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Discussion Starter · #1 ·
Hello all.
Currently replacing rusted brake line and rear brakes. The truck has been in my garage on blocks for two years but I run the motor every month, until the engine is hot enough for the electric radiator fan to start.
Once the electric fan starts, if will never shut off, engine running at idle, even during winter.

Notes:
The viscous fan is working properly
The thermostat was replaced a couple of years before the shutdow, it has run not more that 15,000 miles.
The electric fan was replaced as well because the old one was stuck in rust from never runnning ( I almost never go to town with the Disco)
Coolant was also changed and properly vented during a water pump gasket replacement
Radiator was changed 6 months before shutdown because of a leak
I don't have a scanner showing real-time temperature
I have a whole spare 2003 SE in my backyard.

Anyone been thru that ?
I suppose I could start changing parts (temperature sensor, thermostat, relay) but I would prefer if someone knew what is happening.
Thanks

François
 

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... I run the motor every month, until the engine is hot enough for the electric radiator fan to start.
Once the electric fan starts, if will never shut off, engine running at idle, even during winter.
Hi, i'm affraid you'll not be happy with this....
just to clarify, the electric fan is not supposed to kick in on a normal operating engine, it's there for aircon and to help cooling at higher than normal temps, quite unlikely on a sstationary vehicle, it should come on when the temp reading goes above 212°F and stop when it drops to at 202°F. So as long as you can't monitor the temps it's hard to diagnose cos it can be an overheating issue so those temps to be real or a high reading sensor so you'll need a thermometer and a scanner to compare the coolant temp and the sensor's readings

though if the fan starts immediately as you switch ignition on it means there is an overheat fault code logged in the ECU and it must be cleared for the fan to operate well
 

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Discussion Starter · #3 ·
Well, this is how I figured my secondary fan was dead:
I was stuck in traffic for 15 minutes and I had the red light on the temps guage. I managed to immediately get out of the jam (heart pumping) and drive a bit so the temperature went down fast.
At home, I found the fuse was blown. Got it replaced, blew it again. I couldn't turn the fan by hand...
After the fan was replaced the truck ran well for a year, temperature always normal and no issues or sign of head gasket failure.
So I am not stressed by that fan coming on when the truck is not moving, this is probably normal.
What I think is not, is once it starts, it will not come off, even when I leave the truck running at idle for 10 minutes.

Since the thermo switch and the relay reset themselves when the truck is allowed to cool completely, ( fan will not run with a cold engine) maybe I'm just imagining things.

I was just hoping somebody knew how the control is set.
 

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So I am not stressed by that fan coming on when the truck is not moving, this is probably normal.
What I think is not, is once it starts, it will not come off, even when I leave the truck running at idle for 10 minutes.

...
\
Please read again what i wrote, it's not normal at all for the electric fan to come on unless you are towing uphill in extreme heat or force the engine cos beside that 212F which IMO is high for a normally running engine the inlet air temp must be higher than 140F which is also high... and as i said the ECU is managing that fan based on those temp readings so if it doesnt stop it means that the lower limit was not reached

in a nutshell IMO you have or a cooling issue or a sensor is missreading giving higher than real inputs, the operation of the fan is clear se attachment
 

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Drives like an old man
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I think it's possible that the fan can come on at idle. These things have pathetic little cooling systems. Even with all new components, it's possible to achieve 212 degrees idling. The clutch fan doesn't move enough air by itself, hence the trend to convert to a Chevy fan and clutch. I wouldn't be terribly alarmed about the electric fan coming on. It should definitely turn off once temps return to 202, though. If it's not, it could be the temps aren't coming down low enough, which might indicate a problem.

What kind of coolant do you have in the system? Hopefully not that red crap.
 

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Discussion Starter · #7 ·
OK, Thanks for the info.
hopefully I can take a ride tonight (after 2 years in storage) and if it doesn't stop after a drive, I'll continue working on it.
The list is not very long: Relay, thermo switch and thermostat.
Like I said, the truck is running fine so I'll keep an eye on it.

