Two weeks ago I towed a Uhaul 6x12 across the country and my temperature gauge spiked 3 times while I was driving. The temperature went down pretty quickly afterwards but stayed at just above 210 the whole time. Now my jeep feels like its lacking a bit of power, I've lost some coolant, and the exhaust smells a bit like antifreeze. Im pretty sure this is due to a blown head gasket so I've decided to replace it.

While I have the engine apart, what items should I check or replace while I'm in there?

So far I plan on putting in new gaskets and a new thermostat. Should I replace the water pump?

 

What year is the XJ?

 

if you have any lifters making noise , change the lifers . how many miles does your XJ have .

 

1998 XJ Inline 6

Im at around 198k. I have some ticking noises after a cold start up which go away after the engine gets warm. I can't figure out if it's a lifter tick or piston slap. Would it hurt to just replace all the lifters? Also, all the references I found also say to keep the push rods and rockers in the same order since they wear together. Should I replace the push rods and rockers too if I replace the lifters?

 

I would just do the head gasket. I have seen threads discussing how new lifters may also give you issues because of the different wear between old and new.

As for the thermostat and water pump, if you think they are on the way out, replace them.

 

You should check the head for burnt exhaust valves. You can do that easily by setting the head up on a bench or table with the chambers up and level with the spark plugs installed. Then carefully pour mineral oil or kerosene into the chambers and watch for it leaking out the thru the valve passages. It is common for the valves to burn when exposed to heavy loads at low crankshaft rpms. I suspect this happened because I'd be willing to bet you towed that trailer in top (4th) gear. You should always keep a jeep in 3rd gear on the highway when towing because they are geared to conserve fuel and not produce torque at that speed, putting too much load on the engine. I'll admit that makes the engine run at around 3 grand, but that won't hurt it as much as pulling a load at 2 grand.

If you do have to replace some valves or reseat them, make sure to check them for proper stem height after assembly to get the proper lifter preload. When the rocker bolts are tight, the lifter plunger should be compressed between .020" and .060". This is more important than you think! I'd keep the lifters and valve rockers, pushrods, pivots unless they are worn badly. Also use a head gasket the same thickness as the original.

There's a very good post in this section by 97grand4.0 and I where we discuss how important lifter preload is and how to get it right. This engine has no means of adjusting valve lash and the proper procedures for getting it right are not mentioned in the FSM because the techs that use it are always working with new parts. Any time you change the valve train geometry by grinding the valve faces or milling the head or block surfaces, you can get into trouble.

Sorry this post is so long, but this is extremely important! As far as the thermostat and water pump are concerned, absolutely install a new 'stat. A new waterpump is good insurance and is probably near needing it anyway. This is also a good time to replace the drive belts and coolant hoses and check the fan clutch. When installing the head, be careful of pinching the wiring harness that crosses behind the head at the firewall. The #11 headbolt, the one in front on the right of the thermostat housing, needs to have thread sealer on it and only torqued to 100 lb-ft. It's the only one that's threaded into the water jacket and isn't as strong as the rest. I would also use new bolts.

Good luck and happy Jeepin'!

 

Thanks for all the tips. When I was towing, I did follow forum recommendations and only towed in 3 but the trailer was a bit heavy and it was hot out so I still overheated. Either way I will check for burnt exhaust valves.

 

When the head is off you can check to see if you have a loose piston , I just got done changing the head on my XJ and I did change the lifters and my engine runs quiet now and I have 168k . so you can do what you think you need to do but these engines can run for more than 400K so you are only haft way there , thats why I changed my lifters . I hope to get that many miles out of mine .

 

If you decide to replace your lifters make sure you use some assembly grease on the bottom when you drop them in and then follow proper lifter break in procedure. A while back when I was less informed I did this but didn't break in properly and ended up rounding out a cam lobe. On the plus side, now I have a brand new high torque camshaft

 

What/who's cam did you use? Quite interested.

 

A useful reference:

https://www.cherokeeforum.com/g/picture/4533583

 

Whenever I pull heads of things with mileage on them I take the head in and have it cleaned, checked for straightness, valves ground and guides checked (or re-done if necessary). I mean, if you have it off, that's the time to do that stuff.

Other stuff that's good to check/change while you're in there:
New coolant
Spark plugs (unless they're pretty new)
Ignition wires/cap/rotor/air filter
Starter (if it's really old), Alt too??
Coolant hoses/belt
Cracks in the exhaust manifold (reweld)
Clean carbon out of intake manifold if any
Clean IAC port on carb
Vac / emission hoses
Steering intermediate shaft u-joints for micro-wear ...cause it's a lot easier to access them with the Exh manifold off!!
CPS (also easy to access now than later)
Whats the condition of your tranny lines (Rusty??)
Radiator condition (corroded)??

Just check these things and replace as your budget allows...

Good luck

 

And 3 more things:

Check the compression before you start anything
Check the torque of the rocker nuts as you REMOVE them (watch closely it'll happen fast)
Check the tension of the valve springs. It should be

Spring Tension -- Valve Closed ……………71 to 79 lbf. @ 1.64 in.
Spring Tension -- Valve Opened ……………202 to 218 lbf. @ 1.216 in.