2000headssuck

Found an XJ with 148k miles last month, noticed it wasn't pulling or pushing coolant to the overflow tank so I drained it and added new fluid. About 25 miles after that the upper hose popped. So, I replaced the following...

Rad
T-Stat
H2O Pump
Upper & Lower Lines
OverFlow Reservoir
New pressure release 18lb cap installed
P/S Pump (was whiny and is ok now)

Turned her on, purred like. kitten. Then, this morning I fired it up and it made a sort of straining sound from near the front of the motor and coolant started to drip out of the upper coolant hose (new) and t-stat assembly (likely the same high pressure that popped the upper hose). Turned it off, topped up the oil (was a qt low) then turned it back on and no drips. This seems to be both an intermittently occurring issue and a specific one.

I know it likely needs a new head gasket but I was hoping to get to that at a later date in the next few months seeing as though if I am leaking coolant it must be internal to the head and minimal. But I'm at a loss as to why the upper hose popped before with the old cap, and then after replacing literally the entire cooling system minus the heater box, it looks like it's doing the same thing.

has never overheated
check engine light is on (possible misfire, I know)
reads 200 deg at the t-stat housing using laser thermometer after 15 min idle
gauges all look good
minor tapping at cold start (may be oil pump to bearing issue)

Thoughts? and Thanks!! ( I'm really just worried about the upper hose issue, I'll tackle the misfire, head, and oil pump issues later if need be)

2000headssuck

Info - 4.0L - Auto
check engine light went away

robsjeep

You say the upper hose has popped, what does that mean? blows open with a split in the hose? A drip forms at the hose end? The hose makes a pop sound? Hose comes off of the fitting? Hose greatly expands in diameter?

A head gasket leak may cause excessive coolant pressure. That pressure can conceivably rise so fast or be so great that the pressure relief cap cannot completely relieve that pressure before that pressure in the cooling system does damage. You say you suspect a head gasket leak. Id go and do a compression and or leak down test to confirm diagnosis of a head gasket leak. If confirmed, there is only one solution.....


Also, given the assumed spike in coolant pressure is do to a compression leak in the head gasket, Id think you should be able to detect bubbles from said compression leak visible in the coolant via the filler neck, what do you see there?

Of course given a head gasket compression leak into the coolant, it should be worse at high rpms verses idle rpms, as that will be when the engine is pumping the most gasses thru a leak. Do you notice that?

A test of coolant for trace combustion gasses can also be done to confirm a head gasket failure.

Make sure your pressure cap is good, put it on a pressure tester, make sure she opens at rated pressure. Now days, give red chinese communist slave run manufacturing standards, even new parts are suspect if made there. So check it.

good luck

robsjeep

Please confirm the check engine lamp did not burn out, it happens. Specially with my luck, heck I simply got an old enough car such that there is no check engine light. Ignorance is bliss! Give it a try sometime!

psf4x4

I’d have the rad cap tested to make sure it opens. Pretty sure parts store has the tool to test it.

2000headssuck

Upper hose "popped" meaning it burst a 3" hole just above where it connect to the thermostat housing.
No bubbles detected in coolant neck
I'll check the cap if possible

I ordered the new gaskets a few hours ago...I'll take pics of the job this weekend...seems the writing is on the wall for this XJ...but I ain't giving up...new tires, wheels, springs, shackles, and lift kit are already on their way home.

2000headssuck

Will do, I hadn't thought of that.

BlueRidgeMark

Anybody interested in a cracked head? Or at least, looking for one?

2000headssuck

thanks

2000headssuck

I went and ordered a Nu-Tech cylinder head for $480. According to their techs it is manufactured exactly to the Chrysler blueprint and is perfectly within spec as a stock replacement.

psf4x4

I’d be careful to not put the same piece of **** head casting on that came off, if I was replacing the head. I would only put a TUPY casting Head on. 0331 head different casting. 20 years of data out there. I’d take advantage of it. Don’t end up with a remanufactured 0331 casting or a new old stock.

Tommy Boy said “I can **** in a box and write guarantee on it, but all I’ve done is guarantee you a piece of ****.”

just warning you of potential pit fall

BlueRidgeMark

How did you confirm that the head is cracked?



BTW, I've never heard of Nu-Tech, but psf4x4 is right. If it is an EXACT duplicate of the Chrysler 0331 head, it has the same casting flaw that causes them to crack. Not good.

Clearwater heads have an excellent reputation.

2000headssuck

Thanks for the additional info guys, its a reman with the following casting characteristics:

The website states that it replaces the following but does not provide an actual casting number...makes me think I should assume its a reman 0331 which is scary. Luckily I can return it. Gonna poke around for a Promaxx or clearwater.

This Nu-Tech says it "is manufactured to fit" Block Cast #449AA Crank Cast #767, 0411 In-Line Head Cast #0331

2000headssuck

I hear ya...because it didn't state is was an original 0331 that was reman I went ahead and bought it (returnable) so that I can compare it to the original and a Clearwater. I don't want to make the mistake of putting on a "new" 0331 casted head so I'll take my time and push the job off a few days / weeks until I get a head I like. If the reviews are no good for Clearwater in the end...I may even go brand new aluminum or ProMaxx

2000headssuck

I am being pro-active due to the fact that it is suffering all of the same symptoms that 0331's have except for milky oil. The coolant system and exhaust (or other engine pressure) are def communicating ... so ya I'm just trying to get it done.

I ordered a Clearwater to compare to the Nu-Tech.