Over Heating Jeep, Need Help ASAP, Stuck on Side of Road

New Water Pump, New T-Stat (160*), New Radiator.

No Elec Fan. I've Driven it 8mos. with no fan, with no problem. It's boiled 3 times today, and I'm out of water.

What am I supposed to check now?

Are there special procedures to fill it? It's an 86 4.0L 2wd.

I'm at a lost.

I have to go try and get it moving. Please feel free to post up, or call my Cell with information.

760-608-3409
Thanks!
--Phillip

sounds like its not flowing coolant. make sure the thermostat is opening and allowing flow. also, a 160 degree thermostat is too cool. i have a 180 in mine and if im not mistaken, these things need to run close to 200 deg.

Just a guess but usually when they overheat like that it's because of lack of pressure in the system caused by a bad pressure cap or in your case a bad cap and possibly cracked plastic bottle on the firewall...yes, that bottle is pressureized provided it has not been converted to an open system with the cap on the radiator..

Desert Jeepin said:

New Water Pump, New T-Stat (160*), New Radiator.

No Elec Fan. I've Driven it 8mos. with no fan, with no problem. It's boiled 3 times today, and I'm out of water.

What am I supposed to check now?

Are there special procedures to fill it? It's an 86 4.0L 2wd.

I'm at a lost.

I have to go try and get it moving. Please feel free to post up, or call my Cell with information.

760-608-3409
Thanks!
--Phillip

Click to expand...

86 4.0? I'll give you 5K for it as it sits. I think that seeing as the 4.0 was not made untill 87, I can write my price on the rarity.

Are you SURE there is not a 2.8 V-6 sitting in there?

If there is the v-6, you probably have the thermostat in backwards.

Fill is as follow for the 2.8
Fill Rad with coolant.
Leave cap off, turn heat to hot, and leave the vent fan off
Start vehicle
let it run untill coolant starts to flow
Fill as needed
It'll burp coolant out, that's normal
When level stabilizes replace cap
Let run untill upper hose is firm, and check for leaks
Fill overflow bottle to Full Hot.

You are done.

The 4.0 is different.

EDIT: Do people read threads anymore? or just glance them over?

I would agree with Rick in that the plastic bottle cracks on a regular basis, thereby losing the coolant. Find the leak and seal it temporarily to get it home. Leave the pressure cap loose, so you won't loose too much coolant on the way......

There's an easy way to convert it to an open system, if you're interested. You can even retain the new closed type radiator.

Indeed, My typographical error has been caught.

It's an 88, not an 86. It my attempt to be swift, left me with egg on my face. My sincerest apologies

The Bottle is NOT cracked. How ever, I am unsure as to the integrity of the cap. I know when it gets hot, it steams out from under the cap, as well as when it boils.

I just did a visual, after adding 2gallons of water. The thermostat is open, and water is indeed being pumped into the bottle.

Where do I go from here?

Storydude said:

86 4.0?

Click to expand...

Typo I'm sure - his profile says '88.

Desert - I'll be calling you in a minute..

Runnin'OnEmpty said:

I would agree with Rick in that the plastic bottle cracks on a regular basis, thereby losing the coolant. Find the leak and seal it temporarily to get it home. Leave the pressure cap loose, so you won't loose too much coolant on the way......

There's an easy way to convert it to an open system, if you're interested. You can even retain the new closed type radiator.

Click to expand...

You have my ears perked with a level of undivided attention rarely seen!

Go on

OK Dessert, you'll need one of those radiator cap conversion kits that places the cap in the top radiator hose. I think Summit or Jegs sells them. Then you need a heater hose adaptor from Home Depot; I believe it's 1/2" to 5/8", and it connects the hoses running to the plastic tank.

All that's left is to get a universal overflow tank kit from AutoZone, and run the line from the radiator cap kit to the overflow tank.

I have a similiar setup in my 89, except I bought a new open type radiator, and had to use a different switch setup for the aux fan......

Don't forget to take care of the heater valve in the conversion.

I'm going to say this again -

The RENIX 4.0 is well-served with a drilled thermostat!

I've gone over this again and again - given the trouble with "burping" the RENIX closed system, all you need to do is drill a pair of 1/16" holes in the thermostat flange, and mount the unit with one hole at 12:00 and the other at 6:00.

Why? The upper hole passes air, the lower replaces the air with water. This allows any trapped air to make its way to the "football" tank, and can therefore be purged easily.

When replacing the RENIX thermostat, after drilling the holes and filling, you just start the engine and allow to idle for 10-15 minutes. Blip the throttle a couple times, to cause "flow surges" in the system and encourage air bubbles to break free. Kill the engine and top off the coolant.

How do I know this? Easy -
87XJ 4.0
88XJ 4.0
89XJ 4.0
89XJ 4.0

Oh - and whatever the engineers thought when they built the thing, I think that 210* is too high for a standard operating temperature. I've made a few mods, and I now run about 180* most of the time - with no negative impact on emissions or fuel mileage. My last emissions (last week) was...

689RPM 14ppm HC (120 all, 30avg.) 0.00% CO (1.00 all., .10 avg.)
2592RPM 5ppm HC (180all., 20 avg) 0.00% CO (1.00 all., .10 avg.)

I've never been comfortable with the 210* operating temperature.

5-90

^^ Would you recommend drilling the thermostat on a Renix system converted to the open system? Or does the newer thermostat housing solve the problem?

Drill it. You won't harm anything by doing it.

I learned that little trick from working on industrial engines - especially forklifts. You'd be amazed how many blown head gskets I've seen weeping into the cooling jacket - and then overheating as coolant is displaced by gas. Drilling the thermostat didn't do anything about the head gaskets, but it reduced collateral damage as a result.

So, I've long since decided that's it just a good idea all around, and any thermostat I install into anything gets drilled - TWO holes. It takes an extra minute or so, and is cheap insurance.

It's not a function of thermostat housing (I don't think the two are really that different,) that makes a system burp itself - it's where the inlets and outlets are. Making the system "self-burping" this way just makes sure it gets done.

5-90

5-90 said:

I've made a few mods, and I now run about 180* most of the time - 5-90

Click to expand...

Do you mind elaborating on the few mods that allows you to run at 180 with a closed system?

Also, about drilling *2* holes. What would you do with an OEM t-stat? Drill one additional hole at the 6 o'clock position?

Thanks .. Maz