Coolant: Rad is full, reservoir empty. Wut?

[zazzomicron]

Hey all,

So this has happened a couple of times. When I bought the truck 5 months ago the res was empty but the rad was full. Topped it up during an inspection and last week I rechecked it and the same thing happened: res is empty, rad full!

I've replaced the generic rad cap with a Toyota Genuine to see if that was the problem but was wondering if everyone else has experienced this.

Note:

- rad was pressured tested and past
- no strange exhaust smells

:crutch:

 

[Kotrin]

Hows the temperature during operation? Have you looked at the reservior to make sure it's got no weird cracks/leaks?

I've seen it do some weird vacuum stuff before in my old 97 4Runner. Just took me some cycling to fix it.

 

[jgue467]

It's going somewhere.

I'd check motor oil level and condition, exhaust for excessive white smoke and verify age of radiator (no brown tanks or hairlines - for the pink shake thing) to consider replacing it. Luck. :cowboy:

 

[mtbtim]

I think it's time for a compression test followed by a leak down test for any cylinders that are showing low. If you're not noticing coolant leaking down and pooling under your rig, your engine is eating it.

 

[gamefreakgc]

Check under your timing belt cover (the bottom front of the engine). The water pump will start to weep before it fails, it's a common leak point. A pressure test will not reveal it.

 

[calimobber]

Did you check the obvious? is there a crack in the res and its slowly leaking out? my Silverado had that and it would slowly leak back out if you filled it. Seems unlikely the engine is eating it if rad is always full. it would slowly go down after it emptied the res.

 

[HiLife]

Was the cooling system drained recently?
If not, the system is leaking it somewhere or eating it.

 

[Tyler James Inc]

Seems unlikely the engine is eating it if rad is always full. it would slowly go down after it emptied the res.

I'm with calimobber.
Fill the res to the "Full" level again, and periodically check under the hood after driving. See if there are any signs of leaking from the bottle- or anywhere else, for that matter.

 

[infamousRNR]

what about the fact that if the radiator was filled, but the heater was never turned on wouldn't that take up some of the coolant?.. [MENTION=116470]Tyler James Inc[/MENTION] [MENTION=68424]calimobber[/MENTION] ???

did you fill up the overflow reservoir as well?

 

[tarsun]

i thought that tank was just an overflow and that it would never pull from there... i could be wrong though.

if rad is still full, leave the tank empty and drive the car. if its really pulling from the tank, then the level in the rad should go down.

i put $ on it being a small leak in the tank though.

tank leaks are easy to diagnose too. i put a heaping tablespoon of cinnamon in the tank that i am testing and wait a few days. i then go around to every wetspot on the driveway and smell it. if it smells like cinnamon, then i know the tank is leaking.... but again, thats just me.

 

[Tyler James Inc]

what about the fact that if the radiator was filled, but the heater was never turned on wouldn't that take up some of the coolant?.. [MENTION=116470]Tyler James Inc[/MENTION] [MENTION=68424]calimobber[/MENTION] ???

did you fill up the overflow reservoir as well?

Ummmmm, I suppose it's- theoretically- possible; actually[/I possible? Not quite. The temp control would have to have literally NEVER been turned/slid off 100% cold. Like, not even on initial start up at the factory. Or not since the core was replaced.

The overflow res is what he's actually talking about; he's filled it twice.

i thought that tank was just an overflow and that it would never pull from there... i could be wrong though.

Actually, there is a full line on the res, and it should be at that line when cold. As the engine gets hot(expands; builds pressure), it will dump coolant into the res. When it cools down, it will pull from the res- that's why your res has a straw. If it was just a puke tank, it would have no need for the straw [emoji1360]

 

[mtbtim]

Actually, there is a full line on the res, and it should be at that line when cold. As the engine gets hot(expands; builds pressure), it will dump coolant into the res. When it cools down, it will pull from the res- that's why your res has a straw. If it was just a puke tank, it would have no need for the straw [emoji1360]

This is interesting. I always topped off my reservoir coolant level to the full line at operating temperature and when it cools down it drops somewhere a little above the low level. This made sense to me because when the engine gets to operating temperature and spills coolant into the reservoir, that reservoir level will now be pretty close to the top.

 

[alumarine]

This is interesting. I always topped off my reservoir coolant level to the full line at operating temperature and when it cools down it drops somewhere a little above the low level. This made sense to me because when the engine gets to operating temperature and spills coolant into the reservoir, that reservoir level will now be pretty close to the top.

I always did the same although I just checked my owners manual and this is what it said. I think either way works.
I know I've had other vehicles where the upper line said Hot and the lower line said Cold. Not F and L.

"Checking the engine coolant
level
Look at the see- through coolant reservoir
when the engine is cold. The coolant
level is satisfactory if it is between
the “F” and “L” lines on the reservoir.
If the level is low, add ethylene- glycol
type coolant for a proper corrosion
protection of aluminum components.
The coolant level in the reservoir will vary
with engine temperature. However, if the
level is on or below the “L” line, add
coolant. Bring the level up to the “F” line."

 

[Jason B]

I always did the same although I just checked my owners manual and this is what it said. I think either way works.
I know I've had other vehicles where the upper line said Hot and the lower line said Cold. Not F and L.

"Checking the engine coolant
level
Look at the see- through coolant reservoir
when the engine is cold. The coolant
level is satisfactory if it is between
the “F” and “L” lines on the reservoir.
If the level is low, add ethylene- glycol
type coolant for a proper corrosion
protection of aluminum components.
The coolant level in the reservoir will vary
with engine temperature. However, if the
level is on or below the “L” line, add
coolant. Bring the level up to the “F” line."

Good quote from the manual. I keep mine half full when cold in the reservoir.

 

[TheDurk]

Hey all,

So this has happened a couple of times. When I bought the truck 5 months ago the res was empty but the rad was full. Topped it up during an inspection and last week I rechecked it and the same thing happened: res is empty, rad full!

I've replaced the generic rad cap with a Toyota Genuine to see if that was the problem but was wondering if everyone else has experienced this.

Note:

- rad was pressured tested and past
- no strange exhaust smells

:crutch:

No one has suggested one--verify the hose to the reservoir. A pressure test won't catch a leak here. I had a BMW with a split reservoir hose and it was really hard to figure out. No coolant on the ground (it will lose coolant only when driving as it gets to operating temp), passed the pressure test, nothing going through the engine. Drove me nuts until I opened the hood on a hot, running engine and saw the leak. Check for a blockage as well as a leak. A blockage will leak out from under the cap while driving. You'd probably never notice.

 

[STI_MECE]

if you have coolant leaving the system you could simply pull the throttle linkage cable back alittle bit to rev up the engine.

If there is a leak, you will have tiny tiny air bubbles rise up the surface, but that is only if you have an AIR leak. but you might be have both air entering the system, and coolant leaving the system at the same time.

Your coolant levels can do a bunch of odd things depending on where its leaking and how it begun to leak.

 

[brillo_76]

Also if equipped with rear heater, make sure that heater core or heater lines are not leaking. Pre 01 lines are steel instead of stainless steel and will rot out and start leaking.

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