Engine Overhaul Time - Lots of questions

[ees]

I have a new to me '94 6.5 TD 2500 4x4 Suburban with about 225k on the clock. The driver's side headgasket is leaking. My budget is tight, but I figured it would be wise to fix as much as possible in one go so I am not in there again in a year.

Currently I plan to:

* Change both head gaskets (as described in Diesel Page R&R Guide)
* Change timing chain set
* Change water pump
* Change all hoses and s-belt
* Inspect/replace g-plugs
* Fabricate new cross over exhaust pipe out of mandrel bent stainless (current one is rotted)
* New thermostat
* Plus general stuff like new coolant, oil change, air filter, fuel filter

Am I missing something key?

The primary use of this vehicle is around town weekend projects and once a month towing a race car trailer (about 4000 lbs). My primary goals are fuel economy and reliablity. Sould I consider higher performance parts? Should I install a gear drive instead of timing chain? How about a high flow water pump?

Does anyone have any pointers on things I should look out for?

Thanks for the help!!

-Eric

[Shaun091382]

Don't forget to check and recommend anyways to replace your harmonic balancer and crank pulley..high mileage units tend to wear out the rubber insert on the balancer which may cause it to separate from the pulley which usually results in a broken crank just my 2 cents

[tom.mcinerney]

2 considerations:
If exhaust stock, both muff & cat may be clogged. If exhaust restricted, EGT's elevate, possibly promoting head cracking.

The best upgrades for duration/reliability are
1.) Dual thermo + hi-output water pump.
2.) Restored (for emiss legality) or low-restriction exhaust.
3.) Timing gearset.
4.) EGT + Boost gageset.

My Helm manual said don't renew water pump if it's not leaking.
The water pump mounts to block, not heads; can secure heads without touching pump. If i change my pump, it will be to new, high output model, and probably the dual thermo crossover at same time. The water pump does need removal before the timing set can be accessed; so there's some inclination to do both in same procedure.

As mentioned above, the HB/Crank Pulley are crank cracking issues. Yours may well have been updated all ready.

Given the mileage on your block, pulling the oil pan and inspecting for cracks might be adviseable before putting too much more into it.

1Pulling heads, inspecting bores
2Pulling pan, inspecting webs
3Checking out the Harmonic Balancer
123 probably good idea. [I haven't checked out my block webs yet].

The radiator/condensor/oil-cooler area must be thoroughly washed of dirt, etc, to prevent overheat.

If your engine has a 90* adapter to mount the oil filter, you should renew the orings in the adapter assembly; they are known for springing leaks. [Many of us with IFS 4*4 have remote mounted the oil filter; now no oil 'shower' at oil changes].

[ees]

How easy is it to get to the oil pan on this engine? As for the webs would that be the thin sections of casting going from the main bearings out to the wall of the block?

On the HB should I replace it regardless or just if it has rubber deterioration?

For the guage set I was thinking about putting that off a month or two to spread out the cash outlay. Should I drill/tap a hole for the thermocouple now? If so where and what size?

Thanks again for the help.

-Eric

[MTTwister]

ees - go to http://www.kennedydiesel.com/ -
tech tips link, and poke around. There's a good shot of where to drill for the temp probe. 7/16 drill for 3/8 NPT tap before the turbo.

A few claim that a heavy duty fan Clutch will keep you as cool as the dual thermo and HO pump upgrade. BUT - if your already in there ( versus retro-fitting in my case), it might be worth the trouble. If cost is an issue, research the fan clutch engagement temp discussions versus the HO H2o pump.

No point in trying to spread out the cash outlays, its a perpetual money pit, one upgrade after another... smile.gif

[sidedump]

Dont forget that most dealers price match. Check out http://www.gmpartsdirect.com/ get a price print off a copy and take it to your dealer. When I bought my truck all of the lights were those euro clear junk. By price matching I didn't have to pay for shipping and I got the same price they listed saving me about $40.

[Marty Lau]

I'm with MTTwister if your going to go into the timing set and I would at 200,000+ I would go with the HO water pump. I went through all your talking about but the head gaskets in January plus some stuff. I would do the hoses like you said. I would also do injectors & glow plugs unless they were done less than 100,000 miles ago. I personally decieded to go with stock timing chain and gears which cost $130 vs $350+ for timing gears. I figured with 155,000 miles I was half way done with expected engine life and OEM timing set served me well and I put extra bucks out for other things so I cheaped out on the timing gears. I Also gaged it and did the Heath MaxiTork & TurboMaster, Hayden Fan Clutch.
If you don't tow heavy and you don't have big over heat problems Fan clutch is easy to get at I would consider doing it later if you have to. You also might try "tweeking" your fan clutch with it out.
Check out GM Parts Dirrect. You can get GM parts at nice discount. Oh yeah if it has factory exhaust get a good one more power & better MPG's. It's easy to spend a couple thousand bucks on parts. Labor is yours if you are handy.