Overheating - Coolant leak (from where?)

[MikeGlosta]

2001 Cruiser Base 2.4 112k

Car overheated yesterday, pulled over and saw green coolant leaking. BUT - I can't tell where it's leaking from. A few minutes earlier I heard a metallic sound as I was driving, thought I ran over a piece of metal, but now I'm wondering if a line might have broken.

Added plain water this morning to radiator, didn't take much, then ran the car for about 20 minutes. The temperature gauge hasn't gone past midpoint.

Any ideas where to check for a leak, should I run the car for a longer time, does the water pump come on only after the engine reaches a particular temp. I'm wondering why the leak didn't reappear after running the engine for 20 minutes.

I don't intend to drive the car until I can figure this one out.

[LionPT]

Unless it's a bad leak, most leaks will be visible after you shut car off.
Start car again, let it run to temp...then shut it off. Use a flashlight while your looking around.

[MikeGlosta]

I'll try that suggestion once again. Nothing obvious when I ran the car earlier but certainly worth a second shot.

[ptcruisersteve]

If you have a coolant leak when it dries it leaves a white powder film so if its still leaking look and see if you can see this white powder film anywhere.

Common leaks are at the plastic housing gasket located where you fill it up with coolant and the hose between the radiator cap and overflow tank.

If you still can't find it you can do a coolant pressure test. Check all the coolant hoses including the heater hose. The heater coil can leak but usually a small leak.

[MikeGlosta]

I've run the car twice for 20 minutes each time, turned it off and have not found any leaks - but the car will overheat if I allow the needle to reach the H.

Is there a way for me to check the water pump and/or thermostat without a major breakdown of the housing where the timing belt - pump is located?

[LionPT]

The easiest way would probably be a pressure test. Either buy a kit or take it to a shop.

[quicksilverdon]

If it's your head gasket, you'll never see a leak.
Pressure test and have a test for exhaust in coolant.

[ptcruisersteve]

There are a few things to check before having a block test done.

Does your radiator fan work? There is a high and low speed on the radiator fan. Does it come on when it starts to overheat?

Does it overheat without the A/C running?

To check to see if the thermostat is opening up check the coolant temperature in the upper and lower radiator hoses using a non contact infrared thermometer with laser targeting.

Does your PT Cruiser overheat if you take it on high speeds over 50 miles per hour? If it does overheat at high speeds and your thermostat is okay you might want check your radiator.

[Rennmeister]

Originally Posted by MikeGlosta

Car overheated yesterday, pulled over and saw green coolant leaking. BUT - I can't tell where it's leaking from. A few minutes earlier I heard a metallic sound as I was driving, thought I ran over a piece of metal, but now I'm wondering if a line might have broken.

When the car overheats, the radiator will bleed off coolant into the overflow. The overflow typically has a rubber hose that bleeds off excess coolant. That would cause a puddle of coolant when it overheated, but not when it isn't.

Originally Posted by MikeGlosta

Added plain water this morning to radiator, didn't take much, then ran the car for about 20 minutes. The temperature gauge hasn't gone past midpoint.

ALWAYS use only distilled water. Never tap water. All of the minerals in tap water cause scale build-up and corrosion.

Originally Posted by MikeGlosta

Any ideas where to check for a leak, should I run the car for a longer time, does the water pump come on only after the engine reaches a particular temp. I'm wondering why the leak didn't reappear after running the engine for 20 minutes.

The water pump is mechanical and runs all the time.

Running (read: idling) an engine does not produce much heat. Heat is required to create pressure in the coolant system. Typically leaks get worse or expose themselves when the system pressurizes.

Here's an article I wrote on overheating to give you some more context: Overheating Issues

[tcarlisle]

If you see coolant then simply find where it is leaking from. The thermostat housing to the block is one good place to check which is hard to see unless you are really looking or remove the intake to get a view. A slow leak here is hard to find because it leaks onto the block and evaporates and never hits the ground or the underside of the engine. I'd be really sure there isn't a leak here before I think about a water pump or head gasket. The symptoms mentioned sound like a slow leak.

As for never using plain water, it isn't ideal to use tap but if that is all you have and your only other option is nothing, then do it. Same for the green vs HOAT argument. Some coolant in your system is better than not enough, and if you are forced to use tap or cheap green anti-freeze, you just have to follow-up with a flush and re-fill with the right stuff.