heshhash
NAXJA Forum User
- Location
- Proctor, MN
Thinking outside the box, when was last time you changed tranny fluid and the filter? Also for grins, check your fuel pressure.
Overheating and already replaced all the usual suspects
- Thread starter Qban
- Start date
mako my day
NAXJA Forum User
- Location
- Aliso Viejo
Interesting... Tranny fluid was changed 15500 miles ago, I do have a fuel delivery issue(longer than normal cranking to fire it)
- Location
- San Diego
measure the core width.
Qban
NAXJA Forum User
- Location
- Long Beach, Ca
So I made further progress this weekend =)
To remind where I am at:
I tried to get back to my previous config and diagnose things better
- I ditched the Champion 2 core Rad for the moment and went back to the previous one, a koyo single row rad which had come with the jeep when I bought it used
- Heater Core is bypassed with brass fittings
- Tstat is removed
4 Things that I found and did
1) I borrowed some temperature equipment from work (2 thermocouples) with a meter that was calibrated last month. To verify the thermocouples I tried, my body temperature, boiling water, and ice water. They were spot on within 0.1 degress F.
I slipped these two thermocouples, one in the inlet hose and the other in the outlet hose. Both right at the radiator and in the coolant. I tightened the hose clamps and pressure tested. Guess what... a minor leak, a little more tightening of the clamp and presto, no more leak.
Now I can read 3 temperature very accurately while driving.
2) Airflow! I put back the stock front skid plate and I had a skirt/gasket that went in between the ac condenser and the rad and covered the sides top and bottom. It was nasty so I cut it up and used some duck tape to seal the whole area.
Here's my opinion on airflow. To get air to go through the radiator the air in the engine compartment must go somewhere which should be under the engine and out the back. This can't happen if you create a high air pressure point under the engine compartment and that's what I'm trying to address with the front skid plate. I have a little bit of a prerunner lift with 4.5 front 3 back which I think at highway speeds would shove air under the front of the jeep, by adding the skid plate I'm trying to get closer to an upsidedown plane wing where the air takes a long path and hence a lower pressure point.
HA! hows that for a line of unsubstantiated BS. I'll try and get some results to see if this works...
3) Address something I found with the heater bypass. When I flushed my systems 10,000 times I noticed something with the heater core. High pressure hose in and low pressure out. Water always has to make this heater core trip because when your engine starts cold and the tstat is closed the water pump has to push water somewhere, or it would be kind of mean to the water pump (I would imagine like trying to shove an already closed door). But let too much water through and your recirculating really hot water. Ok So I believe the heatercore regulates the radiator bypassed already hot water back into the water pump a little bit and I also think my bypass lets too much go back to the water pump.
So I put a hose clamp on the heater hose bypass and tightened it a lot to reduce flow. By how much did I reduce the flow (I have no flipping idea) lets just call it less, half, not as much, or any other subjective term for a reduced quantity =)
4) I checked my back brakes. Holy crap, with the hand brake off I couldn't even turn them. One side had the drum feeling very engaged, like stuck as far has my weak arms and hands were concerned, so I cleaned and readjusted, then gave a bunch of slack in the parking brake cable to guarantee me that I would not have any rear drum engagement while driving.
Alright, so my results.
Pretty good thus far. I drove all yesterday and today with no overheating. Yesterday afternoon I was on the freeway going 65 and watched my radiator drop 36 degrees =) which it hadn't done before, I was lucky to see 25 degrees previously.
I'm going to drive like this for a few days and hopefully push it on one of the warmer days.
Thanks and let my know your thoughts and ideas.
To remind where I am at:
I tried to get back to my previous config and diagnose things better
- I ditched the Champion 2 core Rad for the moment and went back to the previous one, a koyo single row rad which had come with the jeep when I bought it used
- Heater Core is bypassed with brass fittings
- Tstat is removed
4 Things that I found and did
1) I borrowed some temperature equipment from work (2 thermocouples) with a meter that was calibrated last month. To verify the thermocouples I tried, my body temperature, boiling water, and ice water. They were spot on within 0.1 degress F.
I slipped these two thermocouples, one in the inlet hose and the other in the outlet hose. Both right at the radiator and in the coolant. I tightened the hose clamps and pressure tested. Guess what... a minor leak, a little more tightening of the clamp and presto, no more leak.
Now I can read 3 temperature very accurately while driving.
2) Airflow! I put back the stock front skid plate and I had a skirt/gasket that went in between the ac condenser and the rad and covered the sides top and bottom. It was nasty so I cut it up and used some duck tape to seal the whole area.
Here's my opinion on airflow. To get air to go through the radiator the air in the engine compartment must go somewhere which should be under the engine and out the back. This can't happen if you create a high air pressure point under the engine compartment and that's what I'm trying to address with the front skid plate. I have a little bit of a prerunner lift with 4.5 front 3 back which I think at highway speeds would shove air under the front of the jeep, by adding the skid plate I'm trying to get closer to an upsidedown plane wing where the air takes a long path and hence a lower pressure point.
