Where did it go?

[GotSmart]

I am having a vanishing coolant problem.  Never more than a couple ounces at a time.  

91 B250 318. 

I have all new hoses and gaskets (including head and intake) and radiator...  

No drips or trails anywhere.  I top the coolant off, and add some to the overflow.  several days later it is down 1/2 inch in the radiator. 

The oil is pristine, so it is not going there. 

I did a pressure test today, and it droped about 4 lbs in 3 minutes.  Tomorrow I will check the heater core, but to get access requires a 12 step process that involves pulling a lot of parts.   :dodgy:

The plugs are not showing any difference when pulled and checked.

 

[Gary68]

check the carpet below the heater core

radiator overflow bottle all hooked up and sealed? had a crack in mine and was doing the same thing

 

[MrNoodly]

Are you using OEM water or cheap aftermarket water?

 

[Txjaybird]

Something similar happened with the Ranger.  Never ran hot.  Coolant kept disappering from over flow tank.  Couldn't see a leak.  Finally after about 50mls stop and go in 2 countys when we came out of a cafe we could see a drip.  New radiator hose was seeping around the hose clamp.  I guess it wasn't stopped long enough after driving for the leak to stop dripping so we were able to locate the source.  It's a mystery sometimes.

Jewellann

 

[highdesertranger]

ha ha ha OEM water. as a note, except in an emergency you should only add distilled water to coolant. Got Smart let us know about the heater core when you check it. I remember you recently had the heads off, did you have them checked for cracks? highdesertranger

 

[GotSmart]

The heads magnafluxed out fine.  No cracks or warps... The old timer that ran the speed shop said they were the cleanest used heads he had seen in a while.

The overflow bottle is fine,  The heater core is in a plastic assembly outside the van.  In the engine compartment.  I am thinking tat it could be leaking into that and evaperating.  Tomorrow I will know.

 

[bullfrog]

Next time you pull the spark plugs see if any have shiny clean (no deposits) electrodes as opposed to the other plugs looking tan or brown and used. The smallest amount of water (antifreeze) will clean the inside of the combustion chamber if it gets in there while running. Smack the plug against your palm or paper towel and see if any liquid is present around the electrode as well.

 

[Raven+Squid]

Marmots!

 

[ccbreder]

Distilled water is more corrosive than most tap water. Be sure to use antifreeze-coolant in combination with water. I compared prices last time I needed coolant, and found Napa 50/50 mix to be slightly less that 100%, diluted-gallon to gallon.

 

[gapper2]

I've got a 2000 Sienna van that I purchased new in 99'.  270k miles.  I replaced timing belt, water pump, bearings, seals, hoses and clamps.  Mine showed no leaks for awhile but recently started the "mysterious coolant leak".  Since it seemed fine for awhile.  I am thinking that the original clamp tightness may be the culprit.  But with 270k and only used as a bkup ride,  so not too concerned. Good luck on your quest.

George

 

[SternWake]

Pretty sure you'd smell it if it were leaking from the heater core, unless perhaps you are/were a smoker.

I'd suspect it is a slow leak from the radiator that evaporates before hitting the ground.

Check the bottom of the radiator where the tubes meet the bottom tank, and also check your ATF level/condition. Perhaps it is getting into your ATF through the failed heat exchanger in the bottom tank.

 

[GotSmart]

I thought I was smelling coolant, but my sniffer is not as good as it once was.  New radiator and heat exchanger. 

It was about 20* this morning, and peaked at 35*.  I got most of the fasteners lose, so tomorrow I will pull it when it warms up.

 

[Bdog1]

Is the cap new also? It has the second rubber seal at the top, for a recovery system? If it has only one the coolant can escape to the bottle but won't return when the motor cools down.


Sent from my iPhone using Tapatalk

 

[GotSmart]

New everything.  I used a brand new pressure tester in place of the cap.  The drop was fairly quick.  I will know tomorrow afternoon.  

$31 for a new unit from RockAuto.  If that is what it needs.

 

[Mrcap]

Bypass heater core and repeat pressure test.

Cliff

 

[GotSmart]

That would be the smart way to do it.  

To "borrow" the tool took a $168 check, and more than 1/2 hour of paperwork.  I got the check back, but I would rather tear the heater out and see gor myself.  I have to replace the intermitant fan motor anyway.

 

[Gary68]

fill the rad,get the engine at running temps,shut it off and inspect/listen when hot,use a 4 foot piece of garden hose as a stethoscope

 

[Optimistic Paranoid]

fill the rad,get the engine at running temps,shut it off and inspect/listen when hot,use a 4 foot piece of garden hose as a stethoscope

Or you can actually get a real stethoscope.  The ones intended for nursing students aren't expensive at all.  And I suspect that for those of us that are "hearing challenged", they're gonna work a hell of a lot better than a piece of garden hose.

https://www.amazon.com/Omron-Spragu...d=1486261092&sr=1-1&keywords=stethoscope&th=1

 

[Mrcap]

Just saying, it's not difficult to isolate the heater core without removing anything by simply bypassing it. Originally you didn't sound so excited about tearing into it.

 

[steamjam1]

Luckily the Dodge B series heater cores aren't that hard to remove. Its right there under the hood. Just a swear word or two required while you maneuver the old one out, and the new one in. Dodge V8's and V'6's tend to weep coolant out the bypass hose, or out the recovery tank hose. I ran into a situation where my B150 would lose a bit of coolant, and the recovery tank hose had a slight leak to where it would allow fluid to pass to the tank, yet suck in air through the leak when the van was cooling down.