semlin
curmudgeon
i thought it might be useful to have a general discussion about how to make your FZJ80 run cooler in terms of monitoring, maintenance, troubleshooting and mods. The problem is that our threads discussing this topic are generally focussed on the problem at hand . Here is an attempt to cover the waterfront and to have an open discussion dredging up some ideas for mods to help address it.
Please add or comment as you see fit. I will start to add links as I go along to help make it user friendly.
Monitoring Temperature
First off my view is that you must have a working temp gauge on your 80 if you plan to run it in the summertime. If you don't you may not know you have a problem until it is too late. The stock "numb" gauge is not going to tell you much since it will not move from centre until you are past 216 degrees. There are at least 3 ways to get a responsive temp gauge:
-raventai's stock gauge modification
https://forum.ih8mud.com/showthread.php?t=64252
-adding an aftermarket gauge with the sender drilled and tapped into the bung on the coolant pipe beside the distributor or else tapped into a rubber rad hose using a greddy in line adaptor.
-if you have a 96-97, installing OBD2 scanner software and monitoring the ECU temp signal on a laptop bolted to your console or carputer screen.
What causes problems?
-An 80 seems to be able to run fine in most driving conditions even with a compromised cooling system. However, as soon as you get one or more of the following you can experience big temp rises if your cooling system does not function perfectly.
Hot weather
Using the AC
Steep highway grades
long steady slight grade
towing anything
lots of weight on board
Day to day monitoring
stuff you need to do regularly, especially on trips or in hot weather:
-watch your sensitive temp gauge.
-keep an eye on the coolant level in your overflow especially on long trips. Having lost a head gasket to a pinhole hose leak, I now do it everytime I gas up along with checking the oil. It is also a good idea to check the overflow and rad stone cold first thing in the morning regularly as a baseline since overflow levels can vary during normal operation.
-If you lose any coolant do not delay in figuring out why.
Driving tips to keep it cool
-I've noticed is it is better to run an 80 up a steep hill at 2800-3200 rpm than to lug it up the hill at 2200 rpm.
-turning the AC off before a long steep hill is a good idea
General coolant system maintenance
when you buy a truck, do the following:
-install a sensitive temp gauge.
-back flush the coolant system including the heater core and removing the block drain plug
-decide on red or green coolant and stick to it
-replace the rad cap
-clean out the overflow checking for grey sludge
-inspect the rad when drained for signs of sludge
-replace the thermostat
-physically inspect the rad, AC condensor and tranny and power steering coolers for signs of dirt build up - clean them up
-inspect all coolant hoses, including the rear heater lines that are above the catalytic converter and replace the pesky heater hose
-check AC belt tension
-check the fan clutch and consider a PM replacement if it has a black hub
-replace your tranny fluid if it has not been done recently (the tranny cooler uses the rad to cool the fluid so aging tranny fluid making the tranny run hot can in theory heat up your rad)
-inspect the foam sealant around your rad and replace it if worn -- it affects air flow. Also ensure the front skid plate just behind the steering damper is in place as it also directs airflow.
Further maintenance
if you have ongoing cooling problems
-check your fan clutch even if new
-do the overflow bubble test for h/g failure. if you have any suspicions of a bad
-consider replacing the rad. If you have a 95-97 aluminum 2 core rad consider installing the 93-94 3 core brass rad.
Other vehicle systems that cause heat
if your truck is running lean it can contribute to heat problems. You will probably hear pinging if you are running lean enough for that to be a factor. It is worthwhile to keep on top of the following:
-timing - do not advance it past the stock 3* btdc if you are running hot
-fuel pump regulator, fuel filer, fuel pump, injector flow
Possible Mods
this part is particularly wide open to discussion.