HA! hows that for a line of unsubstantiated BS. I'll try and get some results to see if this works...
3) Address something I found with the heater bypass. When I flushed my systems 10,000 times I noticed something with the heater core. High pressure hose in and low pressure out. Water always has to make this heater core trip because when your engine starts cold and the tstat is closed the water pump has to push water somewhere, or it would be kind of mean to the water pump (I would imagine like trying to shove an already closed door). But let too much water through and your recirculating really hot water. Ok So I believe the heatercore regulates the radiator bypassed already hot water back into the water pump a little bit and I also think my bypass lets too much go back to the water pump.
So I put a hose clamp on the heater hose bypass and tightened it a lot to reduce flow. By how much did I reduce the flow (I have no flipping idea) lets just call it less, half, not as much, or any other subjective term for a reduced quantity =)
4) I checked my back brakes. Holy crap, with the hand brake off I couldn't even turn them. One side had the drum feeling very engaged, like stuck as far has my weak arms and hands were concerned, so I cleaned and readjusted, then gave a bunch of slack in the parking brake cable to guarantee me that I would not have any rear drum engagement while driving.
Alright, so my results.
Pretty good thus far. I drove all yesterday and today with no overheating. Yesterday afternoon I was on the freeway going 65 and watched my radiator drop 36 degrees =) which it hadn't done before, I was lucky to see 25 degrees previously.
I'm going to drive like this for a few days and hopefully push it on one of the warmer days.
Thanks and let my know your thoughts and ideas.
XJ91limited
NAXJA Forum User
- Location
- Sandy, UT.
friend of mine had over heat and turns out his ECU was fried and climate control system was communicating improperly. He bought a used ECU and all is good for the last 2 months. For what its worth my 2 pennies
Qban
NAXJA Forum User
- Location
- Long Beach, Ca
Thanks for the idea, for right now the engine is checking out as good and it seems like the radiator and/or flow is just not able to keep up with the heat that's being created.
Do you know if the ecu was just messing with the sensor/gauge/engine light or was it actually creating a condition that caused the engine to run in a way that generated too much heat (like running lean or something). I'm asking cause my test setup independently verifies my temperature and my boiling reservoir proves I'm actually running hot.
On a separate note I think I have the puzzle pieces falling in place and I'm becoming more confident on what my issue is.
My "stock" radiator was put in by the PO, its a koyo single row radiator about 3/4 inch. My 98 jeep had the tow package which I believe should have had a modine 2 row (if anyone could confirm this, that would be great). I think the koyo was just barely adequate for the stock config, when I started lifting/bigger tires and all the other fun stuff this became definately not adequate and then after the first overheat things went to hell. After this I chased a lot of ghosts and real problems by my own doing.
I'll write down all the proof and real numbers I've gathered once I get this solved =)
mako my day
NAXJA Forum User
- Location
- Aliso Viejo
I'll be adding a 2 ( or 3 i dont know whats better yet)row aluminum rad, and an additional trans cooler, possibly high flow water pump.
Recap: I can idle and 4x4 all day.(no ac)
High speed (above 50), uphill, or ac on, I overheat.
Fully flushed.
Oem parts replaced-hoses, tstat, rad, pump, exhaust mani, etc, etc.
Recap: I can idle and 4x4 all day.(no ac)
High speed (above 50), uphill, or ac on, I overheat.
Fully flushed.
Oem parts replaced-hoses, tstat, rad, pump, exhaust mani, etc, etc.
Qban
NAXJA Forum User
- Location
- Long Beach, Ca
Well, that sounds a lot like my situation though I think mine is a bit worse. When looking for a radiator try to get the thickness, water capacity, and fin count per square inch. I've been looking and I've seen some 2 rows and 3 rows that are about the same or only slightly thicker than a 1 core. More cores don't necessarily mean better, it could actually be worse. I don't think there is a good market selection for improved (over stock) radiators at affordable prices.
And from my experience at radiatorexpress.com , I wouldn't recommend them. They are just a middlemen who won't offer any support. They kept telling me they would get a tech to contact me and after checking twice nothing came of it and then they said they might be able to sneak my radiator back to the manufacturer for a return but that I would "probably" only get a credit. Great... I return a product just so that I can get a credit for another crappy radiator as that is the only brand they carry for my vehicle. It's my fault for buying from them, but I just figured I would share the experience =)
- Location
- Curtis Bay, MD
For what it's worth I just replaced the original rad in my 99 with a "Spectra Premium" one... got it from an Indy parts store but I believe it's the same one NAPA sells. The original was a two row but don't know who made it. The aux trans cooler has a modine sticker on it though. The new rad is a really wide single row and I'm running between 195 and 210 at all times now. Granted it hasn't been above 65-70 degrees since I put it in but based on how cool it's running I should have replaced the rad a long time ago.
mako my day
NAXJA Forum User
- Location
- Aliso Viejo
Ill do a new aluminum rad, then test it out . Maybe my exhaust is restricted or the engine just doesn't like to work over 30% load.
lazyxj
NAXJA Member #1310
- Location
- Los Angeles
After fighting the overheating problem for the last year or so, I replaced the A/C condenser a couple months ago, which finally cured it.
