[floridascuba]

The other day I noticed my coolant tank was empty when I had a headlight go out. Didn't notice last week when installing an exhaust system. Not to say it had coolant or not. Though I assume I would've noticed. Checked oil. Level seemed normal. (I do testing every other oil change last one a few months ago) fuel economy power seems fine. Added a gal of coolant and marked it with tape. 300 miles later no drop in level. No wet spots on driveway. I replaced water pump last Nov. Any ideas where to check other then hoses? I did have a caliper lose a bolt and vibrate heavy last week as the caliper would dig into wheel upon braking. This was after a short heavy tow in addition.

 

[1985cucv]

Check your trans fluid level the heat exchanger could be leaking.

Also there is a coolant hose under the exhaust manifold thats prone to leaking

 

[floridascuba]

Transmission levels good and clean. Your talking about that 3-4" hose by the turbo correct? That's dry. Saw that was common along with black hose from radiator to tank. Also checked p-chock valve.

 

[1985cucv]

Possible air locked from the water pump change? I had a 12 valve do this i couldnt get the air out of the coolant system for a long time.
Are you in florida and do u ever run the heater? Or have a valve on your heater core by chance

 

[floridascuba]

I am in Florida. I don't recall last time I ran heater. I thought I purged the system correctly running the defrost on high when I installed pump. Though I have ran defrost a couple mornings when close to work due to condensation.

 

[MDSWA]

Look for signs of a pin hole leak around all your hoses and fittings. Sometimes these leaks only occur at higher temps and close up as the engine cools. There is usually some discoloration (gray or white spray pattern) on surrounding parts. Might need a flashlight to see. Check thermostat (O-ring) and water pump weep hole closely.

 

[1985cucv]

After i changed coolant i check everyday for about a week and add coolant to the radiator running the truck with the cap off. Never had an issue.

On another note Being in florida u should cut a valve into the heater core line on the back of the head shut it off in the hot months for ice ice cold air conditioning

 

[floridascuba]

Still haven't lost any further coolant under normal driving. Don't see any signs. Don't like that a gal of coolant is unaccounted for, but I ordered the vacuum pump from Blackstone to do a check to be safe. Normally send in during oil changes. Next check will be after a heavy tow.

 

[floridascuba]

Did heavy tow still no coolant loss or discovered leaks. Must have burped an air pocket. Possibly from defroster and/or driving up a 15% grade levee.

 

[24hrsparkey]

Did heavy tow still no coolant loss or discovered leaks. Must have burped an air pocket. Possibly from defroster and/or driving up a 15% grade levee.

There is a chance I'm wrong ,, and Im real glad your truck isn't missing anymore coolant

BUT there is no old fashioned coolant valve or heater valve modulation on these trucks at all . The AIR path is modulated , hot coolant flows full blast all the time thru heater core . Always .
So you running the defrost ( ac kicks on also ) or heater to burp the air is a moog point .