Hey Vortec Guys! / Sierra pickup / Suburban / Yukon etc - Finally has Index!

[rayra]

The radiator repair was better than I thought. What I took to be water droplets were actually spills / drips of the initial hot epoxy mix. Glossy black on weathered plastic housings, it looked like water. After mixed driving today, the patch area was bone dry. Apparently I managed to seal the cracks with the first mix and reinforced it with the second and fiberglass. Still have the new radiator on the way. But I might just drive it with this patch for a while and see how it fares.

 

[rayra]

The new radiator is here! The new radiator is here!

I'm sorely tempted to slather the hose necks with epoxy as a preventative measure.

Refreshing / baselining the whole cooling system has been on the 'To Do' list since I bought the vehicle 2yrs ago. New water pump & thermostat, new hoses. It's 15-16yrs old, 135k mi now. I'm probably going to accumulate those parts as well and change it all at once sometime over the winter. If the radiator patch holds that long.

 

[rayra]

~200mi of around-town drivign and the patch has begun to very slightly leak, a tiny dribble. More a smell than a volume loss. For now. Went ahead and ordered the new pump, hoses, thermostat and housing / seals. Will change it all at once. Elected NOT to replace the fan clutch. I hope to convert the whole thing to factory electric fans early next year.
So as soon as I have the rest of the parts and a free day, I'm swapping it all in. And I might just do the radiator solo, as I'll probably drive it out of town very soon. No reason to risk it when I have the new radiator sitting in my garage.

I've had fresh coolant sitting around for months (bought on sale). I'll use the old fluid if I do just a radiator swap, save the fresh for when I change it all.


40,991

 

[jgaz]

Thanks for the tutorial and the “real world” product test. The kit looks like it has merit as a get home solution.

Do you think it has a reasonable shelf life? Enough so that it could be carried as an emergency item?

 

[Martinjmpr]

. During that separate issue I decided I would buy the new 78 so my starter would match my Aux battery and permanently donate my 75 to my pickup, whose battery had finally crapped out. So I left off the diagonal bracing rod that spans over the starter battery, intending to swap the battery today. Which I have now done. I cannot imagine that one weekend, one road trip of ~250mi sans that brace was enough to trigger that crack. But there is zero external signs of it existing before this weekend. ~135k mi, 15yrs. And suddenly there it is.

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Dangit! Now you've got me worrying about my radiator cracking! :yikes: I'm pretty sure I left the diagonal brace off mine when I put in the 2nd battery because I thought the brace came too close to the extended positive battery terminal and I was worried that it might short out. After driving on 110+ miles of rough washboard road a couple of weeks ago (drove Hole-in-the-rock road all the way to the end and then back) I'm now worried about this.
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I think maybe what I'll do is (a) wrap the portion of the diagonal brace (the portion closest to the positive terminal) in electrical tape and then put some closed-cell foam padding over it. That should be enough to prevent any arcing/shorting, shouldn't it?

 

[NevadaLover]

The fleet I work for has over 30 different 2000-2016 suburbans, tahoes and yukons, I take that brace off of every one when new and I have never seen our radiators crack like that, I believe that brace is to spread out the forces of a front end collision rather than brace the core support. But I have been wrong before.

 

[rayra]

Martin, you've got the battery clamp on there don't you? Didn't think about top-terminal clearance there.

Probably just a coincidence. Nothing really flops around and the rest of the engineering is pretty solid. Never liked the idea of plastic radiator tanks. Didn't even realize I had such until this failure.

Rockauto inexplicably split my shipment, pump and hoses coming tomorrow but the thermostat and housing coming from another warehouse at least a week later, by their estimate. So I guess I'm swapping the radiator only for now, just as soon as I finish tiling a customer's shower.

 

[bald.eagle]

Just wanted to update the coolant loss issue. Ran the stop leak tabs through a while ago and haven’t had any more loss of coolant. Looking back at the thread, that was around a year ago... crazy that it’s been that long already. My last year has been absolutely nuts and I haven’t gotten NEAR where I wanted to be with the Suburban.

