Over Heating Renix

[WyoXJ]

So I have been searching what to do to keep my Renix cool. I was headed up into the mountians, when I started up the first long pull I over heated right away. So I opened the hood, when it cooled off we took off and once again same result. So long story short I hooked up the tow rope to the girlfriends Ford Explorer(still hearing about that :bang:) it cooled right down. When we were up in the mountians crawling around and moving slow it would get warm but not over heat. I have been told to put a different t-stat in it like a 160. I live in Wyoming and use my Jeep to hunt coyotes in the winter and I don't want to freeze out as it does not have a real great heater. I also have the parts to change it from closed to open. Just not sure if that will help or not. So thats why I am asking you guys for HELP!!! My jeep is an '88 4.0 has A/C. Not sure what else you will need to know. Thanks

[4.3LXJ]

The first thing to check is if you have all the parts and do they all work? Clutch good, shrouds in place, efan working etc.

[Carves]

The first thing to check is if you have all the parts and do they all work? Clutch good, shrouds in place, efan working etc.


X 2

Make sure everything is functioning properly first ... before looking at add-ons and changes.

[BlueXJ]

If you do as suggested and it still overheats then consider having your radiator flushed and check that the fins are not crimped. Keep the closed system if it is functioning as it should.
Another thing that you can do is to upgrade to the later e-fan with the curved blades. It will bolt right in but does need the plug changed, to either the new style on your harness or retain the fan plug from your old fan and graft it to the new fan by soldering and heat shrink tubing.

[Showtime3492]

X3
Eliminate one thing at a time till you reach your cause. Mine was doing that for a little and it was a combination of being a little low on antifreeze and the efan not kicking on all the time due to a short.

[WyoXJ]

I have had the radiator flushed,but the fluid is brown still. Not sure what that is about either. The e-fan works and I think it is kicking in when it is suppose to. I know it turns on when I turn on the A/C. How do I check the fan clutch? If its bad should I change it with one from a Grand Cherokee? I have changed the water pump out awhile back just went back with oem. The fan shrouds are there and in good shape.

[4.3LXJ]

If the clutch is stiff when cold, then it is probably not good. Yes the GC Cherokee clutch is a good upgrade. There is a thread here on this.

[LizardRunner]

If you flushed the radiator and it is still brown, you need to flush it again the first time probably loosened the gunk the first one didn't get. Also I have heard that you need to burp the closed systems, there's a thread on that somewhere here. I would also check the condition of the hoses, particularly the return hose at the bottom and make sure it isn't collapsing (supposed to have a spring inside it to prevent that). Like 4.3 said, the GC clutch fan is a good upgrade and easy to do with the directions on the xjtalk thread.

[WyoXJ]

Fan clutch is good spins freely, Hose has the spring still, and the electric fan seems to come on at the right time. I will flush the radiator again. Anything else I should check?

[mafundzalo]

Take off the fan clutch, see the wound spring on the front of it? Unhook the spring from the retaining clip, spin it 180 degrees COUNTERCLOCKWISE and lock it back to the other clip on the opposite side. This will make it "always on". You fan clutch should roar now and pull a lot of air. If it doesn't, replace it.

Don't put a 160 thermostat in it. It will accomplish nothing.

If this doesn't help, ditch the closed cooling system and get a new radiator for an open system. What kind of radiator do you have? If stock specification - junk it. Get an all aluminum radiator on ebay. You want 2 row with 1" tubes. I paid $169 for mine - shipped. Make sure you get all the brown out of the cooling system before you throw your new radiator in.


Peace

Mafundzalo

[4.3LXJ]

Fan clutch is good spins freely, Hose has the spring still, and the electric fan seems to come on at the right time. I will flush the radiator again. Anything else I should check?

You never said whether or not you had both shrouds on. Are they still there?

[BlueXJ]

The fan shrouds are there and in good shape.


You never said whether or not you had both shrouds on. Are they still there?

Yes he did Steve.

[steph74]

Renix rule #1 keep that @#@#@ clean...

Flush and flush until it is clean... maybe your radiator is really clogged with deposits and rust...

I agree with others there, do not put a lower Tstat.... engine will work at or around 210 the best.

Do you experience overboiling ? It happened to me all the time and overheating.... Burp the system and make sure there is no leak in the CLOSED system. One of the weak spot is the coolant recovery bottle and more so the cap. cost $6 and when replaced, I had no more problem...

[xj4life2]

One thing no one has mentioned yet is putting a toggle on the e fan so you can turn it on and off at will. I have done this on my Renix and it works great. I pull 2000 ft everyday on the way home , temp ranging up to 105* and don't heat at all. I also used a 4" deck plate from a boat and that installed in the hood to push the hot air out better.

[DETOURS]

If 'brown' keeps appearing, you've got rust in the block, which will effect the radiator over & over..

A closed system is burped by loosening & removing temp gauge on the rear of the head, this is the highest point of the engine thats accessable.....start the process with a cold engine, burp until there is no more air.

Drill a 'single' 1/8" hole in your thermostat, this is typically good for a 5*drop in temps.

As previously mentioned, that 6 dollar cap is important.

[prcjeep]

I completely agree with flushing the system again... Flush it until you see water coming out the same color as its going in.
Im not sure on this for closed systems, but with my open system cooling i can pressure test the system with a kit that you can rent from a parts store. Pressure it up and make sure that you have no leaks or look for where the hissing is coming from

[WyoXJ]

Ok first thing to take care of is the brown coolant. If I have rust in the block, how do you get rid of that? I changed the bottle and cap. I cross threaded the old cap. That really caused some trouble. Putting a switch in there does that make it so the fan wont turn on when it gets up to temp? If I switch to the open system would that solve my trouble?

