2012 500 head gasket questions

[JKIDD]

I picked up a 500C, 124K miles, smoking heavily. Looking for advice from anyone who has replaced the head gasket on the Multiair motor. Are there other likely failure points besides the gasket? Am I better off pulling the motor or doing it in the car. Been 30 something years since I replaced one (several early 80's Civics, & early to mid 80's Toyota pickups). I know the principals are the same, but I read the Multiair unit can be difficult. No water in the oil or evidence of oil in the coolant tank. Came up to temp & didn't overheat. Motor starts fine. Will run fine, even though its smoking. Will rev good but will periodically bog down or stall. Worst case I'll throw in a junkyard motor.

 

[JKIDD]

Pulled the plugs & they seems oily. I'd expect at least 1 to be "steam cleaned". Plugs were loose. Cleaned the oil separator & PCV valve & changed the brittle oring (someone had siliconed the separator on..) Couldn't check the compression as I couldn't find the adapter for these threads. Right now its running & no excess smoke after it warmed up.

 

[kmead]

Pulled the plugs & they seems oily. I'd expect at least 1 to be "steam cleaned". Plugs were loose. Cleaned the oil separator & PCV valve & changed the brittle oring (someone had siliconed the separator on..) Couldn't check the compression as I couldn't find the adapter for these threads. Right now its running & no excess smoke after it warmed up.

They certainly are wet. Hard to tell if it is actually running rich or just dark from burning the oil off.

 

[JKIDD]

Well, it cycles thru barely any smoke (in the 30's so looked kinda normal) & billowing white. If I drive it it clears but will start to buck & skip within a mile & almost stall. The plan it to rip it apart & see what everything looks like. Gasket set is reasonable. Gonna check on the machine shop cost for the head. I suppose its possible the oil passages are breached as well as the coolant ones. Its not overheating, so thats a plus. Still interested in hearing from anyone who's done a Multiair head gasket before. I'm not a noob, but know this is a little different setup than the ones I've replaced in the past. Any tips would be appreciated.

 

[lookforjoe]

looked at prices of engines - when I did the one in my wife's 2012 , they were around 500 for a 35K mileage motor. Now, they seem to be in the 1500 or above range. I'd say it's worth trying to do a head gasket for sure...

 

[JKIDD]

looked at prices of engines - when I did the one in my wife's 2012 , they were around 500 for a 35K mileage motor. Now, they seem to be in the 1500 or above range. I'd say it's worth trying to do a head gasket for sure...

YIKES! I hadn't even looked at motor prices yet. I paid less that that for a running, driving 500! (although it had 150K on it) My concern is that this doesn't fit the standard symptoms of the head gasket failure. No over heating, no water in oil or vice versa, Plugs look oily, & the white smoke is intermittent. I'm going to keep my eyes open for a cheap runner on CL or FB. I wouldn't mind 1 in the same milage range since these motors seems pretty reliable.

 

[lookforjoe]

YIKES! I hadn't even looked at motor prices yet. I paid less that that for a running, driving 500! (although it had 150K on it) My concern is that this doesn't fit the standard symptoms of the head gasket failure. No over heating, no water in oil or vice versa, Plugs look oily, & the white smoke is intermittent. I'm going to keep my eyes open for a cheap runner on CL or FB. I wouldn't mind 1 in the same milage range since these motors seems pretty reliable.

Maybe. it's the breather system / vacuum pump not working properly? Never heard of an intermittent head gasket failure, for sure. The best way to test it is with a leak down tester. They are that expensive anymore, and it will definitely guide you as as where / if there is a HG or other failures, as long you have access to a compressor.

Also - are there are error codes that coincide with the erratic running?

 

[fastx19]

Don't forget the head side of things, Valve guides when cooled down shrink enough to allow oil by and pool in the intake/piston. This is a potential for explaining why it goes away after warm up. Not all head gasket failures result in water in the piston. I would plan on at least new valve guides, a lap job, surface, and gaskets. Again if you are comfortable doing this, it is still cheaper than a junk yard engine.

