mysterious coolant leak

[zakkb787]

When I bought my truck I was told it had just had the coolant system flushed. I noticed that it had spewed some coolant out of the overflow but was just told the system needed bled and it would be fine. Well I bled the system and turns out coolant is going somewhere and fast. I haven't noticed coolant in the oil or oil in the coolant. I can't see any physical leaks. I can fill up the system and after about 100 miles the low coolant light comes on. Whenvi crank it and I leave the cap off after I fill it up it starts coming back up at me. There's a tiny puff of white smoke at start up and that's it. The upper hose is not hard. At all. As long as I keep it topped off it stays cool. I was told the injectors were replaced before I got it and there's no lack of power so I am absolutely confused about this. What could this be?

 

[darkone98]

If it isn't dripping out of the tailpipe, or making oil, it is most likely head gaskets. Get a combustion leak tester for the radiator and give that a shot.

 

[ThebigGids]

If injectors were done it is possible a cup is not properly sealed and coolants leaking by it

 

[zakkb787]

How can I go about pinpointing where it is going?

 

[darkone98]

If it is low on coolant every 100 miles, it should be fairly obvious. If it isn't exiting the tailpipe due to a bad EGR cooler or gaining coolant in the oil, It has to be pouring on the ground or being pushed out of the overflow.

 

[onebaddmaxxx]

Easy

Pull the thermostats out, fill the coolant bridge back up with water, take a piece of cardboard and put in front to back to separate the two heads. Start the truck keep adding water in coolant bridge until it evens off then watch for bubbles coming from either side. There should be NO bubbles period. The bubbles you are seeing are from the combustion chamber entering cooling system.

Now that will tell you which head then it's up to you for teardown to determine a cup or HG

 

[zakkb787]

Okay so I know this is a really really old thread. But I figured I'd update everyone after 2 years of throwing parts and money at it. Turns it I believe it was an injector cup leaking. Well. Probably 8 due to a sloppy injector job. Ended up with a LOT of extra work and money into it so it all ended up good I guess. No more leaks and a lot more power:woott: just a tip for everyone new or wondering if they should do injectors themselves. It's not a bad job. But does take a while. Save yourself some headache and get injectors from a REPUTABLE dealer. And don't skimp on extras or try to take the easy road. ALWAYS pull your cups and reseal them with only the red picture that's recommended. And ALWAYS get new or have your lines cleaned in the process. Just my .02

 

[scroberson1957]

I fought these same symptoms. Changed thermostats, engine oil cooler. Finally gave in and pulled the heads. Very small leak on #5 cylinder. It was pressurizing my coolant tank. No visible contamination of coolant or oil. 2008 LMM, 230k. Saw a little carbon build up around the EGR cooler.

 

[Awenta]

There's better things than red loctite to seal with.

You could also pressurize the coolant and pull all the glow plugs then turn the motor and see where it spits out of.


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[zakkb787]

I'm just glad I got this figured out finally lol

 

[Bjoh24]

I'm currently going through the same problem

 

[zakkb787]

I'm currently going through the same problem

If it sounds like what I went through. Most likely it's a leaky cup.