Temp gauge only gets up to about 1/3. Fan motor is good, relay is good, and there's no code for the temp sensor. Radiator was full at the begining. I drained and refilled it just for the hell of it and the same thing happened. There are no leaks anywhere. No rough idle. Not even a sputter. Replaced the thermostat to no avail. As soon as I start the car, the overflow tank begins to slowly fill. Once the car warms up, air bubbles start to come out of the overflow hose in the tank, along with the constant flow of coolant. My Helm's tells me to repair the open in the green wire between the underhood fuse/relay box to the A/C diode. However, the wire is good. I no longer have A/C, so I can't troubleshoot that. I'm figuring since the flow of coolant to the overflow tank is constant, the pump must be working... right? Could a bad A/C diode cause this? The temp gauge does fluctuate & seems to be working fine. I'm thinking that if it were a head gasket, the temp gauge should be showing a high temp. What the hell am I dealing with here?


Still learning...

 

ok, your scaring me when you said you see air bubbles in the cooling system.. you need to start the car cold, radiator cap removed, coolant level topped off and see if you see bubbles coming from the radiator.. it won't be easy to determine because the vibration of the motor will also create some bubbles..

What you need to determine is if there is NOx gases in the cooling system coming from the combustion chamber, this means that combustion is leaking into the cooling system via a bad headgasket, cracked cylinder head or block..

If the coolant and air is being forced into the overflow resovoir and the car is not actually overheating, then this is a good indication that there may be a major problem created by a faulty cooling fan..

There are many other things to consider so don't start to panic yet.. let me know how you make out..

 

It actually turned out to be the radiator cap. The fan now comes on again, but **** still doesn't seem quite right. I have yet to do that compression check, but that should tell the tale about the head gasket.

 

A compression test is not gonna tell you diddy about a blown headgasket so don't go there.. The best way for me to determine a blown headgasket is to do a visual check of the base of the head for any leaks..

Alot of cars on the road have leaking headgaskets but doesn't mean it poses any immediate danger..

Most Plymouth/Dodge Neons - these things leak after 10,000 miles..
90 series Toyota Corolla's
Dodge Caravan/ Plymouth Voyager-- what a joke! check the front motor mount while your under there!
88-91 series Civics
Early series Honda Passports-- I ain't going there..



[Modified by BreakStuff, 3:06 AM 10/7/2001]

 

If you do a compression check and the compression is low in one or more cylinders, what does that mean? It means that pressure is escaping from that cylinder. If the gasket is bad, you WILL be losing pressure somewhere. However, low compression in one or more cylinders could also mean a crack, or warpage. The point here, is that pulling the head is not a thirty minute job. So doing a compression check will tell you whether or not is necessary. If the compression is where it should be, then you just saved yourself a few hours worth of work.

Come on man, don't post some bullshit like this. Better to not post at all than to add to the already excessive amounts of misinformation out there.

 

By your last post you obviously have no concept in the theory and structure that involves the cylinder head, engine block and the multiple cooling, oil and compression ports..

Isn't it possible that a headgasket could leak from an oil or cooling port and not directly affect the compression chamber? .. Yes, the failure of pressed paper/abestos headgasket can occur when the corrosive compounds found in engine coolant deteriorate the headgsket.. Thats why headgasket manufacturers are now using aluminum,copper and steel compound headgaskets..

Would a compression test determine a headgasket leaking from a cooling or oil port that does not interfere with the compression chamber?.. No

Is a compression test an accurate method to detect blown headgaskets, cracked cylinder head or block?.. No, compression readings will also detect worn compression rings, improper valve seats..compression psi measurements can fluctuate with each individual cylinder.. how would you determine what is creating the loss compression?

If compression rings and valve seats are making a complete seal, Then why doesn't someone enlighten 94gsr in what test is actually used to detect structural damage to the block,head or gasket.. Do you know? I do..

 

If you were getting bubbles, I would suspect a blown headgasket. Not real clear on how a radiator cap would cause the bubbles. That air is coming from somewhere. You can go to a store & get a kit to check for the presence of combustion gases in the coolant. Sorry, I can't remember what it is called. Had a friend whose car seemed to run properly but kept losing a small amount of coolant. No leaks found. The kit told the story. Don't let the fact that it isn't overheating lull you into a false sense of security. It won't unless you are really on it for a period of time. Good Luck.


[Modified by civicrr, 1:37 PM 10/7/2001]

 

You reinforced my only point. If the compression is not where it should be, a bad head gasket is one of the possible causes. Your original post made it sound as though it could not be. After reading your second post, this apparently was not the message that you were trying to get across, so I do apologize, but that's how it came through.

Obviously, a compression check does not tell you where you're losing compression, it just tells you if you need to move on to a leakdown & pull the head. Considering that this is my only car, I don't think you can blame me for not wanting to do all that if it's not necessary.