Originally posted in cooling thread but cross posted here as it might be gasket related, pics are there too!

Hi Guys,

I'm in the UK and have recently purchased a 91 3.1 V6 Firebird with 80k on the clock. I'm still finding my way around and checking things as I go, so there could be many more questions to ask! :-)

I topped up the coolant with water until it reached the "Fill Cold" mark. I've since driven the car about 20 miles and the coolant has gone! So I'm wondering if one or both of the cylinder head gaskets have gone? Also praying it's not a cracked block from reading some of the other postings on here!

The engine temperature floats around the half mark on the gauge between 100 and 220. I've checked the oil and it's very black as I don't know when it was last changed, it looks fine though, runny as opposed to thick. The oil filler cap has no gunge on it at all and looking into the head, no gunge there either.

When starting from cold there does appear to be white smoke or at least smoke but that could have been due to it being a frosty morning, about 1-2 deg C. Otherwise and when the engine is warm I can't see any white smoke at all, it's acting normal I'd say.

The only thing I have noticed when removing the radiator cap is, firstly, the coolant level in the radiator is just below the cap and secondly, it's a rusty colour perhaps milky.

Does anyone have any thoughts please? I've attached photos below...

Thanks for any help and it's appreciated,

Ian

 

Sounds like you are due for oil change. Water/coolant in oil looks like chocolate milk. Water boils at 212f, Some of the loss can be from steam/boiling. It needs a 50/50 anti freeze/water mix.

 

I was having the same problem on my 91 firebird V6 formula and all I had to do was seal up the radiator plug because the seal went bad, I would try that first because it cost me a pack of JB Weld and it worked great for me!

 

Oh man I hate JB weld on any part of engine, especially on the radiator. But if it works for you then, what the hey.

Inspect the radiator cap for condition of the gasket and the rubber seal. If the cap is not holding pressure, the coolant will boil at 212 degrees F. Pressure raises the boiling point about 4 degrees for every pound of pressure. You still want 50/50 mix but pressure is the key.

In 40 years as a professional mechanic, I have never seen a coolant to combustion head gasket failure that didn't cause severe overheating within minutes of the engine running due to displaced coolant. A failed head gasket will also cause bubbles in the coolant reservoir as combustion gases escape through the coolant. The standard test for head gasket leakage is to look for hydrocarbons in the cooling system using either a reactive chemical or a gas analyzer. Combustion pressure is 3,400psi roughly, compared to a max of 16 psi coolant pressure. The gases will be pushed out through the coolant, the coolant will not pass back into the chamber, not until the engine is stopped, then, you will get a misfire on cold start up until the coolant is cleared from the cylinder. In a severe HG failure, the engine may hydrolock. I have seen cracked heads that allow coolant to pass into the combustion chamber. Then you generally get steam from the exhaust at all times. Steam from the exhaust on cold start up is normal.

Check the relay tube from the reservoir to the radiator to be sure that it is not leaking. Check all hose connections and with the system under pressure, check for coolant leaking from the AC evaporator drain of the HVAC assembly. This is a clear sign of a leaking heater core.