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89 Renix Cherokee cooling problem.

SilverbackXJ

NAXJA Forum User
Location
CO
I just bought an 89 cherokee and it drove fine for a week or two, but one day I was driving it for a 2.5 hour trip d then I got caught in traffic just as I was almost home I got caught in taffic and it overheated.

The jeep has no electric fan installed . I failed to notice it. I payed $1000 for it.

It blew the head gasket and had to be towed home. I got it looked at, it got a complete head job, and everything re-installed for $900. I was moving and had no place to work on it(now I do).

I just got it back and on the trip home it never really got to operating temp it just stayed at about a 1/4 way or about 150-160 degrees. And the oil pressure was high at 60-70 psi.

Just wondering if its a normal thing after a head job for an engine to stay that cool, or if my mechanic improperly did anything. Im new to renix motors and need some help please. It would be greatly appreciated.
 
My'89 has no electric fan too. Don't think they were OEM at all at that time. Could be that your thermostat is the wrong temperature range type.., but the temp/oil needle gauges are said to often be inaccurate. Take the vehicle back to your mechanic and have them check the temperatures, and pressures with their where-with-all equipment. Should be a free cost in-service-check. However if you have moved far away, you could do the same at some other shop, but it might cost you regular out-of-pocket money.

I'd flush all fluids out, i.e., oil, and water. The Previous Owner, (PO), may have used improper oil, and had never flushed out either system, including heater core. All of which you can do, or some shop. For me the messy hassle is better left to the shop.., but it'll cost 'ya.., lol. Anyways the '89 XJ I like a lot as it does not have a balloon to smash my glasses between it, and my face. Being old school, I just don't like those things, and drive appropriately to not have that 'bang-up' issue, blah, blah.
 
I just bought an 89 cherokee and it drove fine for a week or two, but one day I was driving it for a 2.5 hour trip d then I got caught in traffic just as I was almost home I got caught in taffic and it overheated.

The jeep has no electric fan installed . I failed to notice it. I payed $1000 for it.

It blew the head gasket and had to be towed home. I got it looked at, it got a complete head job, and everything re-installed for $900. I was moving and had no place to work on it(now I do).

I just got it back and on the trip home it never really got to operating temp it just stayed at about a 1/4 way or about 150-160 degrees. And the oil pressure was high at 60-70 psi.

Just wondering if its a normal thing after a head job for an engine to stay that cool, or if my mechanic improperly did anything. Im new to renix motors and need some help please. It would be greatly appreciated.

Check the temp by using an IR thermometer on the thermostat housing. Could be the gauge is off or maybe the mechanic cheaped out and reused the old thermostat. A badly overheated thermostat may not work right. I would hope the mechanic didn't cheap out and not replace it though.

Oil pressure sensor is notoriously inaccurate and they tend to fail a lot. They are after all mechanical inside and they wear out.
 
good suggestion to check temp at the thermostat housing

a simple test for the oil pressure is check resistance to the block, its about 1.1 ohms per psi at the sender, so if the gauge is way higher than the resistance reading then gauge is off

important to verify readings before proceeding
 
If you have the 4.0 you should have and electric fan they were factory. I have a '89 and it has the fan as do all 4.0 motors. Assuming you have the 4.0 the mechanical fan is on the passenger side of the radiator and the electric fan on the drivers side. If you have the 2.5 I got no clue.

Oil pressure is ok, lucky you but your temp is way too low. The 4.0 Renix temp runs at 200-210. Mine gets to 210 the thermostat opens, fan kicks on and cools to about 195 before shutting off. 150-160 degrees is low. Having it checked is a good first step. Some mechanics remove the thermostat to "help" cooling but all it does is have the motor run outside of its intended operating range.
 
If you have the 4.0 you should have and electric fan they were factory.

Oil pressure is ok, lucky you but your temp is way too low. The 4.0 Renix temp runs at 200-210. Mine gets to 210 the thermostat opens, fan kicks on and cools to about 195 before shutting off. 150-160 degrees is low. Having it checked is a good first step. Some mechanics remove the thermostat to "help" cooling but all it does is have the motor run outside of its intended operating range.

Yea thats what it was running at when I first got it, i think its something with the thermostat, Or the sending unit I might asweel just go and replace all temp sensors after the overheating?

The fan is not there on my 89 and with my best eye, the relay is there but I cant find a connector to plug into a fan. Im terrible at wiring. I was gonna do an open cooling sytem swap but was waiting until I have all nessacary parts and can hook everything up correctly.
 
Check the temp by using an IR thermometer on the thermostat housing.

Oil pressure sensor is notoriously inaccurate and they tend to fail a lot. They are after all mechanical inside and they wear out.

Yea im gonna go out and get me a test kit put together after moving i have no tools, it makes all this 100 x more fun to deal with. Im gonna check out the oil pressure sensor and temp at the housing and go from there. Thanks everyone. Illl try a few things out tomorrow and see what works out!
 
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Sounds like you've no thermostat - the function of the device is twofold:
1) To arrest coolant flow until the engine reaches operating temperature, then open.
2) To restrict coolant flow so that the coolant flowing through the radiator has time to reject heat to the surrounding air.

If you have no thermostat, you'll get the symptom you describe (long time - or never - to reach operating temperature.) Presence or absence of a thermostat may be readily verified by removing the upper hose from the engine and probing into the thermostat housing to see if you meet an obstruction at the plane of the cylinder head (use a screwdriver, metal rod, finger if it's long enough - whatever.) If you end up having to install a thermostat, you're best off installing a 192-195*F unit, and be sure to search up "burping RENIX cooling system" here because you'll end up with an air pocket behind the thermostat that MUST be purged for the system to work properly (if you do not purge the air from the system, the thermostat will not open, and the engine WILL overheat.)

