How much coolant?
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Joined: Jul 2014
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From: Everett, WA
How much coolant?
Yesterday I drove 2 miles away to get some things from the store, and on my way back my oil light came on. It went away so I figured it was a fluke, but I'd check it anyway. I pop the hood, check the oil, I'm a little low but still in the hash marks so I put a little more in, but I noticed that my drivers side wheel well was soaked.
It's a green fluid so I'm assuming it's coolant. It looks like it's coming from the reservoir bottle or maybe a crack in the hoses in that area, but I can't see anything leaking. I had my brother get the engine up to 3500-4k RPM to see if that would show me the leak, and I could see nothing. I could see the fluid level in the reservoir drop a lot though. As the truck cooled down (I checked back after dinner a couple hours later), the level rose a little bit. Before we revved it up, I put more coolant in, and I had it in the middle of the cold fill range (when it was cold of course), and when I checked it again last night it was right at the bottom of the cold fill line. When we revved it up to 4k and had the truck warm it was about an inch below the cold fill line. What should the level be when it's warm? Any tips on finding this leak? I currently have my airbox out of the way, I'll probably be taking more out today.
It's a green fluid so I'm assuming it's coolant. It looks like it's coming from the reservoir bottle or maybe a crack in the hoses in that area, but I can't see anything leaking. I had my brother get the engine up to 3500-4k RPM to see if that would show me the leak, and I could see nothing. I could see the fluid level in the reservoir drop a lot though. As the truck cooled down (I checked back after dinner a couple hours later), the level rose a little bit. Before we revved it up, I put more coolant in, and I had it in the middle of the cold fill range (when it was cold of course), and when I checked it again last night it was right at the bottom of the cold fill line. When we revved it up to 4k and had the truck warm it was about an inch below the cold fill line. What should the level be when it's warm? Any tips on finding this leak? I currently have my airbox out of the way, I'll probably be taking more out today.
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Well, the fluctuating level could be due to gas in the system.
The leak, could be out the relief on the radiator cap
Which can be consistent with head gasket leak into coolant system
Gas into system forces liquid out when running .
You develop 1200 psi during combustion, the coolant system only sees 16 psi max due to relief valve in cap. It is easy to have a slight leak that only goes one way.. into coolant..with no other serious symptoms..... yet. In fact, the whole idea of a 1 /4 " wide gasket flat face surfaces sealing this pressure is laughable really. Only works because duration is so short. If you put 1000 psi in a cyl and held it you would blow it out. So, very minor leakage all the time, can happen and be undetectable, and is a reason coolants can degrade.
Not saying thats it, but id start looking real close at it. Fill it to cold line, drive around a few miles and it will purge air and check again. When warm it is higher thsn cold line .
Pressure in system is another sign. If it vents a lot and gurgles when you take cap off warm tank, and level isnt low, ...youve got a head gasket leak. Normally you can take cap off with only small pffft. Gurgling means air trapped , the shear from the water pump impeller makes small bubbles that circulate, they dont disengage.
Do this, rev engine, tank level drops as you noticed. When you release throtttle, liquid comes back up into tank from bottom hose (circulation). If this is foamy....bad head gasket. It might only do it cold, it might only do it hot, but if the coolant is foamy when it flows into tank, its not a good sign.
The leak, could be out the relief on the radiator cap
Which can be consistent with head gasket leak into coolant system
Gas into system forces liquid out when running .
You develop 1200 psi during combustion, the coolant system only sees 16 psi max due to relief valve in cap. It is easy to have a slight leak that only goes one way.. into coolant..with no other serious symptoms..... yet. In fact, the whole idea of a 1 /4 " wide gasket flat face surfaces sealing this pressure is laughable really. Only works because duration is so short. If you put 1000 psi in a cyl and held it you would blow it out. So, very minor leakage all the time, can happen and be undetectable, and is a reason coolants can degrade.
Not saying thats it, but id start looking real close at it. Fill it to cold line, drive around a few miles and it will purge air and check again. When warm it is higher thsn cold line .
Pressure in system is another sign. If it vents a lot and gurgles when you take cap off warm tank, and level isnt low, ...youve got a head gasket leak. Normally you can take cap off with only small pffft. Gurgling means air trapped , the shear from the water pump impeller makes small bubbles that circulate, they dont disengage.
Do this, rev engine, tank level drops as you noticed. When you release throtttle, liquid comes back up into tank from bottom hose (circulation). If this is foamy....bad head gasket. It might only do it cold, it might only do it hot, but if the coolant is foamy when it flows into tank, its not a good sign.
Last edited by mbb; Nov 28, 2015 at 11:55 AM.
Thread Starter
5 Year Member
Joined: Jul 2014
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From: Everett, WA
I'll get a head gasket test, I had a cracked head gasket when I bought the truck but I couldn't afford to fix it so the mechanic put in some fixa fluid stuff. I noticed that if I take my oil cap off it was milky, but as the day got warmer it as normal and not milky. There was no milky substance on the dipstick though.
When the fluid came back into the tank it was not foamy or bubbly. Yesterday I decided that I can't tell where the leak was coming from because it was all over the wheel well and in that area. When it dried I took the truck out and stopped every .5 miles and no new fluid. I drove it the same 2 miles I did when I first found the problem, and no new fluid. I still don't want to drive it any serious distance. Maybe today I'll drive a little bit more and see if any new fluid comes.
When the fluid came back into the tank it was not foamy or bubbly. Yesterday I decided that I can't tell where the leak was coming from because it was all over the wheel well and in that area. When it dried I took the truck out and stopped every .5 miles and no new fluid. I drove it the same 2 miles I did when I first found the problem, and no new fluid. I still don't want to drive it any serious distance. Maybe today I'll drive a little bit more and see if any new fluid comes.
Thread Starter
5 Year Member
Joined: Jul 2014
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From: Everett, WA
I just drove it about 15 miles, no coolant leak. I have a cold fill range, I filled it to the top line, and when I got back home and turned the truck off, it was still at that line. I took the cap off, it took about 5 seconds for it to de-pressurize (untwisting the cap a little bit at a time), and of course the coolant was at the top of the reservoir. I squeezed the big hose on the passenger side of the truck to get some of the coolant out of there so I could tell where the normal level is, and it was again at the top of the cold fill range. When I took the cap off, it did bubble, but no foam.