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  #1  
Old February 16th, 2009, 11:41
overflow overflow is offline
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1990 Jeep Wagoneer Limited Problems

All,

I've been lurking here for a little while now, and am glad to say I went out last week and finally bought an XJ. It wasn't by any means perfect, but I kinda expected that from a 19 year old car, and really bought it as a project car to learn on (admittedly, I don't know much about cars - I'm along time IT guy with little mechanical experience.) With the help of this forum I've located and fixed quite a few things:

Interior Lights (Fuse)
Blower (Fuse)
Oil Pressure Guage Peaked to Right (new oil-pressure sensor)
Replaced Headlights
Changed Oil
Changed front and rear differential fluid

That being said, I still have a few problems I could use some help with. First and foremost is no-heat (tad of an issue in Illinois winter.) I've searched and read all the no-heat threads several times and just have a couple of questions.

The no heat may be related to a vacuum problem. First, the vacuum hose coming from the blower area to the heater control valve (pinkish tube) was not connected to anything. I reconnected it (sorta rigged because I can't seem to find that small of vaccum line anywhere.) This didn't seem to help. The heater control valve is rusted to high hell, so I bought a new one of those and plan to install it tonight.

There's another vacuum problem I discovered when I went to replace to the left front headlight. The vaccuum reservoir right behind the bumper had two big holes in it. I took this into the auto-parts store but it must be pretty rare because no one seems to carry it. Probably going to have to be a junk-yard replacement. I patched the holes with JB weld and put it back in, but I'm not sure if this was really tight enough to keep a vaccum. This may be the cause of my heat problems; maybe more. Is there anyway to bypass this temporarily?

Based on prior posts involving no heat, it sounds like the next step is to burp the system and then flush the heater core. Question here is, do I need to drain the coolant before flushing the heater core? How about before replacing the heater control valve? Also in the Haynes manual it says to have the A/C evacuated before you start messing with the heater core. Is this absolutely neccessary?

Other than that, I've got a few minor problems. Oil leaks, but it's slow and I haven't traced it back yet. Same with coolant, but pretty sure I know where the coolant is leaking.

This all is on a 1990 Jeep Wagoneer Limited (Woody!). IL6 Rendix MPI.

Added bonus: One of the previous owners added a "Y" to the "PART TIME" light so when I throw it in PART TIME it says "PARTY TIME"

Thanks for your help in advance.
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  #2  
Old February 16th, 2009, 12:38
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ParadiseXJ ParadiseXJ is offline
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Re: 1990 Jeep Wagoneer Limited Problems

Heat: Check to see if you are getting any heat from the defrost vents. If so it's related to...

Vacuum: The vacuum from the cannister (behind the bumper with the holes in it) runs the blend doors, so if you are getting heat out of those vents, or any air actually, it's because you have no vacuum. You should also check the lines running along the passenger side fender TO the cannister. They usually crack and corrode, ergo leak. Replace the cannister and all the lines running to/from the cannister. Don't patch, replace. If you bypass it, or delete it, your HVAC system won't work, nor will your Cruise Control (if so equipped). If you are not getting any heat it probably needs...

Flush: The entire system should be drained and flushed. Then flush the heater core independently by taking off the hoses and sticking a garden hose in the top nipple, then the bottom, then the top and so on until all you get is clean water. Be careful removing the heater hoses as the nipples are thin copper and prone to cracking. If you crack or break a nipple you WILL have to replace the core. You can flush the heater core without flushing the whole system but...well, why. while you have all the hoses off, replace the t-stat with a OEM 195 t-stat. You don't have to evacuate the system unless you are REPLACING the core.

Oil leaks: Clean your engine, top, bottom, side, back with Simple Green Max. Spray it on, let it sit, hose it off, let it dry, do it again. then run the beast for a short cruise. Its easier to see where oil is leaking. Most frequent oil leaks involve:
Rear Main Seal - the part costs $14 - the labor, unless you do it yourself is about $600. Once you do that job, everything else will be cake. You'll also be replacing your oil pan gasket during this job - get the one piece FelPro gasket instead of the POS 4 piece thing. Worth the money.
Oil Filter Adapter O-Rings - Same deal, except a mechanic will only charge about $150 - With a '90 4.0L you're lucky becauce the oil filter adapter has a regular hex head not the crazy be-otch Torx.
Valve Cover Gasket - pretty straight forward. Take off the old, clean the valve cover, inside and out as well as the CCV grommets. Replace with a quality gasket and RTV (again FelPro).

