Laundry list of repairs. Got tips?

[zerovandez]

Planning to get a few things done on my 02 LTZ 140k miles this weekend. Specifically, the thermostat. Been having issues with climbing coolant temperature. So while im in there messing about. I thought i would take care of the following items.

Valve cover gasket
Intake and throttle body gasket
Water pump
Idler pully
Fan clutch
Seals - front differential inner and outer (pull diff from top)
Seal - outer 4wd disconnect
Engine mounts
ECT sensor
Fuel filter

I plan on removing the AC compressor completely to make my life easier when replacing the valve cover gasket and removing the front differential from the top through engine bay. Im not sure what technicals are involved with removing the prop shaft from the differential. Does it have to be marked and aligned?

Any tips on any of the repairs and parts that i plan to replace would be extremely helpful. Thanks!

 

[Bondo07]

intermediate shaft doesnt go in any certain way, just make sure the side that came out of the diff goes back in the diff, and so on. Careful with the disconnect, they like to split. And if you have trouble pulling the diff out of the oil pan, DONT pry on it. Try to get it to spin first by pounding down by the driveshaft. I broke a bolt tab on mine by prying. and my disconnect came out in 2 pieces.





Also carefull with the intake. Make sure you get all the bolts, as the plastic can be quite fragile. And Im assuming when you change your valve cover gasket you are also changing all the coil gaskets as well? It would be a good idea.

 

[HARDTRAILZ]

Take your time and be patient. It will help more than anything really. Seems that you got some good plans, so best of luck

 

[zerovandez]

Hi Bondo07, yes i will replace the coil pack vc seals as well. Sorry to hear about your ordeal - hope you got fixed.

Hey hardtrailz, yes i have been planning for this for 2 weeks and have gotten a method down. The other concern I had was with the 4 bolts that connect the front drive shaft to the front differential yoke. Is there a best practice to mark and remove? Or is it just as simple as removing without marking any relationships? And when reinstalling, are the torque values for these 4 bolts only 20ft lb? All of the documentation i found suggests this is the case but i just want to make sure.

Thanks!

 

[Bondo07]

U joint caps, yea.. Just make sure they face the right way so marking them would be a good idea.

 

[Mooseman]

Tape up the u-joint caps to prevent them from dropping off the joint and losing needle bearings.

For the disco, yes, take your time, soak it with PB Blaster or other good penetrant a long while, try to spin it in the oil pan before trying to pry it. I've seen some hit it up and down to get it to turn. All else fails, try heating the pan around it with a propane torch.

Take the disco apart, clean it out of the congealed grease, inspect it and fill it with fresh grease. If it needs repairs:
http://www.offroadtb.com/articles/tech-docs/front-axle-4wd-disconnect/

 

[zerovandez]

Thanks for the tip, guys!

So with all of this going on, im hoping that i dont have to change the head gasket. Maybe you guys can validate my diagnoses.

The truck warms up fine. But when driving for longer periods at constant speed then coming to a stop, the temp gauge reaches almost the last 1/4 mark. I can hear gurgling at a stop or engine off. No bubbling or gurgling while driving. No milky color or consistencies on oil dipstick or under radiator cap and coolant reservoir. The fan clutch is working because the other night, i ran it really hot and can hear the clutch working.

So my thoughts would be - the thermostat is stuck closed. The coolant builds pressure and doesnt have anywhere to escape except the radiator cap after the pressure exceeds what the cap can handle (15psi?) thus shooting coolant to the reservoir causing bubbling and gurgling.

Sound about right?

 

[Mooseman]

I would definitely swap out the t-stat ASAP as a start and go from there. Check also that the condenser and radiator fins are clear by running a hose. Sometimes enough bugs and dirt can clog these up.

I would still check that the fan clutch is operating properly. Here's the how-to:
How to test the electro-viscous fan clutch

 

[Bondo07]

I hate to tell ya. But that's what my cavalier did with a bad head gasket. A slight leak will slip past a compression test and be fine at idle. If you are driving, the fan doesn't do anything since air is constantly pushed through the radiator because you are moving. The gurgling when you stop is all the air inside the head making its way out. You just can't hear it when driving. And just because there's no coolant in the oil doesn't rule out the head gasket. Sounds like you have some fun ahead of you. Oh and just for future headache relief, get the "updated" head bolts. The stretch point on them is higher up in the bolt so when the break off next time (and they will) it will break off above the block surface (hopefully).

