Suggests sign of internal leak. Check dipstick for engine oil to see if there is a sign of coolant mixed with engine oil. (Generally foaming of oil instead of amber or dark solid color) (Could even show level is high due to coolant adding to oil and raising level.)
If there is, it's a very serious problem.
One quick way to try a very inexpensive fix that's worked for me is a product called Barr's Leak. (It's worked twice for me on two cars.) Get the expensive "copper" version (looks like liquid copper) and add to your coolant system following manufacturer's instructions. Top off coolant and then drive car for a couple of full engine temperature sessions.
If coolant then no longer goes down, change engine oil draining out old coolant that may have contaminated it and refill with new filter.
Keep an eye on level after that to see if coolant level remains stable.
If coolant still goes down, a engine over haul or new engine may be needed.
I once had a Jeep with similar problems. I opened the hood in the garage and noticed electrical sparks traveling from the spark plugs to the distributer cap. I replaced the spark plug wires and distributer cap. Everything works well! RICK D
not only that no symptoms stated, just easter egg guess$ing. i guess you want to fix a modern engine with no scan tools?
why ? why go broke guessing?
the J18 engine is easy to diagnose, DOHC, chain cam and all.
forget the DVOM,,
the CMP cam sensor, do not touch it until you match mark its side to base mount or lose, spark timing... ( takes a suzuki tool to cure that, of you loosen it and turn it willly-nillly)
first we scan it, cranking if it dont start.
then if not starting we,..
spark101. COPs" coil over plugs, (4 spark coils)
the engine has 4 COPs
we remove one, and insert a test spark plug in the cop end
then ground the shell of the spark plug, to the engine metal.
then crank engine, see that fat bright blue /white spark.
bingo good spark. (a fully charged battery works best)
then do the other 3, ok, spark tested, 4 times.
Guess 1: (examples help)
lets say #1 spark coil is dead, only
well replace it.?
or swap #2 and 1 , does the failure follow your move?
now 2 is dead, 1 is good, so #2 cop is dead
no, #1 is still dead, bad ecu, or wires to it. from this cop..
lets say all #4 cops are dead.
well its not 4 bad cop's.
end spark testing on the J18
we then must scan the pCM.,
all J18s, j20 on up all report bad ckp /cmp sensors
even 1 pulse in 10 are reported with live DTC or in the pending section of the scan tool. (the FSM book on car tells you this fact)
there are no other way, unless you have a scope like me.
the CMP (cam) sensor has 2 single line, both fast pulses no cheap meter can view)
if spark is good?
try test fuel. yet? run for 3seconds does it.
are spark tips dry or wet with fuel.?? (no starts))
sad you didnt post the symptoms, makes answering 10x harder.
if engine misfires, and runs
that takes a scan tool.
costing from $10 to $150
i use a Innova 3160 tool, for best experience used.
its do no starts
1: battery at 12..6vdc rested or more.
2: check fuses?
3: key on the cluster CEL lamp must glow, or fuses are blown and ecu will be dead, with a dead CEL lamp.
4: ok , i crank engine and it cranks fast.but will not start.
5: so, i try, instant start, spray test fuel, CRC starter, with top end oiling brand is my fav.
6: ok it runs for 3 seconds, engine sounds good, wow., engine and spark are good, all in 5min work
and is fueling issues, too much or too little
if you get here, ask , we can do fueling, but is lots of steps
and you need a fuel pressure gauge.
in all cases SCAN THE PCM first. best is to scan while its failing.