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Trolitised
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236 Posts
Check injector pump timing, as that will make a large differeance
 

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KICKEN BACK IN THE BUSH
nissan gq
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4,690 Posts
I sometimes wonder why people use thermos then complain about rising temps ???
The factory fans flow more CFM of air than a thermo
Wouldnt goin to a thermo be worse for cooling than the higher flowing CFM of the factory clutch fan ???
Wonder what the difference would be like IF you went back ala factory set up ???
 

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BORDERTREK 4X4 & FABRICATION
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8,549 Posts
nope , just the thermos, i would dare say that the coolant temp would be more stable and lower if i had the factory fan and shrowd instead of the thermo fans
Damn right. Shrouding is essential.
 

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The nutty professor
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8,299 Posts
Discussion Starter #24 (Edited)
I sometimes wonder why people use thermos then complain about rising temps ???
The factory fans flow more CFM of air than a thermo
Wouldnt goin to a thermo be worse for cooling than the higher flowing CFM of the factory clutch fan ???
Wonder what the difference would be like IF you went back ala factory set up ???

well in my case i originally had the factory fan and shrowd and an 82 deg thermostat, all working as they should, but it still would overheat or run hot going up a mountain range or up a bit of a rise along the hwy, back then (2 odd years ago) i found by running a hotter thermostat that it would keep the temps more stable, that is although its running temp was hotter it wouldnt get as hot going up a mountain range or up a rise along the hwy, infact i noticed that the factory fan wasnt engaging like it did with the colder thermostat , thats when i fitted the thermo fans and found that they were sufficient enough to do the job,

although this wasnt a proper fix , it did control the temps better than the 82 deg thermostat even with the lower cfm of the thermo fans

then i found the current solution for those that dont like the idea of running a hotter thermostat , although if you combine this mod with a higher temp thermostat i would say that you would never have an over heating issue again unless there is terminal damage to the motor or cooling system
 

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Learned the hard way - RD28t out TD42 in
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4,415 Posts
Nice bit of work Itsa.

I would think that a pukka factory 'stat would be of the correct physical dimensions - an issue with using after market stuff maybe ?

Yes that bleed hose from the 'stat housing to rad top is a bypass IMO for hot coolant to miss out the rad. Blocked mine off (more a case of had to as my old RD28T rad was in much better nick that the TD one, so I just used it and blocked the hose), with no problems. Later TD 'stat housings don't use this hose anyhow.

A quick check to see if the rad and / or fan are on the edge is to put the heater on when it starts to overheat (don't leave it till it's to late), if that brings it back to normal, than you have a problem with rad/fan efficiency, if not, you have other issues.

and yes guys, don't remove the 'stat, that's just plain stupidity and shows you don't know what you are doing LOL !
 

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Gone Fishing
NISSAN 1989 GQ PATROL
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6,203 Posts
Isnt that hose from top of thermo housing to rad to bleed the air out!!!!!, Just done the coolent in my dads GU with the blocked peice of hose on it, Took it off and when filling with coolant and got to temp a whole lot of bubbly air came out then straight coolant,so put it back on and no air in system! Thats what its for on the Q where it goes too the rad.
 

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Registered
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35 Posts
hot

Nice bit of work Itsa.

I would think that a pukka factory 'stat would be of the correct physical dimensions - an issue with using after market stuff maybe ?

Yes that bleed hose from the 'stat housing to rad top is a bypass IMO for hot coolant to miss out the rad. Blocked mine off (more a case of had to as my old RD28T rad was in much better nick that the TD one, so I just used it and blocked the hose), with no problems. Later TD 'stat housings don't use this hose anyhow.

A quick check to see if the rad and / or fan are on the edge is to put the heater on when it starts to overheat (don't leave it till it's to late), if that brings it back to normal, than you have a problem with rad/fan efficiency, if not, you have other issues.

and yes guys, don't remove the 'stat, that's just plain stupidity and shows you don't know what you are doing LOL !
hey mate i have found mine gets hot when the air cons on or heater on
what do reckon that could be
cheers Ross
 

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The nutty professor
Joined
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8,299 Posts
Discussion Starter #28
Nice bit of work Itsa.

I would think that a pukka factory 'stat would be of the correct physical dimensions - an issue with using after market stuff maybe ?

