coolant low when cold but full when hot

[4runnerfiend]

Changed my coolant out recently and have tried to get the level right. Seems to be low when it is cold but full when hot.
I am also worried about a HG leak, but have never had any issues with loosing coolant or over heating in the 10 months I've owned the vehicle.

Couple things to note
There is almost always water coming out of the tailpipe in the morning.
SOMETIMES when I start it up it runs rough when cold.. but I've re done some vacuum hoses and that has seemed to work.

any insight is helpful. Thanks!

 

[4runnerfiend]

update I just started it up after not running since yesterday. Ran rough, blew white smoke for at least a minute, water started to drip out the tail pipe. coolant level was low. yesterday when I checked it hot it was full.. overflowing.

 

[turbo8]

Sounds like a headgasket or cracked head.

 

[phattyduck]

Water out the tailpipe is NORMAL! Burning hydrocarbons makes CO2 and H2O. When the motor/exhaust is hot, it stays suspended in the exhaust. When the exhaust is cold, it condenses and comes out the tail pipe as liquid. Unless it smells like coolant, you are fine there. (we have had unseasonably wet weather here in SoCal for the last few days, so more steam/water would be normal)

Coolant expands when hot. The level in the reservoir should change between cold and hot. As long as the levels are consistent when cold, that is also 100% normal.

-Charlie

 

[4runnerfiend]

Water out the tailpipe is NORMAL! Burning hydrocarbons makes CO2 and H2O. When the motor/exhaust is hot, it stays suspended in the exhaust. When the exhaust is cold, it condenses and comes out the tail pipe as liquid. Unless it smells like coolant, you are fine there. (we have had unseasonably wet weather here in SoCal for the last few days, so more steam/water would be normal)

Coolant expands when hot. The level in the reservoir should change between cold and hot. As long as the levels are consistent when cold, that is also 100% normal.

-Charlie

thanks.
To me the exhaust when cold, smells like gas... like it's running rich, which I think is normal.

 

[revox92]

Water out the tailpipe is NORMAL! Burning hydrocarbons makes CO2 and H2O. When the motor/exhaust is hot, it stays suspended in the exhaust. When the exhaust is cold, it condenses and comes out the tail pipe as liquid. Unless it smells like coolant, you are fine there. (we have had unseasonably wet weather here in SoCal for the last few days, so more steam/water would be normal)

Coolant expands when hot. The level in the reservoir should change between cold and hot. As long as the levels are consistent when cold, that is also 100% normal.

-Charlie

This is what I was told as well. Good to hear it is just normal.

 

[turbo8]

Running rough when cold isn't normal.

Check for bubbles in the radiator, when engine temp is cold.

When engine is cold, start engine, open hood, open radiator cap, and observe if there are constant bubbles coming up.

 

[thegipper]

Rough idle on cold start up definitely isn't normal but it isn't always a HG (leaking injector etc). If you want to rule out a bad HG, do a leak down test. You'll know for certain whether you have a bad HG or not.

 

[4runnerfiend]

Running rough when cold isn't normal.

Check for bubbles in the radiator, when engine temp is cold.

When engine is cold, start engine, open hood, open radiator cap, and observe if there are constant bubbles coming up.

Cold start this morning it was not running rough. I opened the radiator cap and it was pushing coolant out of the top. I did notice constant bubbles but the were extremely tiny.. AKA Tiny Bubbles.

I had topped off the coolant when cold last night and filled resi/marked so I could figure out if was actually loosing coolant.

I will have to do some research on a leak down test. I'm not sure how to do it or if I have to have a shop do it.

 

[thegipper]

You'll need an air compressor and a leak down tester. I bought my leak down tester off of amazon for 60ish bucks, works great. Tim/Sean have a video on their youtube channel showing how to do the test.

 

[JohnMc]

You can also rent a combustion gas tester for free from Autozone (and stores like that) - just buy the tester fluid. It will test for combustion byproducts in the cooling system.

https://www.autozone.com/loan-a-tools/loaner-block-tester/oem-engine-block-tester/391378_0_0

Let the bubbles go through the tester, if the fluid changes color, it's a bad HG.

