Renix water pumps and Fan clutches?s & overheating

I am looking for better after market parts than what O'Reileys, Autozone and Advance auto stock.

Does anyone sell a new cast iron (steel) water pump for the Renix 4.0?

Does anyone sell a better fan clutch, that fits the Renix 4.0, better than Hayden's OEM equivalent, or the standard stock one, made in China one that all three of the stores I listed above stock. I was surprised that the one they stock made in China is beefier ( far more fins for heat sink) than the Hayden one that is assembled in the USA.

What about the high flow water pumps I have heard so much about? Who has those? Has anyone ever been happier with them?

Mike, are you still on the closed system?

I am and my 90 runs too cool with a 3 row brass/copper radiator. I have the grill blocked even in the summer just to stay around 205. I'm considering taking the clutch fan off and installing an electric fan on a t-stat so I can keep it at temp. I know for sure that I have no air in the system and my thermostat is good. Its odd that a properly working closed system is running too warm.

Hm.

I don't recall having seen an OEM water pump for us in anything other than aluminum - the last steel ones I've seen were 1970's-vintage Chevrolets and the like. Aluminum's been used because it's cheaper.

If you want to make a conventional pump a "high volume" pump, just add a baffle plate to the impeller. Cut a disc the same diameter as the impeller, bore a hole in the centre to clear the shaft (if required,) and use three or four evenly-spaced rivets to retain to the bottom of the impeller. Works on the same principal as ducting a fan to make it more efficient.

I think the last fan clutch I bought was a Flex-A-Lite, but it's been a few years. I probably don't even have the box anymore...

xjtrailrider said:

Mike, are you still on the closed system?

I am and my 90 runs too cool with a 3 row brass/copper radiator. I have the grill blocked even in the summer just to stay around 205. I'm considering taking the clutch fan off and installing an electric fan on a t-stat so I can keep it at temp. I know for sure that I have no air in the system and my thermostat is good. Its odd that a properly working closed system is running too warm.

Click to expand...

Yes, it is OEM Renix, closed system. It has run very cool for a good 4 years since I replaced the radiator, 2 row, plastic disposo Radiator, thermostat (160 and later upped it to a 180 a year ago), new hoses and new turtle tank. On my second turtle tank now. I lost the lower radiator hose 4 weeks ago, when it just blew off the radiator nipple. I just figured it was a loose clamp after 4 years, and the plastic nipple has almost no ridge at the end to hold the hose, poor design.

Then it ran fine for a week, then I parked it for a new Harmonic balancer replacement, did that, and starting driving it again this week when it started getting hot again. My dash gauge is reading about 20-30 F cooler than the IR gauge reads on the thermostat housing! That is also a new!

Have you pressure tested the system to see if you have a small leak? It doesn't take much for the closed system to get out of whack.

Ecomike said:

Yes, it is OEM Renix, closed system. It has run very cool for a good 4 years since I replaced the radiator, 2 row, plastic disposo Radiator, thermostat (160 and later upped it to a 180 a year ago), new hoses and new turtle tank. On my second turtle tank now. I lost the lower radiator hose 4 weeks ago, when it just blew off the radiator nipple. I just figured it was a loose clamp after 4 years, and the plastic nipple has almost no ridge at the end to hold the hose, poor design.

Then it ran fine for a week, then I parked it for a new Harmonic balancer replacement, did that, and starting driving it again this week when it started getting hot again. My dash gauge is reading about 20-30 F cooler than the IR gauge reads on the thermostat housing! That is also a new!

Click to expand...

Check the temperature at the back of the head, vice at the front. Recall that the sensor that drives the gage is at the rear, and it's not going to get as much flow over it as it would further forward. Less flow = less heat drop...

xjtrailrider said:

Have you pressure tested the system to see if you have a small leak? It doesn't take much for the closed system to get out of whack.

Click to expand...

Coolant bottle level has not changed in 4 weeks and about 300 miles so far. No signs of leaks anywhere yet. No I have not pressure tested it, except by running it.

