My 99 XK8’s coolant system had a planned summer coolant system overhaul. With Covid19 lock downs, now was as good a time as any. However with temps hitting 40degC, 110 degF, with high humidity. I only have a morning 4 hour time window before the heat becomes unbearable. Sweaty pants time, where you can literally wring sweat from your briefs.


Air box and tunnel out for access - 5 min job. Jack car up for access to drain plug.

I was a bit worried about the Coolant drain plug, but sprayed it with WD40 and it came out without any problem. Already have a drain plug replacement as the old one was the OEM factory original.

Coolant was green, which isn’t uncommon in this part of the world. Most owners switch to green as it’s cheaper to change ever two years, as the Middle East desert climates mean your coolant system works 120 percent harder. In an emergency, garages here only stock green. If you want OAT red, you need to go to dealer and pay dealer prices.


Engine Dual fan pack had to come out too, but had to remove both radiator hoses to manoeuvre the fan pack past my non standard AC pipes. Definitely a bit of a previous AC hack there. Also took serpentine belt out too. Loosened the water pump pulley bolts first before removing belt.



Previous owner had mastic gummed up the thermometer cable clip on the cross over pipe. Bugger!


It’s usual in this part of the world to not have a thermostat, so as expected, no thermostat in my aluminium tower housing. The sludge was a surprise. Someone has previously mixed red with green coolant.


Had to dremel cut the Thermo clip out and the clip broke into pieces. Hence why someone needed to use mastic. Have a new cross over part so wasn’t too concerned, but now need a new male clip. Any ideas?

The cross over plastic pipe wasn’t in a good shape but at least not cracked.

That was it for today, as it just got too hot.
Back at it tomorrow.

 

Damn, that looks bad. I understand the availability problem, but the green coolant is not doing that system any good. I would replace everything as you are doing, then do a chemical flush. Perhaps after the chemical flush you can then use a vinegar solution for a final flush. Before adding the red OAT coolant concentrate. Perhaps just buy a few gallons of the stuff online and keep them as spares. Prestone Dex-Cool meets the spec.

As for the connector, I think you can source them from SNG. Rockauto also sells connectors. You can check with them if they have an appropriate one for that plug.

 

In the limited time I have before it becomes too hot to work, I managed today to reassemble everything and do the first flush with tap water. It’s true what they say in that it’s easier to reassemble than take apart.



I ended changing all front hoses, put in a new plastic cross over pipe, and a new thermostat (there wasn’t one and PO put in a red mastic sealant on the housing which was the source of a minor leak) , but.....

The water pump must have been changed recently, 3 years ago maybe, as it still had a factory sticker on it. Looked fine so left it in. I have a new one in case it starts going.

As John Dee’s To The garage Youtube video reported, I checked there was clearance between the lower radiator hose and the fan pack housing.

All’s well but I had to jury rig the Thermo clip connection until I find a new connector.

I did a quick tap water fill, ran for 30 min, and got a restricted performance dash warning. Probably the knock sensor as coolant f£&king drips everywhere including under the inlet manifold. Maybe the wiring as it’s on the same wiring loom as the dodgey thermo connector. I let the car cool and then ran out of time. Always know when that is as I have to “peel” the soggy socks of your feet.

Plan for next few days is to drain, chemical flush and then put the new coolant in.



All this should be easy but needs to run car for 30 min then let it cool between cycles.

I also plan to check the atmospheric recovery bottle. Other Forum members have reported problems recently.

 

Thought I would do a quick bench check on the Radiator cleaner using residual found inside my cooling hoses. Sludge had dried up overnight into particles.



LHS is a sample of dried up particulates, and RHS is the sample particles with drops of the rad cleaner. Seems to have dissolved larger particles into smaller bits

 

Well done. Here's hoping for a squeaky-clean internal cooling system environment once you finish the project....

 

Well I’m an idiot. Definitely one of those “DOOOH!” Moments.

The coolant system needs to be filled in 2 places
1. At the expansion tank
2. At the coolant tower.
After initial draining of the first flush, I put in the chemical cleaner but I only did fill at no.1 and car over heated in 20 min. I thought it was the cleaner foaming but actually I think I drained approx 3L and only put back 1L.

Still no harm done

 

I’m almost there so I thought I would share some things.

1. The restricted performance message quickly disappers after all the excess messy coolant burns off, probably from the knock sensors.

2. I had some DIY home made tools that helped.



Made a plug/hose connector to fit the Radiator drain plug hole as coolant spills everywhere due to convertible’s bottom X strut. This hose let me control it into a pan. Best thing is that it only drips until you open the expansion tank cap.

The turkey blaster and siphon helped removed coolant from the expansion tank.

Fitted a hose connector on an old tank cap so I could put tap water through for the initial flush. Only problem is you can’t measure how much you put in.

The on/off switched pump relay helps you initially push through what you fill through the expansion cap.

3. Had overheating after only 20min new as flushing distilled water wasn’t getting to the coolant tower fast enough. You need to fill at both the expansion cap and the top of the coolant tower.

4. If you’ve jacked the car up only on front right, like me, to reach radiator drain plug, you need to lower it for the re-fill and to run the engine.

 

To flush the system, I drained both at the radiator drain plug and at the expansion tank. Put in total 5L of distilled battery water at both coolant tower and the expansion tank caps and then ran the car for 30 min. with the cabin heat set on high blast. Car needed 2 hours to cool before I start the next cycle.

After my first flush after adding the chemical cleaner, dirty brown foamy water came out. So I hit the system with the hose trick through the expansion tank cap DIY tool with the radiator drain plug out. Then I did yet another flush with distilled water, and it was clear water at the front drain plug, and slightly discoloured at the expansion tank.

So in went approx 6L of coolant and I had a test run in the car without any issues. After a previous job I did, unblocking the heater matrix, I now find I have cabin heat. Not that you need it here in the Middle East. Still nice to know it works.

That’s part 1 of 2 in my saga, as I plan to dive into the valley to change the feed and return hoses. Plus some of those other unreachable bits ie part load breather, knock sensors etc.
Still that’s for another time.

Part 2 can wait.... when it’s cooler in the winter. LOL

 

Well done. And I agree with waiting for cooler winter temperatures for the rest of this work if you can....