Hoping the crowd can help...01 TJ 3.5
Top radiator hose is vacuuming when engine switched off and cooling down..
Radiator is new (brand new) less than 12 months, as is water pump and thermostat.

What have I done?
1) Topped up radiator with front of car (nose up) on ramps to try to eliminate air bubbles.
2) Ran with heater on whilst filling to again ensure no air bubbles
3) Blown out radiator to coolant tank line to ensure no blockage (nil detected)
4) Refilled coolant tank
5) Changed radiator cap, for new one.

Second problem...
Car now sits in a pool of its own blood every day(oil)....since climbing to 4000ft on a 1 in 8 grade hill with 5 pax......(where it got to the top in a cloud of burning oil !)....is not either of the rocker cover gaskets (from what I can see) nor the sump gasket....any thoughts? (Leak appears to be rear of the sump.)

If your top hose is collapsing you're getting a low pressure in the cooling system when cooling down, which is expected. If this low pressure isn't drawing coolant from the overflow tank it can only be either a blocked overflow hose (check that you can suck coolant up the hose) or the cap is stuffed or the wrong type. Maybe there's something loose in the overflow tank that's being sucked onto the end of the hose? I can't think of anything else. Re the oil, the only thing you can do is clean the engine down and search for the source. The rear valve cover is a common culprit but if definitely eliminated check the distributor seal which seems to be a common leak point if this forum is anything to go by.

If your top hose is collapsing you're getting a low pressure in the cooling system when cooling down, which is expected. If this low pressure isn't drawing coolant from the overflow tank it can only be either a blocked overflow hose (check that you can suck coolant up the hose) or the cap is stuffed or the wrong type. Maybe there's something loose in the overflow tank that's being sucked onto the end of the hose? I can't think of anything else. Re the oil, the only thing you can do is clean the engine down and search for the source. The rear valve cover is a common culprit but if definitely eliminated check the distributor seal which seems to be a common leak point if this forum is anything to go by.

As per list above...changed 1 yr old cap for new one....line to coolant tank blown out and clear..
Is removing coolant tank a pain or a 5 min thing?

Re leak...thanks for tip...will check dizzy oring....once I get some batteries for torch !
Thanks for input.

line to coolant tank blown out and clear..

Understood, but blown and sucked ain't the same thing (well, in one instance they are, but I digress :)). Is it possible there's a blockage that's only apparent when sucking? Regarding removing the tank, no idea how hard it is. Looks like access is up under the front but not removed one before.

The only link for water and oil is he head gasket, which I think is a very remote failure on these engines so I'd treat both problems as separate, if the hose collapses and you are confident all the air is out then it has to either be the old/new cap is defective or the overflow pipe is pinched/collapsing or blocked.

The oil smoke will be from the distributor O ring or the cam/crank seals if you are confident the rocker covers are ok, both will be blown around the back of the engine by wind and inclination.

Where did you get the radiator cap from?

Ive seen this before, some radiator caps that say they are for the 3rd Gen are actually the wrong one.

I got the one Mal told me to get many years ago and the radiator hose was fine from then on.

EDIT: Thread is here (www.aussiemagna.com/forums/showthread.php?t=87756), there is also a link in that thread to another thread. Mal also mentions it could be a blockage in the overflow bottle.

Thanks to all for the help..

Re Caps..
One is of Chinese decent...got it with radiator 12 months ago.
Other is from Repco (repco brand) but I think I is cpc product....will check with another (genuine this time!)

Re overflow bottle and line....removed and flushed (gernie-d) bottle....removed all line and flushed (household hose fits straight over it).

Will report back after a drive today.

Re oil...thanks for guidance...will wait until car is next on hoist to chase, but at least I will know where to look this time..
Again my thanks.
JD

Quick question....
What is the correct radiator cap pressure for a TJ???

My cap (new...non genuine) is 0.9Bar....
However a relatives' TW is 1.1bar......and genuine...

So what is the correct cap pressure.??

TJ's cap is rated 75-105kPa, so your 0.9 bar should be fine. The important thing in your case is the return valve which may not be opening as expected.

EDIT: CPC caps have been known to be a bit rubbish in 3rd Gens, the design of the seal tends to block the overflow hole. Genuine is the way to go if possible.

EDIT: CPC caps have been known to be a bit rubbish in 3rd Gens,

Not had a good time with CPC "Cheapest Posible Crap" I've found - 3 different cars (mitsi, Mazda and Jaguar) all have had problems with new caps - reverting to original or other brands has fixed overflow or overheating each time.

It appears that the two pronged approach of cleaning the overflow bottle and transfer line, and replacing the cap for genuine has solved the sucking issue.
Thanks to all for their assistance and guidance.

Now for that damned leak !

It appears that the two pronged approach of cleaning the overflow bottle and transfer line, and replacing the cap for genuine has solved the sucking issue.
Thanks to all for their assistance and guidance.

Now for that damned leak !

Great - and thanks for posting a solution - SO.. many posts are never concluded on the forums and so you never know if any of the comments helped.

:yeahthat: