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Heat problem

what size socket do think it is? I know last night I tried every tool that I had. I tried unhooking the injector harness cord. nothing worked, so I decided that a socket would be the best way to go. Overall its a pretty good car. I think the previous owners only did fluid changes, and anti-freeze flushes but I doubt they burped the system of air.
 
megabyte5689 said:
what size socket do think it is? I know last night I tried every tool that I had. I tried unhooking the injector harness cord. nothing worked, so I decided that a socket would be the best way to go. Overall its a pretty good car. I think the previous owners only did fluid changes, and anti-freeze flushes but I doubt they burped the system of air.
Click to expand...

socket for what? i must have missed something?

oh, for the sending unit. not sure, but if it was cold out i can see why you would have a problem getting it out, its tough to get to when your freezing your ass off. hate to admit to it, but i use a step stool to reach that part of the engine. i do have 4.5" lift , but its tough to do when im standing on the wheel.
 
Are you sure you plugged the vacuum line back into the MAP sensor and not the bolt that sticks down from there? Just making sure here.:gee:
 
Bad or poor vacuum to the MAP sensor will definitely effect some idle problems. Are you sure that you have the lines from the Throttle Body(TB) connected securely to the MAP sensor? That little rubber plug on the valvecover side of the TB can easily get cracked and remember that the top hole in the plug is blind so the bottom one is the correct hole to get the vacuum from.
Check for other vacuum leaks as well. Vacuum leaks from anywhere can cause irregular idle conditions especially in Renix XJs.
 
Ok I figured out why the map sensor would be acting up. I look at my work that I did last night, and I realize that when a short section of the plastic vacuum line broke off last night, it crimped the end coming from the map sensor. Other than that all other connections are good, I just need to cut this crimped end off. :thumbup:
 
I've decided that I'll burp the system in my garage, because its less cold in there and its insulated. Where exactly do I need to place the jack so I can jack it up? Also what should I be looking for when I do unscrew the sensor?
 
corbinafly said:
Are you sure you plugged the vacuum line back into the MAP sensor and not the bolt that sticks down from there? Just making sure here.:gee:
Click to expand...

wow, i thought i was the only one who has done that.
 
89xj said:
wow, i thought i was the only one who has done that.
Click to expand...
Never done that myself, but I've heard of other people doing that.
 
I have never had to burp my 87 renix, even after installing a new radiator. I do not have the heater control valve, did not exist on the 87 model, so I can not help with it. All I do is connect everything except the upper radiator hose at the thermostat housing, then I elevate and fill the radiator hose, while the bottle cap is off the bottle to allow air to escape the engine block. Once the plastic bottle is about 1/2 full and the radiator hose is nearly topped off I quickly connect the hose to the thermosat housing nipple. I have never had to burp mine. I don't even have burp holes in my thermostat!

That said, I noticed this past weekend while replacing my bottle and heater hoses how easy it would be to connect the 2 heater hoses to the wrong hose nipples at the front of the engine. If this happens the water pump ends up sucking air from the side of the plastic bottle reintroducing air into the engine block instead of sucking coolant from the bottom of the bottle! It might also allow the heater core to vapor lock.

X2 on the checking the MAP sensor tubing connection at the throttle body. It gets knocked loose all the time. Causes your exact symptoms.
 
Not to hi-jack this thread but does anyone know, what the rubber plug in the side of the throttle body, where the MAP vacuum is derived from, is listed as by the dealer.
 
I parked my 90 xj in the driveway yesterday and unscrewed the temp sensor, anti-freeze started to come out and then it stopped. I don't think thats what was supposed to happen. So back to my previous question, where at the rear end do I jack the vehicle up? What should it look like when I unscrew the temp. sensor? Yesterday when the 90 xj was in the drive-way and I unscrewed the temp.sensor some anti-freeze started coming out and then stopped so I kept unscrewing and I accidentally unscrewed the sensor out of the port. I know there is still air in the system. I think it might of let it off a small amount of air and that's it, which isn't saying much.
 
I read on this other website that when burping the XJ coolant system, you have to remove the pressure cap on the overflow bottle after you partially unscrew the sensor. Is this true?
 
megabyte5689 said:
I read on this other website that when burping the XJ coolant system, you have to remove the pressure cap on the overflow bottle after you partially unscrew the sensor. Is this true?
Click to expand...