That being said, I rolled over 200k a couple months ago, and knock on wood, no major issues to speak of this last year. Once I wrap up some work travel I’ll get going on a top end teardown to replace all the seals and gaskets, heater fittings, then I’m going to start beefing things up. Trans aux cooler, rebuilding the axles, probably new shocks and rear springs.

My plan has shifted from building out the Suburban fully, to converting a cargo trailer into a camper. I think it will suit our family of 5 better. I will probably still build some simple storage drawers that can fold out to a sleep platform to augment tent camping this year while I work on the trailer plan. That means my end goal is to get the Suburban solid enough to trust as a tow vehicle, and ride this beast out to 300k.

 

[rayra]

Today's evolution was hoped to take 3hrs+, it took about 6. Had some real trouble getting the fan/clutch assembly off of the old water pump. The only part I did not order new. At one point I was ready to sawzall the shaft / nut attachign it to the old water pump, sacrificing the fan clutch in order to recoup the plastic fan blade assemblage itself, figuring to buy a replacement fan clutch locally. But I talked to my older neighbor shade-tree mechanic and we talked thru a couple ideas and eventually got it removed.
I initially started stripping parts off, had done the same work on the missus' Tahoe, but forgot that hers has electric fans. So I put the tensioner and serpentine back on, in hopes they'd put enough force on the water pump pulley that I could knock the fan clutch nut loose. No joy. So while I thought about other ways to remove it I went ahead and yanked everything out and put the new water pump, radiator, thermostat / housing, upper and lower hoses in.
Then flailed around a bit, trying various methods of clamping the pump / fan / clutch assembly to my workbench, trying to lock it in place so I could get a big wrench on the nut nad hammer it loose. Finally went for the neighbor, walked him thru it, confirmed the direction things should turn and that the pulley on the old pump was not needed (new one came with its own) and he said 'drill a hole thru the side face of the pulley and we can put a screwdriver thru it to keep it from turning. And that's what we did. I clamped the pump on the edge of my workbench, got a big pipe wrench in place and while I got a good grip on the pump and got the pulley / screwdriver positioned against the table and he set to hammering on the end of the wrench. About 4 blows and it was free.
After that it took a very short time to get it the rest of the way together and loaded up with new coolant and run to op temp. No leaks that I could see.

And here's a couple pics of the clean new radiator installed. I can see why it cracked. The radiatior sits on two rubber pylons on its bottom, socketed into holes in the radiator support frame. Then it is held in only by two of these top cantilevered brackets. So all the vertical jounce would cause a flexing in this bracket and stress on the tops of the plastic end tanks of the radiator. I would think some sort of rubber wedges set between the top of the radiator and the support frame would help alleviate the stress. I've driven a bunch of washboarded roads in the last year. I can only figure that hastened the demise of my original radiator.

 

[Hillbilly Heaven]

When I replaced all mine like you are doing, I used a long fan clutch wrench. I still had pump mounted and since I was replacing the belts, I used the old belt like a strap wrench around the pulley to hold it. Fan came right off. If you have a rubber oil filter strap wrench it will work too. I don't think the nylon strap wrenches will grip enough to hold the pulley.

 

[rayra]

tried on the car, tried a rubber strap wrench, tried inserting a long thin screwdriver thru one of the four pulley wrench holes (just bent the screwdriver and dragged it around the face of the pump). Tried a lot of things and couldn't break it loose. Probably should have hit the crescent wrench harder with a bigger BFH. But I was pretty concerned about that fugly-looking plastic fan blade, figuring it was brittle and might break. All worked out in the end. Left me wishing I have a much larger 'real' shop vise, instead of the puny 5" one that I have.


bald.eagle, I noticed while going thru my maintenance notebook - looking for when/if I'd changed the hoses and coolant on this vehicle, problem with two is I can't recall what I've done on which - that it has now been a year and 9000mi since I used that leak-stop and it's been working great. Of course I just lost / replaced half the coolant volume so I should probably drop another couple pellets in.

