My experienced mechanic friend and I recently did the PCV valve install mod, and now we’re about to do a major renovation on the coolant system of a 2000 Discovery 2, which I’ve had since new:

1. Replace what I believe is the original radiator with an all-metal Nissens (I have a copy of the RAVE instructions)

2. Install inline thermostat (Extinct Motorsports)

3. Replace lower hose assembly, including an aluminum four-way connector to replace the plastic one

4. Replace the coolant reservoir (questions on this below)

5. Replace all the original clamps with ones that tighten with a screw

What I am looking for are current tips and best practices in doing this job.

For example, in reading previous threads, advice is given to replace certain O-rings in the radiator connections. What size O-rings are these?

With regard to the coolant reservoir: I had the original one for many years, finally replacing it a few years ago with a used one off eBay. I now need to replace it again, as a small, narrow tube has broken off the top part of it, and the cap also needs to be replaced. There seem to be three options:

A. New plastic reservoir

B. Used plastic reservoir

C. New aluminum reservoir

I’ve read pros and cons of each. What is best?

Any other relevant advice would be appreciated.

 

What I did in addition to your list:

- high flow coolant pump
- throttle body heater delete
- sensor adapter at the radiator outlet (even if you dont use the NPT port for a sensor it can be used as a drain port)

The only O-ring I am aware of is at the heater output on the lower intake.
In addition I installed a sensor on the lower intake in place of the TB heater outlet. But this requires the removal of the lower intake. My sensor sits next to the factory sensor, but it is more accurate (my factory measures a few degrees too low) and you don't need to interfere with your ODB if you want to monitor the temps constantly.

 

Those all seem like worthwhile mods, but I'm afraid I don't have the knowledge to be able to assess or implement them.

For example, I've had to replace the throttle body heater plate gasket previously to stop a leak, so I know it's a problem, but I would have assumed there is some essential function that would be compromised if it were just eliminated.

Are there discussions on the Forum (or elsewhere) you can provide links to for these mods, and/or links to the products/parts you mention?

 

Throttle body heater only needed in climates where temperatures go below 20ish, throttle can freeze open. The sensor adapter at the radiator is in the radiator lower ps, I think all Nissans have it as they only sell one version.

 

The sensor in the radiator is wired by factory already, so it can't be used for other purposes. I use an additional sensor adapter at the radiator outlet like this:

 

Not all trucks have the sensor in the radiator, but I think all the Nissens radiators have the port. Only the SAI trucks had the sensor. The other option for sensor placement is a port up version of the inline thermostat housing.

 

Finally got this done. New radiator, new inline thermostat, new coolant reservoir, new bottom hose, new clamps. So far, the thermostat reading has been solid at 180 Fahrenheit. The test will be this summer, running the A/C when the heat index is over 100 almost every day.

 

Good job, your D2 will be alot more reliable after overhauling the cooling system! One follow-up item...see that hard plastic line coming off the coolant bottle and going to the radiator? They last ~2yrs before becoming brittle/leaking so I would suggest buying ~6ft of 5/16 transmission cooler hose and replace the hard line at your next service interval.

 

For me, an AL puke tank is the only way to go. I've replaced too many failed plastic ones, and as vulnerable as a D2 is to an overheat, aluminum becomes cheap insurance, even with the hefty price tags. If you are replacing anyway, I say go with AL.

 

Yup. Its predecessor’s life ended a few months ago, so that one is relatively new.