 

[JKIDD]

It's definitely burning coolant, just not constantly (at least not at idle). I drive it, it will start to buck & drive barely billowing smoke in a half mile. No codes or CEL. When I bought it, it started hard & tons of smoke. Rough running & struggled to get it on my tow dolly. When I got it home I ran it for 20ish minutes & the smoke decreased to what looked more like a cold day start. No overheating. I moved it for the snow we had & started right up. Blew smoke for less than a minute, & drove fine across the yard. I don't know how long it was sitting when I bought it, but it was still registered. Maybe a slow weep into 1 or more cylinders? Worse under the vacuum or higher RPMs or load? I'll have to look into a leakdown kit & maybe a scope.

 

[ng_randolph]

It's definitely burning coolant, just not constantly (at least not at idle). I drive it, it will start to buck & drive barely billowing smoke in a half mile. No codes or CEL. When I bought it, it started hard & tons of smoke. Rough running & struggled to get it on my tow dolly. When I got it home I ran it for 20ish minutes & the smoke decreased to what looked more like a cold day start. No overheating. I moved it for the snow we had & started right up. Blew smoke for less than a minute, & drove fine across the yard. I don't know how long it was sitting when I bought it, but it was still registered. Maybe a slow weep into 1 or more cylinders? Worse under the vacuum or higher RPMs or load? I'll have to look into a leakdown kit & maybe a scope.

Could coolant make its way into the intake somehow? Perhaps, like on the fuel injected Lampredi engines, there are coolant passages that are supposed to blocked by the intake manifold gasket. A leak here could give you lots of smoke, perhaps poor running, but no immediate cooling problems.

 

[JKIDD]

Could coolant make its way into the intake somehow? Perhaps, like on the fuel injected Lampredi engines, there are coolant passages that are supposed to blocked by the intake manifold gasket. A leak here could give you lots of smoke, perhaps poor running, but no immediate cooling problems.

Hmmmm. interesting idea. I'll have to look into it.

 

[JKIDD]

Now that its getting a little warmer & the snow is gone, I took another look at the 500C. Seems the intake has orings, so I don't thing any coolant can get in from there. Bought a coolant gas test kit. Car passed with no exhaust gasses in the coolant. Have a borescope coming tomorrow. I'll see whats showing in the cylinders. Maybe that will tell something. Just puzzling to me. No overheating, no engine light, starts & idles fine & will go down the road for about a mile before the smoke show starts. It will idle back out of it. The adventure continues...

 

[JKIDD]

So I did look into the cylinders back in March & didn't see anything unusual, so I parked this & walked away. Lately I've been thinking about just passing this on as is since I haven't found the time to even find a motor, never mind replace it or the head gasket. Having some ambition this AM (fresh off vaca) I decided to put it back together & list it on FB. The airbox was off & I noticed oil in the oil separator. I decided to clean it (forgot I had done it when I bought it). The PCV valve was sticking. Cleaned everything up & reinstalled. Something made me check the dipstick & (not sure why I didn't notice before) the oil was 3" farther up the dipstick then the full line. I checked for water, but never paid attention to the level...
Can it be that simple?
I drained the oil & there was about 7 quarts in it. According to the sticker on the window, it had been changed 700 miles ago. The defective oil separator oring leaked oil profusely judging by the oil all over that side of the motor. Maybe the PO overfilled when it got low? Anyways, refilled with oil & let it run. It still was smoking, but not as bad. Let it warm up & decided to take it around the hood. Previously, I could only make it half a mile before it would billow smoke & run rough. This time I was able to put 10 miles on it but it continued to blow (less) smoke, this time more blue. The more I drove the better it got. Its been running in the driveway for about 30 minutes now & nothing from the tailpipe. Took it around the block again didn't notice any smoke while driving & had little smoke when I stopped back in the driveway but it cleared quickly. There's black sludge at the tailpipe so I'm hoping I'm just burning all the excess oil out of the exhaust.
The 1 thing I couldn't get past was, besides excess smoke, I couldn't find any other evidence of gasket failure. No oil/water contamination, no leaks, no overheating, no exhaust gas in the coolant, Next step will be to get a 20 day temp plate & drive it like hell. First I will cross my fingers & say a prayer to the Fiat Gods...

 

[JKIDD]

Update. Got a 20 day plate & had the check engine light pop for the downstream O2 sensor. Got 1 on Amazon & light went out on its own. Car runs & drives great! Rotors are a little rusty. Got the parts for all 4 wheels from Rock Auto for just over 100 bucks. I'm into this for under a grand so far. May keep this & get rid of the 2000 Mustang convertable.