How can I tell if I blew my head gasket?
- Thread starter ObedaTJ
- Start date
That's the way I always understood it to work. @ac_ and others are far more knowledgeable than I, so maybe someone else will chime in on the matter.
I believe that to be true also, but usually if it is cracked, it will steam one or two cylinders. (And usually two next to each other.)
As I stated earlier a good test for this is to pump up the cooling system, and let it sit for a while then pull the plugs keeping track of where they came from, and turn the motor over, and see if it blows coolant out the spark plug holes.
As far has his story I have little confidence in his mechanic. I think he should just check the basis first top off the coolant wait for the thermostat to open and top it off again drive it around for a while let it cool down and recheck it. Make sure there are no air bubbles in it.
If it still overheats, then it is time to dig in a little deeper in my opinion.
Okay, then we see it the same. Thanks, @ac_. And as far as his mechanic goes, as soon as I read what he did with the radiator cap, I knew he needed a different "mechanic". Ummm, sorry, but you don't get much more basic than "Don't remove the radiator cap off a hot radiator". Wonder if he checks for exhaust leaks by grabbing the hot exhaust, too?
I'd really avoid driving the Jeep until you know whether there is coolant in the oil. If there is, every RPM is eating away at your bearings. If it were me, I'd send an oil sample for analysis ASAP. Hopefully it comes back clean. If not, it's time for a new head.
Did you glance at your oil pressure gauge when at hot idle? Was it more or less around the first hash mark (~20 psi)?
Did you glance at your oil pressure gauge when at hot idle? Was it more or less around the first hash mark (~20 psi)?
Okay some quick updates before I head to the mechanic. The reason I am still going to this one is because he’s been there since the start of it, anything after this is resolved will be somewhere else. I opened the oil cap, looks normal. Doesnt look like there’s any coolant mixed, the oil pressure on idle stays at 20. However I did notice some coolant on the left front wheel, I don’t know if this is a leak or if this is just from the other day. The problem with that theory is it has rained so I think the rain would wash that coolant away, plus me driving it for a few days, and it just stays there? doesn’t seem realistic.
Was the Jeep actually overheating or were you just trusting the dash guage? The dash guages aren't know for being very accurate. It seems like after you cleaned out the engine bay you did not have any more issues. A head gasket can leak coolant into a cylinder but it would most likely have to be a large amount of coolant to cause overheating. One sign of of this type of leak is your coolant smelling like exhaust. I recently did a head gasket on a vehicle with a collant leak into the cylinder. It lost coolant but never overheated.
I’m sure it was overheating. The cap was burning hot, and had smoke coming out. After we replaced the radiator, fan clutch and thermostat it was good for about two weeks.
Just an FYI. When my 0331 head cracked, I had the same symptoms as the OP. The combustion gasses were being forced into the coolant system and over pressurizing the system. I didn't see any evidence of the coolant getting into the oil or the cylinders, but the head was cracked nonetheless. I replaced the head with a new Clearwater head 10,000 miles ago and still runs flawlessly. Best of luck Obeda. You should click through the amazon banner and by the kit to detect combustion gasses in your coolant.
there is another kind of engine test where you pressurize the cylinders with air . a cylinder leakdown test I think this lets you pump 100 psi into the cylinder then you pop the radiator cap and check for bubbles. whereas checking the coolant system only uses 18-20 psi
I did all the labor myself. The head itself was $450. I also changed the radiator, water pump, thermostat, and all relevant gaskets. All said and done the job cost me $1000.
Also, if anyone out there wants to change the head by themselves, do yourself a HUGE favor and remove the left fender. Also....... Take lots of pictures 
Okay my mechanic checked it out. He said it’s overheated “too many times” so it’s possible that the head gasket could be blown, if it is he is charging me 600$ to fix it. Right now he changed the radiator cap and said to come by in a few days if it overheats again.
I would still do a coolant analysis, but if you do end up replacing the head gasket, I would not put your existing head back on, even if it isn't cracked. If you're going through the labor of taking the 0331 head off, it should never go back on again.
I know you said you wanted to go back to this guy because he started this work (or something like that) but overheating "too many times" doesn't mean much of anything. For one thing if the engine was shut off and allowed to cool when the dash light came on, 50 times may not be too many but leaving it run (to try to get home or whatever) with the light on just once could result in the whole engine needing replaced.
He also thinks the head gasket could be blown, well he's correct about that, it could be blown but what the heck, lets just change the radiator cap and see what happens. I see two possibilities here, he just changed the cap that he just installed a few weeks ago when changing the radiator or he just changed the original cap that he just reused a few weeks ago when changing the radiator. Either way he'd never see me or my TJ again, maybe not even if he was a family member.
No he used a new cap, we picked it up from a dealer. Brand new, I was with him. I don’t know if that’ll actually change anything though. The last time he installed the radiator, he didn’t change the cap. Another thing I should add is that the heat works fine and blows hot air, I don’t know if this changes anything but yeah.
The Jeep is running and driving fine for now. I am still having it checked by him on Wednesday but also am taking it to a certified Jeep mechanic to get a second opinion
The Jeep is running and driving fine for now. I am still having it checked by him on Wednesday but also am taking it to a certified Jeep mechanic to get a second opinion
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