JeepcoMJ Posted May 28, 2012 Share Posted May 28, 2012 I've got a good used hesco thermostat that I'm putting in my xj this week, 4.0 block fyi. While I'm at it, I was thinking...does anyone have thoughts about putting a smaller pulley on the water pump in order to make it push fluid a bit faster? I've already got dual obd2 efans , one constant with accessory power to replace mechanical fan, one sensor controlled with a bypass. I can't let it run more than 15 minutes at idle without the check gauges light coming on and the temp gauge being at 230 or higher. Granted, my tstat housing is boiling off a very small amount of fluid through a bad gasket... Side note, cooling improved when I removed mechanical fan. Checked with several known good mech fans. It's tough to keep the stroker cooled... Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 28, 2012 Author Share Posted May 28, 2012 Radiator is a full core aluminum btw, almost new. Water pump has under 10k miles , 50% mix green coolant of same age, put in after a flush. Old coolant came out perfectly clean. Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 28, 2012 Share Posted May 28, 2012 No and you really don't what the coolant to exchange any faster, it needs to stay in the rad long enough to cool. The thermostat is there to create a balance, it continually exchanges hot coolant for cool coolant. May be a bad stat. One way to make the flow constant yet restrained is to use a reducer plate instead of the stat. Link to comment Share on other sites More sharing options...
knever3 Posted May 28, 2012 Share Posted May 28, 2012 You can get a high flow water neck and a high flow water pump. In my last XJ I got the high flow water neck but not the pump. I installed a new radiator with a standard flow pump and after flushing the heater core and block everything was excellent. I used a stant fail proof thermostat. I used to have problems running over 220 in the summer with the A/C, after the water neck upgrade and new wp and rad everything was perfect. Right up until someone pulled out in front of me and crushed my front end weeks later. :headpop: I also changed the fan clutch multiple times since it howled draining the power. The parts store ones must be bad because I finally got a good one that releases when it's cold. Link to comment Share on other sites More sharing options...
jimoshel Posted May 28, 2012 Share Posted May 28, 2012 Bad idea, Besides the reason given above, heat transfer, there is also a condition known as 'cavitation'. When a fan blade, or propeller, turns to fast it creates turbulence and no air flow, thus no cooling and loss of HP. This also applies to the vanes on the water pump. They turn to fast they create turbulence, cavitate and no water flow. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 28, 2012 Author Share Posted May 28, 2012 K. Tstat housing is already high flow, and maybe the tstat in it currently is bad. I figured that's why I'd put in the hesco one. It's used, but I did the boil method to determine that it opens and closes at proper temps. Link to comment Share on other sites More sharing options...
knever3 Posted May 28, 2012 Share Posted May 28, 2012 Do you have a pressure tester? If so check your radiator cap and pressure test the system to make sure you have no leaks. After all as you probably know if the system isn't allowed to get up to 16psi your coolant will have a MUCH lower capacity to cool because it can boil quickly since water/antifreeze mix boils at around 225*. Check it out: Fluid - Freezing Point - Boiling Point Pure Water: 0 C / 32 F - 100 C / 212 F 50/50 mix of antifreeze/Water: -37 C / -35 F - 106 C / 223 F 70/30 mix of antifreeze/Water: -55 C / -67 F - 113 C / 235 F The temperature of the coolant can sometimes reach 250 to 275 F (121 to 135 C). Even with ethylene glycol added, these temperatures would boil the coolant, so something additional must be done to raise its boiling point. The cooling system uses pressure to further raise the boiling point of the coolant. Just as the boiling temperature of water is higher in a pressure cooker, the boiling temperature of coolant is higher if you pressurize the system. Most cars have a pressure limit of 14 to 15 pounds per square inch (psi), which raises the boiling point another 45 F (25 C) so the coolant can withstand the high temperatures. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 28, 2012 Author Share Posted May 28, 2012 The rad cap is brand new, and as started the main reason for the new tstat is that the housing weeps a bit of fluid at the gasket. I'm sure I have a pressure tester somewhere, but it's useless until I replace that gasket. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 28, 2012 Share Posted May 28, 2012 After much trial and error, here's what works great for me: 1. Dual 10-blade electric fans (Make sure the shroud of the fan that replaces the mechanical fan is no more than 1/4" away from the rad coils; close as you can get it). This is the main cooling fan. 2. Thicker two core all-aluminum FFD radiator w. 12 PSI pressure cap. (http://www.ffdynamics.com/JeepRadiatorsA.html). 3. Hesco high-flow thermostat housing and water pump, Mopar 195* thermostat. 4. Return hose with the internal spring. 5. Cowl hood (heat really pours out the back when in traffic). Temp gauge never goes above 220*, and the second fan is seldom needed. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 28, 2012 Author Share Posted May 28, 2012 Don, thanks. I'd love to have the cowl good, but $$$. That hesco tstat housing is externally identical to stock, with a, larger internal bore, correct? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 28, 2012 Share Posted May 28, 2012 Don, thanks. I'd love to have the cowl good, but $$$. That hesco tstat housing is externally identical to stock, with a, larger internal bore, correct? Yes, that's correct, at least the one I have is like that. With your skills I would think you have more than enough talent to fab your own cowl hood. It really really helps the underhood air flow. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 28, 2012 Author Share Posted May 28, 2012 I could, but the last one didn't turn out looking nice as I would like. Fit and finish is important. It has to look like it belongs. Don, do you by chance have any pics of the inside of your tstat housing that I could use as a guide for milling mine out? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 28, 2012 Share Posted May 28, 2012 Mine is exactly like this: http://gojeep.willyshotrod.com/HowtoWaterpump.htm Link to comment Share on other sites More sharing options...
Eagle Posted May 28, 2012 Share Posted May 28, 2012 While I'm at it, I was thinking...does anyone have thoughts about putting a smaller pulley on the water pump in order to make it push fluid a bit faster? That may be counter-productive. When I crewed on a stock car, everyone cut down the impellers on their water pumps to flow LESS water, so the water had more "dwell time" in the radiator to allow the heat to transfer. If the water was pushed through too fast, the rate of transfer wasn't sufficient to remove enough heat. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 29, 2012 Share Posted May 29, 2012 While I'm at it, I was thinking...does anyone have thoughts about putting a smaller pulley on the water pump in order to make it push fluid a bit faster? That may be counter-productive. When I crewed on a stock car, everyone cut down the impellers on their water pumps to flow LESS water, so the water had more "dwell time" in the radiator to allow the heat to transfer. If the water was pushed through too fast, the rate of transfer wasn't sufficient to remove enough heat. I kinda agree with that, but for a different reason. Stock cars run flat out for short distances so the flow would be maximum at all times; you can afford to slow the flow. And they don't sit in traffic or rock crawl where you need maximum coolant flow keep the engine cool when there is little air flow. I wouldn't mess with the pulley to increase the pump RPM; more wear and tear and more HP needed to turn it. But I would consider a Hesco or similar high flow H20 pump because of their more efficient impeller design. It pushes more water and takes less HP to turn the pump. In fact, Chrysler used the Hesco-designed impeller on the 01 XJ water pumps and maybe others. Link to comment Share on other sites More sharing options...
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