Warped cylinder head or blown head gasket??

How can you tell the difference between a warped cylinder head and a blown head gasket? Without tearing it down?

2012 JKU, 120k miles. All stock. Good maintenance and vehicle history.

Runs fine. No rough idle. Overheats two or three needles width on long hills. Otherwise no overheating around town on relatively flat or short hills. Cab smells of strong coolant oder. Some coolant loss. No coolant in oil. Misfire codes. Also needs new oil pump, 02 sensor and 02 lead. And probably needs new rocker/lifters.

Trying to decide between repair and engine replacement. And its coming down to whether or not the heads are warped.

2012's were known for head warp. The manufacturer warranty was extended for this issue. But this vehicle is out of manufacturers 10yr warranty.

I assume the only real way to tell if the heads are warped is to tear it down. Which I also assume is at least a grand, right? Which would tip the scales towards engine replacement.

If the heads are not warped. When replacing a head gasket do you have to remove the oil pump or rocker/lifters? Trying to determine how much it would cost in labor to have those replaced while replacing a head gasket.

BLACKJKU said:

A warped cyl head will make a head gasket blow, the only way to know if a head is warped is to check it with a straight edge and feeler gauges. Or take it to a Machine shop and they can check it for you.

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When you say "blow" do you mean fluids immediatley start blowing out from the pressure? Or it can be a small leak? My Jeep only loses very small amounts of coolant. And the cab stinks of it. No matter if ac or fan is off or on.

Snowbird Tom said:

If you have coolant odor in the cabin area, odds are the heater core is leaking. Additionally, you may have damp carpet on the front passenger side. A system pressure check will show if a leak is present by not being able to hold pressure for any length of time. A coolant system pressure tester will help you visually track down the leak. Autozone and others will loan one with a credit card on file.

Generally, if the head gasket is leaking internally, you will see white smoke on startup out the tailpipe. If the engine is run after the gasket is bad, you WILL warp the head and end up in a very expensive repair situation.

ETA: a "blown" head gasket will either leak compression pressure externally or between cylinders. That means the gasket has an eroded gap in it's sealing area.

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The heater core was recently replaced. So I'm pretty sure at least the head gasket is leaking coolant. If not the head being warped as well. I'll check the carpet. But the smell comes in randomly every 15 to 30 minutes maybe. And it doesn't matter if the fan or ac is on or off. I have not turned the heater on though.

If it is the head gasket and not the heater core I don't understand where the coolant smell is coming from though. It's very strong. You have to roll all the windows down to stand it. And even then its obnoxious.

Actually now that I think about there are fitted quadratec rubber mats on the floor. If it was the heater core wouldn't the fluid drip or drain onto the mat? Or does it come down the firewall?

Snowbird Tom said:

If you have coolant smell in the cabin, your heater core is leaking. Period. Pull the mats and feel the carpet. You will not smell coolant odor from a head gasket leak. That fluid stays internal in the engine cylinders.

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Thank you. Will do.

Is the Mopar heater core the preferred part?

Could this explain overheating while going up long hills? Maybe the previous owners assumption that it was a blown head gasket is wrong?

I'm hoping to take it to my mechanic tomorrow. But my wife had a heart transplant. And most of my time is taken up by caring for her.

I checked the fluids and carpet at the firewall tonite. No wetness at all on the carpet. Super dry. Coolant looks good. Plenty in the reservoir. And I took a pic of the fluid with the cap off below.

Oil was low though. And dirty. Smelled a bit like gas. But it seemed normal for dirty oil. I mean not badly of gas.

I also took two videos of the engine running. To hopefully show the tick. Its not bad. I think its maybe the beginning of the rocker arms needing replaced.

It does look like some stuff floating on coolant. Can't tell what it is. Or if thats normal.



Right side. And then left side.




Just a few of the Jeep itself.

macleanflood said:

New parts these days are all shit. Wouldn't be surprised if the new heater core is now leaking. Any idea where the mechanic sourced the part so the rest of us learn from your pain?

Have you done a compression gas test? You can get a tester at any parts store.

Depending on those results...and determining if the heater core is broken again...next steps would be a compression test and maybe a leak down test.

-Mac

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No idea about the heater core. I would not use anything but mopar parts. Unless someone knows something better.

I took it by my mechanic today. Went over with him whats happening. I'm taking it back on Tuesday to have codes pulled and diagnose issues. Did not notice as much coolant smell today. But still there.

I put a half quart of oil in. The oil looked better today after running to warm up. Than I remember it last night.

It runs smoothly. And you can tell from the video the tick is just in the beginning stages. I'm beginning to think this guy was just paranoid. I have a receipt from the dealerships diagnoses last week. That only shows the oil pump issue and the 02 sensor issue. Nothing about a head gasket or anything major. Other than the slight tick on the drivers side.

Once its gone thru I plan to get everything fixed or put a new engine in it. Either way I'm ahead. I figure I have $6000 in savings. And even if I spend the entire $6000 I will have an excellent condition Jeep with a new or newer motor.

The 02 sensor concerns me though. As they can ruin cats if left to long. And CA approved cats are $2200 each! Can you believe that shit?!

As the days pass and it continues to run smooth. My first 48 hour jitters are subsiding. I always get nervous after buying a new car. Waiting for the other shoe to drop. Which it may on tuesday. But I'm not worried about it. Just happy I got out of my TJ and into such a much nicer rig.

The tires are f ing shot tho. Shame as they are k02s with a good amount of tread left. But they are so feathered you can hear them clop along even when parking.