All of these leaks can present themselves as either of the other. A valve cover, or OFA leak can LOOK like an RMS leak, but if it's an OFA or RMS leak there shouldn't be any oil on the back of the top portion of the block so eliminate the valve cover as a suspect first as it's the easiest to fix.

Coolant leaks: Easy to find, look at weep hole at bottom of water pump (indicates replacement necessary). Possible cracked thermostat housing. Pressure bottle (if yours is cracked, replace it) or cap (same deal). Check all hoses and clamps. Check for leaks when running, then check for leaks after it has gotten up to temp and is OFF sitting in driveway. I like to get a clean piece of cardboard and slide it under after I park it to give me a better idea of where to start looking.

PARTY TIME light: I think that may be my next mod. I like it!!
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  #3  
Old February 16th, 2009, 14:41
overflow overflow is offline
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Re: 1990 Jeep Wagoneer Limited Problems

Quote:
Originally Posted by ParadiseXJ View Post
Heat: Check to see if you are getting any heat from the defrost vents. If so it's related to...

Vacuum: The vacuum from the cannister (behind the bumper with the holes in it) runs the blend doors, so if you are getting heat out of those vents, or any air actually, it's because you have no vacuum. You should also check the lines running along the passenger side fender TO the cannister. They usually crack and corrode, ergo leak. Replace the cannister and all the lines running to/from the cannister. Don't patch, replace. If you bypass it, or delete it, your HVAC system won't work, nor will your Cruise Control (if so equipped). If you are not getting any heat it probably needs...

Flush: The entire system should be drained and flushed. Then flush the heater core independently by taking off the hoses and sticking a garden hose in the top nipple, then the bottom, then the top and so on until all you get is clean water. Be careful removing the heater hoses as the nipples are thin copper and prone to cracking. If you crack or break a nipple you WILL have to replace the core. You can flush the heater core without flushing the whole system but...well, why. while you have all the hoses off, replace the t-stat with a OEM 195 t-stat. You don't have to evacuate the system unless you are REPLACING the core.

Oil leaks: Clean your engine, top, bottom, side, back with Simple Green Max. Spray it on, let it sit, hose it off, let it dry, do it again. then run the beast for a short cruise. Its easier to see where oil is leaking. Most frequent oil leaks involve:
Rear Main Seal - the part costs $14 - the labor, unless you do it yourself is about $600. Once you do that job, everything else will be cake. You'll also be replacing your oil pan gasket during this job - get the one piece FelPro gasket instead of the POS 4 piece thing. Worth the money.
Oil Filter Adapter O-Rings - Same deal, except a mechanic will only charge about $150 - With a '90 4.0L you're lucky becauce the oil filter adapter has a regular hex head not the crazy be-otch Torx.
Valve Cover Gasket - pretty straight forward. Take off the old, clean the valve cover, inside and out as well as the CCV grommets. Replace with a quality gasket and RTV (again FelPro).

All of these leaks can present themselves as either of the other. A valve cover, or OFA leak can LOOK like an RMS leak, but if it's an OFA or RMS leak there shouldn't be any oil on the back of the top portion of the block so eliminate the valve cover as a suspect first as it's the easiest to fix.

Coolant leaks: Easy to find, look at weep hole at bottom of water pump (indicates replacement necessary). Possible cracked thermostat housing. Pressure bottle (if yours is cracked, replace it) or cap (same deal). Check all hoses and clamps. Check for leaks when running, then check for leaks after it has gotten up to temp and is OFF sitting in driveway. I like to get a clean piece of cardboard and slide it under after I park it to give me a better idea of where to start looking.

