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1991 Briarwood bought 10min ago and already have issues

SBpunk

SBpunk

NAXJA Forum User
Location
Enid, OK
1991 Briarwood completely stock down to the springs bushings and shocks. Everything is original except the radiator brakes and a few other maintenance parts. 119k Miles 4.0 Dana 35c(yuck) axle in the back 30 in the front.


This is the major problem that I've googled and no one had the exact situation. The PO put a new radiator in and ever since its been running just under the red line. Before hand he said it was running at around 175 degrees. Dont know how thats possible but when I asked he told me he took out the thermostat. Also didnt know you could do that. Anyway the engine feels pretty hot and I dont want to run the risk of over heating this thing. Im guessing the new radiator has something to do with it. It seems to be leaking at the point pictured bellow. A medium speed drip. Enough to annoy me. Anyway suggestions would be great thanks


 
Heater control valve/junction, either buy another one. Or bypass it. The later models got rid of it.
Most likely air in the system. What happens when the heater is on high heat, does it cool down? Confirmed temp with a gauge?
 
That's the heater control valve. The plastic gets old and brittle, cracks and leaks. Replacing it is cheap

As far as running hot try burping it
 
Johnnie Walker said:
Heater control valve/junction, either buy another one. Or bypass it. The later models got rid of it.
Most likely air in the system. What happens when the heater is on high heat, does it cool down? Confirmed temp with a gauge?
Click to expand...


The heater doesn't work. It blows out cool air. Also something supposedly caused by the truck not having a thermostat.

I'll google burping the system see if I can figure it out.
 
SBpunk said:
The heater doesn't work. It blows out cool air. Also something supposedly caused by the truck not having a thermostat.

I'll google burping the system see if I can figure it out.
Click to expand...

Being a 91/HO it has the open cooling system, correct? What psi is the rad cap on currently?
In theory, should run cooler without the t-stat. But usually, there is a bigger problem when most people run without a t-stat.
 
Not sure havent hooked a pressure tester to it. Wont be able to get to the auto parts store until tomorrow. Was hoping this was something simple like the fan wasnt coming on but its out there screaming away now.
 
I would start over, as in drain the coolant, flush the system, including heater core, remove/bypass that heater control valve. Maybe PO put some stop leak or some other crap in the system. Maybe replace water pump?

OT: How's the weather in Hawaii?
 
I agree Johnnie. The engine heat spikes when im sitting at a red light then cools down once I start driving again. Im guessing the water pump is going out so going to snag one of those. While I'm in there learning how to swap that I'm going to install a 195 degree thermostat so I can have heat when I leave here, grab a set of 97 XJ heater hoses to bypass the HCValve and flush the system completely. Hopefully that'll get me started.

Weather isnt to shabby. Its windy as hell right now but sunshine and rainbows 90% of the time. The north side of the island rains a lot but not much here (except when I have time to work on my vehicle) and when it does it doesnt last long. Traffic is what kills this place for me.
 
SBpunk said:
I agree Johnnie. The engine heat spikes when im sitting at a red light then cools down once I start driving again. Im guessing the water pump is going out so going to snag one of those. While I'm in there learning how to swap that I'm going to install a 195 degree thermostat so I can have heat when I leave here, grab a set of 97 XJ heater hoses to bypass the HCValve and flush the system completely. Hopefully that'll get me started.

Weather isnt to shabby. Its windy as hell right now but sunshine and rainbows 90% of the time. The north side of the island rains a lot but not much here (except when I have time to work on my vehicle) and when it does it doesnt last long. Traffic is what kills this place for me.
Click to expand...

It helps if you remove the mech fan as well as the e-fan. Have you thought about running a 2nd stock e-fan or aftermarket setup in place of the mech fan? Will free up some ponies.
That is one very annoying thing about some people and what they do with their vehicles. PO probably assumed Rad. was bad and just swapped it. Unless I knew 100% the pump was good, I would change that too, as it is THAT much easier to swap when the rad is out of the way.


I haven't been to Hawaii in years. Me and my gf want to, were supposed to last turkeyday time but that fell thru.. damn inlaws shenanigans! Ha.
This year is out since we are going to Moab for the 30th, will also be my 30th while out there, unless win the lotto, come into some money you know all the stuff that doesn't happen. So definitely attempt for next year.
 
Yeah the radiator is BRAND new. It was busted when I looked at the vehicle and he said he would fix it prior to sell. Has a lifetime warranty on it too. I thought about getting one of the triple fans from the guy on here that sells them but I've heard mixed reviews on the amount of air e-fans push compared to mechanical. Hopefully the fan clutch is good still and I'll end up running it until it starts to go. Then I'll probably put in an e-fan. Until then though I'm going to try and find some LaBararon (sp?) hood vents to keep it cool.

Man I wouldnt give to do a jeep run at the moab or rubicon... Very cool. Hopefully I'll make it over one year from Oklahoma. Wife is getting into the jeep thing too now so it wont be hard to talk her into it.
 
Don't waste your time with the vents; they do nothing to help the engine run cooler.
Briarwoods are a really nice version of the XJ; I wouldn't hack it up....
If the radiator is new, then I would flush the system, replace the thermostatic clutch fan and radiator cap; replace the heater control with a metal style or remove from the system and replace ALL the hoses.
 
