Cooling at an idle

[tdangle]

Yesterday it was 96 outside. Waiting in line at a restaurant I noticed my temp slowly climb to the top 2/3 of the normal operating range. Of course I had the A/C running. As soon as I hit the road, within a long block it was back down to the bottom 1/3 of normal range. I had an 88 1 ton with a mechanical fan and a small pusher electric fan. Wondering about picking up a pusher fan for my truck and wiring it so it comes on with the A/C. Didn't overheat, I just like to see the temp gauge not move at all from normal. Pros/Cons??

[Southcity]

I run a similar setup to what you are thinking about: AC truck, 454 engine, aluminum Griffin radiator, belt driven fan + pusher fan which can be set to turn on when a specific temp is reached. Many electric fans have a manual override so the electric fan can be switched on/off as desired. Works well and does help in those idling situations. I've always wondered how waterless coolant performs and if it would negate the need for additional electric fans on a cooling system. I'm sure others will chime in with thoughts/recommendations.

[MARKDTN]

Assuming a good water pump and decent radiator. Do you have a fan shroud? Mechanical clutch fan? If you don't have a good shroud, get one. If you do already have a good shroud, sounds like your fan clutch is failing. I'm all for electric fans, but should not be needed for a SB crate motor and then you would need a bigger alternator and then the ammeter has to be bypassed and bigger wiring......

[Andy4639]

Make sure the air is going through the radiator and not around it. Sealing off any air paths around the radiator will help big time on staying cool while sitting still. I have found that a puller is much better than a pusher. If you have the shroud set up as it should you should be able to install a nice puller up inside the shroud right against the radiator and still have the belt fan also.
These are pictures of my 64 SS Impala fan setup. But it is the same idea as for the truck. I have a 2 speed fan setup to come on low with adjustable thermostat and then if I turn the AC on the high speed kicks on. They both run through the same relay. The car runs @ 190* all the time even at a stop.

[Stocker]

As mentioned, radiator & water pump in good shape, correct fan shroud (fits the truck and is not broken), heavy duty thermal fan clutch in good operating condition, six-blade or better yet, seven-blade fan fitting half-in the shroud, 180* or 190* thermostat..... you should be good to go without adding a pusher fan.

[tdangle]

Originally Posted by Stocker

As mentioned, radiator & water pump in good shape, correct fan shroud (fits the truck and is not broken), heavy duty thermal fan clutch in good operating condition, six-blade or better yet, seven-blade fan fitting half-in the shroud, 180* or 190* thermostat..... you should be good to go without adding a pusher fan.

New engine, new water pump, new HD Clutch fan, 7 blade fan, factory shroud, 180 thermostat, Radiator is almost new (HD 3 core I believe) position of fan is correct in shroud. 2 v-belts turning the pump. Like I said, it doesn't overheat I just like to see the temp gauge not move even with sitting for 15 minutes with the engine idling with A/C on in 96* heat. And the fact it cooled down so quickly makes me think air flow at an idle. Stop and go traffic the gauge doesn't move

[tdangle]

Originally Posted by MARKDTN

Assuming a good water pump and decent radiator. Do you have a fan shroud? Mechanical clutch fan? If you don't have a good shroud, get one. If you do already have a good shroud, sounds like your fan clutch is failing. I'm all for electric fans, but should not be needed for a SB crate motor and then you would need a bigger alternator and then the ammeter has to be bypassed and bigger wiring......

I found out a few years ago the the shroud is important. Never run without one. Yes HD Clutch and 7 blade fan. Don't know why if installing a higher amperage alternator you would have to bypass the battery meter. No real current flows thru the battery meter. It just detects the difference in voltage between 2 points and shows charge or discharge.

[tdangle]

Originally Posted by Andy4639

Make sure the air is going through the radiator and not around it. Sealing off any air paths around the radiator will help big time on staying cool while sitting still. I have found that a puller is much better than a pusher. If you have the shroud set up as it should you should be able to install a nice puller up inside the shroud right against the radiator and still have the belt fan also.
These are pictures of my 64 SS Impala fan setup. But it is the same idea as for the truck. I have a 2 speed fan setup to come on low with adjustable thermostat and then if I turn the AC on the high speed kicks on. They both run through the same relay. The car runs @ 190* all the time even at a stop.

Good idea, I'll look into it.

[Lee H]

What temp gauge? If stock these are notoriously inaccurate, even the after market ones are iffy. Did the clutch fan lock up? If not you were probably not very hot, or it’s not operating properly. Best to get as ir heat gun and start taking readings, see if your really getting hot. My factory gauge barely gets to 1/4, my SW gauge reads 230, ir gun says 190 at the hottest points on block, intake, radiator, hoses, even on 100+ days with AC on. My clutch fan rarely locks up but when it does it cools fast.

[Steeveedee]

One of the things I discovered with my truck running hot was that at idle, the flow when the truck was at temperature and the thermostat was open, that there wasn't a lot of flow in the radiator. I bought a high flow thermostat and that helped. This was with a severe duty clutch and a fan that properly engaged the shroud. Drain a couple of quarts out of your radiator and watch the flow with the cap off and the thermostat open. This assumes that the radiator, hoses and water pump are up to snuff.

Although I will have to say that with the AC while on sitting in traffic, it's going to get warmer.