-aftermarket fan clutch
-fixed fan adaptor
-switching to 93-94 radiator if you own a later model truck
-bigger aftermarket rad
-adding the OEM separate ac condensor fan (used on 80s in other markets fitted with rear a/c option)
-bigger aftermarket tranny cooler
-electric fan system to replace fan clutch
-snorkel
-hood vents/louvres (either for expelling or admitting air)
Please add or comment as you see fit. I will start to add links as I go along to help make it user friendly.
Monitoring Temperature
First off my view is that you must have a working temp gauge on your 80 if you plan to run it in the summertime. If you don't you may not know you have a problem until it is too late. The stock "numb" gauge is not going to tell you much since it will not move from centre until you are past 216 degrees. There are at least 3 ways to get a responsive temp gauge:
-raventai's stock gauge modification
https://forum.ih8mud.com/showthread.php?t=64252
-adding an aftermarket gauge with the sender drilled and tapped into the bung on the coolant pipe beside the distributor or else tapped into a rubber rad hose using a greddy in line adaptor.
-if you have a 96-97, installing OBD2 scanner software and monitoring the ECU temp signal on a laptop bolted to your console or carputer screen.
What causes problems?
-An 80 seems to be able to run fine in most driving conditions even with a compromised cooling system. However, as soon as you get one or more of the following you can experience big temp rises if your cooling system does not function perfectly.
Hot weather
Using the AC
Steep highway grades
long steady slight grade
towing anything
lots of weight on board
Day to day monitoring
stuff you need to do regularly, especially on trips or in hot weather:
-watch your sensitive temp gauge.
-keep an eye on the coolant level in your overflow especially on long trips. Having lost a head gasket to a pinhole hose leak, I now do it everytime I gas up along with checking the oil. It is also a good idea to check the overflow and rad stone cold first thing in the morning regularly as a baseline since overflow levels can vary during normal operation.
-If you lose any coolant do not delay in figuring out why.
Driving tips to keep it cool
-I've noticed is it is better to run an 80 up a steep hill at 2800-3200 rpm than to lug it up the hill at 2200 rpm.
-turning the AC off before a long steep hill is a good idea
General coolant system maintenance
when you buy a truck, do the following:
-install a sensitive temp gauge.
-back flush the coolant system including the heater core and removing the block drain plug
-decide on red or green coolant and stick to it
-replace the rad cap
-clean out the overflow checking for grey sludge
-inspect the rad when drained for signs of sludge
-replace the thermostat
-physically inspect the rad, AC condensor and tranny and power steering coolers for signs of dirt build up - clean them up
-inspect all coolant hoses, including the rear heater lines that are above the catalytic converter and replace the pesky heater hose
-check AC belt tension
-check the fan clutch and consider a PM replacement if it has a black hub
-replace your tranny fluid if it has not been done recently (the tranny cooler uses the rad to cool the fluid so aging tranny fluid making the tranny run hot can in theory heat up your rad)
-inspect the foam sealant around your rad and replace it if worn -- it affects air flow. Also ensure the front skid plate just behind the steering damper is in place as it also directs airflow.
Further maintenance
if you have ongoing cooling problems
-check your fan clutch even if new
-do the overflow bubble test for h/g failure. if you have any suspicions of a bad
-consider replacing the rad. If you have a 95-97 aluminum 2 core rad consider installing the 93-94 3 core brass rad.
Other vehicle systems that cause heat
if your truck is running lean it can contribute to heat problems. You will probably hear pinging if you are running lean enough for that to be a factor. It is worthwhile to keep on top of the following:
-timing - do not advance it past the stock 3* btdc if you are running hot
-fuel pump regulator, fuel filer, fuel pump, injector flow
Possible Mods
this part is particularly wide open to discussion.
-aftermarket fan clutch
-fixed fan adaptor
-switching to 93-94 radiator if you own a later model truck
-bigger aftermarket rad
-adding the OEM separate ac condensor fan (used on 80s in other markets fitted with rear a/c option)
-bigger aftermarket tranny cooler
-electric fan system to replace fan clutch
-snorkel
-hood vents/louvres (either for expelling or admitting air)
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