what's a blown MLS Head Gasket like?

[eljefino]

2005 neon 2.0 160k abruptly started using coolant. About a radiator full in 100 miles. No visible leaks, no smoke. Lost power lugging up a hill (oops) but got it back. Random misfire code for cold misfire, but clears out after 15 seconds. (And it will do a few starts "fine" and clear all the emissions monitors.) Tore down to head gasket. Gasket "looks fine". I've had some bad gaskets in the past but not made of multi layer steel.

In the teardown the water pump is (still) fine where you can see it inside the timing cover, and the old head bolts were all uniformly tight.

Can I dissect the old gasket and hope to find something? Did I misdiagnose? I had been under the impression that if you looked at a Neon wrong it would proudly blow said gasket but that it was the older neons, and this was fixed with the MLS gasket.

 

[53' Stude]

Are you by chance getting any steam or sweet smell out of the exhaust? Any bubbling in the overflow container?

 

[dishdude]

I believe '97 was when they started using the updated gaskets and that pretty much solved the head gasket problem. To lose that much coolant in 100 miles and have no visible signs of loss is really odd.

What do the tops of the pistons look like? I'd think if it was going into the combustion chamber one of them would be spotless.

I had a '95 that I think the gasket started to go out around 120k, on rare occasion it would peg the temp gauge but there were no other signs of failure and it never overheated so I ignored it. At 140k the bearing on the timing belt tensioner froze and I had to rip it all apart, but I couldn't find any issues with the gasket.

 

[PandaBear]

Originally Posted By: eljefino
2005 neon 2.0 160k abruptly started using coolant. About a radiator full in 100 miles. No visible leaks, no smoke. Lost power lugging up a hill (oops) but got it back. Random misfire code for cold misfire, but clears out after 15 seconds. (And it will do a few starts "fine" and clear all the emissions monitors.) Tore down to head gasket. Gasket "looks fine". I've had some bad gaskets in the past but not made of multi layer steel.

In the teardown the water pump is (still) fine where you can see it inside the timing cover, and the old head bolts were all uniformly tight.

Can I dissect the old gasket and hope to find something? Did I misdiagnose? I had been under the impression that if you looked at a Neon wrong it would proudly blow said gasket but that it was the older neons, and this was fixed with the MLS gasket.


You got to be able to find something if you lost 1 radiator full of coolant within 100 miles.

When my gasket went, it would have misfire upon startup if the previous drive was long (regardless of what the startup temperature is), as the pressurized coolant went back into the cylinder. It didn't throw any code, and the temperature never goes above normal range until the very last time before I tow it in to rebuild. The coolant lost was minimal as well.

The mechanic told me that it is between 2 cylinder based on the missing sealant / polymer around certain part of the gasket. It is very hard to see as a lot of it is from gasket removal regardless of leak or not.

Most of the time gasket leak because the head warp.

 

[eljefino]

Originally Posted By: car51
Are you by chance getting any steam or sweet smell out of the exhaust? Any bubbling in the overflow container?


Nah it doesn't smell bad. I boiled the coolant in a near overheat, I could hear that. The overflow is on the firewall tucked under the cowl so you can't see straight in to examine for bubbles. The hoses were nice and firm.

In the beginning stages of diagnosis (eg two weeks ago) I put a new thermostat in, with a tiny hole drilled in the flange. I picked this trick up with a 2.5 powered dodge dakota that did indeed bubble the coolant from a going-but-not-gone gasket. If you trap exhaust gas behind the thermostat it never opens, which overheats, and stresses an already weak/failing gasket.

But then I drove the next state over and lost enough coolant my temp rose. It's computer deadened so it needs to go over 220-230 to be noticed, but I shut 'er down before it hit the red/ "dinging" zone.

 

[JHZR2]

The head gasket in my parents' 97 breeze 2.0 was the only thing that went wrong with the car. It was early on and Chrysler covered at least a good chunk as I recall.

I remember with that one it just dumped oil to the ground. But it also sometimes made real funny noises from the expansion bottle when the engine cooled.

 

[Warstud]

At that rate I can't believe it's not leaving a trail of white smoke behind. My guess is you have an external leak some where. Did you pressure test it? Maybe your heater core?

 

[Kuato]

How do your oil and oil level look?

 

[HerrStig]

An exhaust gas analyzer probe held over the radiator fill port will detect exhaust gas getting into the coolant, but it's too late for that.

 

[eljefino]

I'd smell it inside if it was my heater core. It's mostly back together already.

This engine is remarkably dry underneath; it impressed me when I pre-purchase inspected it, and was used to saturn s-series. Saturns set the bar for greasy, ugly, drippy engine tech.