It would help.. definetly do it...

As i said in my original "how-to" post on the previous page, you will un-screw your sensor until coolant comes out... but it doesnt do any good to do this unless that point of the head is higher then the rest of the engine by jacking up the rear-end.

I jack up the rear at the lowest portion of the pumpkin on my d35. Then support each end of the axle with jack stands. I think i read somewhere that jacking up the vehicle at this spot is not a good idea, and i can understand why it wouldnt be... but i know im swapping it out in the future so the long term effects of doing things this way are not out-weighing the thought of trying to find out what the "proper" way to jack the rear up is.... so bottom line you may want to find out what the proper way is to jack the rear up. Maybe someone will chime in.

If your really having that much of an issue with figuring out how to burp the system this way, then try something like this:
Take out your current thermostat, and look at it closely. It should have a small hole in it that goes at the 12 o-clock position when installed properly. Find a 1/16" drill bit or go get one, and drill another hole at the opposite end of the thermostat. Giving you two small holes in the thermostat. When re-installing, make sure that one hole is at the 12 o-clock position forcing the other at 6 o-clock. This pretty much makes your system self burping, and should prevent you from having to unscrew that sending unit again unless you ever need to replace it. (At least that is the result i have gotten from doing this)

Hope that helps.
 
I cant believe you guys lost "The burping thread". I havent been gone that long, and things disappear.

burping the renix-(its been listed above, heres my version)

Jack the rear end up so the engine valve cover is high in the rear-
unscrew, but DO NOT remove the temp sender- leave it on but loose-
leave the cap on the plastic bottle on for now. it needs the pressure to work.

start engine- let it run, and when the thermostat opens, the air is forced out of the senders hole- through the threads(if you took it off, it will gyser-engoy the antifreeze bath, if you left it on just a few threads, the sender will be somewhere in the front of the vehicle when it shoots out like a missle-hopefully mising your head). When the air is out, theres plenty of force behind it, and the antifreeze will creep out(or spew)- hand tighten it back, shut off engine, count fingers and make sure their all there. retighten the sender.

let jeep cool for a minute, then carefully remove the bottle cap- restart engine and let the fluid spit and jump- its equalizing. turn off engine, refill bottle. Enjoy heat. repeat as necessary.

The heater bypass valve on renix systems is a lie- but, they do stick- check them by manually forceing the valve over- if it moves, its probably working. its a vac system- designed by deranged elves on crack paid by bendix corp- if its not leaking, it will soon enough. The french were good at something- Vacuum systems (they DO suck after all)

If the temp gauge is jumping, its air stuck in the top end- remove by burping-
if the guage is low consistantly, its usually a stuck open thermostat(or backwards-if you can find one that fits backwards)-
if its high all the time, the thermostat is stuck closed, or the engine IS actually overheating.

Its that simple.
 
The thermostat that I have in it right now is a Duralast 195 t-stat, with a small hole in it. The box said it had a by pass valve in it to remove air pockets. I wasn't aware that you had to make sure the hole was at 12 'o clock. I went off my what my hayne's repair manual told me to do. I know the t-stat wasn't installed backwards. I'm really not in the mood to drain coolant again and rip off my t-stat housing and gasket and sealant. Whenever I have to replace the thermostat again I will drill the holes then. But yes I will look into properly jacking the car up. I was thinking getting two jacks, and placing one on the left rear passenger side and the other on the right rear passenger side.
 
Jack it up one side at a time and throw a block under each tire-
I use drive on jackstands and take the air out of the front tires-

Having the little hole at 12 high lets the air pass, because the air is at the highest point- unless your jeep is upside down, at which point you wont care much about air in the top end. I like Robert Shaw all brass thermostats- but, being completely different than most in here, I run a 165 degree one for my own reasons- (and I aint changing it).

Do yourself a favor though- go get a chilton manual, and look for a fullsize manual- both are extremely better than a haynes manual-
Unless you like reading " This is beyond the scope of the home mechanic, take to an authorized service tech".....I hated that! :smsoap:
 
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