When a HG gets bad enough, it's easy to tell. It's those marginal failures that can be harder to diagnose. Sometimes they only leak when it's hot. Or you have it floored. Or both.

 

[thegipper]

You can also rent a combustion gas tester for free from Autozone (and stores like that) - just buy the tester fluid. It will test for combustion byproducts in the cooling system.

https://www.autozone.com/loan-a-tools/loaner-block-tester/oem-engine-block-tester/391378_0_0

Let the bubbles go through the tester, if the fluid changes color, it's a bad HG.

When a HG gets bad enough, it's easy to tell. It's those marginal failures that can be harder to diagnose. Sometimes they only leak when it's hot. Or you have it floored. Or both.

I have to disagree with this. I bought one of those dye tests and the blue dye never even remotely changed color when I had a blown HG. I even made sure I didn't get a bad batch of dye by sucking air by the exhaust and it turned yellow instantly.

Once I did a leak down test and pressurized cylinder #3 (the cylinder I had a misfire on), bubbles came out of the radiator and I knew, 100%, I had a blown HG.

I wouldn't waste your time/money on the dye test. I'm sure they work if you have a really bad HG leak but at that point, it should be blatantly obvious you have a bad HG.

My 2 pennies..

 

[JohnMc]

To be honest, I've never had a situation where I used one to diagnose it. Usually, they're just so obvious that there's no reason to finesse a diagnosis. Just off with the head.

I just thought that this case, where it seems to be pushing coolant even at idle, might be a case where it would work.

Usually, the cloud of sweet smelling white fog is all you need to see.

 

[4runnerfiend]

To be honest, I've never had a situation where I used one to diagnose it. Usually, they're just so obvious that there's no reason to finesse a diagnosis. Just off with the head.

I just thought that this case, where it seems to be pushing coolant even at idle, might be a case where it would work.

Usually, the cloud of sweet smelling white fog is all you need to see.

So the fact that its pushing coolant out is an indicator? White smoke out of the exhaust is a new thing. yesterday it was as bad as I've ever seen it. today it did it but not so bad... and to me it smells like fuel not coolant. I did power wash my under carriage on Monday due to some mud pits. maybe I got a bunch of water in the exhaust.

I guess the take away is just for me to keep an eye on it.

 

[Quantumkiwi]

So the fact that its pushing coolant out is an indicator? White smoke out of the exhaust is a new thing. yesterday it was as bad as I've ever seen it. today it did it but not so bad... and to me it smells like fuel not coolant. I did power wash my under carriage on Monday due to some mud pits. maybe I got a bunch of water in the exhaust.

I guess the take away is just for me to keep an eye on it.

If the engine is warm/hot and its still putting out a lot of white smoke and its not too cold outside, then that's not normal. But white "smoke" (condensation) while warming up if cold/humid is rather normal.

 

[Ehahn84]

This was happening to my 4Runner and got worse and worse. Ended up being a trashed HG that was opening up when cooled down and seeping coolant into cylinders 3 and 5. Ended up throwing a new motor in.

 

[plcfcng]

I purchased a 97 with a bad head gasket the heads were still good sent them to the machine shop had them resurfaced and valves cut 350.00 at the machine shop, head gasket set bolts, water pump hoses ,timing belt. It's running great doing a full service going to be giving it to my brother and sister inlaw soon. Hoping it will treat them well. This part of the repair was about 1,000.00. I could have gone a JDM or other used engine but could have been back at the same place. I us higher end parts I get mine threw Rock Auto. There are a lot cheaper parts out there but would hate to have to redo work so I spent the money up front. op2:

 

[4runnerfiend]

update

took the rig into the shop and it failed the block test.
Ended up with 2 cracked heads.

Hope this helps someone diagnose in the future.
Seems like white smoke, running rough at start up is the tell tell sign

 

[19963.4lsr5]

Seems like white smoke, running rough at start up is the tell tell sign

That is how it was for me twice.


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[4runnerfiend]

That is how it was for me twice.


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ouch! twice. yeah I hope this is it for me. I went with the shops recommendation rebuilding the top end with brand new heads. trying to get it right the first time.