Overheating

[ijdupuis]

1997 discovery with 145K
At idle or low speeds runs good. At highway speeds starts to overheat.
I have read many posts on overheating. I have changed the thermostat and purged air from system. Viscous fan looks good, checked for resistance as engine heats up. I am planning on having radiator checked. I have lost coolant and notice that the upper radiator hose gets very stiff as it heats up. I purchased the vehicle recently and don't have any history on maintenance. Does the stiff hose indicate resistance in radiator or something else. I am considering purchasing block test kit to look for hydrocarbons in coolant.
Thanks

 

[joey]

If heating up at highway speeds, I will think the radiator may be clogged.

 

[greg409]

Have you checked the routing of the serpentine belt?

It's easy to install incorrectly & will result in water pump running backwards.

I'm not wild about hard upper hose when warmed up - I'd let it warm up with cap removed from top of radiator & watch for bubbles indicating combustion gases. (You can judge coolant flow also then- should be flowing from driver's to pass side of radiator.)


luck,greg

 

[ijdupuis]

overheating Problem solved

Thanks for the replies, this forum has been a great help.
My problem was caused by two things, Radiator was really clogged and the heater core had a bad leak. On top of that both radiator fans are bad, while I had the radiator out I disconnected them and hooked them up to 12 volts and they didn't turn on. I ran the Disco for 45 min at highway speeds and it stayed cool.

Once again thanks for the info

 

[greg409]

Nice,

I replaced my viscous fan with a set of 12" from summit on ebay. love 'em

A set for your condensor might be good

luck,greg