For the triumph, I purchased it at 22, rode it only one summer, figured I would surely (...) have time to rebuild it completely at 40.
Now I'm passed 55 and it keeps sinking deeper in the priority list !!!
 

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I will completely agree with Frey on this one.
The electric booster fan will not come on unlessyou have problems.
If you are hitting 212 in traffic you do have a problem and even though your truck is still going you are killing it slowly but for sure killing it!
As mentioned in a multitude of threads you need to monitor engine temperature more accurately that the useless gauge on the dash!

As for the electric fan not shutting off..... It could possibly be a bad relay (contacts sticking on) and you could try either testing the circuit or as a quick and easy trial , swap the relay with another.

A properly running engine with a properly operating cooling system with the commonly recommended 180 deg thermostat (or conversion to a conventional thermostat should never exceed 200 at idle or ever!
 

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Rad is probably full of crud or DexCool goo. Or both. Hooking a hose and flushing tells you nothing. Flow isn't that important. Flow through every core is what cools. A full-on garden hose will flow through ten open rows.

Don't assume the fan clutch is good. They can "feel" OK and not pull air worth a damn. If you don't hear it kick on as temp rises and get a strong fan sound, it probably needs replaced.

Also, most of the Chinese radiators are total crap. Not unusual to get one that won't cool right out of the box. You could take it to a shop and have it flushed, but you'd be better off putting that $$ towards the Nissens.

After that much sitting I would definitely replace every hose. At a minimum, replace the thermostat with either OEM or MotoRad and replace the expansion tank cap. These would be musts.
 

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Discussion Starter · #10 ·
Did my drive, cool weather, fan still running.

I'll do my homework and come back later, when I have found the problem.
François
 

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Did my drive, cool weather, fan still running.

I'll do my homework and come back later, when I have found the problem.
François
If you aren't able to measure your temperature accurately, then everything you're doing is based upon an assumption, which is a polite word for guessing. Hence, anything suggested here is nothing more than guessing as well. It is highly unlikely your ECU is "stuck" and leaving your fan in a permanently "on" mode. If you have eliminated the stuck relay possibility, you're down to ruling out the rest of the absolutes.
 

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I will completely agree with Frey on this one.
The electric booster fan will not come on unlessyou have problems.
If you are hitting 212 in traffic you do have a problem and even though your truck is still going you are killing it slowly but for sure killing it!
As mentioned in a multitude of threads you need to monitor engine temperature more accurately that the useless gauge on the dash!

As for the electric fan not shutting off..... It could possibly be a bad relay (contacts sticking on) and you could try either testing the circuit or as a quick and easy trial , swap the relay with another.

A properly running engine with a properly operating cooling system with the commonly recommended 180 deg thermostat (or conversion to a conventional thermostat should never exceed 200 at idle or ever!
I'm only noting my own experience. I have just replaced the entire cooling system on my D2 (radiator, pump, hoses, stat) and temps still rise to 210 or so after prolonged idle. So it is possible to have a well maintained cooling system and still reach 210-212, neither of which is abnormal nor harmful.
 

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IMO 212 might not be normal though cos only the secondary purpose of the electric fan is to help cooling as to not exceed that temperature if possible, that's why the factory fitted thermostat has to be fully opened at 204 and on every well working engine the temp should not grow after the thermostat fully opens unless it's forced but not on idle whatsoever.... that fan is mainly for aircon there not for engine cooling that's why modells without aircon dont even have it(cos those modells were dedicated for arctic cold countries) so if 212 was normal they would have not bothered to make it kick in then.

here's the description from the management's point of view:
Cooling fan request
The A/C fan request is an input to the ECM from the ATC ECU to request that the engine's electric cooling fan is activated to provide additional cooling for the A/C condenser.
The cooling fan relay is located in the engine compartment fuse box and is also controlled by the ECM. It is a four pin normally open relay. This means that the relay must be energised to drive the cooling fan. The cooling fan is used especially when the engine is operating at excessively high temperatures. ....
So IMHO better not consider temps above 204 to be normal and take some action to improve cooling of the vehicle if if it's above that too often if you want the engine to last more.
 

