Coolant Vanishing Mystery

[theragtopguy]

Well, this is really nuts. Every day, I'm adding about 300 ML of coolant to my 92 3-cylinder. Absolutely no obvious leaks anywhere. Checked all hoses, water pump weep hole, heater core, radiator area, you name it I checked it. And the oil is perfectly normal. Trouble is, when it gets a little low, at idle she gets really hot. I don't get it.

Also, is it true that the timing belt must be removed to install a new water pump? I was thinking of putting a new one in for the hell of it, since I can't figure out where the crap is going.

[geozukigti]

You can put a UV dye in your coolant, wait till nighttime, and then run the car with a blacklight over the motor. That'll be the best way to track the leak.

[rjolly87]

also, you may have a blown head gasket. it might be good to get your cooling system pressure tested.

[ewfw]

yup timing belt must be removed to change th water pump

[Mike_Van]

Could it be entering the engine and leaving via the exhaust?

[theragtopguy]

Well, she overheated on me today after running at 65-70 MPH on the expressway for around 10 minutes. Had to pull over and let her cool down, added water and drove rest of the way to work (about 15 miles) with no problem. I'm really suspecting blown head gasket or maybe cracked head even though there's no coolant in the oil. When she runs, lots of bubbles present in the radiator. Have a pressure tester, but the radiator neck is too small, it won't fit.

I'm gonna use some K&W Block Seal on her this weekend and see if that works. I may be in the market for another Metro soon.

[geozukigti]

block seal won't work well for a blown headgasket passing pressure into the cooling system. It will more than likely plug the heater core, and the radiator first. A headgasket job isn't too hard. And you can replace the water pump and timing belt at the same time. Perhaps have the head rebuilt too with new exhaust valves.