But I was on the freeway 4 weeks ago when it dumped the coolant because the lower radiator hose blew off at the lower radiator connection. It went from 240 F to 260 F on the dash gauge while I pulled off the freeway to stop and park, and shut it down. IT was at 240 F when I first noticed the problem. I never saw any steam while still driving, so I did not know it had dumped the coolant already. I let it cool down for 2 hours before refilling it with 50/50 coolant. Drove it home, 30 miles, AC off that night with no more problems. Next day toped off the coolant bottle, ran it at idle for 30 minutes in the drive way, on a hot day (the next day) with AC on, and no problem, it ran normal. Drove it for a week on short local trips, no problem. Drove it 33 miles each way on freeway, not problem. Then parked it to replace the Harmonic balancer. Next long freeway trip it tripped out, LOL.

5-90 said:

Check the temperature at the back of the head, vice at the front. Recall that the sensor that drives the gage is at the rear, and it's not going to get as much flow over it as it would further forward. Less flow = less heat drop...

Click to expand...

In the past I have had good correlation between the dash gauge reading and the thermostat temperature. Currently, once it is hot, I am seeing a 20 to 30 degree F rise between the dash gauge sensor temperature and the thermostat housing temperature. Using the IR I am seeing as much as 20 F delta T from the dash gauge sensor location, rear of the head, to the thermostat housing temperature measuring both with the IR gauge.

I drilled 2 holes in a 160 F thermostat (new), installing it today. Will bleed the rear block head at the gauge sensor this time. Will also replace the fan clutch, and maybe the water pump today.

Since it ran dry on the freeway for 1-2 minutes before I shut it down (4 weeks ago, note that I did know it has lost any coolant until after I shut it off and raised the hood) maybe the water pump seal took a hit and is sucking a little air now.

I just hope the head and HG is still OK. I have done 2 head jobs the last 12 months on my family fleet already!:tears:

I installed the ZJ HD fan clutch, direct fit, NAPA #272310, $44.

joe_peters said:

I installed the ZJ HD fan clutch, direct fit, NAPA #272310, $44.

Click to expand...

I checked that number at NAPA online, and their picture looks exactly like the one everyone else has here, but they are all made in China. :shiver:

I replaced my fan clutch, thermostat (drilled 2, 5-90 style holes at 180 degrees apart in it), and replaced the water pump. Will bleed the gauge temp sensor at rear of block during file up this time. Putting coolant in it shortly for a test drive.

5-90 said:

Check the temperature at the back of the head, vice at the front. Recall that the sensor that drives the gage is at the rear, and it's not going to get as much flow over it as it would further forward. Less flow = less heat drop...

Click to expand...

Mine seems to be getting more flow, and seems to run about 30 F cooler that the coolant at the thermostat housing. I suspect the gauge sensor is seeing coolant just coming out of the water pump (still cooler from the trip through the radiator), and it heats up going forward through the head due to exhaust heat heading it through the head to the exhaust manifold. At least that is what my IR gauge and dash readings are telling me.

You may also want to check temperature at the front of the head, instead of at the thermostat housing. Recall that aluminum conducts heat better than iron does...

IR is also color sensitive. For most accurate reading, they say to paint flat black. My aluminum tstat hsg is silver. Cast iron head is different (darker) color.

Ecomike said:

Yes, it is OEM Renix, closed system. It has run very cool for a good 4 years since I replaced the radiator, 2 row, plastic disposo Radiator, thermostat (160 and later upped it to a 180 a year ago), new hoses and new turtle tank.

Click to expand...

You need to go back to a 195 thermostat and see what your temperature is.
I run at 210-215 all the time now with everything dialed in on this closed system. And the zj fan clutch is a big improvement no need for anything else

dellstopjeep said:

You need to go back to a 195 thermostat and see what your temperature is.
I run at 210-215 all the time now with everything dialed in on this closed system. And the zj fan clutch is a big improvement no need for anything else

Click to expand...

