The ol' Tahoe is down for the count - coolant in cylinder(s)

[Yukon6.2]

Or...
buy a donar with the gear ratio you want in front and rear diff's and change them both.If you watch and not in a rush you may get lucky and end up with cheap diffs and some stuff to sell to cover the costs.

[trbankii]

That's what I did. I picked up a pickup for $800 for the axles and manual transmission plus got a spare t-case and other parts.

[arveetek]

The Ol' Tahoe has 11K miles now since the rebuild was completed back on New Year's Eve. I've had zero problems with the engine or transmission, except for one small minor issue: I've noticed the past few weeks that on cold mornings the engine would miss just a little and blow a little more smoke for a few seconds at cold start. I could tell one cylinder wasn't firing right away.

While changing the oil today and checking things over, I discovered the problem: one of the glow plugs had a broken wire. The terminal had broken off the end of the wire. Naturally, it was one of the most difficult to access: number 6 right behind the down pipe. Thankfully I was able to wiggle the heat shield out of the way without too much problem and get to the glow plug.

Here is the wire as I found it just laying on the frame:







I was able to put a new terminal on the end of the wire, and all is good!

Casey

[Robyn]

Glad it was a simple issue....

One of the Burbs we had in years past was getting really hard to start......I removed the plugs that were the easy ones....Two on the Right side were not wanting to come out of the head, so I decided to leave them and not risk breaking them off.

All the others got replaced.....Yeah it smoked a bit during a cold start.....But no worries....

Not worth breaking the plugs off and having a big mess to fight..


RH side anything on these engines is usually not fun......

[More Power]

I was able to put a new terminal on the end of the wire, and all is good!

Casey

Good job!

[arveetek]

I recorded my best fuel mileage to date with the new engine yesterday: 17.35 mpg. It had been hovering around 15.5 to 16.5 previously. I'm hoping that wasn't a fluke and that she's finally getting broken in and will keep providing better fuel economy.

Casey

[More Power]

I recorded my best fuel mileage to date with the new engine yesterday: 17.35 mpg. It had been hovering around 15.5 to 16.5 previously. I'm hoping that wasn't a fluke and that she's finally getting broken in and will keep providing better fuel economy.

Casey

That's encouraging!

I'd like to experiment with Sarah's Blazer in an effort to improve fuel economy... First up, install a DB2, though it's not quite that easy. My Banks 6.2L TD 1982 GMC would get 24+mpg at 65-mph. I was always a little disappointed that this Blazer, with 3.73 gearing, produced 5-7 mpg less. That 1982 GMC had a TH700R4 and 3.42 gearing, but I'm guessing the 6.5 would do better with a DB2 than it does with the DS4. But, it would be a costly experiment - a good DB2, fuel injector line set and electronics package (TCM/harness) for the 4L80-E... ~ A couple grand... to experiment.

From your summer post...

Fuel economy - This is still a concern area. We had one long stretch of 4 lane highway that I pushed her hard to keep up with traffic (67 mph, 2600 rpm in 3rd), and that tank came back up at only 8.47 mpg!! I was shocked. After that, I backed the speed down closer to 62 mph, and used less of the cruise control. I noticed that with the cruise on, the ECM was often commanding a lot more fuel to keep up the speed, whereas if I just let it slow down a little on the hills, I would use much less fuel. After that, I averaged 10-11 mpg on the following tanks. Overall, after 1100 miles round trip, I averaged 11.7 mpg for the whole trip. I still think it should be better than that, but again, the 3.42 gears and 33" tires hurts the towing mileage for sure.

Just as a frame of reference.... Our 6.5TD Project truck did the run from Montana to Dayton Ohio and back in 2001, while towing a medium sized 5th-wheel travel trailer - that trailer probably weighed about 7,000-8,000-lbs. The 6.5 averaged 10.8-mpg for the ~4.5K mile round trip, running mostly at 70-mph. That truck had 4.10 gearing, and always ran in OD (4L80-E) unless pulling a grade. I wish we'd had your Holset turbo, but it ran with a GM-8. It could pull grades about as well as a similarly loaded stock LB7 Duramax/travel-trailer that traveled with it. Never had a heat issue while pulling grades or on the flat, even though it was pretty warm... i.e. 105F running across South Dakota in late August. You can see pics of the truck/trailer and read more about that trip here: https://www.thedieselpage.com/finale.htm

[arveetek]

I just turned over 20K on the 'new' engine, and it's been right at 2 years now since the head gasket blew starting this whole project. The whole rig has been running great, no issues at all now. I do have a slight coolant leak (a few drops on the ground periodically), but it appears to be either the radiator or lower radiator hose. I can't see where it's coming from, even with removing the fan shroud and the lower skid plate. It hasn't gotten worse, so I haven't paid a whole lot of attention to it. I fear the next step would be to pull the radiator, and I just haven't been concerned enough to do that just yet.

