By stecz on Thursday, August 02, 2001 - 09:49 am: Edit

When I sit in traffic (100'ish degrees, AC on). The temp gauge gets way up near the top (hasn't overheated yet, but it's come close). It doesn't seem like the thermostat, because as soon as I start moving at a reasonable pace, it cools down to just below half on the gauge. I checked yesterday and both fans seem to be running (although it wasn't way hot at the exact moment).

I'm probably going to change the thermostat even though it only overheats when I stop (and not everytime), just because it's cheap and easy.

One thing I thought of, since it intermittently overheats, maybe one of the fans (or both) is stopping intermittently. I'll have to check on that tonight.

Any other ideas?

By Kyle Van Tassel (Kyle) on Thursday, August 02, 2001 - 10:14 am: Edit

Does it have a clutch fan on it? If it does it is probably fried..

Kyle

By Ron on Thursday, August 02, 2001 - 10:32 am: Edit

VCU on fan might not be working right. Or pump, clogged rad, when was the last time you changed coolent?

Ron

By stecz on Thursday, August 02, 2001 - 11:39 am: Edit

I haven't ever changed the coolant, I'll do that when I swap the thermostat. The wierd part is that it doesn't always run hot, only sometimes.

My cooling system has the mechanical fan and two electric fans.

How do I tell if the fan clutch is fried? I know that it should semi-freewheel with the engine turned off.

By Ron on Thursday, August 02, 2001 - 11:41 am: Edit

After it gets hot turn off the car and move the fan. If it spins freely it is toast. I am betting clogged rad though.

Ron

150 from BP if you need a new one

By Robert Mann (Oldscout) on Thursday, August 02, 2001 - 12:45 pm: Edit

Go electric. A nice twin 12" set up is 180.00 and there is a well done "how to on" D90.com. Better mileage and 10/15 hp.

By Perrone Ford on Thursday, August 02, 2001 - 07:07 pm: Edit

Be careful if you decide to go electric. In hot climates like you mentioned, electrics simply don't move enough air to keep our engines cool. I know far too many people who have gone to the electrics and had to go back to stock because they overheated constantly.

You also have to remember that the D90s don't have near the load on the engine a Disco does. Our auto tranny, crowded underhood area, A/C, etc all draw more power and make the engine run harder.

I'd check for blockage in the radiator, but if you've never changed the coolant, you're way behind the curve. Hopefully you won't have to shell out the $800 for a new one. Change your coolant once a year, its simple and farily cheap.

-Perrone

By bobfleming on Friday, August 03, 2001 - 04:10 am: Edit

I agree with blockage theories. Had similar problem and agonized for a year over it; just had the radiator "rodded" which did the trick. No more driving in 100 deg temp with heater on for me! cost about $200 at non-dealer Rover shop. Probably not much more at dealer. Good luck.

By stecz on Friday, August 03, 2001 - 04:35 am: Edit

Thanks for the advice. I'll flush the coolant and swap the thermostat this weekend.

In my previous experience, when a thermostat goes bad, it goes bad permanently (gets stuck opened or closed). But my problem is intermittent. Usually, it runs at just below half on the guage, regardless of outside temp and occasionally in sitting with the AC on in 100+ degree temps, or towing my jet skis, it will get to half on the guage. Occasionally, it gets really hot (up to the top of the guage, but out of the red) and as soon as you start moving, it cools down. On the same trip later on, I can sit in traffic again and it won't get hot. That's why I started thinking about the fan running intermittently.

FYI, My disco already has dual electric fans and a crank mounted fan (all factory as far as I know).

By Scott Bowden on Monday, August 06, 2001 - 02:54 am: Edit

Pull the radiator and take to a radiator shop. The shop told me it was common with Range Rovers. The complete radiator is metal and was easy and inexpensive for them to "rod" the core. It was only $65.00 in the Atlanta area. While it is off change your thermostat and hoses if they are old, soft or swollen. Hoses will usually go bad where they are connected to the engine.

By mike w on Monday, August 06, 2001 - 04:33 am: Edit

stecz
i have been living with this very same problem for about a month. in the winter i had plenty of heat but now, too much too much . it will stay within the normal, whatever that may be, range for an hour then it warms up. the a/c does not have to be on but it does increase the speed at which it heats up. if you turn the heat on with the a/c on the gage indicaor drops. this leads me to believe that there is a flow/capacity problem. my mechanic indicates that the head gasket is in good order due to the rate it heats up. i replaced the thermostat. that did not cure the problem, i was thinknig that since it did not boil over there was an error in the gage so i replaced the temp gage sending unit, the problemed remains. then i took the truck to a radiator shop, had them pull the radiator and flush it my means of air and water. alot of scale was removed and it did help the problem a bit but it still will get very warm. all the other symptons remain the same, so i gave up, i ordered a new radiator from nathan crabtree. getting it rodded is an option, however u run the risk of loosing capacity due to damage to the tubes or just rot within the radiator. if it works eamil me and let me know if not a new radiator may be in your future. good luck

By mike w on Monday, August 06, 2001 - 04:37 am: Edit

oh i paid 400.00 plus shipping from nathan!
nice thing about nathan you wont pay the dealer mark up. hmm i wonder what he would sell a d90 for?
lrover94@yahoo.com