Can it be a BHG?

[MaNNy919]

ive searched around but cant find a similar situation to mine...So my car started to over heat just last week. It would spike up to H and it would come back down below half to its normal operating temp when i would jump on the freeway. Then the bird cage came on and ignored it and kept driving. Couple minutes later it went away.

I changed out the thermostat and did a radiator flush 2 days ago and it seemed like it fixed the problem. Checked it today in the morning and radiator was full with water and resevoir tank was filled up to the full mark. Today it started to overheat again but the bird cage would come on after couple minutes of driving then it would go off after a while. car would run hot most of the time then the birdcage would come on and it would run at normal operating temps then the birdcage would come off and would start to overheat again. Car is feels normal and runs strong. Motor has about 24k mi on a rebuilt. Im running out of ideas on what to do with it. Hope its understandable im trying my best to describe this problem...and i dont have a fan shroud but ive been running with out it for a good while and never had this type of problems...any help will be appreciated...

 

[IJ.]

Sounds like it may just have a big guttfull of air in the cooling system after you worked on it.

Run the engine when it's cold with the rad cap off and the heater on full and fill it slowly, as it heats up the t stat will open and the coolant will drop, top it and the overflow tank off put the cap on and go for a gentle drive.

It will puke any excess out and after it's cycled hot cold a few times check the rad and top off as needed.

Helps if you can park it nose up while doing this.

 

[MaNNy919]

thx IJ appreciate the help im hoping this can solve my problem...:biglaugh:

 

[IJ.]

<fingers crossed> for ya Manny!

 

[MaNNy919]

it seems like the car did have air in the system...I burped it for about 10min yesterday before i left to work...it helped out a little since i dont see the birdcage coming on here and there no more...now it just overheats when i drive it for a while. Ima burp the car tommorow with the car leveled and hopefully this will resolve my problem overall.:nono:

 

[IJ.]

Overheat is a bad sign

Does the car have a fan shoud and working fan clutch

Does it have an undertray

What's your base ign timing set to?

Is the rad in good condition and is the air con condensor clear of leaves/crap?

 

[MaNNy919]

Overheat is a bad sign

Does the car have a fan shoud and working fan clutch

Does it have an undertray

What's your base ign timing set to?

Is the rad in good condition and is the air con condensor clear of leaves/crap?

my tempeture gage goes up 3/4 then i turn on the heater for couple of seconds it goes back down to 2/4 and stays like that for a good while...

i dont have a fan shoud

my fan clutch seems to work good...what are the signs of a bad fan clutch?

i dont have a undertray if its that thing that covers the bottom of the car my drive way decided to rip it off like 5 years ago:3d_frown: and ever since then i never ran one...

base ign timing? have no idea what that means

 

[IJ.]

The things I outlined are VERY important to keeping a Mk3 cool Manny.

You really need a shroud and an undertray.

With the car at operating temp (engine off) the fan should be stiff to turn by hand and easier to turn when it's all cold.

Did you have the heater on full when you were filling the coolant?
(sounds like it still has a guttfull of air)

 

[Kckazdude]

my tempeture gage goes up 3/4 then i turn on the heater for couple of seconds it goes back down to 2/4 and stays like that for a good while...

You didnt really just type that did you?
Oh, yes you did.

Check your radiator for cold spots when the thermostat is open as well as all the things IJ has pointed out.

 

[MaNNy919]

The things I outlined are VERY important to keeping a Mk3 cool Manny.

You really need a shroud and an undertray.

With the car at operating temp (engine off) the fan should be stiff to turn by hand and easier to turn when it's all cold.

Did you have the heater on full when you were filling the coolant?
(sounds like it still has a guttfull of air)

when i burped the car i only left it running for like 10min and it was not leveled...i turned off the car and filled it up with water... then drove it because i had to go to work...im guessing there is still a guttfull of air...

 

[IJ.]

Sounds like it may just have a big guttfull of air in the cooling system after you worked on it.

Run the engine when it's cold with the rad cap off and the heater on full and fill it slowly, as it heats up the t stat will open and the coolant will drop, top it and the overflow tank off put the cap on and go for a gentle drive.

It will puke any excess out and after it's cycled hot cold a few times check the rad and top off as needed.

Helps if you can park it nose up while doing this.

Reread this please ^

With the nose up just keep filling it with the engine running and the heater on full.

2/4 aka 1/2

 

[MaNNy919]

Reread this please ^

With the nose up just keep filling it with the engine running and the heater on full.

2/4 aka 1/2

ahhh...:biglaugh:

 

[supramang]

When the head gasket blew in the n/a motor i had a very similar situation. It would spike up like that and then go back down. Even after burping it, it would get the exhaust bubbles in the system and heat everything up for a bit. Try not to overheat it too much or youll be lookin for a new head:3d_frown:

 

[AJ'S 88NA]

When the head gasket blew in the n/a motor i had a very similar situation. It would spike up like that and then go back down. Even after burping it, it would get the exhaust bubbles in the system and heat everything up for a bit. Try not to overheat it too much or youll be lookin for a new head:3d_frown:

A lot more than a new head. :3d_frown:

 

[supramang]

LOL yeah no kidding!!

 

[MaNNy919]

I think i have a BHG cause now im just losing water like every day but the car doesnt over heat no more like it used to:icon_evil...

 

[IJ.]

Any other signs?

Time for some tests then Manny.

 

[bigaaron]

I have found that on a properly working cooling system a small amount of air will work its way out of the cooling system the first time you get the engine up to operating temperature and let it cool. If no coolant is leaking out of anywhere but the overflow bottle keeps filling up and it is overheating, 99.9% of the time it's either a bad radiator cap, bad fan clutch or water pump, or a bhg. Usually if there is air trapped in the cooling system it's because you were too quick in pouring the coolant in and thinking it was full. If you squeeze the upper radiator hose several times as you fill it, you can easily fill it full and never have to burp anything, as long as the overflow bottle is connected and it has some coolant in it.

I know it's nice to have, but I don't even remember the last time I saw a Supra still running an undertray, so I don't think that would be very high on my list of reasons it might be overheating.

 

[IJ.]

I have an undertray

 

[Kckazdude]

^^You're an exception not the standard.