I currently am trying to diagnose if I have a blown head gasket. This morning my coolant started pouring everywhere all over the engine bay. I haven't found the leak yet but it caused me to check all of my fluids and I found a tiny bit of sludge on my oil cap. During this process I also drained the oil because of this, and it smelled slightly abnormal. It is a 98 civic EX with the 1.6l vtec d16y8 engine. If it blew it must have happened very recently as when I drained the oil and checked it, it was not milky in any way as of yet, only the slightly abnormal smell. The car is still running ok. The coolant leak remains undiagnosed but it stopped working when the heat also gave out when it worked just the day prior, so I'm assuming it may be the thermostat. I haven't let it overheat or even go above half on the temp gauge. The oil was still brown as well, I have only used conventional since I got it and changed twice in 500 miles as I wasn't sure of the last change to keep it cheap until I put in on full synthetic. Valve adjust was performed about 100 miles ago so I imagine any gasket issues would have been caught then. I'm not super experienced with stuff like this as it's the first time this has happened to any car I own.
Attached is 2 images, one of the oil cap and the other of the coolant reservoir. Please let me know if any other pictures or information I may have missed can be provided.
Get a head gasket tester at AutoZone and check for leaks. You need to have a cold engine, one that sat overnight is ideal, but after 3 or 4 hours, it's probably OK. Coolant is under pressure when the engine is at operating temperature and it can seriously burn/scald you. Increased pressure equals a higher boiling point. If the engine is still hot, once you remove the cap, fluid that was previously under pressure is now released and it instantaneously forms steam.
Take a few inches out of the radiator and start sucking air through the special fluid when it reaches operating temperature and the thermostat opens. If it changes from blue to yellow, you have a head gasket leak.
Another way is use a water pump checker. Once pumped up, it should maintain around 16 PSI for around 10 minutes. If it goes noticeably toward 0 PSI, you definitely have a leak.