Yes that bleed hose from the 'stat housing to rad top is a bypass IMO for hot coolant to miss out the rad. Blocked mine off (more a case of had to as my old RD28T rad was in much better nick that the TD one, so I just used it and blocked the hose), with no problems. Later TD 'stat housings don't use this hose anyhow.

A quick check to see if the rad and / or fan are on the edge is to put the heater on when it starts to overheat (don't leave it till it's to late), if that brings it back to normal, than you have a problem with rad/fan efficiency, if not, you have other issues.

and yes guys, don't remove the 'stat, that's just plain stupidity and shows you don't know what you are doing LOL !

it may be an issue with aftermarket stuff but i have seen plenty on here complain about overheating even with genuine stuff fitted , i do believe that tridon list the incorrect thermostat for td42`s for the years 93 to 97, where dayco list a different spec thermostat for all td42`s which i believe is the correct spec, but the dayco would still have to reach temps 20 plus deg above the opening temp of the thermostat before blocking the flow of recirculated coolant which i think is too far above the thermostats rated operating temp
 

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Registered
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145 Posts
Nice bit of work Itsa.

I would think that a pukka factory 'stat would be of the correct physical dimensions - an issue with using after market stuff maybe ?

Yes that bleed hose from the 'stat housing to rad top is a bypass IMO for hot coolant to miss out the rad. Blocked mine off (more a case of had to as my old RD28T rad was in much better nick that the TD one, so I just used it and blocked the hose), with no problems. Later TD 'stat housings don't use this hose anyhow.

A quick check to see if the rad and / or fan are on the edge is to put the heater on when it starts to overheat (don't leave it till it's to late), if that brings it back to normal, than you have a problem with rad/fan efficiency, if not, you have other issues.

and yes guys, don't remove the 'stat, that's just plain stupidity and shows you don't know what you are doing LOL !
"and yes guys, don't remove the 'stat, that's just plain stupidity and shows you don't know what you are doing LOL !"

And that's a statement from someone who lives in France;)
 

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The nutty professor
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8,299 Posts
Discussion Starter #30 (Edited)
hey mate i have found mine gets hot when the air cons on or heater on
what do reckon that could be
cheers Ross

i would say there is a flow problem somewhere if it gets hot with the heater on, i would be looking at having your radiator cleaned out internally, the heater acts like a bypass system but it should be returning cooled coolant to the motor maki8ng the temps drop, unless there is a restriction in the radiator then the water pump would force more coolant through the heater hose bypassing the radiator

could be a faulty thermostat as well
 

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The nutty professor
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8,299 Posts
Discussion Starter #31
Isnt that hose from top of thermo housing to rad to bleed the air out!!!!!, Just done the coolent in my dads GU with the blocked peice of hose on it, Took it off and when filling with coolant and got to temp a whole lot of bubbly air came out then straight coolant,so put it back on and no air in system! Thats what its for on the Q where it goes too the rad.
yes it is there to bleed the air out , but it still allows a lot of uncooled coolant to bypass the radiator , on a gq i would either block it or fit a restrictor in there , if you block it just top up your overflow bottle every couple of days after a few runs as it will self bleed the air out anyway
 

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Learned the hard way - RD28t out TD42 in
Joined
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4,415 Posts
"and yes guys, don't remove the 'stat, that's just plain stupidity and shows you don't know what you are doing LOL !"

And that's a statement from someone who lives in France;)
Oh Oh, he of little faith ! :rolleyes:
 

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Gone Fishing
NISSAN 1989 GQ PATROL
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6,203 Posts
yes it is there to bleed the air out , but it still allows a lot of uncooled coolant to bypass the radiator , on a gq i would either block it or fit a restrictor in there , if you block it just top up your overflow bottle every couple of days after a few runs as it will self bleed the air out anyway
Nah!!! thats wrong in my book to easy to overheat, should get all the air out at coolant change,Thats why its there!How can it bypass the rad it goes too it. All thats in it is the coolent from the top of the thermo doing nothing till the thermostat opens, then it all circulates. Hence letting the air out at the highest point.
 

