Jonmueller1

Hopefully I can field some suggestions of a remedy. Recently I installed a new radiator, thermostat and hoses on my 330 engine.
Last weekend took a 90 mile trip.
Last nite, went out and red light faintly came on, noticed coolant was down by at least 1.5 gallons so I added water to get home.
What else could cause this? Water pump not working at capacity?
Somehow the coolant came out during the highway trip and it was gradual so I didn't notice it anywhere on ground or in my garage.
Should I replace water pump and expect that would solve the issue?
I turned heater on to alleviate situation and air was hot, so coolant seems to be circulating through the heater core okay.
I am very appreciative of all the members on this site. Thank you, Jon M

Koda

Make sure you are actually losing coolant. Look in the radiator each time before you drive it when it's cold to get an idea. Do you have an overflow bottle?

Also, running it in place and watching everything is a good idea. A hot engine will boil off the coolant spilled on it, if you have a leaky hose connection or mis-set thermostat.

I would look at all connections before blaming the waterpump, it's usually awful when it doesn't work, and before that it just seeps some, not 2 gallons worth.

ent72olds

Did you bleed the system after doing the work? Sounds like air pockets....

oldcutlass

When you installed the new items did you make sure all the air pockets were flushed out? Since you have no evidence of a leak, you may want to perform a pressure test on your cooling system.

joe_padavano

First, these older radiators should not be filled to the top. The coolant level should be down about an inch or so from the filler neck. Second, is the radiator cap a new 15 psi cap? Third, have you checked all hose clamps for tightness? Fourth, is the water pump new or old? If old, check for leaks from the weep hole on the underside of the shout. Failing all that, run a leakdown test on the engine to check for a head gasket problem.

Jonmueller1

I put on a new radiator cap because the old one had a bad seal and was old, filled up with water and hoped for the best. Let the car run for several minutes and then noticed water leaking finally out of the bottom of the water pump. Removed old water pump and waiting for one from the local NAPA store and will put in one evening next week. Any suggestions or things to look out for in the installation, torques etc, use gasket glue or not? Thank you all for your input. JM

Octania

Yes...
keep your old pump 1) to compare features and sizes to the replacement. The chance of getting the same thing the 1st time are slim... 2) factory castings are worth more than the core funds you will get at the store.

Then main things to compare are the length- distance from gasket surface to pulley mounting flange- can vary by 1/2" or 1".... and the diameter of the inlet nipple where the radiator hoes goes- they are 1-3/4 or 2", so get the right one to match your car's hose.

Use sealer such as Permatex Aviation 3H or Form-a-gasket #2. NOT SILICONE.

Torque 5/16 bolts to spec- about 15-20 ft lbs, and the 1/4" bolts much less torque- you do not want to strip these. I forget the exact figure, but "finger tight" is about right. None of the bolts NEEEEEDS sealer, but the bottom two small ones do go into the engine, so a tiny bit of form-a-gasket #2 on the tip 1/2" or so would not hurt.

A thin coat of silicone grease as used on spark plug boots on the hose nipples will ease later removal.

stan 65 cutlass

make sure your new pump is exactly the same, there are three different length snouts, meaning pulleys wont line up, woops, octania beat me, much better description too

Jonmueller1

TO: Koda;Ent72olds;Old Cutlass;Joe Padavano;Octonia;Stan65 Cutlass

Thank you all for your replies to my post. I just finished installing a water pump from NAPA and it was the same size as the old pump in all respects and I let the car get up to normal temp and so far no leaks.
I appreciate all the replies because it helped me to think my way through this and complete the repair with minimal cost by doing it myself. I am going to keep the old core as it appears this leak may have been simply a gasket issue because I couldn't detect the shaft being loose, nor was there a seep hole in the pump I took off.
I think this website is really great because the sharing of information allows us to keep these cars running without spending money on labor at today's rates, hence being able to enjoy the ride and going to shows. Thank you all and have a good week. JM

rustyroger

And thank you JM for letting us know how you got on.

Too many threads leave us hanging in the air wondering if our ideas were right or wrong, if our guesses were wrong it might help us one day if we have similar problems.

Roger.

Jonmueller1

Joe Padavo mentioned a "leakdown test" on the engine. Could you be more specific as to how that is done. Thanks, JM

Boiler_81

It's pretty straight forward, you pressurize the system by pumping air into it and look for leaks. If the pressure holds without leaking down, you are good to go.

MDchanic

I believe that Joe was talking about a cylinder leakdown test.

You use a leakdown tester to pressurize a cylinder at TDC, with the valves closed, and measure the amount of leakage. You listen and feel at the intake, the exhaust, in the crankcase, and in the water filler to see whether valves or head gasket are leaking.

Of course, the question of whether the cooling system will hold pressure, as in the above video, is fundamental as well.

- Eric

Boiler_81

That's what I get for not reading the post, assuming will get you in trouble every time!