A 195 F thermostat just speeds my trip to an overheat condition. I saw no difference between a 160 F and 180 F T-stat as far as final equilibrium values goes, except that it takes longer to overheat. The 160 F versus 195 F T-Stat buys me 10 to 20, sometimes 30 minutes of extra time before it gets to range where I start worrying about the plastic bottle in the closed system, or another radiator hose blowing off the rad nipples.

I don't like running it over 200 F.

Regarding the IR comments below, most everything is black where I taking readings, including the T-stat housing. The IR I have samples an area, not a small point, so it is difficult to get precise numbers on the front head near the # exhaust manifold where there is less than an inch between it and the edge of the T-stat housing. But I have compared mine to my daughters 89, I see no unusual spike areas, just a general over all increase in ALL test location temps of about 20 F higher on mine versus hers at peak saturation temps (after a good 20 minute run on both).

I do get higher IR gauge temp readings if I get the sensor closer to the sample point, and it drops off as I back the IR gauge away. So it gives more of a reference point check, than an absolute T value to sampling verability using the IR gauge. For instance at 3" I might read 210 F, then at 12" away the same location only reads about 195 F.

I can get closer to some sample points with the IR gauge than others. The IR gauges sample an increasingly larger area as the gauge gets farther from the tested surface.

I read most of what you've stated about your overheating. This sounds like a tough one. Could the timing be retarded and causing the overheating? Can you put a timing light on it and check what the timing is? Maybe the CPS has moved and the timing is retarded? Likewise, maybe FlowKooler makes a water pump for this year XJ.

Best regards,

CJR

dellstopjeep said:

You need to go back to a 195 thermostat and see what your temperature is.
I run at 210-215 all the time now with everything dialed in on this closed system. And the zj fan clutch is a big improvement no need for anything else

Click to expand...

How did you get a ZJ fan clutch to clear the radiator?

CJR said:

I read most of what you've stated about your overheating. This sounds like a tough one. Could the timing be retarded and causing the overheating? Can you put a timing light on it and check what the timing is? Maybe the CPS has moved and the timing is retarded? Likewise, maybe FlowKooler makes a water pump for this year XJ.

Best regards,

CJR

Click to expand...

Getting the CKP to move would be difficult - it's located by shoulders on the retaining screws, and the shoulders are a relatively close fit in the sensor bracket holes (I took advantage of this factoid when I notch the CKP brackets for easier service.)

The timing retardation would be caused by the ECU, and it's not something that can be readily adjusted (drat!)

As far as making a water pump flow more, I've told everyone how to do it before - and it's fairly simple. You just put a baffle plate on the impeller - it's the same principle as ducting a fan to make it move more air (you reduce undesired flow in directions you don't want to maximise flow in directions you do want.)

Ecomike said:

How did you get a ZJ fan clutch to clear the radiator?

Click to expand...

The ZJ HD fan clutch, NAPA #272310, $44, is a direct fit with no change in radiator clearance.

The ZJ MAX COOL fan clutch will not fit.

joe_peters said:

The ZJ HD fan clutch, NAPA #272310, $44, is a direct fit with no change in radiator clearance.

The ZJ MAX COOL fan clutch will not fit.

Click to expand...

I got the Imperial brand (Hayden, made in USA) from Advance auto for $36. Same upgrade, 97 ZJ clutch, but made in USA by Hayden, Imperial brand. It fit fine, only about 0.1" longer than CC (Cheap China) stock import they have for the 87.

Did not solve my problem, but helped a bunch. I can now hold about 210 to 220 F with AC off in 104 F ambient. I would probably be OK at 85 F with AC on.

Have ordered a CFS 3 row, all metal, copper brass rad, and a new 97, parallel flow AC condenser. Installing a filler neck (radiator cap style) in my upper radiator hose (87 Renix jeep) today.

May dig around the manifolds this week end to look for possible exhaust leaks blowing on the block. May also replace the temp sensor for the dash gauge.