How to coolant flush a land rover diesel engine

Napalm00

Technical Excellence Contributor
Bringing over some of my older tech posts to here. Hope these help.

Exact steps I took (overkill prob) as follows:
  1. drain coolant from lower rad hose and block
  2. Block drain is near the oil drain pipe for the turbo connection on the block
  3. reconnect lower hose but leave block drain open
  4. open top of rad filling plug
  5. spray garden hose into filler on rad and overflow canister until it runs out of the block drain
  6. flush like this for a few min with cool water
  7. refit block drain
  8. fill with water and a tub of sulfamic acid (premixed)
  9. Warm up truck to operating temp and let idle for 20 or so min
  10. Drain above mixture
  11. fill with water and a tub of oxalic acid (premixed)
  12. Warm up truck to operating temp and let idle for 20 or so min
  13. Drain above mixture
  14. Flush again with garden hose
  15. Fill with water and a mixture of washing Soda (not baking soda)
  16. Warm up truck to operating temp and let idle for 20 or so min
  17. Drain above mixture
  18. Fill with garden hose again
  19. remove block drain then lower rad hose
  20. refit block drain and rad hose
  21. mix you choice of extended life coolant (I use standard green w/o silicates) and bottled distilled water
  22. Add bottle of anti cavitation additive for diesels
  23. Fill and bleed system


This took me about 2 hours to do on a huge ass tarp, Had about 4 five gallon buckets of waste water to be dropped off for recycling


System is now fully free of rust oil, sludge and mud. Coolant is perfect mixture and bright green.

As long as you dont let the acids sit in the system for an extended period it is safe for the mixed metal engines we have. I adapted this from a post on H.A.M.B, it worked flawlessly...system runs cooler, warms up faster and the heat works better. Its a great time to replace any sensors and hoses FYI


Chemicals reqired:

https://www.amazon.com/dp/B000VBGH82?tag=vs-auto-convert-amazon-20

https://www.amazon.com/dp/B001AZL24M?tag=vs-auto-convert-amazon-20

https://www.amazon.com/dp/B000NU3LPS?tag=vs-auto-convert-amazon-20

https://www.amazon.com/dp/B00K6ON8BI?tag=vs-auto-convert-amazon-20
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Thanks!

Could someone elaborate on bleeding? I just put a heater core in where there was a 6" U at the back end of the engine block. So I assumed the two longer hoses to the heater core, and the core itself would fill with water, meaning I would need to add water to the system. Well, I ended up only adding about 1/2 of what I estimated. So I think there is a bubble someplace that I can't get out.

I've tried parking it on hill with front end and overflow tank just a bit higher than everything else. Ran it till warm, then let it cool. No extra air, and no coolant drop.


Also, this is the first I've heard of anti-cavitation additive. More info?
 

Napalm00

Technical Excellence Contributor
If you have heat and the temp gauge is acting normal you are probably pretty close to full.

  1. Park truck on ramps or jack up front
  2. Remove fill plug on rad and fill to top
  3. Refit plug
  4. Remove Cap from overflow tank
  5. Start truck and adjust accelerator cable to be above idle or put brick on the pedal
  6. Squeeze top radiator hose firmly/hard until truck is warmed up and thermostat opens (like constantly over and over... To burp it)
  7. Top off overflow tank
  8. Refit cap on tank
  9. Take off ramps
  10. Done


This is the absolute way to bleed all rover v8 and 4cly diesels.



Anti cavitation additive keeps the coolant from becoming too acidic and eating away the block and cylinder liners. It's always used in semis that have long periods between coolant changes. It's just extra protection, not required but a nice touch.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
The only thing I didn't do is lock the RPMs at higher than idle. I did rev it a bit while waiting for the level to drop, but I'm wondering if maybe it's because it won't get warm enough to pop the thermostat while sitting. Over the weekend I timed it at 45 minutes while driving with the radiator halfway covered before it got to 185.

Thanks for the chart too, I'll use it when I change out coolant this Spring.
 

