Hi all,

I'm hoping to find some suggestions to help with an engine coolant problem I'm having.

I recently removed the supercharger for servicing and fitting of a smaller pulley.
All went well and I refitted the supercharger with new gaskets.
I also replaced the coolant valley hose that goes to the throttle body and the hose from the EGR valve back to the coolant manifold. I also replaced the electric heater matrix water pump and the electric intercooler water pump with a high flow bosch item.
I replaced the coolant temperature sensor and the thermostat at the same time and a fitted new fan belt and supercharger belt along with tensioner and idler pulleys for the supercharger belt.
Put the car back together, filled and bled coolant and thought all was good.

Then I noticed the cooling fans running on high speed, so assumed it was an airlock and bled the system again, but it still heated up very fast.
So I checked further and the radiator was stone cold. I took my laser thermometer and took readings all over the engine. Seems the thermostat wasn't opening.
So I tested my old thermostat in hot water to confirm it was good, which it was, and went to swap it out for the new one.
When I opened the thermostat housing there was no water either side of the thermostat, so I cursed myself for not replacing the water pump when I had everything apart and bought a new water pump.

So I have now fitted the pump and replaced the bonnet cable at the same time, filled and bled the system and it seems I'm back at square one.

Gets hot quickly, brings the fans in on high speed, but the thermostat hasn't opened and the radiator is cold. Again it's as though the water isn't circulating.

Starting to tear my hair out now and doubt myself on all sorts of things, so hoping someone might have an idea.

I also noticed that the heater vents inside the car do blow hot air, but the drivers side vents seem a little hotter than the passenger side which is odd.

Any ideas????

Many thanks.

 

Are you bleeding system correctly? I find having the front passenger side either jacked up or on a ramp helps significantly.

 

The cooling system on XJR's and supercharged models are especially complex and not easy to bleed.

Suggest you get the front up as high a you can as has been said.

 

Curious as to how much coolant you used to fill the system Tesla?

I have done everything you have done, several times, over the last 2 years and just recently replaced the water pump for the 2nd time in 10,000 miles.

I took note of how much coolant I drained.

When I filled with Dexcool 50% I did not bother ramping up the the front of the car as I was within a quart of what I had drained out and after a few test drives went on a 450 mile trip.

No overheating however I did need to put about a quart of coolant into the reservoir which I was prepared to do as I carried it with me.

Point I am making is that unless you are way off, more than quart, of coolant to full there must be something fairly serious wrong.

 

As stated raising the front makes a big difference in allow the air out the intercoolers
The key is to also leave it with the IGN and cap off

With the Ign on the Aux and Supercharger pumps are running.
This allows the coolant to circulate and the air to escape out the cap.
Top up as need then run it up to temp, shutdown and let it cool
Finally check if it needs a top up

Cheers
34by151

 

Many thanks for the replies, I've not been confident at all that I've been getting it bled right but have been convinced that it's more than a simple airlock, no matter how stubborn it might be.
So after some thought it occurred to me that the aux pump, despite being new, might not be running.
As I had drained so much coolant with the work I'd done I realised the aux pump was crucial to prime the coolant manifold so that the main water pump had something to start pumping.
As I suffer from being fairly deaf I find it very hard to discern the direction of a sound. I had just about been able to hear an electric pump running with the ignition on but couldn't tell you which pump it was.
So I checked and found the fuse for the aux pump was blown. Once I changed it the system primed and started circulating correctly, so now I can bleed it as normal.

Typical that after so much work a tiny little thing can send you on a wild goose chase. Also a salutary lesson not to assume new parts are doing their job correctly!