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6000.00 later still overheating

95heep

95heep

NAXJA Forum User
Location
OREGON
'95 new jasper motor with EVERYTHING NEW but the alternator, also complete new ext w/ banks header, cat, flowmaster, jet chip stg2, custom intake, thrtl bdy spcr, no joke over 6 g's. and here we are in L.A. got up to about 80 today(mon) and my temp gauge is more than half way between 210 and the red going up the 2 freeway (semi steep grade for 3 to 4 miles). used a laser temp gauge same readings as the stock gauge. HELP!!!!!!!!! dont know what to do. also know a lot of people in the auto world to no avail
 
get a 160temp tstat make sure your e fan is working ...was the radiator new???if not get a new one they make 4 core radaitor for the 4.0s..with a 4 core it will cool alot more
 
new oem rad, 180 stat, who makes the 4 core
 
Try running without a stat, I do it in my stroker... It never gets passed 150, even with the electric fan off... I'm not really worried about the poor mileage involved with low engine temps, because it's not my daily driver... Plus I have over 3K into the motor alone, and i'm not about to overheat it.
 
This might be a stupid question, but did you change the radiator cap? If not then do. Also, you might want to verify that your thermostat is operating correctly. Even new ones might not operate correctly. I'd get a Robert Shaw or a Mr. Gasket. Since you are in a Southern Climate, a 180F or 160F might help to an extent. I'd try the 180F first. Still that only sets the lower range. Once fully open, then it would help is the temp rise further. I'd didn't see if you put in a Flowcooler or a HESCo water pump. They might help.
Tom
 
What coolant and what % mix are you running. Is the belt installed properly and did you get the correct water pump so that the impeller is spinning the proper direction? ( I don't know first hand but have read on this forum that that can be an issue, apparently theres a waterpump that fits but has the impeller the wrong direction). Is your transmission and trans fluid in good shape with a trans cooler (assuming its a AW4)? What rpm does it take you to go up this "semi-steep grade"? What gears do you have installed? What size tires?
X2 on verifying your T stat opens properly. If you have a cooling issue an OEM t stat is usually a best bet. Robert Shaw (mr gasket) is a good one, but you have to verify that it works as they aren't all perfect ( just read about a bad one on here yesterday). Bring it to a shop and have them perform a pressure test. Just my .02 but with more info, more people may have more ideas.
 
lower radiator hose sucking shut?
does it overheat at idle or just freeway speeds?
 
I would run a 195 t-stat if you run a cooler one the truck will overheat the coolant will not have enuff time in the radiator to cool down. Do you have a 4 core brass raidaitor? How old is it? When you overheat at speed it a sign of a cloged raidaitor, at slow speed a bad fan clutch. What about the tubro city t-stat housing?
 
thanks to all for your input, has 206000 miles on tranny, no slippage,4.56 w/33s proper water pump, hits a ltl over 210 on grades, get on streets the temp starts to rise, no tranny cooler THINKING ABOUT PUTING ONE THO WHERE DO YOU PUT IT????? new oem fan clutch, so less time in rad high flow hesco pump?? dosent make sence. lower hose oem w/spring, 185 t stat(stant tho)
 
First, does the lower hose have the spring in it ? It needs it.
The pressure cap, when it gets hot is the upper hose under pressure, if not you have a pressure leak.
The first thing I would check, big time, is the belt tension, if it's not 170lbs and someone used the twist it method to set it they are wrong and it's probably more like 90-125lbs, this won't spin the waterpump enough to cool.
One overheat will ruin a thermostat.
 
If the cooling problem is only in city driving then it sounds like aether your elect, cooling fan isn't working or you vicious drive(mechanical fan ) is bad.


Flash.
 
cherokee89 said:
I had to laugh out loud when I read this, but I am wondering the same thing.
Click to expand...
YEA HAD AN XTRA 6 G'S LAYING AROUND. NO!!!!! HAD HORRIBLE COMR. RATIOS PISTON SLAP VERY TIRED MOTOR. OVER 210,000 MILES
 
95heep said:
YEA HAD AN XTRA 6 G'S LAYING AROUND. NO!!!!! HAD HORRIBLE COMR. RATIOS PISTON SLAP VERY TIRED MOTOR. OVER 210,000 MILES
Click to expand...


WELL, WITH A TITLE LIKE THAT, YOU HAVE TO WONDER!!!

:gee:
 
What RichP said. It doesn't take much of a leak to let the pressure out of your system.
Loss of pressure lowers the boiling point of your coolant, the gage is an average, not the hottest part of the motor. Air in the system (steam) reduces efficiency.
Less likely but possibly is it's running way lean. Check your plug color. Light gray to reddish, bone white may mean trouble. Most of your trouble seems to be during low vacuum conditions. A prime time to run way lean.
A leaky head gasket can push enough exhaust gas into the cooling system causing vapor problems and heats up the coolant.
If it starts to heat up at road speeds 40-60 MPH, put it in neutral and rev up the RPM's (3000-3500) for 10-15 seconds, if the temp. goes down it's likely poor coolant flow for some reason. A restriction or air block in the cooling system. Off idle I've rarely noticed XJ's lacking in coolant flow volume unless there was a restriction. The higher the RPM. the better the pump works, there is usually excess capacity, except at low idle.
Your aux fan should come on around 220 or so and bring the temp. back down pretty quick.
You see a lot of guys with high horsepower XJ's vent the hood someway. The air doesn't flow very well through the engine compartment.
IMO Adding another row in the radiator is marginally helpful, but usually not as helpful as increasing air flow some way (bang for the buck).
 
