By kevkor on Wednesday, May 16, 2001 - 06:27 pm: Edit

Truck getting way too hot on the highway.Driving around town and on the trail its fine. Recently replaced waterpump, thermostat,and temp sensor.Just had radiator cleaned , rodded and flow tested.Didn't do any good.95 Disco 105k mi.Any ideas appreciated.

By Norm Orschnorschki (Norm) on Thursday, May 17, 2001 - 12:07 am: Edit

Have you checked the timing?

By kevkor on Thursday, May 17, 2001 - 07:08 am: Edit

No I would think that would make it a constant thing not just on the highway.Am I right about that? Getting advice from others that the radiator may just need to be replaced,rodding wouldn't do it.Thanks.

By Jon on Thursday, May 17, 2001 - 10:16 am: Edit

How about your water pump flow capacity? Even on a Disco, the pump turns slower (relatively) in highway driving than it does in the city. I've had that happen with a vehicle before when I replaced the water pump, as the replacement pump had a different impeller than the factory and it didn't move enough water at slower speeds to sufficiently cool the engine.

By Chris Browne on Thursday, May 17, 2001 - 10:40 am: Edit

Checked the Fan viscous coupling?
When the truck has overheating, stop.
Shut it off.
Now remove the top of the radiator cowl (clips) and see if you can rotate the fan by hand. It should be impossible as the viscous connection should have heated up and "locked" it.
If it rotates by hand, its defective and needs replacing

By Jon on Thursday, May 17, 2001 - 11:24 am: Edit

Oh yeah, forgot about that. Fan clutches are pretty cheap to replace. But I've had the situation on my truck that when the engine began to get too hot, the A/C fans kicked on and cooled that puppy right on down.

By kevkor on Thursday, May 17, 2001 - 07:07 pm: Edit

Fan clutch seems OK. Thinking the radiator just needs to be replaced. Life expectancy is only 5 years from what I've been hearing.That would really explain why its only getting too hot under load. Pretty much everything else would lead to it getting hot at idle and in traffic.Thanks.

By dave on Thursday, May 17, 2001 - 09:51 pm: Edit

Is your cooling system holding pressure?

By Chris Browne on Thursday, May 17, 2001 - 10:40 pm: Edit

Kevkor, this ain't making much sense right now. You've replaced the pump, thermostat, had the radiator serviced etc etc.
Assume level of coolant is correct and no apparent leaks. Do you get good heat out of heater?
I presume you've replaced the hoses etc and have no leaks in old pipes... Did they pressure test the radiator?
So just how far up the gauge is the temperature going?

By Kevkor on Friday, May 18, 2001 - 07:20 am: Edit

Guage is getting to the top of the safe zone at 70mph constant(not stop and go traffic),in about 85 degree weather.Radiator was pressure and flow tested.They said its OK.No coolant leaks anywhere.You don't think the radiator can just go bad? I've received advice that a flow test wouldn't show it bad compared to high speed driving for a while.It has me stumped also,not very much to a cooling system.

By ken on Friday, May 18, 2001 - 09:06 am: Edit

Quick check, see if the belt is routed correctly. It is possible to route the belt more than one way (bone head me... had done it)

Ken

By Bob Fleming on Friday, May 18, 2001 - 09:31 am: Edit

I'm having similar problem with my '95 (140000 mi). Two dealers (LRDallas, LRHouston) could not make it overheat and assured me the radiator pressure tested fine, thermostat was fine and fans are all turning on when they should. I will check the viscous fan clutch. I have read about a process of "burping" the radiator to get rid of air pockets. Has anyone tried this and is it a possible solution for these kinds of symptoms? Mine overheats at higher speed and occasionally around town; only with the A/C on, though.

By Ron on Friday, May 18, 2001 - 09:42 am: Edit

DO the aux. AC fans come on when your turn on the AC?

Ron

By Ken on Friday, May 18, 2001 - 11:09 am: Edit

I don't think is your Viscous fan at high speed (what speed?). After reading Land Rover Magazine (UK publish), I had tried to increase a couple HP by removing the viscous fan, and replacing it with a 16" electric fan (where the viscous fan located). Getting to the point, the electric fan only came on at idle, and turn off at speed. Last summer, at temp of 95-100 (florida) 45mph+ did not have any cooling problem, the temp needle is normal.

However, the electric fan can not keep up the air flow compare to the viscous fan at idle. And I was having idle and slow speed (overheating) problem. Since then, I had pulled the electric fan off and reinstall the viscous fan.

If you are crusing at hwy speed 50+mph, and having cooling problem, I don't think it can come from the viscous fan (ie more air is passing your radiator at 50mph that your viscous fan can pull)

In the Rover manuel, it suggest that the temp sensor maybe bad, next to driverside fuel rail, the single wire/plug on the manifold.

Another suggestion, look for a leak, my expansion tank had a hairline crack btw the upper and lower section.

Ken

By kevkor on Friday, May 18, 2001 - 07:22 pm: Edit

Bob are you saying that they couldn't make it overheat actual temp wise or temp guage reading wise.So did they say "don't worry about it" or "we can't find a problem"?I'm curious. Thanks.

By Gary Sharp on Friday, May 18, 2001 - 09:22 pm: Edit

I had the same problem on my 95. Mine ended up being partially clogged oil return lines in the valve train. The Temp would maintain normal around town but would climb if I exceeded 70 mph on the interstate. It never overheated but would run just below the red line. My mechanic told me that the oil was probably getting backed up and pooling in the valve cover, which would caused the engine to run hot. Have you ever noticed the oil pressure light flickering while driving at high speed?

By kevkor on Sunday, May 20, 2001 - 10:55 am: Edit

I pulled the 4 HELLA 500's off the brush bar(blocking air flow)that I've had on there at least a year before problem arose.Couldn't get temp to rise.Solved. Radiator even though being rodded ,steamcleaned,and flow tested, wasn't doing its job.Thanks everyone for ideas.