[Carves]

Ok first thing to take care of is the brown coolant. If I have rust in the block, how do you get rid of that?

X 2 ... and you may need to use a flushing agent to have any success.

Personally ... and just for starters ...
- I'd pull the rad, stand it on its inlet end and flush the heck out it in reverse,
- Then reverse flush the engine,
- Then reverse flush the heater core.

Removing the components to do this also gives you an opportunity to inspect the condition of thermostat, waterpump impellor etc ....


Next thing to do ... is work out why the "coolant" is all brown & murky ... coz its pointless recreating the same problem in a clean system with new components .

Is your "coolant" just water ?
Is your "coolant" just plain water and eth-gly without the anti-corrosive additives ?
Is the water, distilled water ... or tap water/ground water which is full of corrosion causing chemicals/minerals ?
Was the "coolant" just left in for too long ? ... exceeding the service life of the anti-corrosive additives ? ... Some products - are only good for 12mnths or 2yrs or 3yrs or 4yrs etc.,

... and even tho its a bit of rip off buying factory diluted pre-mix "coolants" IMHO .... It does guarantee to a certain extent - that the mix is always right, every time you do a change / top up.


I changed the bottle and cap. I cross threaded the old cap. That really caused some trouble. Putting a switch in there does that make it so the fan wont turn on when it gets up to temp? If I switch to the open system would that solve my trouble?

A dodgy cap on a "closed" system can cause a number of issues ... make sure the new bottle & cap is of good quality.

An over-ride switch generally allows the fan to function as per the factory specs .... and whenever you want to turn it on .... It just depends on whose wiring tips you follow.

Switching systems wont solve your problem .... as a "closed" system can work fine .... as long as its maintained properly. Altho an "open" system is a bit more user friendly ...

[steph74]

when you say your coolant is brown, it is not that there is oil in it right ? Just had to ask.....
That might be a bigger problem if it is oil....

your jeep is from 88.... if the system is original, It really probably need a good flush with a flushing agent maybe.... however, you may not want something too agressive because chances are that some parts are more fragile with age and you may end up with more trouble....

[DETOURS]

Prior to your next flushing, remove the thermostat.
If you leave it in and flush with COLD water, it will NOT open.....Thus, you're not flushing the block, the brown is rust in the BLOCK......

While it's out, drill that hole in it I mentioned.

As a matter of fact, while the thermostat area is open......disconnect the lower hose, squirt as hard as you can with the hose into the thermostat area, flush it out cold........reattach hoses and again flush a warm motor.

[BlueXJ]

This is what I have and I can easily pressure test this tank. It uses a regular radiator cap which you can select the pressure of.
http://macsradiator.com/shop/surge-overflow-tanks/replacment-jeep-radiator-fill-tanks.html

[WyoXJ]

Well since I have been working late every night and have not had time to work on the XJ. Mother nature is helping me out here in Wyoming, it snowed and cooled way off from 80 deg. Ha Ha Looking like I will have time to work on it tomorrow. Planning on flushing the system and putting the 1/8 inch hole in the t-stat. Will check back in with progress on problem. Thanks for all of your help.

[pvt.tadpolxj]

Hey I'm wondering if a fail-safe T-state is really better than the factory mech. T-state... Anybody been trying both ?...

[jeepxj95]

i did and it failed with in 6 months. did what it was so post to do. it was at 140 deg. for 3 hours. but it was 26 deg out side. that was a cold day in the jeep.

[Olie's87XJ]

how brown is that coolant? I got an XJ in at work, it was overheating and the coolant was really rusty. I pulled the water pump and found this:

http://i1097.photobucket.com/albums/g343/oliethegoalie32/IMG00183.jpg

I cut my finger on the impeller, it was razor sharp! But the damage was already done. I ended up doing the rad and head gasket, as well as a thorough back flush of the heater core and block.

[4.3LXJ]

Well since I have been working late every night and have not had time to work on the XJ. Mother nature is helping me out here in Wyoming, it snowed and cooled way off from 80 deg. Ha Ha Looking like I will have time to work on it tomorrow. Planning on flushing the system and putting the 1/8 inch hole in the t-stat. Will check back in with progress on problem. Thanks for all of your help.

I would recommend something like a 1/32 hole. 1/8" will pass too much water for those cold WY winters and not let the engine idle and be warm enough.

[WyoXJ]

Finally got to flush everything out, put the small hole in the t-stat, and new anti-freeze. So far so good but it is pretty cool here. It did have some crud in the whole system. The other great thing is my heater seems to be working better. So now we will see how it does when it warms back up. Have my fingures crossed that it is fixed. Thanks for all the help.

[uberxj92]

i fought this exact issue with my 90. my best friend has an 88 ( with thee d44 the luck turd!:cool: ) . his issue ended up being the water tank on the firewall. they "banana" when the get hot the first time & then they just quit working at all. & since that is the res & overflow & backbone of that closed system...there ya go. $75 at a stealership & back on the road with him.
on my 90 i tried everything from a new radiator to burping valves on the system to get out all of the air. i finally just swapped the new radiator with one out of a 92 & connected a couple of hoses together & have not had 1 problem yet!!!!!