Napalm00

Technical Excellence Contributor
The only thing I didn't do is lock the RPMs at higher than idle. I did rev it a bit while waiting for the level to drop, but I'm wondering if maybe it's because it won't get warm enough to pop the thermostat while sitting. Over the weekend I timed it at 45 minutes while driving with the radiator halfway covered before it got to 185.

Thanks for the chart too, I'll use it when I change out coolant this Spring.


The higher rpm is really just to get the coolant moving, the 200/300 waterpump is not effective at low rpm. The higher rate allows for it to actually pump some coolant under pressure to the rear of the engine.

I know it's getting cold up there and if it's taking you 45min to warm up you need to start fully blocking the radiator. Running that's long while under temp is hard on the engine and seriously effects mpg/efficiency.

I doubt you have a bubble or air pocket as the truck would either never come to temp or it would overheat in minutes. You sound gtg
 

Red90

Well-known member
Your thermostat is leaking. You should never need to block the radiator as no coolant should be flowing through it until the engine is at normal temperature. I'll guarantee I drive in a lot colder weather than you do.

If you have a 200TDI, get a Stant 45779. Easy to find anywhere as it is the same stat used on most Ford V8/V10s.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Your thermostat is leaking. You should never need to block the radiator as no coolant should be flowing through it until the engine is at normal temperature. I'll guarantee I drive in a lot colder weather than you do.

If you have a 200TDI, get a Stant 45779. Easy to find anywhere as it is the same stat used on most Ford V8/V10s.

I block it off so that air won't cool it down as well when driving. That is to say, it isn't uncommon to see it get to normal temps, but then drop back down when going down hill or while sitting at a light.

I see what you're saying about the thermostat leaking though; seems like that may be happening. But even a new OEM stat shouldn't leak after only 3k miles. Right? But anything could happen.

As far as running at higher RPMs to stir the coolant; yes, that was what I was thinking when I was doing it. It's just that you mentioned getting it up to temps to pop the thermostat to get full flow in all parts of the system, and that won't happen with it sitting in my driveway unless it's over 80 degrees out. I bet it would take a lot of time and RPMs to get it warmed up unless it's under load.

Even when driving over the mountain pass this weekend, with half the radiator blocked, after 45 minutes of driving, 40 degrees outside, total elevation gain of 4500 feet, 45-55mph, it only just broke 190 degrees.
 

Red90

Well-known member
But even a new OEM stat shouldn't leak after only 3k miles. Right? But anything could happen.

It is very common. IME, 4 out of 5 new OEM thermostats leak.

As long as you are using some power it should get right up to 190 in under ten minutes, regardless of how cold it is outside. The upper radiator hose should be cold until it gets to temperature. It is easy to check.
 

Napalm00

Technical Excellence Contributor
Agreed the oem "waxstat" kinda suck. They have a plastic sleeve covering the brass bimetal bulb that gets cockeyed and keep the tstat from closing.

It's easy to check by removing the housing.

I also run a stant but, in upstate ny I would have to fully block my rad to get any type of heat or temp in the truck.

I like to use the political lawn signs made of the corrugated plastic board, also available at home depot. Slips right in between the radiator and the radiator frame, no tape no screws if you cut it to size
 

Red90

Well-known member
Thermostats don't use a bimetal strip. They all use a "wax" that melts at a specific temperature. When the phase change happens, the wax expands and opens the stat.

The Stant I recommend is a "Superstat". It controls a lot better than the regular stats.

I run at -40 every year. Zero problem getting the engine to operating temperature. No need to block the rad.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Always looking for an excuse for an upgrade!

Interesting that you don't block rad at all. I know of a lot of people here who do, and I'm not the only one running with no fan.

Along these lines, I'm installing a warning indicator for low coolant in the overflow. Not a perfect solution, but would let me know if I've sprung a leak on a long drive.
 

Napalm00

Technical Excellence Contributor
I think depending on your overflow tank type some rovers came with a coolant level sensor in the cap.

If I recall, the later model rrc with the black plastic overflow tank has the sensor/switch in the cap
 

Napalm00

Technical Excellence Contributor
Gallon jug works great and is easy to pour, fill the rest of the truck with hose water
 
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