I quit keeping track of my fuel mileage; I discovered my odometer is not recording mileage correctly. The speedometer is spot on, but when I check the odometer with my GPS app, it's showing a bit slow/behind. The trip odometer quit years ago, so after 395K miles, I guess it's not hard to believe that the main odometer would be a bit worn out by now as well.

The engine starts immediately, in any weather, with very little smoke at startup. I've been on quite a few camping trips now, and she loves to pull hard, and never even gets close to being hot when towing. The old engine ran hot all the time when towing, and I always had to keep one eye glued to the temp gauge. Now I can tow as hard as I want, and not worry one bit. I still plan to swap to 4:10 gears one of these days in order to improve towing performance.

The HX35 turbo works great, but there is quite a bit of turbo lag. The low-stall torque converter combined with 3.42 gears and 33" tires means that I have a lot of black smoke when pulling away from a stop when towing my camper. It takes a bit longer to spool up than the original GM4 I was using before, but the cooler running engine and less backpressure is really worth the trade off. Once it spools up, though, the smoke clears away and she pulls hard. I can barely detect any smoke at all, even at full throttle, so she's burning the fuel quite well at that point. Unless I really push it, boost stays around 10-13 psi on hard pulls. Once in a while it will climb to 15 psi if I really keep my foot in it, but generally that's not needed.

I feel very confident in this rig now, and wouldn't hesitate to jump in and drive to anywhere in the country. I love driving an old school diesel rig, and love getting comments at fuel stations; a majority of folks are surprised to find out that this is, in fact, a factory diesel.

Casey

[DieselDavy]

That is awesome Casey! Looks good too!
Makes my 131K unit seem like a pup!
Dave

[Robyn]

Glad to hear the good news....

Just being anal here.....I would chase down that coolant leak.....Issues rarely happen at a convenient time ....Out on the road is not at all the place to have trouble..

May be just a quick tweak on a hose clamp....Or maybe a leaking water pump seal....

Never know......

[arveetek]

The leak is from the passenger side under the radiator; it's either the radiator or lower hose. It's just a drop or two periodically, but I agree, I need to get it figured out.

Casey

[CoyleJR]

Casey/arvteek,
I agree with you I get a lot of questions and comments at the fuel stations about my 2005 Jeep Liberty CRD diesel. Yesterday I got some unexpected help while filling up at the diesel pump. The pump was on automatic shut off when full and I was cleaning the windshield when a woung girl pulled up behind me in a PS Ferd and jumped out and shut off the pump. She then came around to the front of the Jeep to tell me how she saved the day. When I told her it was a diesel her face turned so red with embarrassment that it may still be red today. We both got a good laugh out of it and I thanked her for the good intension. It was nice of her to attempt to help a stranger.

[JohnC]

jumped out and shut off the pump

Now that's funny!

[DmaxMaverick]

I have had, twice, a station owner rush out to tell me I can't get fuel at their station. They "didn't need the business from anyone so stupid to pump the wrong gas in their car". I suspect their insurance company put them on notice (I noticed the pump handles, at least at one station, were all the same). The owners weren't born in The 'States. Probably somewhere more east of here. It's also happened to my wife (although, she's pumped the wrong fuel a couple times).

[More Power]

I just turned over 20K on the 'new' engine, and it's been right at 2 years now since the head gasket blew starting this whole project. The whole rig has been running great, no issues at all now. I do have a slight coolant leak (a few drops on the ground periodically), but it appears to be either the radiator or lower radiator hose. I can't see where it's coming from, even with removing the fan shroud and the lower skid plate. It hasn't gotten worse, so I haven't paid a whole lot of attention to it. I fear the next step would be to pull the radiator, and I just haven't been concerned enough to do that just yet.

I quit keeping track of my fuel mileage; I discovered my odometer is not recording mileage correctly. The speedometer is spot on, but when I check the odometer with my GPS app, it's showing a bit slow/behind. The trip odometer quit years ago, so after 395K miles, I guess it's not hard to believe that the main odometer would be a bit worn out by now as well.

The engine starts immediately, in any weather, with very little smoke at startup. I've been on quite a few camping trips now, and she loves to pull hard, and never even gets close to being hot when towing. The old engine ran hot all the time when towing, and I always had to keep one eye glued to the temp gauge. Now I can tow as hard as I want, and not worry one bit. I still plan to swap to 4:10 gears one of these days in order to improve towing performance.

