Air leak critical

[George130]

Fitted the new thermostat last weekend and bleed the system several times. The cooling system is sucking air and then overheating again. The head is ok but I can't drive it in this state. I have checked all pipes and tightened two and the fault still persists.
Other than turning the rear into a water tank to just pump fresh water in the system all the time any ideas out there on the cause?

I'm loosing patience rapidly and am about to cop the told you not to buy a Landy

[dullbird]

sorry george

i can't help you but i will be really interested in what people say.......as we to had an over heating problem in the uk and changed everything except the water pump so we to are in the same postion with our 200tdi with the over heating......not knowing where to look next

the only thing a friend said is that the gauges on a deffender are renowned for being inacurate and to actually check the temp your self to make sure gauge is reading properly

we never actually had the car over heat we only had the gauage climb into the red on frequent occasions..................

dullbird

[George130]

I pull over as soon as it hits near or in the red but then spend a while letting the pressure and steam out slowly without loosing to much water. The last run I limped home from town without letting it rev over 2000rpm. I was a real pain in the but on the freeway as I only had a top speed of 85 down hill and slower than the B doubles going up hill.

[DEFENDERZOOK]

<span style="color:blue">the system will be under pressure when its hot....therefore it cant suck in any air.....

a faulty radiator cap will let in air as it cools rather than draw in the coolant
from the expansion tank.....

OR.....


a headgasket or cracked head will allow cylinder compression into the cooling system....
forcing the coolant out.....


is it actually over heating.....?
as dullbird said it could just be the guage.....
if you pop the bonnet you will know if its hotter than normal if you know your car....</span>

[dullbird]

the only thing a friend said to us is it sounded like we had a restriction in the cooling system (but yeh thanks mate) neve actually got round to telling us where to start looking..............as by the time we got to that bit he was so drunk he was incoherant

the other thing was we had changed our thermostat but although it is uncommon it is possible that the second one to could not be working properly..........

the other thing was one time when we were out off roading we got a pin ***** hole in the radiator and to get us home we put some radweld in which enabled us to get home with out being towed
the only problem with that is sometimes using radweld or using alot can to also block up coolant system as bts break off and clog in place's


been off roading at all (i'm not trying to teach you how to suck eggs as i know you have probably checked everything but i'm just taking you through all the things we have done)

double check the top of your radiator isn't blocked as i have been tol that is where the radiator does most of its work.........

the other thing was we took anything off the front that was restricting air flow to the radiator i.e. we moved the winch solinoid pack off to one side and also we had a number plate at the bottom of the radiator grill we moved that too.......and believe it or not it helped a hell of a lot

although did not completly solve the problem we flushed the system so many times...........although just before we shipped the car here we were not having any problems with the over heating after spending hours cleaning the rad and constantly flushing the system i don't hold much hope on he car not over heating when it gets here in the australian summer..................

could be a trip to the landy people on the paramatta rd......

but yes george the problm you are having sounds exactly like te problem we were having so i can understand your frustration.........

if you do solve the problem would appreicate you letting me know

dullbird

[Steinzy]

I would try replacing your radiator cap and see if that makes any difference!

[George130]

Updates Radiator cap was the first thing replaced. The new thermostat went in last weekend after the repairs up at Aces, This is what started the problem again. Today new top radiator hose and water pump. After removing the pump I did find some movement in the spline so lets hope that is the cause. I just finnished bleeding the system and it took forever to get the coolant flowing :x . Tomorrow I will be bleeding the system again, checking for leaks and also giving it a test run.

The head is definatly OK. That was the first thing I checked after the disaster trip to Aces.

It could be the mod chip im running. Found out today that they used my rig as a test bed to see how far they could go. Apparently its got a lot more omph than the normal bruce davis chip mod 8O 8O

If the problem persists I will have to sweet talk the engineer in canberra that knows the beast. Apparently he was telling a mutual friend that he realy misses the thing so he might be ameanable to trying to sort it out :?

[disconut]

I had a problem with an XJ6 Jag at one time. Running hot most of the time.
Did all the radiator flushing, thermostat changing etc. Finally knocked out the frost plugs and pressure cleaned the block. (used a garden hose with a 1/4" tube stuffed in it to get the pressure up). What I got out looked like mud?
Rust and sediment I think, from around the cylinders.
Replaced the frost plugs with brass ones, and it ran as new. Never went over the normal mark on the temp gauge again.
Worth a look particuarly if the car is second hand and may have had crappy water put in it.

Trev.

[George130]

Short run today and it behaved perfectly. I even pushwed it up a steep hill at 120kmh ops:
Big run still to happen but all looks fine.
Dullbird the water pump seems to be the culprit. Didn't leak but sucked air in. Restriction in the cooling was one of the sujestions I was given. To check yours unfortunatly on the TD5 you have to remove it but if the spline can wobble or move back and forth (mine did both) it is a likely cause.