Three things come to mind. One, is the dash reading correct? Get an IR, Infrared temperature tester (about $20) and read the temp at the T-stat housing. Jeep temp gauges are often wrong.

If it is getting hot, then the Fan clutch is most likely not locking up when hot anymore.

Also check the AC condenser for dirt, blocking the air flow to the radiator.

Lastly, the Temp sensor in the T-stat housing talks to the ECU, and the ECU turns on the E-fan. If the e-fan is not running when the dash gauge reads too hot, the temp sensor in the T-stat, or wiring may be bad. Or the fan relay or e-fan fuse maybe bad, or the e-fan maybe be bad if it never runs.

What happened to the other jeep?

SBpunk said:
I agree Johnnie. The engine heat spikes when im sitting at a red light then cools down once I start driving again. Im guessing the water pump is going out so going to snag one of those. While I'm in there learning how to swap that I'm going to install a 195 degree thermostat so I can have heat when I leave here, grab a set of 97 XJ heater hoses to bypass the HCValve and flush the system completely. Hopefully that'll get me started.

Weather isnt to shabby. Its windy as hell right now but sunshine and rainbows 90% of the time. The north side of the island rains a lot but not much here (except when I have time to work on my vehicle) and when it does it doesnt last long. Traffic is what kills this place for me.
Click to expand...
 
I ended up selling it to one of the jeep mechanics. It was never ending issues and he still wanted it. So 3 grand later here I sit lol.

Ill check out the temp and what not to compare to the guage but it feels like an oven down there. It only starts getting hot at low RPMs. If I throw it in neutral mad rev it up the temp drops to normal. I picked up a new water pump, hoses from a 97 to delete the leaky plastic piece and a 195 thermostat. If that doesn't work ill start pulling the clutch fan. If its out I might just replace it with an e fan. The factory one is coming on and blowing like a champ.
 
If you rev it up the temp drops to normal tells me that you have a flow problem. You also stated that it runs cooler at highway speed....this could be the clutch fan, BUT I suspect that again your coolant flow is not there either due to air in the system or bad water pump.
 
CMNCHE said:
If you rev it up the temp drops to normal tells me that you have a flow problem. You also stated that it runs cooler at highway speed....this could be the clutch fan, BUT I suspect that again your coolant flow is not there either due to air in the system or bad water pump.
Click to expand...

I'm with CMNCHE on the clutch fan. Classic clutch fan is warms up at idle, rev up engine and dying clutch engages, cools engine down. There is a long, involved test for the fan clutch--just replace it.
 
Ecomike said:
Three things come to mind. One, is the dash reading correct? Get an IR, Infrared temperature tester (about $20) and read the temp at the T-stat housing. Jeep temp gauges are often wrong.

If it is getting hot, then the Fan clutch is most likely not locking up when hot anymore.

Also check the AC condenser for dirt, blocking the air flow to the radiator.

Lastly, the Temp sensor in the T-stat housing talks to the ECU, and the ECU turns on the E-fan. If the e-fan is not running when the dash gauge reads too hot, the temp sensor in the T-stat, or wiring may be bad. Or the fan relay or e-fan fuse maybe bad, or the e-fan maybe be bad if it never runs.

What happened to the other jeep?
Click to expand...

I thought that the sensor in the t-stat housing was something that started around OBD2 time?
 
LOL, I call that trading one problem for another, LOL.

SBpunk said:
I ended up selling it to one of the jeep mechanics. It was never ending issues and he still wanted it. So 3 grand later here I sit lol.

Ill check out the temp and what not to compare to the guage but it feels like an oven down there. It only starts getting hot at low RPMs. If I throw it in neutral mad rev it up the temp drops to normal. I picked up a new water pump, hoses from a 97 to delete the leaky plastic piece and a 195 thermostat. If that doesn't work ill start pulling the clutch fan. If its out I might just replace it with an e fan. The factory one is coming on and blowing like a champ.
Click to expand...

"If its out I might just replace it with an e fan."

IMHO you are better off fixing what is broken, rather than complicating the situation. For one, those e-fans suck a lot of power from the alternator and do not save horsepower, they eat it via the alternator.

Sorry you never got that last one debugged, you were so close, IMHO.
 
Johnnie Walker said:
I thought that the sensor in the t-stat housing was something that started around OBD2 time?
Click to expand...

IIRC they moved the CTS from the block to the T-stat housing in 1991, and eliminated the Temp switch for the E-Fan in the cold side of the radiator that same year. In 1996 IIRC they eliminated the dash gauge temp sensor in the rear of the head?
 
I replaced the water pump (took forever because apparently mixing crappy red rtv with a guy that sucks at applying it doesnt make for a good seal), put a 195 tstat since the jeep didnt have one and and direct hoses from the thermo to the heater. Getting rid of that black piece (still cannot remember the name) that leaked was a great feeling.

Eco I have a 136a alternator running through it now think that will compensate for the electrical drain or still not worth putting an e-fan in? Hopefuĺly Ill be dropping a Platinum Die Hard in it this weekend too. Anyway Ive never messed with electrical fans so I have no personal experience.

Im leaving Hawaii in October so its pretty much a beater car that Im still not sure if I'll take with me. $1000 bucks it wasnt bad plus my wife loves the wood panel.
 
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