Elusive Coolant Leak
 

1999 1.8L w/ FMII Turbo Kit

I have a coolant leak that is driving me nuts. I know it is there because I can smell it. I can't find the damn thing though.

Degreased the driver side engine area and cleaned it up thinking it might be a water pump issue. Nope.

Found a thread on here from 2008 through a search mentioning the turbo coolant lines leaking. Nope, couldn't find anything there either.

Bought a coolant pressure tester kit from Harbor Freight. Nice kit btw! Got it up to 15psi and... nothing. Held firm there for 5 minutes with no loss before I took it off.

What am I missing? If it is a pinhole leak, how do you find them, dye?

Any advice would be greatly appreciated!

Look around the head gasket area. My friend had a similar issue where it held good under a pressure test but when he got into higher boost numbers it was stretching the head studs and causing a leak only in boost then would seal back up at a stop and pass a pressure test. That all stopped with arp hardware though

Personally, the best way to find it is with dye OR when your done playing for the night, when you park it in the garage, lay some paper towels, or cardboard under the engine. Then in the morning if there is even a pinhole leak, you'll have a drop or two and you can see where it landed. Then just see where it came from matching up with the leak spot on the cardboard and it will help greatly. I've done that a couple times with oil and coolant. Always works for me! But if you don't see anything on the cardboard at night, try keeping the cardboard under the car and let it idle for a little bit, and if that doesn't work, gives it some revs, sometimes with a pinhole leak it can handle certain pressures, but not others, so maybe it can handle cruising around but not when you start taking it to redline. Good Luck, let us know how it goes.

If the system holds pressure, then most probably your leak is from the radiator cap.

Is the smell apparent in the engine bay or in the cabin? I've borked up my heater hose before and got a coolant leak in the cabin down in the driver's side foot well.

That's what I was thinking too, but replaced it with a better cap and the smell still persists.

Not in the cabin at all. Just around the engine compartment. No heater too.

Son of a bitch. That might be it. I also noticed about an ounce of a clear liquid for the first time yesterday in my catch can. I thought it was gas because it smelled strong, but tried to light a little bit on fire on the ground and it wouldn't light making me think it might be water.

What exactly should I be looking for around the head gasket? There are no visible leaks.

It wont be drips but more of just a wet look on the outside of the block. My stock motor might be doing it now that im pushing a 14psi time bomb. Ill snap some pictures when i get home. It would be right where the head gasket is and is easily fixed by a new gasket and arp hardware. As far as the catch can thats not coolant it is mostly fuel/water vapor and possibly some oil blow by

Gotcha, thanks a ton!

Is the ARP stud swap as simple as removing the head, cleaning the mating surfaces, install new gasket and studs and retorque?

Kinda sorta. The absolute best way would be to pull motor and have the head and block decked then put the studs and gasket on. However you would most likely be just fine pulling head cleaning and re assembling. If i dont get the good motor together this winter the stock motor will be getting this same treatment and ill just get the mating surfaces super clean.

I have also decked motorcycle heads/cylinders with a piece of granite with super fine sand paper on the granite then you swirl it around the surface until it is all fresh. With a BP head that would be tricky but still doable.

Thanks man!!!

Anytime let me know if that works. If you post up some pictures too, i can look to see if i notice any signs of leaking.

Have you tried licking the engine? I hear coolant tastes sweet.

hope this helps

Occasionally you can see traces across the deck of the block or the face of the head or even on the head gasket itself if there's been a leak. But not always. Look for pitting or corrosion on that flat surface as well.

Thanks for all the help guys! I'm pretty sure it is the damn head gasket at this point. I have noticed weird dampness and rust in places there shouldn't be water as I never drive the car in the rain. The unused bolt holes on the block under the header always seem to be damp. Not sure what they are for, but pretty sure they don't leak water which means it has to be coming from somewhere.

Next question... Is it dangerous to be driving the car with a small head gasket leak? Is this a problem where I should stop driving immediately and fix it, or is it more of a get to it when i can thing? Oil looks fine and there is no noticeable coolant loss or oil in the coolant.

Pics

https://cimg1.ibsrv.net/gimg/www.mia...7bf7c61a7f.jpg
https://cimg2.ibsrv.net/gimg/www.mia...428f352702.jpg
https://cimg3.ibsrv.net/gimg/www.mia...e3c927d7d8.jpg

It shouldnt hurt to drive on it with a little leak like that i know a few that did for a while. You should still take care of it though. Sounds like you have another car to drive and since its winter i would just fix it now so its all good to go for summer

Yup! This is making me want to do an LFX swap even more...

I really like the lfx but hp wise you dont get all that much from where you are now 285whp 278tq then maybe 330whp with a cam and intake and stuff. The k swap can make massive hp since there is a billion aftermarket parts available. But this is all up to your goals and probably better discussion in your thread