PARTY TIME light: I think that may be my next mod. I like it!!
Thanks, I'll try all this stuff. To clarify, I am not getting ANY heat. Blower works, but only cold air comes through. The valve cover is definitely leaking and there is some oil leaking near the oil filter as well.
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  #4  
Old February 16th, 2009, 15:51
tugalo tugalo is offline
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Re: 1990 Jeep Wagoneer Limited Problems

Be careful when flushing your heater core with a hose...too much pressure will split it.
If you cannot find a vacuum accumulator at the junkyard, any sturdy container will work, tin can, piece of 4" pvc pipe, etc,etc.
Rear main seal is cheap....installing it is pricey......do the front seal at the same time while you have the pan off.
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  #5  
Old February 16th, 2009, 21:39
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ParadiseXJ ParadiseXJ is offline
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Re: 1990 Jeep Wagoneer Limited Problems

A tin can?? How ghetto is that!! Does that get wrapped in duct tape too? Or saran wrap? What about the fittings?

Just go to the boneyard, get a solid cannister and do it right! ...and REPLACE the lines, don't seal them with toothpaste or KY jelly, just replace them, they're cheap.

A tin can??

Last edited by ParadiseXJ; February 16th, 2009 at 21:43.
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  #6  
Old February 16th, 2009, 22:39
joe_peters joe_peters is offline
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Re: 1990 Jeep Wagoneer Limited Problems

Vacuum reservoir at teamcherokee.com $9.95 +s/h.

You should be able to relocate the reservoir from the asinine OEM location to under the coolant bottle on the firewall. Leave it there loose, duct tape it, or drill two holes and use pop rivets to mount it.
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  #7  
Old February 17th, 2009, 14:08
overflow overflow is offline
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Re: 1990 Jeep Wagoneer Limited Problems

Quote:
Originally Posted by joe_peters View Post
Vacuum reservoir at teamcherokee.com $9.95 +s/h.

You should be able to relocate the reservoir from the asinine OEM location to under the coolant bottle on the firewall. Leave it there loose, duct tape it, or drill two holes and use pop rivets to mount it.
Exactly what I'm gonna do. Ordered the reservoir from team cherokee last night (along with some other choice parts I needed - great site.) I'm gonna flush the coolant and do some engine cleaning as soon as the temperature gets above freezing here.
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  #8  
Old February 17th, 2009, 15:11
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winterbeater winterbeater is offline
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Re: 1990 Jeep Wagoneer Limited Problems

For the heat situation:
1.) Is the engine getting hot enough?
2.) Are both of the heater hoses getting as hot as the radiator hoses?
3.) Is the temperature door moving properly?
4.) Is there air in the coolant system? (Baby needs burping.)

There are many threads on checking this stuff out if you search.
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  #9  
Old February 18th, 2009, 14:08
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TiRod TiRod is offline
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Re: 1990 Jeep Wagoneer Limited Problems

The vacuum controlled heater control valve is the plastic tubing thingy with a little canister that moves a lever, plumbed into the heater hoses at the firewall. There should be a vacuum hose running back inside to the dash control. No vac from the control, no heat.

All the other sounds like it needs repair, too. And Fords use a freaking tin can for vacuum big enough to serve a family juice for a week. If the darn Lincoln wasn't still driveable I'd steal it and put in on the Jeep.
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  #10  
Old February 18th, 2009, 15:58
overflow overflow is offline
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Re: 1990 Jeep Wagoneer Limited Problems

Well, I figured out the heat problem - which was the main issue. Apparently at some point the heater control valve died on the previous owner, but rather that replace the valve (I'm guessing he couldn't figure it out) he just put in a valve to manually open/close flow to the heater core. Removed this valve and replaced heater control valve - woolah, heat.

Also, valve cover was definitely leaking in the back, when I went to tighten the bolts the back couple were very loose. Still need to get a new valve cover gasket, but tightening down for now is helping.

I got my vacuum reservoir from teamcherokee today (extremely quick shipping!) but it's different then the one I have so not sure if I requested the wrong part or what. On the original one there are two inlets on each side of the reservoir, with one line coming from each. The reservoir I received only has one inlet on one side. Do you think it would be a problem if I just "T'd" all the other connections into this one inlet?

Also, my compass/temp readout doesn't read anything (took apart upper console today.) Replacement board on teamcherokee is something like $170, anyone else know if there are any other tricks to fixing this guy? If not, no big deal, but I'd rather stick my hand out the window than pay $170 for a new one.
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