Keeping the 454 cool at idle...

[BratRod]

96 k2500 w/l29 bigblock

The truck runs great and stays about 180-190 on the move. But when it sits idle in the ever gridlocked DFW traffic it starts to creep up. A/C then shuts off and nobody is a happy camper.

There's this cute little pusher fan on the passenger side but it doesn't seem to do much when it comes down to things. I've read plenty of threads on the MARKVIII upgrade, but nobody seems to have done one on the big engine.

I'm also looking at FLex-a-Lite 208 kit that advertises 5,500CFM. This truck sees some towing that reaches close to 8k at times. And I'm a little worried that the efans will not be able to keep up vs the 10,000cfm clutch fan.

Thoughts... advice?

Thanks

 

[my name is alex]

My 99 454 stays cool regardless of idle time and outside temp (gets well over 100 here, frequently) so I wonder what the underlying issue might be with your truck?

 

[BratRod]

Not sure... I've only had it for a few months. I checked for combustion gases. And it doesn't use any coolant. So I'm not terribly sure. Maybe old/clogged rad or old coolant.

 

[90halfton]

About every 5 years I pull the radiator out, set it flat on a set of saw horses, rinse out the fins with a garden hose (low psi), soak it in mean green, or equivalent degreaser, let it set for an hour or so, rinse out again. Repeat as necessary until you can see through the fins as clear as day. Do this to the condenser too. I never pull the condenser out, just do it with the hoses still attached. Use this opportunity to stick the garden hose down the neck of the radiator and rinse all the crap out of the inside, and switch hose from top neck to bottom one and rinse it out both ways until only drinkably clear water is coming out. Also while you're dickin with it take a knife blade or long terminating screw driver and carefully straighten out all the condenser fins that have been jacked up by years of pressure washings, bugs, and birds or what the hell ever. Take your time doing this and you'll appreciate the results.

 

[BowtieBrody]

Holy hell my big block runs hot then; constant 210 running temp, just had a coolant flush done a couple thousand miles ago and a new thermostat. PO put in a new radiator 2 months or so before I bought it to boot,

I figured it was normal operating temps as my dad's 454 C3500 sits about the same, my old 350 Suburban ran ice cold but I put in an HD rad, had the severe service fan clutch and a 11-blade fan.

Any upgrades I could do to make my old pig run better?

 

[DerekTheGreat]

Hmm. Is it the original water pump? I've heard that a poorly rebuilt one won't really pump much at idle, so that could be part of the problem. Another thing is like what 90halfton said, make sure the radiator is clean & free of debris, especially between the radiator & condenser. Also, if the coolant is murky and such, have it flushed. It's no bueno to pump chocolate milk around.

We once had an '88 C3500 with a 454. A/C didn't work but it never overheated. Had that little fan you mentioned but IIRC it is only supposed to come on when you switch the A/C on or if it gets to hot. The engine did get hot two times though. Once when we first bought it, as the coolant had never been changed in it's life and was black and nasty and then when the serpentine belt snapped. I only remember that fan coming on when the belt snapped but by then I had spent a lot of time cleaning up grounds & connections so I think that's what the problem was with the fan. Oh, I replaced the thermostat, replaced the radiator & thermostat when we got it home.

 

[Christian Steffen]

I'm going to guess a good cleaning of the radiator will help, but there has to be another issue that's causing it to get hot. Is your fan clutch good?

These trucks are supposed to run right at about 195 degrees, so the temps you're seeing while moving are good.

Also, it must be getting quite hot. The AC disable temp in the stock tune (mine anyway) was set to 256 degrees. I've never seen my truck get that hot, even pulling a 10k horse trailer around western SD in the heat of the summer, sometimes sitting idle for awhile with the AC running, or pulling large hills in the Black Hills or Big Horns.

Edit: I would be curious to see someone try the mark VIII fans on one of these though, I've been kicking around the idea of swapping to them.

 

[BratRod]

The hottest I've seen it is 230. If I get a chance I'll pull the radiator and see what kinda debris is stashed between the condenser.

The clutch fan seems to be fine. Kicks in when hot and will cut out at about 2500rpm. Just doesn't move enough air at idle it seems.

Thanks for the ideas. Keem em coming.

 

[c1500deathtrap]

If you are running hot, verify radiator efficiency via inlet and outlet temps. I use an ir thermometer.If that's good check airflow, I.E. is the clutch in your fan operating properly ( or at all)? If those fail then suspect blocked water path or FUBAR water-pump. Given that your temp drops while moving i would suspect inadequate airflow at idle I.E. bad fan clutch.

 

[Tom P]

I had a similar issue with my '00 k3500. Sitting in construction traffic in Eastern WA in late July, the truck started to get hot and my A/C died. Made for a very crabby family, especially when I had to turn the heat on to finally stem the tide of over heating. But other than that it never got hot unless I was pulling a hill with a decent load. I have a 180* thermostat in my truck which I've decided to pull now and replace with a 195*. I'll probably do a new water pump and a radiator and condenser cleaning while I'm at it. The under hood temp on my truck seems high too, compared to my Dad's '06 1500 when we just pulled the same mountain pass. An IR thermometer would have been fun to have at that point.

I would hesitate to try an aftermarket solution before making sure you don't have a real issue at the root of this problem. Like the other guys said, could be a semi clogged radiator, could be a bad water pump, could be a sticky thermostat, it could even be that your coolant is bad, who knows. But throwing a bunch of new parts or investing in a new system may not even solve your root cause.