everything new, and yet still overheating!

[mxracer624]

well once again i think i just was want to park my jeep in the garage and forget about it.. i have a 89 xj 4.0 auto with a closed system. I have replaced EVERYTHING possible in the last 2 months...
Brand New head gasket
Brand New pressure bottle
Brand new hd fan clutch
Brand new water pump
Brand new CSF 3 core radiator with brand new upper and lower hoses
70/30 mixture
i have burped the system by parking nose down, taking out the temp sending unit and filling pressure bottle until no more air escapes from the head.
Tstat was removed until i find the overheating problem so i can eliminated that as the prob.
And ive wired my efan to a switch

Ok so heres whats going on. My jeep would around 220-225 so i would replace one thing at a time.. after id replace something like the fan clutch it would work for a few days then start overheating again.. then i replaced the waterpump it worked for a few days then start overheating and so on and so on for everything ive replaced. well my last thing i replaced was the radiator. I thought for sure since this was the last thing i could possibly replace it must be the prob after all of the hassle. Sure enough i installed it, and it ran perfect.. It actually ran very cold because i still didnt put the tstat in it. But i would drive it around town, in traffic, up some USNF control roads in 90 degree weather and it would stay solid at like 160. i wouldnt even have to turn my fan on. it ran like this for about 3 days. Well i was just about ready to put a tstat in because i thought i figured out the prob. Until today. I decided to take it out and cruise up a control road everything was at 160 till about half way and then out of nowhere it started creeping to 210 then 215 the 225ish with the fan on. So i stopped and checked everything.. the only thing i found was there was a faint hissing sound (like air escaping) from the top of the water pump/bottom of the tstat housing/ head and block area. i couldnt pinpoint where it was coming from. I had the same problem before i installed the radiator and after i installed the water pump so when i installed the rad i pulled the water pump and put on a new gasket and resealed it very well. I dont think its the tstat housing cause i havent touched it and it wasnt doing it before.. so i let it cool down then started driving again.. and sure enough about 10 mins later same thing around 220. so i pulled over, let it cool then continued.. this time it didnt get to 220 but it got to about 190 which isnt bad at all and it stayed that way till we got to the top. we ate lunch and headed back down the mountain. On the way back the temp didnt even get past 150ish the whole way. my head has been hurting soo bad trying to think of what the problem is. This much thinking from me is dangerous, so im asking for anyone elses advice! please help me out before i roll this jeep off a cliff and it becomes a nice new rabbit shelter! thanks!

[robsjeepxj]

1.Spray some soapy water on the areas that you think might be leaking, it will help with finding them. If there's a leak then the system will not be able to hold the proper amount of pressure. Having it run at the right pressure helps it to control the temperature.

2.Speaking of pressure after it heats up is the upper hose hard, pressurized?

3.You may want to replace the radiator cap too to see if that helps. Not sure if the closed system uses one or not.

4.Also the 70/30 thing, are you running 70% water or coolant?

5.Lastly and this is a long shot you could try to bypass the heater core to see if that is somehow causing some restriction in coolant flow.

6.Do you have the spring inside the lower hose?

7. Anything blocking the front of the radiator like a winch, lights etc?

8. Have you verified that the gauge/sensor are in fact correct with a thermal infrared tester?

[dave92cherokee]

The rad cap on the pressure bottle and the temp sender are the only things that haven't been replaced. As was suggested get a IR gun and get some real temps from the engine rather than relying on the gauges that are known to lie to us.

[cruiser54]

Good thought on the IR gun. You can pinpoint hot spots, too. Some senders sold by the aftermarket are known to read high. Didn't your new coolant bottle come with a new cap? If not, replace it for sure.

[gradon]

I picked up the stant 10244 cap for my 88 eliminator and it no longer overheats.

[2stix]

seems you pretty much replaced everything that "normally" goes out. but try checking for any clogs in the system. i recently had the same problem with my 89 (closed system) and found that the "T" that is on the upper return hose to the bottle was clogged. it has a very small hole and can clog easily. its a metal "T" that allows the coolant to return to the bottle from the thermastat housing, and to the heater core. i removed mine and tried to blow air through it and it was totally clogged. a little angeled pick cleared it right out and solved the over heating problem. something to try.

if all else fails, im betting the transmission is the culprit. a bad trans will cause the overheating even in cool weather. especially when climbing or towing. try disconnecting the trans lines from the radiator, and installing an external trans cooler in front of the radiator. the trans will still heat up but it wont heat up the engine/coolant. if the coolant issue gets resolved this way, get the trans checked REAL soon. i once had a 1 ton duelly that overheated in a snow storm. trans was working fine, but had it checked and so much junk was in there and the converter was ready to explode. im lucky i didnt get stranded, but i did need a new transmission. and i would have never known if it didnt heat up the radiator and cause the problem to check.