 

[rayra]

well just returned from a 280mi round trip up the coast and the vehicle temps were wonderful. Just confirmed that I'd inadvertently gone with the 'alternate'/'optional' low temp thermostat - 160F vice the normal 187F. Thus explaining how tooling down the highway at 75-80mph in 70F ambient temps I was getting a coolant temp of only 170F. And on top of that, with my new larger trans cooler - and still plumbed thru my shiny new radiator - my trans temps never exceeded 120F. Yes, 120F. That's a full 150F+ below the 'death zone' for a 4L60-E (275F+). That should help greatly extend the life of this transmission. Vehicle performance was fine, not noticeably different from before the cooling system overhaul.

The Missus' Tahoe always seems piping hot when she gets home from her highway commute. Usually runs around 200-205F. I'm now giving serious thought to dropping the thermostat rating in her vehicle, too. Going to try and do some research and see if I can find any real downsides to it. These motors seem designed to run a the hotter temps, I'm sure the smog outputs are lessened by doing so. PResumably. But I think I'd rather have things running cooler. Especially re their high mileage 4L60-E transmissions. At this point in their life-cycles, that's my greatest concern. The Tahoe is about to turn over 200k mi. The Sub is at ~135k.

 

[Hillbilly Heaven]

Two downfalls I know are increased fuel mileage and increased cylinder wear.

 

[rayra]

Of cooler operating temps? How weird.

 

[Hillbilly Heaven]

Sorry meant to say decreased fuel mileage because the ECU adjust fuel mixture by engine temp and it was calibrated with engine operating temp of 190 therefore it thinks the engine is not up to temp and uses a richer mixture.

As to the increased cylinder wear well calling it cylinder wear is not completely accurate. OEMs have spec'd bore finish, piston shape, and ring design based on the baseline operating temp. Baseline being 190 degrees. Engine temps do affect piston rings sealing ability. Also in raising the operating temp level they found the rings were sealing better and bore wear was decreased. The cooling systems of today's design are more efficient than designs 30 years ago. Now instead of recovery tanks we have expansion tanks. Granted some folks still think they are recovery tanks but they are wrong. Think of wear your actual radiator cap is. It is now on the expansion tanks. This is why it is stamp with big bold letters not to open hot. The use of a closed loop cooling system allows them to eliminate air pockets and possible steam forming. With 190-192 degree thermostat and a good expansion tank cap engine temps can safely go 215-220 although it is not recommended for the long term. Make that engine stay in the 190-195 and it will live a long happy life.

Like you I had to replace a radiator due to a tank crack and at same time I did a water pump change because after a long drive I could smell coolant. I had a weeping pump just an occasional drip. Before the radiator and water pump change my engine temps always ran 190 no matter the weather. Even on cool days it would hit 190 and stay there. After the change I had to beg the engine to reach 180. It was scarey to see the engine run so cold. Radiator was identical to the one I took off no upgrade. The water pump was identical. For some strange reason it just ran colder in cold weather. Now I did flush the system before tearing it apart and used premixed coolant. I do not remember which brand again nothing special just whatever the local parts store carried. I pulled a rabbit out of the hat and used an old diesel truck trick and used a piece of cardboard to cover a portion of the radiator. Remember it is a cross flow radiator so I cut a piece the width of the radiator. I experimented with different heights and ended up covering the bottom 3 inches. Brought my engine temps back inline to where they should be. My only thought is it had to be the coolant I used as it had the factory coolant in it. Now I do remove the cover when the temps hits the 70s.

Oh while you are doing the cooling system do not forget those heater hose connections on the firewall. They will ruin your day without any prior notice. It does take a special tool similar to the tools used to remove fuel lines. Luckily when mine let go it was very close to the house. No part store in town had the tool to remove them but they had the part. So I carefully used a dremel tool with a cutoff wheel to remove them. I now keep a heater hose fitting tool in every vehicle.