Losing coolant

[1stimer]

OK....I need some advice. My 72 C20 is losing coolant. I drove it about 3-4 miles with it full of fluid...parked it and came out to a puddle near the passenger side.

Drove it less than a mile home from there. When I started it in my driveway, it seems like the coolant level is going down in the radiator. I was going to try and get it up to operating temperature and see if I could locate the leak, but I'm afraid I could do more damage if it is a head issue. I don't want to make things worse.

Should I buy a pressure tester?


Should I empty coolant? From radiator and where else?

I don't see milky oil on the dipstick and I don't see oil in the coolant, but I was getting white smoke out of the tailpipe when I was going with my original plan to get it up to operating temperature. Shut it off after I noticed the white smoke.

Also....noticed some vapors coming up the radiator neck.....and there is no flow of coolant in the radiator...just stagnent coolant.

Sorry for the newb questions, but guess what?.....I'm a newb! Thanks for any insights.

[Beat68CST]

The side of the block will have little drain plugs you can unbolt.

Sometimes they're square head, allen head, brass, just be careful pullin em out. If the coolant seems a little too nasty for your liking, (seemed like mud when the plug broke off our vette that had been sitting for 10yrs and splashes out in your face) just keep runnin water through it until it clears up.

Are the hoses and pump good? Possibly the backing plate on the pump or the front seal?

[1stimer]

I dont know if the hoses and pump are good. I don't know where to start. Thanks for the reply.

[special-K]

It doesn't sound like a head problem.That would burn the coolant,not leak it.Where exactly is the puddle?The heater core/hoses are on that side.Do you see coolant laying in the intake manifold?Thermostat housings are notorious leakers.Also,the lower radiator hose at either the water pump or radiator.Dead center points to the pump.

[cdowns]

lots of time coolant leaks out the radiator overflow when people dont know how to properly fill these old trucks cooling systems

[Shyguy]

First fill the radiator to the proper level. I am not real sure what it is but I usually fill mine 1.5 to 2 inches from the top of the fill neck.

Check hoses, pump and freeze plugs when engine is up to temperature and pressure.

Is this a 350? The reason I ask is I have a 454 in one of my trucks and it kept losing a little anti-freeze. I found out a few days ago when the bypass hose at the water pump let go spraying down the engine. I was not far from home when it happened so I was able to get home ok with out any overheating problems.

Any time you have a question don't hesitate to ask, there are some real knowledgeable, helpful people on this forum. I have learned a lot from them.

[1stimer]

Thanks guys......it is either a 402 or a 454....not sure.

What if I fill up the radiator....start it up and the level is dropping with no signs of leaking? This is what I am afraid of.....should I use distilled water just for testing purposes?

I am doing this with the radiator cap off so I can see the level, correct?

[KEL]

Are you familiar with "Click and Clack" ?
over the weekend they said to NOT use distilled water.
just thought I would pass that along.

[ChevLoRay]

Borrow a cooling system pressure tester....pump it up to the proper point and then watch the needle on the guage. If it drops, you have a leak. I have been told that it can drop from one reference point to the one below it within one minute and that's acceptable. In my mind, it if drops, there's a leak. If it drops faster than the guideline above, the leak should be evident.

That's the first thing that I would do. What you do is up to you. It's hard to watch it run and have the fan blowing air past the engine and try to figure out where the leak is.

[Lee H]

Yes, fill it up, a few inched from the top, and start it with cap off watch it for a while. You may have to add more as the circulation fills all the voids sometimes causing bubbles to appear. As it warms up the level will stabilize. Be careful, as it heats up the water will expand and start to raise. Once it's stabilized you should see the water circulating. If it's full of bubbles it could be a head gasket. Put the cap on and after it gets up to temp shut it off and search for the leak. May have to have a flash light and small mirror to find it. More likely a hose or water pump than a head gasket problem. I would use antifreeze because it's easier to see when it leaks.

[rsavage]

As for filling the system, also make sure that the heat control is set to hot when you are filling coolant so that no air is trapped in the heater core. Let it run with the cap off (in the driveway, not moving) burping it by giving it a little gas periodically to speed up the water pump. Coolant level will rise and fall as the air is burped out, sometimes even overflowing the filler neck briefly. You will have to add coolant as the air is displaced.
As for finding a leak, the pressure tester is the best way. Good luck, keep us posted.

[1stimer]

I really appreciate it guys. I'm sure you guys get tired of answering basic questions so really.....thanks!

I was all set to buy a pressure tester at Harbor Freight, but I couldn't justify the expense....only $60 right now though. I thought Kragen or auto zone might rent them, but I decided to just fill it up with the heater on and the truck running. I revved it a few times during the process.

Symptoms:

1. I'm getting water out of my tailpipe as it idles and slight white.grey smoke.

2. I'm getting a little steam/gas/vapor from the radiator filler neck.

3. When I shut it off after ~10 minutes I get radiator fluid coming out of a hose under the right (passenger) side front, bottom of the engine bay. I can't tell where it originates.

I took a few pictures.

So.....find where the hose originates? What about the other symptoms?