$6K, and I thought I had a lot of $$$ in my long rod stroker :scared:

You didn't say anything about swapping out your radiator. If it has 200+K miles like the first motor it's due a retirement. Go with a 2 core Modine unit or better. I do not recommend the three core GDI. It works for some, but there are several that haven't seen any benefit because of one problem or another with the GDI (I’m one of them). Make sure the condenser isn’t plugged as well. It can really block airflow to the radiator and cause problems out on the highway.

You said you are running a Jet stage two. I think Jet says you need a 180* t-stat with it. Jet makes a good T-stat. What Rich said about the lower rad hose needing a spring inside and the cap change are very important. I don't recommend the 160* stat. I have seen some over-heating problems with it as the engine will not get to closed loop well at that low a temp. The 4.0 likes to run more than 160. It needs at least a 180*.

The other thing to remember, if the cooling system is having problems lower temp t-stats won't make the motor run cooler. The stat will just open earlier on the way to an overheating situation. It’s the same running without a t-stat; sometimes running without a t-stat will actually make an engine overheat easier.

Make sure you have bled the air out of the head. You can pull the temp sensor out of the head to aid in air removal. I also like to drill a small hole in the t-stat if it doesn’t already have an air bleed to aid in removing the trapped air.

High flow water pumps aren’t the answer if the radiator isn’t up to the task either. I have run a HESCO and FlowKooler in the past. I run a stock pump now and have no heat issues.

Hood vents are nice, but again not a fix if the rest of the cooling system isn’t up to the task. I don’t think they do a darn thing at low speeds without being able to switch on the aux fan manually.

Water wetter helps as does running a 50/50 or less antifreeze/water mix if your climate allows.

Another thing I would suggest for those with heat problems when at slow speeds (I know it’s not what your problem is, but I’m on a roll here ;)) is to run a relay and new power wire to the aux fan. On my ’91 the aux fan was powered by a tiny wire for the amps that the electric motor pulls. I ran a relay set up triggered by the small wire and powered by a bigger wire off the battery. It really sounds like it helped the fan’s RPMs and hopefully CFMs as well. The relay set up also makes running a manual aux fan switch easier.


Good Luck,

Bones :skull1:

 
Bones said:
$6K, and I thought I had a lot of $$$ in my long rod stroker :scared:

You didn't say anything about swapping out your radiator. If it has 200+K miles like the first motor it's due a retirement. Go with a 2 core Modine unit or better. I do not recommend the three core GDI. It works for some, but there are several that haven't seen any benefit because of one problem or another with the GDI (I’m one of them). Make sure the condenser isn’t plugged as well. It can really block airflow to the radiator and cause problems out on the highway.

You said you are running a Jet stage two. I think Jet says you need a 180* t-stat with it. Jet makes a good T-stat. What Rich said about the lower rad hose needing a spring inside and the cap change are very important. I don't recommend the 160* stat. I have seen some over-heating problems with it as the engine will not get to closed loop well at that low a temp. The 4.0 likes to run more than 160. It needs at least a 180*.

The other thing to remember, if the cooling system is having problems lower temp t-stats won't make the motor run cooler. The stat will just open earlier on the way to an overheating situation. It’s the same running without a t-stat; sometimes running without a t-stat will actually make an engine overheat easier.

Make sure you have bled the air out of the head. You can pull the temp sensor out of the head to aid in air removal. I also like to drill a small hole in the t-stat if it doesn’t already have an air bleed to aid in removing the trapped air.

High flow water pumps aren’t the answer if the radiator isn’t up to the task either. I have run a HESCO and FlowKooler in the past. I run a stock pump now and have no heat issues.

Hood vents are nice, but again not a fix if the rest of the cooling system isn’t up to the task. I don’t think they do a darn thing at low speeds without being able to switch on the aux fan manually.

Water wetter helps as does running a 50/50 or less antifreeze/water mix if your climate allows.

Another thing I would suggest for those with heat problems when at slow speeds (I know it’s not what your problem is, but I’m on a roll here ;)) is to run a relay and new power wire to the aux fan. On my ’91 the aux fan was powered by a tiny wire for the amps that the electric motor pulls. I ran a relay set up triggered by the small wire and powered by a bigger wire off the battery. It really sounds like it helped the fan’s RPMs and hopefully CFMs as well. The relay set up also makes running a manual aux fan switch easier.


Good Luck,

Bones :skull1:

Click to expand...
thanks for your help, new visteon rad, heard its oem, new a/c cond. has stock relay for fan already, put a manual switch on the aux fan today, 180 stat already, also heard you dont have to burp with open cooling sys. $$$$ added up w/ all new a/c condenser, comp (factory crossed the threads one one of the hoses, and on torque conv, the list goes on n on. then the xtras msd6 off road, chip, msd wires, custom alum intake, flowmstr exht, adv adpt sye tom woods shaft ect..... moving to oregon in 2 wks lots of wheelin wanted to take advantage of it. didnt want to buy someone elses headache i like MINE!!!!!!! THANKS AGAIN BRO LTR
 
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