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The nutty professor
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8,299 Posts
Discussion Starter #34
Nah!!! thats wrong in my book to easy to overheat, should get all the air out at coolant change,Thats why its there!How can it bypass the rad it goes too it. All thats in it is the coolent from the top of the thermo doing nothing till the thermostat opens, then it all circulates. Hence letting the air out at the highest point.
as soon as you start the car from cold the coolant will start to expand , any air in the cooling system will collect on the cold side of the radiator , the liquid that goes through the radiator will fall to the bottom of the cool side of the radiator leaving the air up top , as the motor gets to about 60 deg the cooling system should be pressurized and any excess pressure will go out the radiator cap ie : the air, when the motor cools down again it should suck in the coolant stored in the overflow bottle

you would have to leave a lot of air in the system for it to be a problem, it probly takes my car 2 trips to bleed all the air out by itself, no need for that bypass hose , it just easier and quicker to bleed the air out with it there

and that little hose does bypass the cooling part of the radiator and it does flow alot of coolant
 

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Gone Fishing
NISSAN 1989 GQ PATROL
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6,203 Posts
Oh well each to there own it wasn't flowing when i was doing the coolant with it off, Untill the thermostat opened then it circulates and blew bubbles then coolant.
 

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The nutty professor
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8,299 Posts
Discussion Starter #36
once the thermostat opens and you give the motor a bit of a rev , watch how much coolant comes flying out
 

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Gone Fishing
NISSAN 1989 GQ PATROL
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6,203 Posts
once the thermostat opens and you give the motor a bit of a rev , watch how much coolant comes flying out
Exactly thats what ime saying theres no coolant flow up to 60 deg. or when under preasure, Only when it hits thermo temp opening and it opens then the whole motor circulates the coolant. Thats why they put it above the thermostat, Its a great deign either on the Q or GU, just on the Q you dont have to take anything of to bleed the cooling system, Its there on the GU to take off for bleeding otherwise they would have just blanked it off.
 

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Registered
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145 Posts
Please forgive me for my ignorance, but my understanding of the purpose of a thermostat is to bring the operating temperature of the engine up to an efficient operating temperature in a cold climate. Once the maximum temperature rating of the thermostat is reached, it is fully open, allowing maximum flow of coolant through the thermostat housing, the engine water jacket and the radiator. I really cannot see how restricting the flow through the radiator (to cool the coolant more) will be effective when by doing this you are also restricting the flow of coolant through the water jacket, thus increasing the temperature of the coolant that has to be cooled. Catch 22. Shoot me down in flames.:D
 

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Gone Fishing
NISSAN 1989 GQ PATROL
Joined
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6,203 Posts
Please forgive me for my ignorance, but my understanding of the purpose of a thermostat is to bring the operating temperature of the engine up to an efficient operating temperature in a cold climate. Once the maximum temperature rating of the thermostat is reached, it is fully open, allowing maximum flow of coolant through the thermostat housing, the engine water jacket and the radiator. I really cannot see how restricting the flow through the radiator (to cool the coolant more) will be effective when by doing this you are also restricting the flow of coolant through the water jacket, thus increasing the temperature of the coolant that has to be cooled. Catch 22. Shoot me down in flames.:D
Spot on!!
 

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The nutty professor
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8,299 Posts
Discussion Starter #40
Please forgive me for my ignorance, but my understanding of the purpose of a thermostat is to bring the operating temperature of the engine up to an efficient operating temperature in a cold climate. Once the maximum temperature rating of the thermostat is reached, it is fully open, allowing maximum flow of coolant through the thermostat housing, the engine water jacket and the radiator. I really cannot see how restricting the flow through the radiator (to cool the coolant more) will be effective when by doing this you are also restricting the flow of coolant through the water jacket, thus increasing the temperature of the coolant that has to be cooled. Catch 22. Shoot me down in flames.:D

but i am not reducing the flow of coolant through the thermostat, i am reducing the amount of coolant that bypasses the thermostat, remember we are talking about a bypass type thermostat , it does 2 things, it controls how much coolant goes from the thermostat housing strait back to the water pump (bypassing the radiator) as well as how much coolant goes through the radiator

the coolant will always be circulating through the motor whether the thermostat is open or not, all i am doing is reducing the amount of coolant that gets bypassed (runs out the thermostat housing strait back to the water pump) once the motor has reached its normal operating temp, and normal operating temp would be just above the thermostats opening temp, you dont want to run a thermostat at its maximum operating temp cause thats when the thermostat loses control of the cooling system ie: it has no more adjustment to control flow

what you are talking about is the older standard thermostat which only controls flow through the radiator, which in fact when the motor is cold holds the coolant stationary till the thermostat opens

the temperature of the coolant will always determin how far open the thermostat is and how much coolant goes through the radiator, this im not changing
 
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