[ehall]

go to autozone and buy the cheap gauge sender, part number TU108

[kastein]

Originally Posted by 2stix

seems you pretty much replaced everything that "normally" goes out. but try checking for any clogs in the system. i recently had the same problem with my 89 (closed system) and found that the "T" that is on the upper return hose to the bottle was clogged. it has a very small hole and can clog easily. its a metal "T" that allows the coolant to return to the bottle from the thermastat housing, and to the heater core. i removed mine and tried to blow air through it and it was totally clogged. a little angeled pick cleared it right out and solved the over heating problem. something to try.

if all else fails, im betting the transmission is the culprit. a bad trans will cause the overheating even in cool weather. especially when climbing or towing. try disconnecting the trans lines from the radiator, and installing an external trans cooler in front of the radiator. the trans will still heat up but it wont heat up the engine/coolant. if the coolant issue gets resolved this way, get the trans checked REAL soon. i once had a 1 ton duelly that overheated in a snow storm. trans was working fine, but had it checked and so much junk was in there and the converter was ready to explode. im lucky i didnt get stranded, but i did need a new transmission. and i would have never known if it didnt heat up the radiator and cause the problem to check.

this probably explains why my 96 is overheating right now... fortunately I already knew the trans was damn near blown. It's been shifting funny and randomly deciding to do nothing but slip since January.

[daszanto]

Tstat was removed until i find the overheating problem so i can eliminated that as the prob.

Try it with the T-stat in. Without the stat, the coolant can flow too fast thru the engine to pickup heat and too fast thru the rad to dissipate the heat. Cooling systems are designed to give the correct flow with the stat in, the stat acts as kind of a restrictor.

Also, here's a pretty good cooling system link:

http://www.troubleshooters.com/tprom...g_systems_work

Good luck.

[2stix]

Originally Posted by kastein

this probably explains why my 96 is overheating right now... fortunately I already knew the trans was damn near blown. It's been shifting funny and randomly deciding to do nothing but slip since January.

slipping clutches will cause a large amount of heat. but whats worse is that the material from the clutches are being sent through the rest of the trans and possibly damaging it worse. get it repaired as soon as possible. unless you just plan to swap it with another trans. then drive it like you stole it and keep your AAA card handy.

[kastein]

Originally Posted by 2stix

slipping clutches will cause a large amount of heat. but whats worse is that the material from the clutches are being sent through the rest of the trans and possibly damaging it worse. get it repaired as soon as possible. unless you just plan to swap it with another trans. then drive it like you stole it and keep your AAA card handy.

Yep, I know... it's presently doing so as far as I can tell. Fluid was gross when I did a drain and fill. I am planning on swapping out the trans and turning the old one into a coffee table of sorts.

Approximate plan changes - it blew up in January, I drove to NJ in a friend's MJ to buy a new trans, never ended up swapping it in because it magically started working again. Drove it to work every day till sometime in February when I bought the MJ off my friend (had originally convinced him to buy it) and started DDing that. Now I've just bought a massive cargo truck (the M54A2 in my sig) and I have materials on hand to build loading ramps for it... no AAA needed!

I'll stop hijacking this thread now though... my bet is the OP's issue is the cooling system failing to build pressure due to a leak somewhere, possibly (hopefully) in the pressure bottle cap.

[SteveT]

Also check the cat converter. Often overlooked, but can cause overheating issues.

[joe_peters]

Originally Posted by gradon

I picked up the stant 10244 cap for my 88 eliminator and it no longer overheats.

BRILLIANT! The Chinese pressure bottles with Chinese caps are junk; the Chinese pressure bottles with OEM dealer caps are junk; ALL pressure bottles without the Stant 10244 pressure bottle cap (off mid-late eighties Volvo 700 series with the 2.3 L engine) are JUNK.

1. The Stant cap will screw down and stay put instead of "stripping" and popping loose.

2. The Stant cap is lower profile, so when the pressure bottle expands the cap isn't being beat against the hood--take a look at the paint on the underside of the hood over the cap. Not being beat upon reduces stress cracks in the pressure bottles.

3. The Stant cap has a higher pressure rating and that further reduces the boiling point of the coolant.

[joe_peters]

Originally Posted by 2stix

i recently had the same problem with my 89 (closed system) and found that the "T" that is on the upper return hose to the bottle was clogged. it has a very small hole and can clog easily. its a metal "T" that allows the coolant to return to the bottle from the thermastat housing, and to the heater core. i removed mine and tried to blow air through it and it was totally clogged. a little angeled pick cleared it right out and solved the over heating problem. something to try.

I haven't run into this, yet, but a damn good tech find for the closed systems!

[joe_peters]

Originally Posted by mxracer624

So i stopped and checked everything.. the only thing i found was there was a faint hissing sound (like air escaping) from the top of the water pump/bottom of the tstat housing/ head and block area. i couldnt pinpoint where it was coming from.

One of the greatest "tools" for your kit is a 3' piece of vinyl tubing, 1/2" inch in I.D. or less. Stick on end in your ear, move the other end around the engine, whatever, and it will allow you to isolate the source of the sound. Note: standard warning about flesh and clothing around moving engine parts.

This comes with my personal guaranty, standard exception clauses in effect. It works, it will allow you to find the pressure leak--no pressure on the coolant the boiling point DROPS--and it is DIRT CHEAP. Do it.

Good luck.