpump by hand, it should spin smoothly. If its hard to turn by hand, chances are the belt just slides across it when your driving. I wouldn't rely on the smoke and oil tests, since you usually don't catch a BHG early using either of those methods. I don't know If I'm understanding this right, but it sounds like your getting excess pressure in the coolant system? Have you done a combustion leak test? Lisle Corp LIS 75500 - Combustion Leak Detector You could have a break in the headgasket that is pushing exhaust directly into a coolant jacket, it will pressurize your coolant system and push everything into your overflow bottle. It starts small, then boom. And I dont know what your doing with your bleed valves, but it shouldn't be hooked up to the radiator cap. If its leaking when closed it needs replaced asap.