I had cleaned the condenser and straighten the fins but it still showed serious blockage when held up to a bright light and looking through the fins.
The blockage was a combination of oil, bugs, dirt, pollen and whatever else had stuck itself in the fins. It just wouldn't clean up. Being as big as it is, the condenser was blocking the flow of air through the radiator. The XJ is now running 10-15 degree cooler than it was, a huge difference.
In years past, working on several different XJs, I have tried several radiators and found the Mopar HD XJ radiator (52080104AC) works well, better than the 2 and 3-row CSFs or Napa's HD replacement.
I had cleaned the condenser and straighten the fins but it still showed serious blockage when held up to a bright light and looking through the fins.
The blockage was a combination of oil, bugs, dirt, pollen and whatever else had stuck itself in the fins. It just wouldn't clean up. Being as big as it is, the condenser was blocking the flow of air through the radiator. The XJ is now running 10-15 degree cooler than it was, a huge difference.
In years past, working on several different XJs, I have tried several radiators and found the Mopar HD XJ radiator (52080104AC) works well, better than the 2 and 3-row CSFs or Napa's HD replacement.
Qban
NAXJA Forum User
- Location
- Long Beach, Ca
That's some good info thanks. I'm curious, do you know the thickness of the core on the Mopar HD?
lazyxj
NAXJA Member #1310
- Location
- Los Angeles
1-1/2" 2-row.
Qban
NAXJA Forum User
- Location
- Long Beach, Ca
Alright, so I ordered a Mopar HD Radiator and I'll get it tomorrow, wish me luck
Digger87xj
NAXJA Forum User
- Location
- Buffalo Creek/Lakewood CO
Cool! I'm anxious to hear the results!
mako my day
NAXJA Forum User
- Location
- Aliso Viejo
I am replacing with all stock. AGAIN. Lets see what happens.
Qban
NAXJA Forum User
- Location
- Long Beach, Ca
I'm officially calling it fixed!
Very stable temperatures in the 195-205 range, even while driving fast on warmer days on the hwy and up the mountain with the AC blasting =) I'm extremely happy about the cooling efficiency.
The final numbers while pushing the XJ really hard:
Inlet Temp: 142
Outlet Temp: 193
Temp Gauge: 203
The primary cause were the Radiators. =)
The PO was in a front end collision before I bought it and he had the radiator replaced with an aftermarket one that was less than adequate for stock (my jeep always ran on the hotter side of things and this is why). It didn't take much to push my jeep in to overheating.
The champion 2row I bought and installed did not cool enough either. I would get heat creep at hwy speeds with the AC on. When I replaced with a Mopar HD my temps went into the normal/great range.
The secondary causes and other problems:
1.) One of the rear drum brakes was badly adjusted and always engaged.
2.) I still believe in the airflow concerns I discussed in a previous post. The front skid plate and rubber around the radiator are staying on.
3.) A bad radiator cap at one point
4.) A leak between the heater hose and tstat housing
5.) A really plugged up heater core (I pressure tested this one independently and used clr)
Thanks Everyone!
Very stable temperatures in the 195-205 range, even while driving fast on warmer days on the hwy and up the mountain with the AC blasting =) I'm extremely happy about the cooling efficiency.
The final numbers while pushing the XJ really hard:
Inlet Temp: 142
Outlet Temp: 193
Temp Gauge: 203
The primary cause were the Radiators. =)
The PO was in a front end collision before I bought it and he had the radiator replaced with an aftermarket one that was less than adequate for stock (my jeep always ran on the hotter side of things and this is why). It didn't take much to push my jeep in to overheating.
The champion 2row I bought and installed did not cool enough either. I would get heat creep at hwy speeds with the AC on. When I replaced with a Mopar HD my temps went into the normal/great range.
The secondary causes and other problems:
1.) One of the rear drum brakes was badly adjusted and always engaged.
2.) I still believe in the airflow concerns I discussed in a previous post. The front skid plate and rubber around the radiator are staying on.
3.) A bad radiator cap at one point
4.) A leak between the heater hose and tstat housing
5.) A really plugged up heater core (I pressure tested this one independently and used clr)
Thanks Everyone!
Tony_SS
NAXJA Supporting Vendor
- Location
- Washington MO
Thanks for keeping things updated Qban. Very helpful.
lazyxj
NAXJA Member #1310
- Location
- Los Angeles
Glad that worked for you. Using the same radiator, my XJ is running at or below 200 much of the time, so much cooler the CSF 3-core.
What ultimately lead me back to the Factory HD unit, was remembering it never had cooling problems when the Jeep was new and radiator Factory stock. One or two postings, on other forums, had members experiencing the same results.
As Goatman has said many times, a stock cooling system in good shape, will adequately cool a 4.0. I'm convinced.
