Towing maiden voyage. Yikes!

[bgiovan]

Loaded up the kids, gear and the 30' Keystone Springdale and headed 4 hours north to the Michigan Riveria - Sleeping Bear Sand Dunes and wine country in the Leelanau Peninsula.

2.5 rather uneventful hours into a 4 hour trip, my 7 year old is complaining about needing to go to the bathroom (our second such stop along the way). Despite me suggesting he wait it out, the kid always wins so we pulled into the nearest rest stop. Took care of bidness, got back in the Suburban, turned the key over and POOF! big old puff of white smoke comes from under the hood and thru the vents inside the truck but quickly vanishes.

Now, we'd just pulled a decent grade prior to the stop and I was running at 210-220F on the factory gauge but it started to go down when we stopped so I thought nothing of it. Truck seemed fine after that and we were just about to get off the interstate at the next exit anyway (2 miles), so decided to go ahead. As we went the temp gauge took off like a rocket. Just got off the exit and rolled into a NAPA that was closing (praise God!), popped the hood and coolant smell everywhere. Plastic f-ing tee broke, the one going into the heater core.

Let the motor cool down, replaced the T, new coolant/water and some Water Wetter. Drove with the heat on for about a half hour (in 90 degree weather of course). After that, really ran fine. Was thinking head gasket the entire time (or worse). Uneventful rest of trip. Looks like I dodged a bullet.

Before the trip, put in the 4" DE exhaust, DMax fan blade upgrade and the derailer trans oil pan off Amazon. Unloaded, runs at 180F-185F all day long. Drop the trailer on the back, 210F is the norm and hitting 230F pulling any decent grades.

F Vin 1997 K2500 Suburban with 4:10's. What else do I have left to do to cool this beast down? Got an A Team turbo and KOJO tuned for towing from Walking J (KOJO took almost 2 months to get after I ordered it, another story). I had planned top have both installed prior to this trip but due to the length of time waiting on the KOJO, didn't have time. I guess the bright side is I get to see factory spec 6.5 vs. the mod but damn...on the stock set up, some of the massive grades, it was floored and I was doing 40MPH. Barely. Got 8 MPG also which was an added kick in the nuts.

Optimistic that the new turbo and tune will help the power situation. The cooling one has me baffled though. This Suburban is a beast and has every single heavy duty option available in 1997 for the K2500. I get confused on the threads since most of them are for 94-95 rigs and cooling/power.


Help? What else can I do to cool this pig down and give it more umph towing?

Thanks!

 

[JiFaire]

Have you pulled the rad and thoroughly cleaned it and the rest of the stack?

I mean *really* cleaned it... externally, get the bugs, tree fuzz, grit, stray hitchikers, and Prius parts out?

If not, that's likely it. It's SCARY how much crap gets stuck in your rad, and trying to clean it while it's in the truck just doesn't work so good.

 

[toddlnrd]

x2 what JiFaire said.

I pulled my rad and could not believe the crap that was in it an between the other coolers!

Todd

 

[THEFERMANATOR]

Have you pulled the rad and thoroughly cleaned it and the rest of the stack?

I mean *really* cleaned it... externally, get the bugs, tree fuzz, grit, stray hitchikers, and Prius parts out?

If not, that's likely it. It's SCARY how much crap gets stuck in your rad, and trying to clean it while it's in the truck just doesn't work so good.

What he said, and also make sure you have a good severe duty fan clutch on it with that DMAX faN blade. Only other upgrades will be 99+ threaded style water pump and a single t-stat housing(or install the retrictor in your current one). The turbo and tune will help though as the stock turbo runs some pretty high EGT's.

 

[3500GMC]

Yep, all the cores in the front can plug 'cumulatively' and heat things up quick. Even take the time and straighten the fins out too. Every little bit.

Careful.. Easy on the power washer, you can mess things up quick..

They sell a Foaming cleaner for AC coil cleaning. (for home AC, buy at Lowes Homo Depot, etc) It's decent stuff, few different brands, same basic 'stuff'..

Hot water will work best on the bug skeletons. Flush all cores from the back to the front.

Internally, you could have some cores plugged too. Even sediment in the block, etc. I've used Cascade dishwasher soap with plain water to flush before.. You'd be surprised. Commercially available flush I've found it softens the hoses too much for my liking. It's like it attacks the rubber..