[rsavage]

That looks like the radiator overflow hose to me. If so, that's where the coolant should be coming from when the cooling system is pushing coolant out due to air, over heating or too much coolant. What are you running temperature wise? Did you overheat the motor? If so, you could very easily have cooked the thermostat so that it no longer opens properly. If you overheated it, replace it.

[1stimer]

Thanks. The temperature gauge was VERY slow to rise, and didn't rise much at all. I don't know if it is functioning properly. I haven't driven the truck except to get it home when I bought it. It very well could have been overheated by PO, or even by myself on the drive home. It was low on coolant when I got it home. It was filled up to the brim at the mechanics....then the incident which I described above.

So....now what? Thermostat first?

[buttrock slp ss]

i agree with the thermostat idea..on a side note have you thought about a overflow bottle? if you have white smoke coming out it could be coolant which would lead me to belive a head gasket leak..you can have a small head gasket leak and not get any coolant in the oil if it burns up in the cylinder or cylinders first. i added this overflow to my truck to save my coolant from just draining on the ground.

[buttrock slp ss]

it looks like thats the "leak" tho and thats due to like stated b4 a air pocket or overheating

[crushermechanic]

mine kept burping out the overflow and i found out the cap spring was weak and wouldnt hold enough pressure. it is also normal to see some condensation come out the tail pipe. it is a by product of combustion.

[joes50pu]

water out the tailpipe and white smoke is a clear case of a blown head gasket.

[cdowns]

if you filled it to the brim like you stated you overfilled the cooling system and it is to be expected that the overflow dumps the excess on the ground// if you take a known good thermometer and take the temp of the coolant in the radiator i think you'll find everything is quite alright and all you really need is to learn the proper way to fill a cooling system on an old vehicle to prevent it from happening again

[mrein3]

Originally Posted by cdowns

if you filled it to the brim like you stated you overfilled the cooling system and it is to be expected that the overflow dumps the excess on the ground// if you take a known good thermometer and take the temp of the coolant in the radiator i think you'll find everything is quite alright and all you really need is to learn the proper way to fill a cooling system on an old vehicle to prevent it from happening again

I'm with cdowns on this one. There is nothing wrong with this truck.

I would carry a one gallong jug of 50-50 with me for a while just to be sure but I'm thinking your coolant loss is out the overflow tube. Monitor the situation by watching your temp gauge. If it stays in the normal range don't worry about it. Eventually your overflow tube will stop puking when you get the right amount of coolant in the system.

ALL vehicles have steam/water come out the tailpipe. No worries there either.

Drive this thing and forget about it.

[special-K]

Originally Posted by joes50pu

water out the tailpipe and white smoke is a clear case of a blown head gasket.

You should see bubbling in the radiator and eventually greyish tannish milky oil if it is the head gaskets as well.Just water out the pipe can be condensation,especially when the vehicle rarely sees full operating temp.

[1stimer]

OK......thanks again for all the advice.

I attempted to change the thermostat after work today. Broke both housing bolts off (told you I was a newb!).

Quick trip to harbor freight and bought a bolt extractor kit. It worked and I got both bolts out. Had already purchased a gasket and new thermostat during my lunchbreak.

Originally when removing the radiator to housing hose, I did see some milkshake sludge seep out from the housing....not a lot but it was definitely there.

After getting the bolts out....a quick trip to NAPA for more bolts. I forgot that one of the bolts was longer....so I couldn't even finish a thermostat replacement.

I have a kid with accompanying responsibilities otherwise I'd at least finish this job tonight.

Thanks again for the help......It has to be a head gasket with the sludge I saw tonight, right? --- Well----maybe I should try and stay positive.

[special-K]

The sludge would be the oil.It's due to the water/coolant mixing with the oil.I guess you could be getting oil in your coolant.That could be something other than head gasket,especially if oil isn't contaminated.It could be an intake leak.Do you see smoke from the tail pipe once it's warmed up?Just check your dipstick.Have you changed your oil lately?Now would be a good time.Check your plugs,too.Also,the PCV valve or oil fill cap will show oil sludge.

[1stimer]

OK.....got the new thermostat in just now. Filled with 50/50 as per instructions. Once it got up to operating temperature(midway on the gauge) it started to boil over....shut it off.....leaked out of the overflow tube....put cap on and drove around the block.....man this thing can move.....stopped (shut off engine) and checked for drips......nothing.....drove again for 1 mile....stopped (shut off engine).....tiny amount of drips from overflow tube. Once it cools down I will check for coolant loss.

I will keep an eye on the coolant level and temp gauge.....I guess my next concern is... is my temp gauge accurate. Is it normal for it to stay at the same temp after truck is shut off?

Also....the radiator is scalding hot top to bottom....the manual states that it should be warm on bottom and hot on the top.

[Lee H]

You'll need to measure the temp with an IR gun or some other device. Everyones feel is different, scalding to you may be warm to someone else. Don't trust the gage until you verify "normal" for your truck. Keep you eye on the level for several heat cycles. If it's continues to eat coolant further diagnostics will be necessary.