03-15-06, 03:25 PM
Ok car is a 89 Brougham d'Elegance 75k miles been at the mechanics for two days. I called them and they can not find anything leaking, checked hoses, radiator, etc. Yes, it could be the beginning of a head gasket prob. but would like to think it is my radiator cap. Do you think that a mechanic would pick up on this or is it something that I should just replace myself, its just the cap itself right? How could this cause loss of coolant? Where can I get one and which one do I need to get, not mechanically inclined just want the right part. They are putting a new thermostat in and replacing two belts, put some kind of oil switch in which takes care of my oil leak.
Also could replacing the thermastat correct the issue of loosing coolant?
A good mechanic will pressure test the cooling system after he does a visual check. This should reveal the issue fairly quickly and point to the general direction. Some other ideas (not in any special order, just random thoughts....):
1. Check the intake manifold, Olds V8's had some issues in the 80's with the aluminum intakes not sealing well at the ends over time. This could be an under the intake manifold leak, so it won't be visible, but will show up in the oil. The gaskets can rust over time and start to leak. Corners of the intake manifold are key places to observe closely.
2. Head Gaskets. Pull spark plugs and examine CLOSELY for sparkly dots. This is a sign of antifreeze entering the combustion chamber. White smoke in tailpipe is a good sign. Also, an emissions test over an open radiator cap will also indicate if coolant is getting into the rad.
3. Water pump leaking and evaporating where it isn't seen. This occurs around the weep hole on the bottom of the pump.
4. Start and drive the car (with coolant full). Once hot, and you verify the radiator hose is firm, shut down, and monitor how long it takes to bleed off pressure. It should have SOME pressure in overnight, but if it drops off and has no pressure in a short time, there is a leak somewhere.
5. Do you smell that sweet antifreeze smell when you are running or shut it off hot? Look for leaks.
1. Is cap new? Have mech PRESSURE TEST CAP, not blindly replace it. They have a pump that can seal and pressure test it.
2. Pressure test radiator. Is it holding? Signs of leaks will be visible in most cases.
3. Pressure test block. Is it holding?
4. Pressure test heater core. Is it holding?