Keeping a 4.7 cool

[Spjewell]

I took my 4.7 stroker on a test run this weekend and overheated 20 min in . What do you guys run to keep it cool?

Currently have a flow cooler pump, 4 row aluminum radiator, and 2 10" jdm eBay special pushers, and 2 pullers. Supposedly 1700 cfm each, but I suspect far less is actually produced. Before dropping any more $$$ I would like to know a setup that works.

Can't run a mechanical fan due to space restrictions (~3" rad to water pump center pin.)

[6TIME]

What Tstat and how hot did it get? Are you saying you are running electric pullers and pushers on both sides of your radiator?? My experience with electric fans is buy cheap and get crappy overrated airflow...been there done that. Buy quality fans and get great cooling. Spal is on the top of my list for electric fans that provide legit airflow. 2 good pullers should work fine. I've been running a 14" Flexalite and a 10" Spal. for 6 years, they cool adequate on 100* days. Will switch to 2 11" Spal hp fans in near future for towing steep grades.

[Cheromaniac]

My cooling system is entirely stock except for a 1600cfm electric fan that I have in place of the original mechanical fan, and a Robertshaw 180* t'stat. I have no problems keeping my engine cool.
How hot does your engine run and when? On the highway or pootling at low speeds around town?
I noticed you have a 4-row radiator and that could be your problem. Each row has to be much thinner than stock to fit within the same radiator thickness and the result is reduced coolant flow. It's better to have a radiator of the same thickness with only two rows rather than four.
Your pusher fans may actually be hurting the efficiency of the puller fans by blocking part of the radiator so I suggest you remove them.
You'll know if the puller fans are doing their job 'cause you'll feel a blast of hot air when you put your hand behind the radiator.

[Spjewell]

Currently I am running a 160* tstat. Around town its fine, overheated at alt off-roading. ~240 deg, then it locked in and oil pressure started dropping.

[SilverXJ]

2 10" jdm eBay special pushers, and 2 pullers. Supposedly 1700 cfm each, but I suspect far less is actually produced.

I wouldn't trust those. That 4 row rad could also be questioned.

Currently I am running a 160* tstat.

Thats too cold.

[Spjewell]

For the time being I am trusting the radiator... it is much thicker than stock and internal tube Dia seems to be about the same.

What would be good to run for a t-stat? I don't fully understand why 160 is bad. Fyi, I run fan control switches set at off <180 med <210 high. With 4x fans that's 2x low, 4x high.

I think my culprit is the cheap fans... who puts out a line of fans that meet their spec?

[SilverXJ]

The engine needs to be at a certain temperature to achieve proper burn of the air/fuel mixture, not fight with the PCM, proper oil film, and to burn off pollutants in the oil and crank case. 195* is stock and what you should be using. 180* the lowest. Also, any tstat will have no bearing on an over heating issue unless it is faulty.

I can't recommend as I am not that familiar with the engine bay layout.

[amceaglesx4]

I would just use pull fans not push at all. Like it was said push block the radiator. Its very easy to wire them in the wrong direction. Maybe your push fan and pull fan are going against eachother basically leaving no flow through the radiator.

[gradon]

I'm running two stock '97+ XJ 10-blade e-fans in mine(guy over on NAXJA measured them to flow 2300cfm each). I just fixed the bad connection at the relay for the second fan yesterday(in time for the 20+ run autocross on Sunday). The 160* t-stat is a no-no(I'm running 195* super stant). And as others said, you don't need more than two-rows.

[Radioactivexj]

I would say the fans you have are overkill. I'm running the stock electric fan and a 1700cfm ebay special, no mechanical fan. I've never gone above 180* with the fans on. Seems like your issue is elsewhere. Just so you can rule it out I would replace your t-stat with a 180* replacement. This might be obvious but have you made sure that their is no air in your cooling system? Sometimes it's the small things that give us the biggest issues.

[jsawduste]

From your profile I see you are running a YJ.

A stock cooling system is all my stroker has ever needed. I did run a Spal electric at one point but after several fan failures I went back to all factory parts. Never would consider an electric again. The Spal, even when working well didn't do a very good job compared to the factory parts.

Be it running at 80 mph or crawling at Rocks and Valleys. Do yourself a favor and revert back.

[Spjewell]

Thanks for the feedback guys! I will be out of town in TN for the summer (live in ca) due to work, but once I get into the trouble shooting I will post back.

[Cheromaniac]

Be it running at 80 mph or crawling at Rocks and Valleys. Do yourself a favor and revert back.

At 80mph there should be enough airflow through the radiator to keep the engine cool without a fan.
If the engine's running hot on the highway, the problem isn't the fan(s) but either insufficient airflow through the radiator (blocked fins, obstruction in front of radiator) or insufficient coolant flow through the radiator (clogged up radiator or cooling passages, insufficient core area, worn water pump vanes, thermostat stuck partially closed, lower radiator hose collapsing due to rusted out internal spring).
An engine that runs cool on the highway but runs hot at rockcrawling speeds has insufficient fan capacity to pull cool air through the radiator. Some aftermarket fans don't cut the mustard and others that do may have a high amp draw, requiring an upgraded alternator to prevent the battery from being drained. Large mechanical fans don't have that problem but have other disadvantages such as parasitic HP drainage and shortened water pump life (if mounted on water pump pulley) so pick your poison.

[jsawduste]

Your right Dino but do recall that a mechincal fan driven by a thermal clutch should only cause a parasitic drag when the clutch is I engaged. Once the bi metal spring cools the clutch disengaged and the fan is considered free spinning.

[Cheromaniac]

Your right Dino but do recall that a mechincal fan driven by a thermal clutch should only cause a parasitic drag when the clutch is I engaged. Once the bi metal spring cools the clutch disengaged and the fan is considered free spinning.

Absolutely correct sir.