Cooling issue

[disco_nex]

I apologise for this. I know I have a seperate thread where I discussed these issues, but I want to get some slightly different opinions and pretend this is a new issue.

The XJ is getting to the stage where the overheating is almost unbearable. Under load (up hills, more weight in the car, faster you go above 90 km/h, etc), the greater the temperature. Obviously, the hotter the day, the hotter it runs.

I am willing to say that airflow through the radiator is not an issue and the thermostat is correct and new.

I have it at the mechanic today. Pressure is excellent, the dye test proved it is not leaking fluid, and the timing is spot on.

Some items have been replaced recently. I am sure the gauge to the instrument panel works as it has boiled during a Stockton Beach Run.

If I could get any opinion or suggestion, no matter how stupid, I would love to hear it! (You know you are in trouble when your mechanic is as lost as you).

Thanks!

[bruggz351]

Is the pump working?
Is there restrictions/blockages in the block?
Is the bottom radiator hose serviceable? .. is it collapsing when the revs rise?

HTH

cheers

[Billnick]

Check out the 'STICKY' on overheating. Pretty much all is covered there.

[Tims_Jeep]

Have you replaced any of the cooling system besides the thermostat? My troubleshooting would be:
1. Inspect the viscous fan coupling while the engine is hot, replace if it spins freely.
2. Check cylinder compression, open radiator cap (make sure the engine is cold) start it and watch for bubbles
3. Pull the radiator out and reverse flush it and the engine block, check upper and lower hoses while it's out. Reassemble and test.
4. Replace the water pump, if you pull it off to inspect it you might as well replace it and keep the old one as an emergency spare.
5. Replace the radiator with an ADRAD, maybe the old one is blocked and restricting coolant flow

I think most of this is covered in the sticky though.

You look like you've got a bullbar and some decent sized lights, maybe your first step should be removing the lights and seeing if it makes any difference in temp.

[Billnick]

One other thing....if the aircon is busted and never likely to work again, rip out the condenser. It restricts airflow through the radiator no end.

[disco_nex]

Originally Posted by bruggz351

Is the pump working?
Is there restrictions/blockages in the block?
Is the bottom radiator hose serviceable? .. is it collapsing when the revs rise?

HTH

cheers

Thanks for the response everyone. I appreciate it. When your mechanic is stumped as much as you, it can be an issue.

A pressure test confirmed that the pump is working.

Restrictions in the block is worth considering, and I will be looking into it.

I will try out the bottom radiator hose tomorrow. I like that idea!

[disco_nex]

Originally Posted by Billnick

Check out the 'STICKY' on overheating. Pretty much all is covered there.

Thanks. I have been through that, plus the search function. Still coming up short.