Keeping the 454 cool at idle...

[Mike Napolitano]

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

If it runs hot at idle only then the fan clutch is worn and it could be possible that the propeller in the water pump could be an issue. Also flush out air passages in radiator and condenser with compressed air and spray some degreaser that you can get at an auto parts store and let it soak and then rinse with a garden hose.

 

[BratRod]

Well unfortunately it wasn't as simple as debris clogging up the condenser or rad. Very clean in here...

Coolant looks a little nasty. Thoughts on Dexcool vs the generic stuff.

You must be registered for see images attach

 

[Black_cirrus]

Make sure your radiator cap is good. When I got mine it was border line on cooling system and I was looking over it. Noticed staining on the radiator neck, cap wasn't holding pressure. The elec fan was also seized. I put in a heavy duty fan clutch and 9 blade fan vs the old school 5 blade also. I still have coolant flush on my to do list that never gets smaller.

 

[BratRod]

Make sure your radiator cap is good. When I got mine it was border line on cooling system and I was looking over it. Noticed staining on the radiator neck, cap wasn't holding pressure. The elec fan was also seized. I put in a heavy duty fan clutch and 9 blade fan vs the old school 5 blade also. I still have coolant flush on my to do list that never gets smaller.

I ended up flushing the system yesterday, and put a new cap on. Filled her up with the green stuff and I've yet to see it hit 210 while at idle. Which is a big improvement. I've also wired the aux fan to come on with the A/C.

Where did you source your 9 blade from?

 

[DerekTheGreat]

Looks like it was DexDie gumming up the system that was the problem. Nothing wrong with the green stuff, especially if swapped out every 3 to 4 years. I thought that fan was supposed to come on with the A/C anyway?

 

[Tom P]

Looks like it was DexDie gumming up the system that was the problem. Nothing wrong with the green stuff, especially if swapped out every 3 to 4 years. I thought that fan was supposed to come on with the A/C anyway?

Supposedly not until the coolant reaches a certain temp... 200*+ I believe. Can be adjusted if you get a PCM Tune or you rewire the relay to kick on with the A/C

 

[Black_cirrus]

I ended up flushing the system yesterday, and put a new cap on. Filled her up with the green stuff and I've yet to see it hit 210 while at idle. Which is a big improvement. I've also wired the aux fan to come on with the A/C.

Where did you source your 9 blade from?

So it's just the plastic blade from a 350 vortec with heavy duty cooling off rock auto for about $40. They list the stock 5 blade metal fan as standard so I figured it's at least a minor upgrade. Some vortec 7.4s got an 11 blade metal fan but that piece was almost $200 hoping to find a junkyard one someday but I'm not looking to hard. I think my aux fan runs with the ac but mines a 95 tbi so it's a bit different.

 

[DerekTheGreat]

Oh, that would explain why I never saw mine kick on while we had that truck, but why it would power on if I powered it directly..

Sweet, did you have to change the shroud to accommodate the better fan?