Coolant disappearing act I

[Bryan Hoytema]

So cars heat gauge started fluctuating between running temp and halfway to the danger zone , so first thought was a faulty thermostat, replaced 2 months ago , but that wasn't the case. I popped my coolant fill cap and what do ya know it had lost some coolant and what ever was left was sloshing around in there hitting the temp sensor so I guess that is what could have been making the guage go nuts. Anyway, I have a slow leak somewhere . ... Nothing noticeable from exhaust , oil looks fine, and no leaks that I can see.
What are your thoughts ? Head gasket ? Or turbo ? Any way to test it ?.
Thanks

[Travis Koch]

pressure tester and/or UV die.

or stand around with a beer and watch and listen.

[KevinBuckham]

Just borrowed a pressure tester last night and found a good sized leak myself on the lines heading to my throttle body.  I was running distilled water w/ water wetter so I didn't have any obvious coolant lying around after the car was cool enough to hunt around in. 

With the pressure tester we could easily hear and then eventually see the active dripping.

A few things to check:
- replace you rad cap - just do it, it's cheap
- check to see if your water pump is weeping coolant (suggests a bad water pump)
- borrow / rent / buy a cooling system pressure tester and make sure your cooling system holds at least your rad cap pressure rating
- when the car is cool, take off the rad cap, and put in a funnel that fits tightly to where the rad cap goes.  Start the car and watch the coolant level rise.  Burp out air if there is any.  If air is continuously showing up, it suggests a bad head gasket.  Don't overheat the car with the cap off, this is just to test for air pockets or air production while the water pump is moving coolant.

[Bryan Hoytema]

I had the water pump replaced last year, new rad cap installed, ill have to do a pressure test, I hope it's not a head gasket lol, if it is time for some arp head studs, not sure if a MLS head gasket would be best to replace the old one with..

[Eddie ly]

With MLS hg, you'll need to smooth out the mateing surfaces. I tried just replacing without, and it pushes coolant after a few 30psi pull. I went back to composite with my rebuilt, so I don't have to go to the machine shop every time the head comes a part. Also composite hg's cheaper

[Brett Haviland]

Yeah, unless ur doing a engine build and pulling/dissaembling the block, mls gasket is not a good idea. The block as well as the head need to be perfect, which only can happen after a good resurfacing.


Anyways, as far as finding where the coolant is going I have a few good tests I can perform. First is to obviously pressure test the system... and then if no leaks show up checking the headgasket would be next. is it pushing coolant out the overflow tank after a hard rip? If so suspect headgasket. I have a gas analyzer at work, and with that I can test your cooling system for excessive hydrocarbons (exhaust gasses) and be 100% sure if the head gasket is leaking or not.

[Bryan Hoytema]

Update on the scenario doing an oil change on the weekend, noticed that I have coolant leaking on my oil cooler, dripping downward from the alternator area. Made me think about when I replaced my alternator, I may have did damage to the pipe that crosses under the exhaust manifold, if I can remember correctly that pipe is just a press fit on the one side right?   

[Brett Haviland]

There is some coolant hoses in that area. The onei would suspect comes from the oil cooler and goes up towards the water pipe. In a tricky spot to get at, if u take the oil filter off tho, it's fairly easy to access then I think.