The HX35 turbo works great, but there is quite a bit of turbo lag. The low-stall torque converter combined with 3.42 gears and 33" tires means that I have a lot of black smoke when pulling away from a stop when towing my camper. It takes a bit longer to spool up than the original GM4 I was using before, but the cooler running engine and less backpressure is really worth the trade off. Once it spools up, though, the smoke clears away and she pulls hard. I can barely detect any smoke at all, even at full throttle, so she's burning the fuel quite well at that point. Unless I really push it, boost stays around 10-13 psi on hard pulls. Once in a while it will climb to 15 psi if I really keep my foot in it, but generally that's not needed.

I feel very confident in this rig now, and wouldn't hesitate to jump in and drive to anywhere in the country. I love driving an old school diesel rig, and love getting comments at fuel stations; a majority of folks are surprised to find out that this is, in fact, a factory diesel.

Casey

Nice update!

It sounds like the HX responds similar to the Banks turbo I had on my 6.2. A little black smoke at the beginning is worth getting a cooler running engine and more power.

Sarah took the Blazer back to her home some 120 miles distant, mostly I-90 traveling. Said she drives about 75 on the interstate. We filled the Blazer's tank just before she left and reset the trip meter. Hoping to get a better handle on fuel economy... though there'll be some town driving on that tank before we check it again.

It's interesting to note that she immediately saw the difference in how the 6.5TD Blazer climbs grades compared to her Malibu. The Blazer didn't downshift on the grade over McDonald's Pass on US-12, where her car always dropped a couple of gears. The wonders of turbochargers and diesel torque!
Jim

[arveetek]

I just got back from a 1,200 mile round trip to French Lick, IN for an RV trade show. I drove my own personal vehicle, since I don't trust any of our company's currently available, high-mileage trucks! Even though the ol' Tahoe has over 405K on the odometer now, I feel perfectly comfortable driving her anywhere.

This is the first time in many years that I've taken the Tahoe on a road trip without a trailer of some sort. I used my GPS app to check my odometer, and currently the odometer is off by 1%, not as much as I thought. But, I was able to set a record high of 18.9 mpg on leg of the trip. That's the highest I ever recorded with the Tahoe.

She ran great for the whole trip with no issues whatsoever. Still running like a champ. I have narrowed down the small coolant leak to my "new" aluminum radiator (which is actually going on 6 years old now), and I'm still debating what to do about that. It didn't leak enough coolant on this trip to warrant topping off the reservoir, but it's still annoying knowing that I have that leak. I've also noticed my power steering gear box is leaking a little fluid, so those are a couple of maintenance items I will need to address eventually.

I've also recently replaced the exhaust with a new, complete 4" system (3" downpipe to 4" after that). It was a tight squeeze, especially near the rear fuel tank. I'm still thinking of tweaking the tail pipe a bit for more clearance by the tank.

I also just installed a Badland Apex 12K winch on the front! It's "hidden" behind the front bumper. I'll try to get pics uploaded soon of all that.

Casey

[Robyn]

Glad you had a good trip....
Those pesky little things (Leaks) Can be managed for a while ....But getting them fixed is surely the best plan........

[arveetek]

My Tahoe currently has a 10 bolt rear axle with 3.42 gears. Last weekend I picked up these jewels:








That's a 14 bolt semi float rear axle with 3.73 gears and a G80 locker, and a matching front diff with 3.73 gears. I wanted to go with 4.10 gears, but I didn't really want to put that kind of money into a 10 bolt, as I feel I'm already pushing that axle to the limit when I'm towing my camper or off-roading, and trying to find a 14 bolt semi float in a 6 lug configuration with anything lower than a 3.73 ratio is next to impossible to find, so this will be a good compromise in gearing and strength.

I am in the process of cleaning up the axle, and will be installing new wheel cylinders and steel brake lines for good measure. Thankfully the rest of the brake components look really good.

I will be installing new rear leaf springs and Bilstein shocks while I'm at it, since after 400K miles, the rear springs are sagging real bad.

I'm looking forward to finally getting some lower gears! With my current 33" tires, this will get me back to just slightly lower gearing than a stock setup.

Casey

[a5150nut]

Casey Timbrin bump stops would be a nice add while your in that far

[arveetek]

Casey Timbrin bump stops would be a nice add while your in that far

I currently have RAS (Road Active Suspension) helper springs:

https://activesuspension.com/

I have them cranked to full max, but the original springs are so flattened out, they weren't helping as much as possible!

The Timbrens look nice, but I've about maxed out my allowance, so I got stop the spending somewhere!

Casey