 

[bgiovan]

I did have it "flushed" before I went on the trip. Agree it looks like a removal and deep douching is in order. Wondering on the T-stats also. Reading conflicting info about using a DMax fan blade and changing the stats to 180F. I bought the Dmax kit from SS diesel and installed it a few weeks ago but did not change the t-stats.

 

[THEFERMANATOR]

The 180 stats do nothing to help it run cooler, all it does is make it take a little longer before it gets hot. Put a set of stock ACDELCO stats back in it for best milage and flow.

 

[bgiovan]

Fermanator, curious about the dual to single comment. I thought everyone wanted to go the other direction?

 

[racedaymechanic]

My Radiator looked like every other 200k plus one does, dirty bent fins, Overall a POS, I just said screw it and bought a New Delphi one, and replaced the rest of the hoses that I didnt do when i put the new engine in, also new AC delco thermostats, and a severe duty fan clutch, it hasnt gone over 200F since and I sleep a little better less than 500 Bucks for everything

 

[skypilotj]

Same here. I ran 210+ towing with Modded Hays SD clutch. I cleaned and I mean cleaned AC condenser and oil cooler before the trip. I ordered a radiator before the trip, but they shipped the wrong one. So I went on without it.
I changed radiator before the return trip and stayed at 195 even on long grades pulling the same load. I seldom had to downshift the NV4500 out of fifth. My only other mod is the PMD relocate. It went out on the way down to Texas. I kept it running for a week with a wet hand towel wrapped around it and kept it wet before the Big Brown Truck arrived with the new one. The trip home was a breeze.

 

[HighSierra86]

Fermanator, curious about the dual to single comment. I thought everyone wanted to go the other direction?

Alot of people claim the single stat housing flows better with a more equal flow to either side. My 96' has the dual settup from the factory and I have ZERO problems with overheating.

I would suggest clean the radiator youself or bring it to a rad. shop and have it professionaly cleaned. And like noted above, make sure the t-stats are AcDelco.

-Nick

 

[THEFERMANATOR]

Alot of people claim the single stat housing flows better with a more equal flow to either side. My 96' has the dual settup from the factory and I have ZERO problems with overheating.

I would suggest clean the radiator youself or bring it to a rad. shop and have it professionaly cleaned. And like noted above, make sure the t-stats are AcDelco.

-Nick

The new threaded style water pump gives you the better balanced flow to each side. Teh theory behind going back to a single stat is it has a bypass in it that gets blocked when engine temps climb whereas the dual stat does not. GM realized the error later on because the DMAX uses a ual stat housing, but they made it with a T-stat that blocks off the bypass at higher engine temps to give full flow through the radiator whereas teh dual stat design will bypass coolant through the bypass hose even if both stats are wide open. This is why many have put a restrictor in the bypass hose so it cannot flow as much which forces more through the radiator. Also it is wierd to note that the 6.5 uses a HUGE water pump in it from late 96 on. The 96- used a 80 GPM pump, but mid year 96 went to the 130 GPM pump. In 99 when they went to the threaded style fan clutch they improved the balance flow, but kept it at 130 GPM of flow. The DURAMAX in 01 though went to a 96 GPM pump, and in 06 with the LBZ I believe they went to a 120 GPM pump.

 

[Raleigh]

Water Wetter is a must for any 6.5 IMO...

 

[Twisted Steel Performance]

Water Wetter is a must for any 6.5 IMO...

Yep, or one better I think is Evans NPG coolant with a low pressure cap.....

 

[Chief915]

Agree with everyone else..... clean out the stack and stuff thats between them. I had dirt, pine needles, bugs, etc in between my stack but it looked clean from the engine side and from the grille side.

After cleaning out my stack, and with the cooling mods in my sig, I have no problems at all with tempratures. Last weekend I towed a vehicle and 18' trailer down the interstate with the cruise set on 70, and A/C on (it was 90 outside), and it never went above 210 on the factory guage. The time that it did go to 210 was going up a long, and decent, grade with the cruise set on 70. The scanner shows 200* coolant temp while the factory guage, which is notoriously inaccurate, shows 210.

The turbo and tune will really make a big difference. It's kind of a good thing that you did this trip on the factory turbo and tune. Reason being, now you know what the "baseline" is and you will really be amazed at the improvement in power, mpg, and general drivability with the new tune and ATT.

 

[racer55]

Another factor of a clean cooling stack is that the fan clutch can only engage when it has hot airflow on it-not enough airflow through the stack and no fan clutch engagement.