jorjio_k

jorjio_k

Active Member
hello;
am i having an overheating problem?or is my temp gauge playing tricks on me?it is a 95 4.6 hse
i have replaced the thermostat,i have removed and flushed and cleaned the rad at a radiator repair garage,it was clogged.now again with ac on and at idle the temp gauge is creeping up but not reaching the red mark,no coolant is loss,and the elec fans kick in when the temp gauge reach the first mark after half.
when i rotate the hevac knob for the fan speed the gauge seems to creep more,when i press the rear glass demist it creeps more.when i turn off the ac the temp move back to middle,and if i rotate the hevac dial for full with the ac off,the temp gauge doesn't move from middle.
i have replaced the fuse box,the viscous fan is engaging and no play in it.
ac condenser cleaned,water circulation is up to normal,water pump is ok.
i have checked the grounds in the engine bay they seem tight and clean.
it is driving me insane folks,and if it is an electrical fault the aux fans shouldn't kick in right?unless i am wrong.
pleasssssssssse help
how can i fix that without paying any extra money for replacing unrelated things?
 
have a look at the sender unit ti may be faulty as i had the same or very simaler fault with my 90 almost lost the plot replaced the guage no good then the sender joy of joys its all good
 
drewster said:
have a look at the sender unit ti may be faulty as i had the same or very simaler fault with my 90 almost lost the plot replaced the guage no good then the sender joy of joys its all good
Click to expand...
u mean the coolant sensor the one with a single wire?
i thought about replacing it but if it is the coolant sensor acting up,will it bring the aux fans on when the temp gauge goes above middle?
 
ive got a dodgy temp gauge as well but ive been told it was prone to it on diesel and to clean up all the earths under the bonnet and underneath the drivers seat by the becm and the one by the back of the becm you got to pull the carpet back a few inchs and you can see it
 
what gives the order for the aux fans to kick in when the gauge is above the middle?it isn't the coolant sensor right?it is the engine coolant sensor plug (the one with the 2 wires near the coolant sensor).so i supose the engine is overheating for real, not the gauge?
for the aux fans to kick in means that coolant sensor is not related.it overheats only with the a/c on and on idle not while driving.
my head hurts now
 
dont think so as the senser gos straight to the guage unless the aux is wired into the guage ????
 
drewster said:
dont think so as the senser gos straight to the guage unless the aux is wired into the guage ????
Click to expand...
exactly my point.and it isn't wired to the guage.
the cooling system is working properly,EXCEPT for the heater core,the previous owner blocked it and didn't bypass it.so coolant isn't running through it.and after my search,having a blocked heater matrix will not cause the engine to overheat.
 
forgot to mention that temperatures these days are reaching the 40 ies more or less.if it is normal to be like that in these temperature and it wouldn't harm the engine as long as it isn't reaching the red zone, i am willing to ease at it.can any one confirm if it is normal to have the temp rising at idle with aircon,with temperatures exceeding the 35 celsius?than droping to the middle when car moves?
 
I recently has a similar problem on my 4.6. The temp guage did whatever it felt like doing and was driving me nuts! It turned out to be a bad earth connection in the engine bay. Have you replaced any of the battery cables? There is a well hidden earth connection behind the engine ECU on my 4.6.
 
i had the same as karl. a quick test is to wiggle the connections on the bat or put a temporary earth on the chassis/engine and battery, a jump lead will suffice for testing!! i got a new generic cable for about a fiver and put it to a good earth on the body and to the battery, it cured it!!
 
Karl702123 said:
I recently has a similar problem on my 4.6. The temp guage did whatever it felt like doing and was driving me nuts! It turned out to be a bad earth connection in the engine bay. Have you replaced any of the battery cables? There is a well hidden earth connection behind the engine ECU on my 4.6.
Click to expand...
Tried something 2day,when the guage was on the 1 oclock i switched the engine off then i put the key in pos 2 and guess wht,the gauge is at the middle but the aux fans were on.when i started the engine again the aux fans turned off and the guage was in the middle.bat cables r ok,ground seems ok,u mean behind the ecu under the fuse box?will check it again.but y the aux fans kick in?did they kick in with u also?
 
gavbriggs said:
i had the same as karl. a quick test is to wiggle the connections on the bat or put a temporary earth on the chassis/engine and battery, a jump lead will suffice for testing!! i got a new generic cable for about a fiver and put it to a good earth on the body and to the battery, it cured it!!
Click to expand...
Hi gav.
How do u test 4 the grounds,they r tight and the cables seem in a good shape.my q is y the aux fans r kicking in if it is a bad ground?they r not related 2 the guage.sorry but i am not an elec man,i more kean on mechanical stuff.
 
Last edited:
additional query.
Under the big rad top hose there is a sensor with a single wire attached 2 it,the sensor is screwed 2 the engine just beneith the rad hose emerging from the engine.wht is this sensor and wht does it do?
 
Jorjio, Hope you are having some success. I can't comment on the situation with the air con running as my air con is currently fooked! (No pressure in system at all, so obviously I need to get mine checked for leaks). But as a rule, my temp guage never goes more than a couple of lines above the blue end of the scale - even in hot weather. But some vehicles just run a bit hotter than others. Like I said - my temp guage problem was purely electrical in the end. Do you have the Rangey RAVE manual? If not, it might be of some help and I can email that to you.

Karl.
 
If your temp gauge is playing up, first thing to do is check connection to sensor, if that is good, change sensor BEFORE you start looking for problems elswhere. Keep it simple.
 
Karl702123 said:
Jorjio, Hope you are having some success. I can't comment on the situation with the air con running as my air con is currently fooked! (No pressure in system at all, so obviously I need to get mine checked for leaks). But as a rule, my temp guage never goes more than a couple of lines above the blue end of the scale - even in hot weather. But some vehicles just run a bit hotter than others. Like I said - my temp guage problem was purely electrical in the end. Do you have the Rangey RAVE manual? If not, it might be of some help and I can email that to you.

Karl.
Click to expand...

Thank you kind karl.i have rave and read it hundreds of times.i was looking also 4 this sensor and didn't find it in rave and doubt it's the oil presure sensor coz it is mounted under the hose on top of the pulley in the block.if it is overheating and guage at 1 oclock w ac,the compressor must shut off according to rave,but it doesn't and i still get cool air from ac so no real overheat.as long as ac is on,temp needle won't go down,as soon as i put ac off temp goes back 2 middle and aux fans shut off.the guage moves only w ac at idle.i turned off the engine then key on pos 2 the needle went back 2 middle.i am confused.
 
wammers said:
If your temp gauge is playing up, first thing to do is check connection to sensor, if that is good, change sensor BEFORE you start looking for problems elswhere. Keep it simple.
Click to expand...

Thanks wammers.u mean the sensor with the single wire near the ecu temp sensor,named (coolant sensor according 2 rave).but this one isn't related 2 the aux fans.i doubt replacing it will solve the pro coz the fans r kicking in.guess i have 2 problems here.wht about the sensor i am querying about?wht is it?
 
jorjio_k said:
Thanks wammers.u mean the sensor with the single wire near the ecu temp sensor,named (coolant sensor according 2 rave).but this one isn't related 2 the aux fans.i doubt replacing it will solve the pro coz the fans r kicking in.guess i have 2 problems here.wht about the sensor i am querying about?wht is it?
Click to expand...

It is related to auxilary fans, if the engine temp gets to high the aircon fans will come on at slow speed to assist the viscous fan. If it is giving a false reading that could be your problem.
 
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