 

[zerovandez]

Thanks. It only gurgles when driving it hot for a longer period of time. When driving with the temp needle at 210, there is no gurgling. The coolant in this truck has never been flushed to my knowledge so do you think that the coolant is breaking down and contributing to this boil over?

 

[Mooseman]

Quite possible. How does the coolant look? Check for a coolant tester that detects exhaust gases. Inspect the radiator and get it rotted out at a rad shop if it's plugged up.

@Bondo07 , that was quite possibly the experience you had but may not be the case here. Start looking at other possibilities before jumping to the worse case scenario. Hope for the best, plan for the worse.

 

[zerovandez]

The coolant looks old - rusty-ish color without any debris. No signs of a "rainbow" film either.

 

[Mooseman]

Start with the basics, change the coolant and do the stat as it sounds like it was neglected in its past life. A flush prior might not be a bad idea neither as per this video since it sounds like yours is pretty nasty.

 

[zerovandez]

My coolant doesnt look that bad but thats a great video. Thanks!

I have access to a torque angle gauge and my local auto parts store has head bolts and head gaskets in stock. Work on this starts tomorrow night. I think after i remove the thermostat, i will fully submerge it boiling water and monitor for any activity. Not sure where else to look if that thing does open...

 

[Mooseman]

Head R&R is no trivial job on this engine where head bolts ALWAYS break. Also need a specialty tool (wedge) to prevent the timing chain adjuster from extending. One member had issues with this and wound up pulling the entire engine out, which is ongoing.

 

[zerovandez]

so I did a little more poking around today. After driving stop and go traffic, the temp needle goes to the last 1/4 mark, then drops back a little, then goes back to 210, then climbs up again. Typical for driving in these conditions I guess. I get to my office then pop the hood. The resevoir is fuller because of coolant expansion. I reach for the lower radiator hose and it's cold. Maybe a clogged radiator? Bah could be anything :/

 

[Mooseman]

That would be a stuck closed thermostat. These are reverse flow so cold coolant flows into the thermostat. It should be at least warm.

 

[zerovandez]

Reverse flow - can you please explain that to me? I guess my assumptions and diagnostics were pretty good

 

[Mooseman]

Simply means that the cooled coolant goes to the top hose and inlet to go through the head first rather than the block (and lower hose). The hot coolant comes out of the lower hose from the thermostat. That hose should have been hot. Even if the rad would have been blocked, some circulation would have still happened and the hose would have been at least warm. With a stuck closed thermostat, hot coolant can't get through to that hose.

 

[zerovandez]

Thanks!

Thus far i have managed to remove everything needed to access the thermostat. What a pain in the ass that fan shroud was! I found it much easier when i removed the transmission hard lines. Everything else was a relatively easy.

 

[jsheahawk]

Did you end up taking the AC compressor out? If so, are you replacing the orifice tube and accumulator?

 

[zerovandez]

I actucally did a very novice thing and didnt discharge the r134a before servicing. So im not going to be replace the front differential inner seal. I checked the differential fluid level and its still fullish. So the leak isn't horribly bad.

But everything else is about done. Ik going to play with the radiator a little bit today. After reviewing the FSM yesterday, it would seem that installing the radiator, fan, and shroud would be easier.

 

[zerovandez]

Just a couple broken clips and shes all done!

Kind of scary with new motor mounts. Can hardly feel her start. No more coolant gurgling or bubbling and now the temp sits just right under 210. Fresh new gaskets where needed, fresh oil, coolant, and spark plugs.

The only comment that I have regarding existing how to's on the fan clutch and shroud is that its so much easier to remove and install that stuff with taking the radiator with it. It seriously only took me 15 mins to put the fan clutch, shroud, and radiator in the engine bay. Getting that fan clutch nut to thread was another story though. What a pain in the ass that was.

All in all, good experienxe. Thanks guys!