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02 LS430 Overheating. Only one fan running. Motor or something else?
My 02 LS430 has been overheating if it idles for too long in warmer temperatures. So far the main issue I can see is that the driver's side fan is not working.
I would assume if it was something like the control module or relay that neither fan would be working, correct? Does that mean that its most likely just the fan motor and not something else? The fan blades don't appear to be broken/stuck.
Finally, this looks like a fairly simple DIY repair based on the diagram I've posted. Do you just unbolt the fan assembly(#1) and unscrew/unplug the motor (#6)? Is it even necessary to remove the entire assembly or can you just lift it out enough to gain access to the nut(#4) on the other side of the fan?
Attached is the COOLING section of the Service Manual. It shows how to test the fan motors with a multi meter. It's fairly common with cooling system diagnosis people spend money on one part only to find out another part ( radiator or WP ) is actually the issue...
You sure that you don't have a coolant leak or your not low on coolant?
I don't know, maybe someone else will chime in, do both fans run simultaneously. The cooling system has it's own ECU, is it smart enough to decide if it should turn on just one fan or both...?
Keep digging..based on this one person's experience:
On my '04, both fan motors were bad.
Have to presume one died long before the other.
NEVER overheated even with both fans dead.
Only telltale: Air conditioning would kick out at idle due to lack of airflow over the condenser.
A/C was fine at speed
On my car: no fans run normally, as long as A/C is off.
I have never had a situation where any fan(s) came on, except:
Both fans run as soon as you turn on the A/C.
YMMV of course.
I don't know, maybe someone else will chime in, do both fans run simultaneously. The cooling system has it's own ECU, is it smart enough to decide if it should turn on just one fan or both...?
This is really what I want to know. Regardless of what else could possibly be wrong, if both fans should be working together and yet one of them is not functioning at all, that clearly points to a fan issue... However if it is normal for only one fan to be running under some conditions, that would make some of the other suggested issues more likely. Admittedly I have not checked the fan under all possible conditions. I have not observed the fans while the engine is overheating (trying to avoid that obviously) and I am not sure at what point the second fan (if they operate independently) would turn on.
So does anyone know if there are any conditions where only one fan would be running?
Lets start with the basics- How many miles are on the odometer? When (if) was the timing belt and WATER PUMP(?) last serviced?
If you recently had a TB service which included a new water pump we can probably rule that out. TB service often includes a new thermostat as well but not necessarily. These details speak volumes.
Radiators on a high mileage car can become gummed up inside and slowly drag the entire cooling system down.
The LS is extremely over engineered. You would have to be towing a boat up a mountain in an Arizona summer (assuming all major components are healthy) before you over taxed the motor/transmission/cooling system.
Test the fan motors using the procedure shown in the manual. If you don't have one Harbor Freight practically gives them away! It's a process of elimination...
Lets start with the basics- How many miles are on the odometer? When (if) was the timing belt and WATER PUMP(?) last serviced?
If you recently had a TB service which included a new water pump we can probably rule that out. TB service often includes a new thermostat as well but not necessarily. These details speak volumes.
Radiators on a high mileage car can become gummed up inside and slowly drag the entire cooling system down.
The LS is extremely over engineered. You would have to be towing a boat up a mountain in an Arizona summer (assuming all major components are healthy) before you over taxed the motor/transmission/cooling system.
Test the fan motors using the procedure shown in the manual. If you don't have one Harbor Freight practically gives them away! It's a process of elimination...
So far that's the only way I've found to overheat an LS430 with a good, working cooling system. If its overheating both fans should be roaring away, and they bring the temperature down quite quickly. The Whale has its fans wired up with an override, and from right in the red to normal operating temperature was roughly a minute or so at idle. Under normal circumstances its near impossible to overheat one of these, so I'd say you have underlying problems in your cooling system as well as a dicky fan
I highly doubt that your water pump is bad. As mentioned, did you look both inside your radiator and the overflow tank to check the level of coolant?
When you say it overheats, is that based strictly on seeing the coolant temperature gauge rise or do you start seeing steam coming from the engine?
The coolant and radiator seem to be fine.
And the overheating is based just the temperature gauge (AC also stops blowing cold air). I've never seen steam from the engine and it doesn't overheat every time I idle. I can drive around town and it won't overheat at a stoplight (at least not yet, but it hasn't gotten really hot here yet). But if I sit in the car for 10-15 minutes or in a long traffic jam it will overheat. Luckily it cools down quickly as soon as I start driving 20+ mph or so.
Last edited by LSDriver94; 05-11-18 at 11:32 AM.
Reason: Edit reply
05-10-18, 11:46 AM
02 LS430 Overheating. Only one fan running. Motor or something else?