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I'm pretty sure that 212-215 degrees on a "modern" engine is not abnormal or dangerous, though I'd like it to be closer to 200 just for peace of mind. I think the only thing I could do to lower the temps is the inline stat project. I'll have to look that over. But it's more work than I'm willing to do right now. It's just a car. If it burns up because it's such a POS, I'm better off without it.
 

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I'm pretty sure that 212-215 degrees on a "modern" engine is not abnormal or dangerous,....
I agree, though naming the rover V8 Thor engine "modern" is a bit exagerated :wink
 
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Discussion Starter · #17 ·
Hello everybody. I finally had some time to start looking for a solution.

1- I checked the engine bay fuse box fan relay. It looks fine, moves freely and is not stuck. Since I blew a couple of fuses before realizing the fan was jammed a couples of years ago, I suspected this could be a part of the problem, but since the fan is not running when the engine is cold, this is not the answer. I will replace with another used unit.

2- I inspected the thermostat I installed in 2010 (British Atlantic). When compared to the OEM 2003 one I have sitting on blocks (I have a 2003 Disco for parts), I noticed there is some kind of internal shroud around the thermostatic unit, compared to the 2003. I suppose this is a better arrangement ? I might try on the old thermostat to see if it makes a difference.

3- There are 2 different temperature sensors. I suppose the one at the bottom of the radiator is the thermo switch and the other one beside the top coolant vent (that goes to the throttle body heater) is probably the sensor for the dash gage. Both models (2003 & 2004) are differents in shape and connector style. The wiring is intact on both, so they are both OEM.

4- And no, the new radiator is not made in china, it's Nissen, from Norway.

From here I will probably test-compare the 2 thermostats and all those switches.

Francois
 

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Drives like an old man
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I'd like to update my info also. My rig doesn't idle hot - never over 202. It's at highway speeds (70+) where it creeps up to 210-212 in 100 degree ambient temps. I wish it were lower, but that's it. Everything replaced. Guess it just doesn't like running that fast. Now, back to our regularly scheduled conversation, already in progress.
 

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Just my 2 bits on temps and fan operation

A little history on my truck
Complete rebuild with top hat /flanged liners just over a year ago, new hoses pump, hoses thermostat (180deg. from brittish parts of Utah )
Rad was not replaced but cleaned and checked through a local Rad shop I have dealt with for many years.
Only modification is throttle body bypass.

I will admit we don't get the extreme ambient temperatures that you guys in the southern U.S. Do but it does get into the 90s.
I recently did a drive on a hot day
In town steady 189
Sat in traffic hit 190
30 minute run on the highway - dropped as low as 183 and never any higher than 189

These are the same temperatures that I get in winter (real winter snow, ice way below freezing)

I figure with all that has been done to and gone over on this truck it is as good as new engine and cooling system wise.

As for the 2 temp switches

Sierrafery explained it very well in another thread I believe

The one in the rad is only for thermostat monitoring . Has no effect on fan operation!

My fan only runs when the a/c is on in warm ambient temps unless you reach high engine temps (215 as I recall) which should never happen unless you have a problem

So why does my truck run in the 180s regardless of ambient temps and others run 30-40 deg hotter ??????????
I know that I tried to do everything as right as I could when I built it, cleaned and inspected every part, every bolt cleans inspected painted etc.

I would expect that a thermostat from 2010 is likely no longer reliable????
 

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....
So why does my truck run in the 180s regardless of ambient temps and others run 30-40 deg hotter ??????????
I know that I tried to do everything as right as I could when I built it, cleaned and inspected every part, every bolt cleans inspected painted etc.
Maybe due to the TLC you gave it :) ... at least it proves how all of them should be cos your's is behaveing perfecly normal, IMO that's how it should be.
 
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