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]

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]

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.

[disco_nex]

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.

Viscous fan is brand new and you can hear it working nicely..

Cylinder compression is good. I will try the bubbling check tomorrow.

The radiator is only 3 months old (and is an ADRAD). Hoses are good, but it am considering replacing them soon anyway.

Water pump has been in consideration, but it is building pressure nicely.

And airflow isn't an issue. The temperature will rise even with the Jeep at 100 km/h, and it has never been an issue since I have had it.

Thanks for the help people.

[disco_nex]

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.

That's an interesting one. I want to get the air con working soon though.

[Antiferret]

has it been "burped" properly? this will cause the issues you described precisely

i always have the car facing uphill when i replace coolant. if there is a bubble there it'll be more likely drawn into radiator and dispensed with next cycle. have the cap off and (from cold) start her up and let it warm up.

let excess drain out to the ground. top up as necessary (will need a few times).once thermostat has opened, REV IT, top up, REV IT, repeat till no more bubbling and your driveway is a mess.

top up the radiator reserve bottle just over the full mark, shutdown and let cool..

done

there is only 1 motor worse for air pockets, its a holden/nissan straight 6. (even with its block bleed screw).

[Billnick]

has it been "burped" properly? this will cause the issues you described precisely

i always have the car facing uphill when i replace coolant. if there is a bubble there it'll be more likely drawn into radiator and dispensed with next cycle. have the cap off and (from cold) start her up and let it warm up.

let excess drain out to the ground. top up as necessary (will need a few times).once thermostat has opened, REV IT, top up, REV IT, repeat till no more bubbling and your driveway is a mess.

top up the radiator reserve bottle just over the full mark, shutdown and let cool..

done

there is only 1 motor worse for air pockets, its a holden/nissan straight 6. (even with its block bleed screw).

Just while we are on the subject...don't be tempted to put a roofing screw air bleed in the top hose....it will drip onto the alternator and blow it up.

[jake]

Blocked or collapsed catalyst converter will cause overheating due to excessive back pressure. Could possibly get worse at speed.

[Tims_Jeep]

And airflow isn't an issue. The temperature will rise even with the Jeep at 100 km/h, and it has never been an issue since I have had it.

Thanks for the help people.

I have an ARB bullbar and 180mm lights, when towing in summer my Jeep runs hotter at speeds above 80km/hr. The airflow changes at speed and instead of being drawn past the lights and through the radiator it is drawn over the lights and over the bonnet, at low speed temperature is fine. Might be a similar issue to yours, sorry to keep on with the airflow...

[disco_nex]

Thanks for the responses everyone. I tried a few of the tricks you recommended over the weekend. The "burping method" didn't do much, but was worth the effort.

It is not the catalytic converter, as it is brand new.

I took it to a radiator specialist and he reckons the radiator could be blocked. His theory is that some crap from the motor has come through and blocked it up. Seems to make sense at this point of time, so out comes the radiator!

[bruggz351]

Good luck disco nex.
Let us know what happens...

cheers

[sime]

Thanks for the responses everyone. I tried a few of the tricks you recommended over the weekend. The "burping method" didn't do much, but was worth the effort.

It is not the catalytic converter, as it is brand new.

I took it to a radiator specialist and he reckons the radiator could be blocked. His theory is that some crap from the motor has come through and blocked it up. Seems to make sense at this point of time, so out comes the radiator!

tend to think this is the most likely cause. The reason I say this is because I have fitted a Tefba filter and after changing my radiator and flushing my block the filter was still collecting small rusty bits of steel floating throughout the system would could have quite easily blocked my new radiator.

check out http://franktonitto.com/tefba.php

Ive been using one for a 3-4 years now and it continually catches small pieces of metal in my cooling system.

[disco_nex]

tend to think this is the most likely cause. The reason I say this is because I have fitted a Tefba filter and after changing my radiator and flushing my block the filter was still collecting small rusty bits of steel floating throughout the system would could have quite easily blocked my new radiator.

check out http://franktonitto.com/tefba.php

Ive been using one for a 3-4 years now and it continually catches small pieces of metal in my cooling system.

Very very interesting. Where does it connect? Just along the top radiator hose?

[sime]

Very very interesting. Where does it connect? Just along the top radiator hose?

yes thats where I installed mine and I also found it works well as a air bleeder for the cooling system

[disco_nex]

yes thats where I installed mine and I also found it works well as a air bleeder for the cooling system

Cheers mate. I will be looking into it

[davesta]

I also have a tefba filter and find it works really well. I've had it installed for over 2 years now and it still picks up little bits of rust floating around in the system.

[Pandave]

hows the tranny cooler. that could be cactus.

[disco_nex]

hows the tranny cooler. that could be cactus.

Tranny cooler is fine. I have aftermarket ones with a temp gauge and it is running properly.

[disco_nex]

To finish this thread up, the solution has been found. Radiator was heavily clogged with crap. A clean out was done by a radiator specialist and problem is solved. An inline radiator filter will be added as well. Thanks for the help!