99 D1 overheating up hill only.

[syke]

radiator

Radiator might be nasty on the inside. I was staring to have the same issues as you with my 99. It never overheated but was starting to show signs of runing hot only while traveling under heavy loads.
It would idle all day long with no issue, flat land with no issue, start pulling a hill and the temp would creep up.

I pulled the radiator and sent it down to the local mechanic. He did a general cleaning and rodded the core. It cost me $150 bucks and let me tell you... well worth it.

I ended up doing the fan clutch even though it was not a low speed cooling issue. (that was a pain in the a#@)

Might be worth a shot as it seems you have covered all the normal bases.

 

[Antichrist]

On one edition of this thread on one of the Rover sites someone asked if it was a new or used radiator, I never saw an answer.

 

[SMD]

As previously mentioned - did you replace the thermostat? You said it seemed to be working right, but that doesn't mean you replaced it or pulled it out and tested it.

I ask because I had to chase down a similar issue a few years ago. Truck would heat up under certain conditions but then cool back down once out of that driving condition. I figured the t-stat was fine b/c it was able to cool back down. Wrong answer. Ended up being a simple t-stat replacement. It's a cheap and easy job; give it a shot if you haven't already.

 

[discocolin]

Still broken!!

Sorry, I have not been on in a while, I was a little pissed at the truck, so I have just been driving my other disco for a while, but now the stock one has 2 flat tires, so I started working back on the green overheating one.

Yes it is still overheating up hill, better, but still unusable for the most part.

Here is what I done to it so far.

New (used but nice radiator)
new fan clutch
new water pump
new thermostat (I boiled both and the new one opened and the old one didnt)
I have also tested for blown head gaskets using a chemical test (some weird blue liquid in a turkey baster over the radiator opening LOL) and it said no exhaust fumes were in the coolant.
the ac fans to come on if the AC is on, and I think also if it starts getting really hot, (but I might need to make sure they are without the AC on. I know they stay on after the truck is turned off while hot.
Also I have found no leaks and there is plenty of pressure when I open the cap.

I dont know what else to check for??? It does seam to really overheat too, (using a therm. the heater in the normal range is 170ish. when it starts to overheat the air coming out of the vents is over 200!)

Could it be that the trans-fluid is old and is overheating, which is in-turn overheating the car? and when I say up hill, I am going up a mountain going from my work at 4k to my house at 7k feet in about 6 miles. it only starts to overheat at about the half way point. and if I turn around the temp drops right back down in about 1 min.

I have also never let it get out of the white lines, I pull over and let it cool down, as not to let it melt down. LOL

PLEASE HELP! I miss my truck and I'm sick of my stock one as its got its own issues ( It was a stolen and recovered truck that somebody really worked over)

 

[sven]

I really didnt bother reading this whole thread, but you need a radiator. Classic symptoms of overheat while under load (climbing hills) is either a clogged up radiator, or the fins are rotting away. Buy new or have your old one recored.

 

[JSQ]

I think that used radiator you got was junk.

Do you know it's provenance? Was it rodded?

 

[David Harris]

If it was a HG or liner, wouldn't it over heat ALL the time. Not to mention, the GEMS motors used in the DI were much less problematic (IMHO).

How are you "burping" the system? I believe you're supposed to fill via the overflow with the front of the truck elevated. At least that's the method I've used on my DII.

The factory service manual says to remove both the radiator fill plug, and the overflow tank cap. Fill the radiator as high as you can from the overflow tank. Start the motor and run it with both caps off until the thermostat opens, then top up the coolant via the overflow. Replace the caps on the radiator and overflow. This is for the D1. I have always used this on my D1's and RRC and it works great. Don't need to elevate the engine.

 

[Antichrist]

What thermostat did you put in?
http://www.expeditionportal.com/forum/showpost.php?p=702194&postcount=127

It would help if you're clear about the radiator. "Used but nice" really doesn't tell us anything other than it was a used one. If you didn't have it at least flow tested then you could very well have replaced bad for bad.
I wouldn't install a used one without having it rodded.
If your old one has good tanks have it recored, make sure the thermostat is good, install the recored radiator and I bet that will take care of your problem.

It's true the AC fans should come on when it's overheating even with the AC off, but they aren't needed for a cooling system in good shape. It should be able to stay within range without them.

 

[JSQ]

It's far better to fill the cooling system by creating a vacuum then to just pour gallons in and try to "burp" it over and over again.

 

[piper109]

The factory procedure as outlined by Aliatel works and works well.
The thermostat housing is higher than the overflow tank.
Why would you mess around trying to find a "better" method?

 

[muskyman]

The factory procedure as outlined by Aliatel works and works well.
The thermostat housing is higher than the overflow tank.
Why would you mess around trying to find a "better" method?

Simple...you can do a better faster job.

by putting the truck nose up and running the heat you can very quickly get all the air out of the whole cooling circuit. Its not that the factory method dosent work but by simple doing it with the nose of the truck a bit up hill the process just works better.

The D1's and RRC are a snap, the DII not so much and getting the truck very nose up and allowing it percolate for awhile with the bottle popped out and raised.