Ok so 1998 Disco 1.

Got is smogged today no problems. drove 8 miles there mostly highway no overheating issues. Ambient temps are over 100 F today.

Left smog place and went through a costco car wash. Idled in line for maybe 5 minutes and truck started to overheat (gauge past half closer to 3/4) I turned off the engine and A/C and let the truck cool off going through the car wash.

On the way home on the highway it started to get hot again. I turn off A/C and she cools down again. Same thing getting closer to home, When A/C was on truck starts to over heat. I pulled into my garage with the gauge closer to 3/4 and turned the engine off. The electric fans did not stay on. I think they are supposed to for about 5 minutes to cool the engine down. So I turned key back to acc on and turned A/C back on so electric fans would come on, they did.

I let the car cool down for about 10 minutes and checked the temp, it was below half, so I thinking the truck should be cooled off enough. I turned key off and the fans stayed on....I thought this was weird and didnt want to risk draining the battery, so I went key on to acc and turned A/C back on and then off, and the electric fans turned off as they should....

Im wondering if some relay is not turning on or off the electric fans when it is supposed to causing over heating?

If the A/C is on and the electric fans turn off does this cause overheating?

What are some things I should check for?

 

Get a scangauge or Bluetooth OBDll adapter and use it to monitor your temps. On a 98 the fans come on with the A/C or when it's overheating not during normal driving conditions. It sounds like you need to check the usual suspects, clutch fan, t-stat and radiator and if none have been replaced I'd consider replacing all of them and go with a 180 tstat.

 

I second that. (98 disco 108k)
just had the same issues - was a leaking rad - and I replaced the entire system, pump, rad, hoses, tstat -(180d), have not done the fan clutch yet but its next in line. have not had any issues with heat since -even with A/C blasting at idle in 98d high humidity northeast weather

FYI if you do replace the rad with a aftermarket aluminum one - https://landroverforums.com/forum/di...num-fyi-84417/

 

Your symptoms are VERY typical of these trucks. One or more pieces of your cooling system are in need. Fan clutch is the first step.

 

I checked the fan clutch. I spun the fan and it seemed to only move a quarter turn. does that sound right?

 

I wish I could tell you for sure. There are all sorts of 'tests' for the fan clutch and I tried them all last summer. They all indicated my fan clutch was good. It wasn't. Sorry I couldn't be more help.

This thread should help....
https://landroverforums.com/forum/di...-clutch-65690/

 

I got a OBD2 scanner tool and drove the truck around for about 45 minutes of combined city and idle time. Ambient temps were about 85-90 degrees. Coolant temps were 210-212 at idle 216 cruising at about 50 MPH and 219 idling once I got home.

I have 3 questions.

Are these temps bad?
How likely is the high temps I was originally seeing are caused by a bad temp gauge in the dash?
If its not a bad gauge and I start to read OBD2 temps that are above 220, what would cause INTERMITTENT overheating?

I plan on replacing the water pump, thermostat and flushing the radiator anyways but I am just interested in understanding the problem more.

 

Are you losing coolant? In other words, do you find yourself adding anti-freeze (and/or water) fairly consistently?

If the answer is yes, I have some bad news for you.

If the answer is no, I'd start with a thermostat and fan clutch and would expect your radiator needs some attention (or replacement).

 

I have not had the truck long enough to tell. I topped off the overflow to the proper level and will keep an eye on it.

I checked the fan resistance with engine cold and engine hot. The resistance felt the same. I guess that means the fan clutch is bad?

QUESTION-

Previous owner bypassed the heater core. The pipe that leaves the water pump and goes to the heater core and then leaves the heater core has a hose on it. This hose is completely kinked. Can this cause overheating problems?

 

my OBD2 reader reads temps on the high side too - not sure why. but truck runs fine.
I would remove that kink.