Replacing the thermostat requires use of a 1/2" socket wrench and a 3" extension rod, you'll need to loosen the belt to reach the lower screw properly (takes a 13m/m socket for the screws on the power steering pump, I don't recall if the tensioner crossbolt is 13m/m or 1/2", but I am inclined to think it is 1/2".)
 
So I took the upper hose off and put it up and out of the way, dranied the litttle fluid left in the t stat housing so I could stick a finger in there. I felt the thermostat but then after I concluded it was there and was about to button it back up I noticed the thermostat housing was full again. I know that the coolant comes in to the left of the housing so I clamped off the hoses from the bottle and the hater core and there was still a continuous spout of water coming from the housing. Not a lot, but it would fill back up every time even with the hoses clamped up. Is this just fluid from the bottle or is the tstat open.
 
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The housing has an opening on the side that goes to the heater hoses and back to the pump. Lets coolant flow even when the thermostat is closed.

There has to be constant flow to keep the coolant from boiling off over the heads. Also the heater core needs constant supply of hot coolant to do its thing.

The thermostat only controls coolant flow to the radiator
 
"Well Ill be a suck egg mule",:laugh3: Lol you back?

WE missed you!!!

Merry Christmas!!!

I survived 4 operations and a 3 year kick the bucket phase that failed, the last 3.5 years. Doing a lit better health wise.

Sounds like you've no thermostat - the function of the device is twofold:
1) To arrest coolant flow until the engine reaches operating temperature, then open.
2) To restrict coolant flow so that the coolant flowing through the radiator has time to reject heat to the surrounding air.

If you have no thermostat, you'll get the symptom you describe (long time - or never - to reach operating temperature.) Presence or absence of a thermostat may be readily verified by removing the upper hose from the engine and probing into the thermostat housing to see if you meet an obstruction at the plane of the cylinder head (use a screwdriver, metal rod, finger if it's long enough - whatever.) If you end up having to install a thermostat, you're best off installing a 192-195*F unit, and be sure to search up "burping RENIX cooling system" here because you'll end up with an air pocket behind the thermostat that MUST be purged for the system to work properly (if you do not purge the air from the system, the thermostat will not open, and the engine WILL overheat.)

Replacing the thermostat requires use of a 1/2" socket wrench and a 3" extension rod, you'll need to loosen the belt to reach the lower screw properly (takes a 13m/m socket for the screws on the power steering pump, I don't recall if the tensioner crossbolt is 13m/m or 1/2", but I am inclined to think it is 1/2".)
 
What engine does it have???

So I took the upper hose off and put it up and out of the way, dranied the litttle fluid left in the t stat housing so I could stick a finger in there. I felt the thermostat but then after I concluded it was there and was about to button it back up I noticed the thermostat housing was full again. I know that the coolant comes in to the left of the housing so I clamped off the hoses from the bottle and the hater core and there was still a continuous spout of water coming from the housing. Not a lot, but it would fill back up every time even with the hoses clamped up. Is this just fluid from the bottle or is the tstat open.
 
What engine does it have???

Its the trusty 4.0, but I solved the problem, my mechanic had put a 160 degree tstat. Replaced it burped it and ran at a perfect temp just long enough for the torque converter to start slipping. Kinda planned for this just did not think it would go this soon. Gonna lay out my options and see what would cost me the least...
 
What makes you think it is the torque converter slipping?
 
What makes you think it is the torque converter slipping?

Well its trying to die in gear at a stop lights and when I let off the bake to give it some gas I feel slippage on the pedals( especially on hills), the PO put 35s on and left it stock gears. Was waiting for the issues but like I said they came way sooner than I thought they would. It idles just fine in P and N just in gear it gets down to just about stalling before it pops back up to regular rpms.
 
I have no idea what this means or transates into?

" I feel slippage on the pedals( especially on hills)" ???


Well its trying to die in gear at a stop lights and when I let off the bake to give it some gas I feel slippage on the pedals( especially on hills), the PO put 35s on and left it stock gears. Was waiting for the issues but like I said they came way sooner than I thought they would. It idles just fine in P and N just in gear it gets down to just about stalling before it pops back up to regular rpms.

Are you trying to say the engine bogs down when you give it gas, or the engine revs way up when you give it gas?

Revving up is slippage if it runs to 3000 rpm with little vehicle movement while in gear. That would be TC or Transmission, or transmission linkage or the throttle body cable adjustment that controls pump pressure.

I have never heard of "PEDAL" slipping???

Engine bogging down is not the transmission or TC. If the TC did not unlock the engine would die at a stop.
 
I have never heard of "PEDAL" slipping???

Engine bogging down is not the transmission or TC. If the TC did not unlock the engine would die at a stop.

I dont beat on my jeep. AT a stop light on any kind of hill the the car shakes a little bit the rpms dont shoot up too much yet but it definitely feels like the car wont respond to your input at all. I guess if my response would have been to hit the gas even harder then yes im sure the rpms might have gone up but I needed to limp it home.

The car stutters a few times upon initial acceleration.
Look I dont know exactly how to describe what im feeling because it barely started doing it as I was getting home.

It would get to about 150-200 rpms on the brake at a stop light and upon acceleration it would just stutter a few times like maybe first gear wasnt grabbing, I would just steadily give it gas until it would accelerate fine. Until the next stop light that is.

Im doing this all on a phone with no iternet trying to get a house set up please bear with me.
 
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