Coolant bubbling in resevoir..

[vdaily89]

Got out of the car today and heard a strange noise. Popped the hood and the coolant in the resevoir was bubbling. I don't think the engine was hot. What would cause this? Do I need to flush the coolant or is there maybe a bigger problem?

 

Thanks,

Vince

 

94 Cutlass Supreme, 3100 V6

[Z34door]

you sir have blown a head gasket.........

[sl3196]

Might need to flush your cooling system. My cutlass used to bubble like that. I flushed mine and it didn't bubble anymore. Make sure to also bleed out the air too!

[vdaily89]

Man I hope it's not the head gasket. Are there rebuild kits for the engine?

 

What's the best way to bleed the air out after flushing and refilling?

[Z34door]

i dont know if you'd want to go through the hassle of rebuilding a 3100...... they're a dime a dozen..... you can get a low mileage one from the J/Y for like 400$

[THe_DeTAiL3R]

THERMOSTAT and maybe a flush! Plugged (closed) T-stat will cause hot coolant to overflow. $10 fix.

 

What's the best way to bleed the air out after flushing and refilling?

 

I'm not 100% sure about the 3100, but the 2.8/3.1 use the bleed screw on the top of the t-stat housing (or even the screws that hold the housing on).

[supreme_style21]

It could just be the wrong mixture of coolant/water. Too much water will cause the coolant to boil.

[sl3196]

How to bleed:

Fill to proper level

Open both bleed screws (one on water pump housing other on thermostat pipe)

Run engine until coolant flows out of both holes. Once it flows out of one put the screw back in and keep engine going until it comes out of the other one. Might have to add more coolant during this process.

[cutlassdude96]

the intake gaskets maybe going out too

[vdaily89]

Thanks guys. I will see if I can mess with it this weekend.

God I hope it is simple..

[vdaily89]

How can I tell if the head gasket is blown?

[rudefyet]

i wouldn't go straight to assuming it's the head gaskets...because the slighest leak anywhere can cause it to bubble...it could just be the radiator cap

 

but to check for the head gasket...here are the signs

 

1. White Exhaust smoke

 

2. Oil in the coolant...you'll be able to see the oil floating on top since they don't mix well

 

3. Coolant in the oil....check around your oil cap and if the oil is a milky brown color then you may have a bad headgasket

[DiscoStudd]

You say it's boiling over into the tank before it's hot? That sounds like a bad radiator cap to me.

[Guest TurboSedan]

You say it's boiling over into the tank before it's hot? That sounds like a bad radiator cap to me.

 

yup, if the radiator cap isn't allowing the system to pressurize it will boil over....

[vdaily89]

Just messed with it. Thermostat seems to be working fine. The upper radiator hose is hot but the engine temp is runing at around 210 degrees but doen't go higher. There is plenty of coolant in system. The thing is the fans aren't kicking on; neither of them. So I am thinking it is the coolant temp. sensor that is back behind the ignition module.

 

What do you think?

 

Thanks,

Vince

[god910]

Well, if it's 210 the fans shouldn't be on yet. Dont' know about the 3100 but the 3.1 fan on setpoints are like 217 and 223*

[vdaily89]

210* was an estimate. Could have been a little higher. When the engine was running hot I cranked up the heat and the temp didn't come down. Could it be the t-stat? I just figured if it was stuck closed the temp would keep going up and if it was open the temp would stay down lower than normal( my old Eagle Talon did this).

[musthavemuzk]

good chance it is the head gaskets, but could be any of the mentioned items.

today we started the reassembly process of the 3.1 in my 90 cutlass.

last fall i had a coolant leak. the fitting on the drivers side of the engine on the lower intake started leaking. removing it to replace it the fitting broke. so out came the lower intake to replace the lower intake and the fitting.

then at xmas time i had heating and overheating problems and bubbling in the cooling system. tried to bleed the system but could never get the air out.

ended up taking it in and they did a test to see if there were exhaust gases in the cooling system and there was. so i limped it from central IA to NW MN.

before i took it in i did multiple t-stats, rad caps, bled the system...to no avail. was looking for the easy and cheap fix. there are several threads by me alone find them with the search function.

 

for myself i used some coolant but not alot. did not have the steam cloud from behind car or underhood as some have had when the head gaskets go.

 

the 90 cutlass has 1 bleeder on top of the t-stat housing.

the 93 GP has 2 bleeders. one on top of the t-stat housing the other on the bypass coolant line on top of the water pump.

 

pics of the lower intake job last fall

http://www.dbfanatics.com/forum/photo_album_view.asp?cname=underhood&mid=16&cid=248

 

pics of the headgasket in the cutlass job

http://www.dbfanatics.com/forum/photo_album_view.asp?cname=cutlassheadgaskets&mid=16&cid=261

 

pics of the 93 GP

http://www.dbfanatics.com/forum/photo_album_view.asp?cname=93gplemar04&mid=16&cid=255

 

Monty

[vdaily89]

Thanks for the reply. I just am not for sure. It runs at 210-220* and holds. The coolant temp sensor seems to be working. When I unplug it temp gauge doesn't move & when I plug it in it shoots right up. I am still going to replace it, t-stat and rad. cap then see what happens.

The fans don't seem to be coming on though. Someone mentioned that they don't come on until 217-223* but it shouldn't get that hot to begin with, should it? I am going to test them to see if they are working but I may have to unbolt and half way take them out because I can't seem to get them unplugged the way they are. What tells the fans when to come on exactly?

 

Thanks again,

Vince

[musthavemuzk]

Thanks for the reply. I just am not for sure. It runs at 210-220* and holds. The coolant temp sensor seems to be working. When I unplug it temp gauge doesn't move & when I plug it in it shoots right up. I am still going to replace it, t-stat and rad. cap then see what happens.

The fans don't seem to be coming on though. Someone mentioned that they don't come on until 217-223* but it shouldn't get that hot to begin with, should it? I am going to test them to see if they are working but I may have to unbolt and half way take them out because I can't seem to get them unplugged the way they are. What tells the fans when to come on exactly?

 

Thanks again,

Vince

dunno the temp it should run at as my cutlass has no guage for now. got the UB3 cluster to go in it but have not done it. that has 6 gauges. you can find info on the main page and into upgrade section http://www.w-body.com. the GP gauge goes all over the place from cold to 220. fans never come on in it either. so i dunno.

it could get that hot. all depends on driving habits and such and if there are any problems or not with the engine itself. if the head gaskets are going then that is pumping hot exhaust into the already hot cooling system adding heat to make it run hotter. something to think about.

 

not 100% on what tells the fan to come on.

i am refering to the 3.1 here

the coolant sensor on the drivers rear corner of the head is for the gauge or dummy light. all depends on which the car has. this has a single green wire on it.

the other coolant sensor is on the lower intake just to the rear and below the t-stat housing. it has no wires coming off of it. the two wire plug from the harness plugs into it as it sits close to the lower intake. pretty sure there is a pic of this one amongst the pics from above thread. this one tells the ECM what the engine temp is for best operation and fuel economy.

 

but i am not sure which one tells the fans to turn on. i would guess the one that talks to the ECM.

 

Monty